Advertisement

The Prevalence of Social Frailty Among Older Adults: A Systematic Review and Meta-Analysis

  • Xiao-Ming Zhang
    Affiliations
    Department of Nursing, Chinese Academy of Medical Sciences Peking Union Medical College, Peking Union Medical College Hospital (Dongdan Campus), Beijing, China
    Search for articles by this author
  • Simin Cao
    Affiliations
    School of Nursing, Guangzhou Medical University, Guangzhou, China

    Department of Nursing, The First Affiliated Hospital of Shenzhen University / Shenzhen Second People's Hospital, Shenzhen, China
    Search for articles by this author
  • Maofeng Gao
    Affiliations
    Department of Nursing, The First Affiliated Hospital of Shenzhen University / Shenzhen Second People's Hospital, Shenzhen, China

    School of Nursing, Anhui Medical University, Hefei, China
    Search for articles by this author
  • Shiyan Xiao
    Affiliations
    Department of Nursing, The First Affiliated Hospital of Shenzhen University / Shenzhen Second People's Hospital, Shenzhen, China

    School of Nursing, University of South China, Hengyang, China
    Search for articles by this author
  • Xiaohua Xie
    Correspondence
    Address correspondence to Xiaohua Xie, MPH, Department of Nursing, The First Affiliated Hospital of Shenzhen University / Shenzhen Second People's Hospital, Shenzhen, China; or Xinjuan Wu, MSN, Department of Nursing, Chinese Academy of Medical Sciences Peking Union Medical College, Peking Union Medical College Hospital (Dongdan Campus), Beijing, China.
    Affiliations
    Department of Nursing, The First Affiliated Hospital of Shenzhen University / Shenzhen Second People's Hospital, Shenzhen, China
    Search for articles by this author
  • Xinjuan Wu
    Correspondence
    Address correspondence to Xiaohua Xie, MPH, Department of Nursing, The First Affiliated Hospital of Shenzhen University / Shenzhen Second People's Hospital, Shenzhen, China; or Xinjuan Wu, MSN, Department of Nursing, Chinese Academy of Medical Sciences Peking Union Medical College, Peking Union Medical College Hospital (Dongdan Campus), Beijing, China.
    Affiliations
    Department of Nursing, Chinese Academy of Medical Sciences Peking Union Medical College, Peking Union Medical College Hospital (Dongdan Campus), Beijing, China
    Search for articles by this author
Open AccessPublished:November 16, 2022DOI:https://doi.org/10.1016/j.jamda.2022.10.007

      Abstract

      Objective

      To report the overall prevalence of social frailty among older people and provide information for policymakers and authorities to use in developing policies and social care.

      Design

      A systematic review and meta-analysis.

      Setting and participants

      We searched 4 databases (PubMed, Embase, Web of Science, and Google Scholar) to find articles from inception to July 30, 2022. We included cross-sectional and cohort studies that provided the prevalence of social frailty among adults aged 60 years or older, in any setting.

      Methods

      Three researchers independently reviewed the literature and retrieved the data. A risk of bias tool was used to assess each study’s quality. A random-effect meta-analysis was performed to pool the data, followed by subgroup analysis, sensitivity analysis, and meta-regression.

      Results

      From 761 records, we extracted 43 studies with 83,907 participants for meta-analysis. The pooled prevalence of social frailty in hospital settings was 47.3% (95% CI: 32.2%–62.4%); among studies in community settings, the pooled prevalence was 18.8% (95% CI: 14.9%–22.7%; P < .001). The prevalence of social frailty was higher when assessed using the Tilburg Frailty Indicator (32.3%; 95% CI: 23.1%–41.5%) than the Makizako Social Frailty Index (27.7%; 95% CI: 21.6%–33.8%) or Social Frailty Screening Index (13.4%; 95% CI: 8.4%–18.4%). Based on limited community studies in individual countries using various instruments, social frailty was lowest in China (4.9%; 95% CI: 4.2%–5.7%), followed by Spain (11.6%; 95% CI: 9.9%–13.3%), Japan (16.2%; 95% CI: 12.2%–20.3%), Korea (26.6%; 95% CI: 7.1%–46.1%), European urban centers (29.2%; 95% CI: 27.9%–30.5%), and the Netherlands (27.2%; 95% CI: 16.9%–37.5%). No other subgroup analyses showed any statistically significant prevalence difference between groups.

      Conclusion and Implications

      The prevalence of social frailty among older adults is high. Settings, country, and method for assessing social frailty affected the prevalence. More valid comparisons will await consensus on measurement tools and more research on geographically representative populations. Nevertheless, these results suggest that public health professionals and policymakers should seriously consider social frailty in research and program planning involving older adults.

      Keywords

      Older adults tend to experience more chronic diseases,
      • Lin T.
      • Zhao Y.
      • Xia X.
      • et al.
      Association between frailty and chronic pain among older adults: a systematic review and meta-analysis.
      multiple diseases,
      • Vetrano D.L.
      • Palmer K.
      • Marengoni A.
      • et al.
      Frailty and multimorbidity: a systematic review and meta-analysis.
      decreased body activity, and increased sedentary behavior,
      • Kehler D.S.
      • Hay J.L.
      • Stammers A.N.
      • et al.
      A systematic review of the association between sedentary behaviors with frailty.
      all of which can lead to frailty, a clinical geriatric syndrome. Frailty was defined as a state with abnormal physiology and reduced reserves, resulting in increasing vulnerability, individual dependence, and susceptibility to death.
      • Morley J.E.
      • Vellas B.
      • van Kan G.A.
      • et al.
      Frailty consensus: a call to action.
      The original definition of frailty was predominantly physical. Nowadays, the concept of frailty has extended to include cognitive, psychological, physical, and social aspects.
      • Pek K.
      • Chew J.
      • Lim J.P.
      • et al.
      Social frailty is independently associated with mood, nutrition, physical performance, and physical activity: insights from a theory-guided approach.
      Physical frailty, cognitive frailty, and social frailty have been reported to be associated with poor health outcomes and to interact with each other.
      • Sugie M.
      • Harada K.
      • Nara M.
      • et al.
      Prevalence, overlap, and interrelationships of physical, cognitive, psychological, and social frailty among community-dwelling older people in Japan.
      Physical frailty and cognitive frailty have been well described, and a systematic review showed that the pooled prevalence rates of physical frailty and cognitive frailty were 12% (95% CI: 11%–13%) and 9% (95% CI: 8%–11%).
      • Qiu Y.
      • Li G.
      • Wang X.
      • et al.
      Prevalence of cognitive frailty among community-dwelling older adults: a systematic review and meta-analysis.
      ,
      • O'Caoimh R.
      • Sezgin D.
      • O'Donovan M.R.
      • et al.
      Prevalence of frailty in 62 countries across the world: a systematic review and meta-analysis of population-level studies.
      Social frailty is a relatively new concept, with less information available about it, and deserves further exploration.
      Social frailty was first proposed by Gobbens et al. in 2010.
      • Gobbens R.J.
      • van Assen M.A.
      • Luijkx K.G.
      • et al.
      Determinants of frailty.
      In 2017, based on the concept of social needs in the social production functions theory, social frailty was defined as a continuum of being at risk of losing, or having lost social resources, social behaviors, social activities, and self-management abilities to fulfill basic social needs.
      • Bunt S.
      • Steverink N.
      • Olthof J.
      • et al.
      Social frailty in older adults: a scoping review.
      Various assessment tools exist for social frailty, such as the Makizako Social Frailty Index,
      • Kume Y.
      • Kodama A.
      • Takahashi T.
      • et al.
      Social frailty is independently associated with geriatric depression among older adults living in northern Japan: a cross-sectional study of ORANGE registry.
      the Social Frailty Screening Index,
      • Yamada M.
      • Arai H.
      Social frailty predicts incident disability and mortality among community-dwelling japanese older adults.
      and the Tilburg Frailty Indicator.
      • Verver D.
      • Merten H.
      • de Blok C.
      • et al.
      A cross sectional study on the different domains of frailty for independent living older adults.
      The Makizako Social Frailty Index of 5 items is the most common assessment method. It was developed by Makizako et al.
      • Makizako H.
      • Shimada H.
      • Tsutsumimoto K.
      • et al.
      Social frailty in community-dwelling older adults as a risk factor for disability.
      and is widely used among older adults. Social frailty is a serious concern among older adults because it has a negative impact on physical and mental health, resulting in declining self-care ability,
      • Yamada M.
      • Arai H.
      Social frailty predicts incident disability and mortality among community-dwelling japanese older adults.
      increasing depression among older adults,
      • Hayashi T.
      • Noguchi T.
      • Kubo Y.
      • et al.
      Social frailty and depressive symptoms during the COVID-19 pandemic among older adults in Japan: Role of home exercise habits.
      and even increased risk of death.
      • Ragusa F.S.
      • Veronese N.
      • Smith L.
      • et al.
      Social frailty increases the risk of all-cause mortality: a longitudinal analysis of the English Longitudinal Study of Ageing.
      In addition, there is an association between loneliness and social frailty among older adults.
      • Ge L.
      • Yap C.W.
      • Heng B.H.
      Associations of social isolation, social participation, and loneliness with frailty in older adults in Singapore: a panel data analysis.
      Given that loneliness is most prevalent among older adults,
      • Rapolienė G.
      • Aartsen M.
      Lonely societies: low trust societies? Further explanations for national variations in loneliness among older Europeans.
      social frailty is therefore very important and needs more attention.
      Several studies have reported the prevalence of social frailty among older adults in different settings. In 2013, Garre-Olmo et al.
      • Garre-Olmo J.
      • Calvó-Perxas L.
      • López-Pousa S.
      • et al.
      Prevalence of frailty phenotypes and risk of mortality in a community-dwelling elderly cohort.
      reported the prevalence of social frailty among older adults in Spain as 8.9%. Ono et al.
      • Ono R.
      • Murata S.
      • Uchida K.
      • et al.
      Reciprocal relationship between locomotive syndrome and social frailty in older adults.
      reported that the prevalence of social frailty among community-dwelling older people was 23.26% in Japan. Gobbens and Andreason
      • Gobbens R.J.J.
      • Andreasen J.
      Multidimensional frailty and its determinants among acutely admitted older people: a cross-sectional study using the Tilburg Frailty Indicator.
      conducted a study among hospitalized older adults and found the prevalence of social frailty was 53.13%. The prevalence of social frailty therefore varies across countries and settings and can also be different when assessed using different tools. Recently, several new studies have explored the prevalence of social frailty among older adults.
      • Sugie M.
      • Harada K.
      • Nara M.
      • et al.
      Prevalence, overlap, and interrelationships of physical, cognitive, psychological, and social frailty among community-dwelling older people in Japan.
      ,
      • Miyata H.
      • Maruta M.
      • Makizako H.
      • et al.
      Association between satisfaction with meaningful activities and social frailty in community-dwelling Japanese older adults.
      However, social frailty is a relatively new concept, and a critical systematic look at the literature is merited. There are also no data on the prevalence of social frailty worldwide. This systematic review, therefore, aimed to conduct a meta-analysis synthesizing the pooled prevalence of social frailty among older adults, and to identify which factors could influence the prevalence of social frailty among older adults.

      Materials and Methods

      Protocol

      This review complied with the PRISMA guidelines for meta-analysis.
      • Liberati A.
      • Altman D.G.
      • Tetzlaff J.
      • et al.
      The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration.
      All the articles were published on the Internet, and institutional review board approval was therefore not sought. We have registered our protocol in PROSPERO (CRD42022321635).

      Search Strategy

      We searched in PubMed, EMBASE, Web of Science, and Google Scholar for studies from the date of the database’s establishment to July 30, 2022. The search terms included MESH terms and keywords. The keywords were: (elder∗ OR “older people” OR “older adult∗” OR aged OR senior∗) AND (“social frailty” OR “social vulnerability” OR “social frail∗”) AND (Prevalence OR Epidemiology∗). The detailed search strategy is shown in Supplementary Material 1. To avoid missing any relevant studies, we also examined all references from the included literature and other relevant articles.

      Inclusion and Exclusion Criteria

      The inclusion criteria were as follows: (1) participants aged 60 or older; (2) studies that reported the prevalence of social frailty, using a clear definition of social frailty; and (3) cross-sectional studies and cohort studies, regardless of language or country. The exclusion criteria were as follows: (1) abstracts, reviews, comments, or conferences; and (2) data on the prevalence of social frailty were not available or were insufficient to calculate the prevalence of frailty.

      Study Selection and Data Extraction

      Two of us (X.M.Z. and S.M.C.) independently screened records based on the title, abstract, and full texts, after deleting duplicated articles using EndnoteX9. A third reviewer with extensive experience in evidence-based training settled any disagreements.
      The data were extracted by 3 authors (S.Y.X., M.F.G., and S.M.C.), who checked each other’s results. Any disagreements were discussed until reaching a consensus. The following data were extracted from individual articles: author, year of publication, country, setting, study design, age (mean or median), sample size, case of female/male participants, prevalence of social frailty, social frailty definition, sample frame, and selection method. For cohort studies, we also extracted the baseline data measuring social frailty, when appropriate. When studies used a multidimensional frailty assessment, such as the Tilburg Frailty Indicator, we extracted only the data on social frailty.

      Assessment of Study Quality

      Eligible studies were assessed by 3 investigators (S.M.C., M.F.G., S.Y.X.) using a risk of bias tool
      • Hoy D.
      • Brooks P.
      • Woolf A.
      • et al.
      Assessing risk of bias in prevalence studies: modification of an existing tool and evidence of interrater agreement.
      to evaluate the study’s quality. It consists of 10 items and a summary assessment. Items 1 to 4 assess the external validity of the study in the areas of selection and nonresponse bias, and items 5 to 10 assess the internal validity. Items 5 to 9 evaluate measurement deviations, and item 10 evaluates deviations associated with the analysis. When the study received a score of 1, this indicated that it was a low risk of that particular type of bias. When checklist items were not reported or unclear, they were given a score of zero, and considered to be high risk. The overall risk of bias was classified into 3 categories: low (score > 8), moderate (score 6–8), and high (score ≤ 5).

      Statistical Analysis

      The prevalence of social frailty was either obtained directly from the article or calculated from available data. Cochran’s Q and the I2 statistic were used to determine whether there was significant heterogeneity among the studies. I2 values of 25%, 50%, and 75% represent low, moderate, and high heterogeneity. There was a significant degree of heterogeneity across the studies (I2 = 99.66%) because of the various assessments of social frailty used, as well as the location, sample size, population, and study design. We therefore used the random-effects model to pool the prevalence of social frailty. Visual Funnel plots and Begg’s test were used to analyze publication bias. We also performed a broad subgroup analysis based on country, age (<75 years vs ≥75 years), setting, sample size (≤500 and >500), study design, the tool used to assess social frailty (Makizako social frailty index, Social Frailty Screening Index, Tilburg Frailty Indicator, and others) and gender. Finally, we also used sensitivity and meta-regression analysis. We used Stata 16.0 (StataCorp) for all the data analyses.

      Results

      Search Results

      We obtained 761 records from 4 databases, with 339 from PubMed, 166 from Embase, 116 from Web of Science, and 140 from Google Scholar. A total of 492 duplicated records were removed using EndnoteX9 software. After selecting based on titles and abstracts, we examined the full text of 93 papers. Of these, 14 records were review or conference abstracts, 29 records did not provide the prevalence of social frailty, and 7 studies focused on people younger than 60 years. This gave a total of 43 studies for review and analysis.
      • Sugie M.
      • Harada K.
      • Nara M.
      • et al.
      Prevalence, overlap, and interrelationships of physical, cognitive, psychological, and social frailty among community-dwelling older people in Japan.
      ,
      • Kume Y.
      • Kodama A.
      • Takahashi T.
      • et al.
      Social frailty is independently associated with geriatric depression among older adults living in northern Japan: a cross-sectional study of ORANGE registry.
      • Yamada M.
      • Arai H.
      Social frailty predicts incident disability and mortality among community-dwelling japanese older adults.
      • Verver D.
      • Merten H.
      • de Blok C.
      • et al.
      A cross sectional study on the different domains of frailty for independent living older adults.
      • Makizako H.
      • Shimada H.
      • Tsutsumimoto K.
      • et al.
      Social frailty in community-dwelling older adults as a risk factor for disability.
      • Hayashi T.
      • Noguchi T.
      • Kubo Y.
      • et al.
      Social frailty and depressive symptoms during the COVID-19 pandemic among older adults in Japan: Role of home exercise habits.
      ,
      • Garre-Olmo J.
      • Calvó-Perxas L.
      • López-Pousa S.
      • et al.
      Prevalence of frailty phenotypes and risk of mortality in a community-dwelling elderly cohort.
      • Ono R.
      • Murata S.
      • Uchida K.
      • et al.
      Reciprocal relationship between locomotive syndrome and social frailty in older adults.
      • Gobbens R.J.J.
      • Andreasen J.
      Multidimensional frailty and its determinants among acutely admitted older people: a cross-sectional study using the Tilburg Frailty Indicator.
      • Miyata H.
      • Maruta M.
      • Makizako H.
      • et al.
      Association between satisfaction with meaningful activities and social frailty in community-dwelling Japanese older adults.
      ,
      • Adachi T.
      • Tsunekawa Y.
      • Tanimura D.
      Association among mild cognitive impairment, social frailty, and clinical events in elderly patients with cardiovascular disease.
      • Bae S.
      • Lee S.
      • Lee S.
      • et al.
      The role of social frailty in explaining the association between hearing problems and mild cognitive impairment in older adults.
      • Chen Z.
      • Jiang X.
      • Shi G.
      • et al.
      Social frailty and longitudinal risk of depressive symptoms in a Chinese population: the Rugao Longevity and Aging Study.
      • Díaz-Alonso J.
      • Bueno-Pérez A.
      • Toraño-Ladero L.
      • et al.
      [Hearing loss and social frailty in older men and women].
      • Doi T.
      • Tsutsumimoto K.
      • Ishii H.
      • et al.
      Impact of social frailty on the association between driving status and disability in older adults.
      • Gobbens R.J.J.
      • van Assen M.
      Associations between multidimensional frailty and quality of life among Dutch older people.
      • Hirase T.
      • Makizako H.
      • Okubo Y.
      • et al.
      Chronic pain is independently associated with social frailty in community-dwelling older adults.
      • Hironaka S.
      • Kugimiya Y.
      • Watanabe Y.
      • et al.
      Association between oral, social, and physical frailty in community-dwelling older adults.
      • Huang C.H.
      • Okada K.
      • Matsushita E.
      • et al.
      The association of social frailty with intrinsic capacity in community-dwelling older adults: a prospective cohort study.
      • Inoue T.
      • Maeda K.
      • Satake S.
      • et al.
      Osteosarcopenia, the co-existence of osteoporosis and sarcopenia, is associated with social frailty in older adults.
      • Jujo K.
      • Kagiyama N.
      • Saito K.
      • et al.
      Impact of social frailty in hospitalized elderly patients with heart failure: a FRAGILE-HF registry subanalysis.
      • Ko H.
      • Jung S.
      Association of social frailty with physical health, cognitive function, psychological health, and life satisfaction in community-dwelling older Koreans.
      • Ko Y.
      • Lee K.
      Social frailty and health-related quality of life in community-dwelling older adults.
      • Kodama A.
      • Kume Y.
      • Lee S.
      • et al.
      Impact of COVID-19 Pandemic Exacerbation of Depressive Symptoms for Social Frailty from the ORANGE Registry.
      • Lee Y.
      • Chon D.
      • Kim J.
      • et al.
      The predictive value of social frailty on adverse outcomes in older adults living in the community.
      • Ma L.
      • Sun F.
      • Tang Z.
      Social frailty is associated with physical functioning, cognition, and depression, and predicts mortality.
      • Makizako H.
      • Kubozono T.
      • Kiyama R.
      • et al.
      Associations of social frailty with loss of muscle mass and muscle weakness among community-dwelling older adults.
      • Makizako H.
      • Shimada H.
      • Doi T.
      • et al.
      Social frailty leads to the development of physical frailty among physically non-frail adults: a four-year follow-up longitudinal cohort study.
      • Nagai K.
      • Tamaki K.
      • Kusunoki H.
      • et al.
      Physical frailty predicts the development of social frailty: a prospective cohort study.
      • Nakakubo S.
      • Doi T.
      • Makizako H.
      • et al.
      Association of sleep condition and social frailty in community-dwelling older people.
      • Noguchi T.
      • Nojima I.
      • Inoue-Hirakawa T.
      • et al.
      Association between social frailty and sleep quality among community-dwelling older adults: a cross-sectional study.
      • Okumura M.
      • Inoue T.
      • Melinda G.
      • et al.
      Social frailty as a risk factor for new-onset depressive symptoms at one year post-surgery in older patients with gastrointestinal cancer.
      • Ono R.
      • Makiura D.
      • Nakamura T.
      • et al.
      Impact of preoperative social frailty on overall survival and cancer-specific survival among older patients with gastrointestinal cancer.
      • Park H.
      • Jang I.Y.
      • Lee H.Y.
      • et al.
      Screening value of social frailty and its association with physical frailty and disability in community-dwelling older koreans: aging study of pyeongchang rural area.
      • Renne I.
      • Gobbens R.J.
      Effects of frailty and chronic diseases on quality of life in Dutch community-dwelling older adults: a cross-sectional study.
      • Tsutsumimoto K.
      • Doi T.
      • Makizako H.
      • et al.
      Social frailty has a stronger impact on the onset of depressive symptoms than physical frailty or cognitive impairment: a 4-year follow-up longitudinal cohort study.
      • Tsutsumimoto K.
      • Doi T.
      • Makizako H.
      • et al.
      Association of social frailty with both cognitive and physical deficits among older people.
      • Tsutsumimoto K.
      • Doi T.
      • Nakakubo S.
      • et al.
      Impact of social frailty on Alzheimer's disease onset: a 53-month longitudinal cohort study.
      • Usui N.
      • Yokoyama M.
      • Nakata J.
      • et al.
      Association between social frailty as well as early physical dysfunction and exercise intolerance among older patients receiving hemodialysis.
      • Yamashita M.
      • Kamiya K.
      • Hamazaki N.
      • et al.
      Work status before admission relates to prognosis in older patients with heart failure partly through social frailty.
      • Ye L.
      • Elstgeest L.E.M.
      • Zhang X.
      • et al.
      Factors associated with physical, psychological and social frailty among community-dwelling older persons in Europe: a cross-sectional study of Urban Health Centres Europe (UHCE).
      • Yoo M.
      • Kim S.
      • Kim B.S.
      • et al.
      Moderate hearing loss is related with social frailty in a community-dwelling older adults: the Korean Frailty and Aging Cohort Study (KFACS).
      • Zhang X.
      • Tan S.S.
      • Franse C.B.
      • et al.
      Association between physical, psychological and social frailty and health-related quality of life among older people.
      A flowchart of the selection process is shown in Figure 1.

      Study Characteristics

      The characteristics of the 43 included studies are summarized in Table 1. They were published between 2013 and 2022, contained 83,907 participants from 10 countries, and had sample sizes ranging from 48 to 11,241. The mean or median age ranged from 69.5 to 81.7 years, and 6 studies did not provide the detailed mean or median age for the total sample.
      • Jujo K.
      • Kagiyama N.
      • Saito K.
      • et al.
      Impact of social frailty in hospitalized elderly patients with heart failure: a FRAGILE-HF registry subanalysis.
      ,
      • Ko Y.
      • Lee K.
      Social frailty and health-related quality of life in community-dwelling older adults.
      ,
      • Kodama A.
      • Kume Y.
      • Lee S.
      • et al.
      Impact of COVID-19 Pandemic Exacerbation of Depressive Symptoms for Social Frailty from the ORANGE Registry.
      ,
      • Ma L.
      • Sun F.
      • Tang Z.
      Social frailty is associated with physical functioning, cognition, and depression, and predicts mortality.
      ,
      • Nagai K.
      • Tamaki K.
      • Kusunoki H.
      • et al.
      Physical frailty predicts the development of social frailty: a prospective cohort study.
      ,
      • Ono R.
      • Makiura D.
      • Nakamura T.
      • et al.
      Impact of preoperative social frailty on overall survival and cancer-specific survival among older patients with gastrointestinal cancer.
      Most studies were cross-sectional (26), with 17 cohort studies. Most of the studies were from Asia, with 28 from Japan,
      • Sugie M.
      • Harada K.
      • Nara M.
      • et al.
      Prevalence, overlap, and interrelationships of physical, cognitive, psychological, and social frailty among community-dwelling older people in Japan.
      ,
      • Kume Y.
      • Kodama A.
      • Takahashi T.
      • et al.
      Social frailty is independently associated with geriatric depression among older adults living in northern Japan: a cross-sectional study of ORANGE registry.
      ,
      • Yamada M.
      • Arai H.
      Social frailty predicts incident disability and mortality among community-dwelling japanese older adults.
      ,
      • Makizako H.
      • Shimada H.
      • Tsutsumimoto K.
      • et al.
      Social frailty in community-dwelling older adults as a risk factor for disability.
      ,
      • Hayashi T.
      • Noguchi T.
      • Kubo Y.
      • et al.
      Social frailty and depressive symptoms during the COVID-19 pandemic among older adults in Japan: Role of home exercise habits.
      ,
      • Ono R.
      • Murata S.
      • Uchida K.
      • et al.
      Reciprocal relationship between locomotive syndrome and social frailty in older adults.
      ,
      • Miyata H.
      • Maruta M.
      • Makizako H.
      • et al.
      Association between satisfaction with meaningful activities and social frailty in community-dwelling Japanese older adults.
      ,
      • Adachi T.
      • Tsunekawa Y.
      • Tanimura D.
      Association among mild cognitive impairment, social frailty, and clinical events in elderly patients with cardiovascular disease.
      ,
      • Bae S.
      • Lee S.
      • Lee S.
      • et al.
      The role of social frailty in explaining the association between hearing problems and mild cognitive impairment in older adults.
      ,
      • Doi T.
      • Tsutsumimoto K.
      • Ishii H.
      • et al.
      Impact of social frailty on the association between driving status and disability in older adults.
      ,
      • Hirase T.
      • Makizako H.
      • Okubo Y.
      • et al.
      Chronic pain is independently associated with social frailty in community-dwelling older adults.
      • Hironaka S.
      • Kugimiya Y.
      • Watanabe Y.
      • et al.
      Association between oral, social, and physical frailty in community-dwelling older adults.
      • Huang C.H.
      • Okada K.
      • Matsushita E.
      • et al.
      The association of social frailty with intrinsic capacity in community-dwelling older adults: a prospective cohort study.
      • Inoue T.
      • Maeda K.
      • Satake S.
      • et al.
      Osteosarcopenia, the co-existence of osteoporosis and sarcopenia, is associated with social frailty in older adults.
      • Jujo K.
      • Kagiyama N.
      • Saito K.
      • et al.
      Impact of social frailty in hospitalized elderly patients with heart failure: a FRAGILE-HF registry subanalysis.
      ,
      • Kodama A.
      • Kume Y.
      • Lee S.
      • et al.
      Impact of COVID-19 Pandemic Exacerbation of Depressive Symptoms for Social Frailty from the ORANGE Registry.
      ,
      • Makizako H.
      • Kubozono T.
      • Kiyama R.
      • et al.
      Associations of social frailty with loss of muscle mass and muscle weakness among community-dwelling older adults.
      • Makizako H.
      • Shimada H.
      • Doi T.
      • et al.
      Social frailty leads to the development of physical frailty among physically non-frail adults: a four-year follow-up longitudinal cohort study.
      • Nagai K.
      • Tamaki K.
      • Kusunoki H.
      • et al.
      Physical frailty predicts the development of social frailty: a prospective cohort study.
      • Nakakubo S.
      • Doi T.
      • Makizako H.
      • et al.
      Association of sleep condition and social frailty in community-dwelling older people.
      • Noguchi T.
      • Nojima I.
      • Inoue-Hirakawa T.
      • et al.
      Association between social frailty and sleep quality among community-dwelling older adults: a cross-sectional study.
      • Okumura M.
      • Inoue T.
      • Melinda G.
      • et al.
      Social frailty as a risk factor for new-onset depressive symptoms at one year post-surgery in older patients with gastrointestinal cancer.
      • Ono R.
      • Makiura D.
      • Nakamura T.
      • et al.
      Impact of preoperative social frailty on overall survival and cancer-specific survival among older patients with gastrointestinal cancer.
      ,
      • Tsutsumimoto K.
      • Doi T.
      • Makizako H.
      • et al.
      Social frailty has a stronger impact on the onset of depressive symptoms than physical frailty or cognitive impairment: a 4-year follow-up longitudinal cohort study.
      • Tsutsumimoto K.
      • Doi T.
      • Makizako H.
      • et al.
      Association of social frailty with both cognitive and physical deficits among older people.
      • Tsutsumimoto K.
      • Doi T.
      • Nakakubo S.
      • et al.
      Impact of social frailty on Alzheimer's disease onset: a 53-month longitudinal cohort study.
      • Usui N.
      • Yokoyama M.
      • Nakata J.
      • et al.
      Association between social frailty as well as early physical dysfunction and exercise intolerance among older patients receiving hemodialysis.
      • Yamashita M.
      • Kamiya K.
      • Hamazaki N.
      • et al.
      Work status before admission relates to prognosis in older patients with heart failure partly through social frailty.
      7 from other Asian countries,
      • Chen Z.
      • Jiang X.
      • Shi G.
      • et al.
      Social frailty and longitudinal risk of depressive symptoms in a Chinese population: the Rugao Longevity and Aging Study.
      ,
      • Ko H.
      • Jung S.
      Association of social frailty with physical health, cognitive function, psychological health, and life satisfaction in community-dwelling older Koreans.
      ,
      • Ko Y.
      • Lee K.
      Social frailty and health-related quality of life in community-dwelling older adults.
      ,
      • Lee Y.
      • Chon D.
      • Kim J.
      • et al.
      The predictive value of social frailty on adverse outcomes in older adults living in the community.
      ,
      • Ma L.
      • Sun F.
      • Tang Z.
      Social frailty is associated with physical functioning, cognition, and depression, and predicts mortality.
      ,
      • Park H.
      • Jang I.Y.
      • Lee H.Y.
      • et al.
      Screening value of social frailty and its association with physical frailty and disability in community-dwelling older koreans: aging study of pyeongchang rural area.
      ,
      • Yoo M.
      • Kim S.
      • Kim B.S.
      • et al.
      Moderate hearing loss is related with social frailty in a community-dwelling older adults: the Korean Frailty and Aging Cohort Study (KFACS).
      and 8 from Europe.
      • Verver D.
      • Merten H.
      • de Blok C.
      • et al.
      A cross sectional study on the different domains of frailty for independent living older adults.
      ,
      • Garre-Olmo J.
      • Calvó-Perxas L.
      • López-Pousa S.
      • et al.
      Prevalence of frailty phenotypes and risk of mortality in a community-dwelling elderly cohort.
      ,
      • Gobbens R.J.J.
      • Andreasen J.
      Multidimensional frailty and its determinants among acutely admitted older people: a cross-sectional study using the Tilburg Frailty Indicator.
      ,
      • Díaz-Alonso J.
      • Bueno-Pérez A.
      • Toraño-Ladero L.
      • et al.
      [Hearing loss and social frailty in older men and women].
      ,
      • Gobbens R.J.J.
      • van Assen M.
      Associations between multidimensional frailty and quality of life among Dutch older people.
      ,
      • Renne I.
      • Gobbens R.J.
      Effects of frailty and chronic diseases on quality of life in Dutch community-dwelling older adults: a cross-sectional study.
      ,
      • Ye L.
      • Elstgeest L.E.M.
      • Zhang X.
      • et al.
      Factors associated with physical, psychological and social frailty among community-dwelling older persons in Europe: a cross-sectional study of Urban Health Centres Europe (UHCE).
      ,
      • Zhang X.
      • Tan S.S.
      • Franse C.B.
      • et al.
      Association between physical, psychological and social frailty and health-related quality of life among older people.
      The studies used several different assessment measurements, including the Makizako Social Frailty Index,
      • Kume Y.
      • Kodama A.
      • Takahashi T.
      • et al.
      Social frailty is independently associated with geriatric depression among older adults living in northern Japan: a cross-sectional study of ORANGE registry.
      ,
      • Makizako H.
      • Shimada H.
      • Tsutsumimoto K.
      • et al.
      Social frailty in community-dwelling older adults as a risk factor for disability.
      ,
      • Ono R.
      • Murata S.
      • Uchida K.
      • et al.
      Reciprocal relationship between locomotive syndrome and social frailty in older adults.
      ,
      • Miyata H.
      • Maruta M.
      • Makizako H.
      • et al.
      Association between satisfaction with meaningful activities and social frailty in community-dwelling Japanese older adults.
      ,
      • Adachi T.
      • Tsunekawa Y.
      • Tanimura D.
      Association among mild cognitive impairment, social frailty, and clinical events in elderly patients with cardiovascular disease.
      ,
      • Bae S.
      • Lee S.
      • Lee S.
      • et al.
      The role of social frailty in explaining the association between hearing problems and mild cognitive impairment in older adults.
      ,
      • Doi T.
      • Tsutsumimoto K.
      • Ishii H.
      • et al.
      Impact of social frailty on the association between driving status and disability in older adults.
      ,
      • Hirase T.
      • Makizako H.
      • Okubo Y.
      • et al.
      Chronic pain is independently associated with social frailty in community-dwelling older adults.
      ,
      • Hironaka S.
      • Kugimiya Y.
      • Watanabe Y.
      • et al.
      Association between oral, social, and physical frailty in community-dwelling older adults.
      ,
      • Jujo K.
      • Kagiyama N.
      • Saito K.
      • et al.
      Impact of social frailty in hospitalized elderly patients with heart failure: a FRAGILE-HF registry subanalysis.
      • Ko H.
      • Jung S.
      Association of social frailty with physical health, cognitive function, psychological health, and life satisfaction in community-dwelling older Koreans.
      • Ko Y.
      • Lee K.
      Social frailty and health-related quality of life in community-dwelling older adults.
      • Kodama A.
      • Kume Y.
      • Lee S.
      • et al.
      Impact of COVID-19 Pandemic Exacerbation of Depressive Symptoms for Social Frailty from the ORANGE Registry.
      ,
      • Makizako H.
      • Kubozono T.
      • Kiyama R.
      • et al.
      Associations of social frailty with loss of muscle mass and muscle weakness among community-dwelling older adults.
      ,
      • Makizako H.
      • Shimada H.
      • Doi T.
      • et al.
      Social frailty leads to the development of physical frailty among physically non-frail adults: a four-year follow-up longitudinal cohort study.
      ,
      • Nakakubo S.
      • Doi T.
      • Makizako H.
      • et al.
      Association of sleep condition and social frailty in community-dwelling older people.
      • Noguchi T.
      • Nojima I.
      • Inoue-Hirakawa T.
      • et al.
      Association between social frailty and sleep quality among community-dwelling older adults: a cross-sectional study.
      • Okumura M.
      • Inoue T.
      • Melinda G.
      • et al.
      Social frailty as a risk factor for new-onset depressive symptoms at one year post-surgery in older patients with gastrointestinal cancer.
      • Ono R.
      • Makiura D.
      • Nakamura T.
      • et al.
      Impact of preoperative social frailty on overall survival and cancer-specific survival among older patients with gastrointestinal cancer.
      • Park H.
      • Jang I.Y.
      • Lee H.Y.
      • et al.
      Screening value of social frailty and its association with physical frailty and disability in community-dwelling older koreans: aging study of pyeongchang rural area.
      ,
      • Tsutsumimoto K.
      • Doi T.
      • Makizako H.
      • et al.
      Social frailty has a stronger impact on the onset of depressive symptoms than physical frailty or cognitive impairment: a 4-year follow-up longitudinal cohort study.
      • Tsutsumimoto K.
      • Doi T.
      • Makizako H.
      • et al.
      Association of social frailty with both cognitive and physical deficits among older people.
      • Tsutsumimoto K.
      • Doi T.
      • Nakakubo S.
      • et al.
      Impact of social frailty on Alzheimer's disease onset: a 53-month longitudinal cohort study.
      • Usui N.
      • Yokoyama M.
      • Nakata J.
      • et al.
      Association between social frailty as well as early physical dysfunction and exercise intolerance among older patients receiving hemodialysis.
      • Yamashita M.
      • Kamiya K.
      • Hamazaki N.
      • et al.
      Work status before admission relates to prognosis in older patients with heart failure partly through social frailty.
      ,
      • Yoo M.
      • Kim S.
      • Kim B.S.
      • et al.
      Moderate hearing loss is related with social frailty in a community-dwelling older adults: the Korean Frailty and Aging Cohort Study (KFACS).
      Tilburg Frailty Indicator,
      • Verver D.
      • Merten H.
      • de Blok C.
      • et al.
      A cross sectional study on the different domains of frailty for independent living older adults.
      ,
      • Gobbens R.J.J.
      • Andreasen J.
      Multidimensional frailty and its determinants among acutely admitted older people: a cross-sectional study using the Tilburg Frailty Indicator.
      ,
      • Gobbens R.J.J.
      • van Assen M.
      Associations between multidimensional frailty and quality of life among Dutch older people.
      ,
      • Renne I.
      • Gobbens R.J.
      Effects of frailty and chronic diseases on quality of life in Dutch community-dwelling older adults: a cross-sectional study.
      ,
      • Ye L.
      • Elstgeest L.E.M.
      • Zhang X.
      • et al.
      Factors associated with physical, psychological and social frailty among community-dwelling older persons in Europe: a cross-sectional study of Urban Health Centres Europe (UHCE).
      ,
      • Zhang X.
      • Tan S.S.
      • Franse C.B.
      • et al.
      Association between physical, psychological and social frailty and health-related quality of life among older people.
      Social Frailty Screening Index,
      • Yamada M.
      • Arai H.
      Social frailty predicts incident disability and mortality among community-dwelling japanese older adults.
      ,
      • Hayashi T.
      • Noguchi T.
      • Kubo Y.
      • et al.
      Social frailty and depressive symptoms during the COVID-19 pandemic among older adults in Japan: Role of home exercise habits.
      ,
      • Inoue T.
      • Maeda K.
      • Satake S.
      • et al.
      Osteosarcopenia, the co-existence of osteoporosis and sarcopenia, is associated with social frailty in older adults.
      ,
      • Nagai K.
      • Tamaki K.
      • Kusunoki H.
      • et al.
      Physical frailty predicts the development of social frailty: a prospective cohort study.
      and others.
      • Sugie M.
      • Harada K.
      • Nara M.
      • et al.
      Prevalence, overlap, and interrelationships of physical, cognitive, psychological, and social frailty among community-dwelling older people in Japan.
      ,
      • Garre-Olmo J.
      • Calvó-Perxas L.
      • López-Pousa S.
      • et al.
      Prevalence of frailty phenotypes and risk of mortality in a community-dwelling elderly cohort.
      ,
      • Chen Z.
      • Jiang X.
      • Shi G.
      • et al.
      Social frailty and longitudinal risk of depressive symptoms in a Chinese population: the Rugao Longevity and Aging Study.
      ,
      • Díaz-Alonso J.
      • Bueno-Pérez A.
      • Toraño-Ladero L.
      • et al.
      [Hearing loss and social frailty in older men and women].
      ,
      • Huang C.H.
      • Okada K.
      • Matsushita E.
      • et al.
      The association of social frailty with intrinsic capacity in community-dwelling older adults: a prospective cohort study.
      ,
      • Lee Y.
      • Chon D.
      • Kim J.
      • et al.
      The predictive value of social frailty on adverse outcomes in older adults living in the community.
      ,
      • Ma L.
      • Sun F.
      • Tang Z.
      Social frailty is associated with physical functioning, cognition, and depression, and predicts mortality.
      Detailed information on how social frailty was measured and defined in each study is shown in Supplementary Table 1. Overall, 35 studies involved community-dwelling older people,
      • Sugie M.
      • Harada K.
      • Nara M.
      • et al.
      Prevalence, overlap, and interrelationships of physical, cognitive, psychological, and social frailty among community-dwelling older people in Japan.
      ,
      • Kume Y.
      • Kodama A.
      • Takahashi T.
      • et al.
      Social frailty is independently associated with geriatric depression among older adults living in northern Japan: a cross-sectional study of ORANGE registry.
      • Yamada M.
      • Arai H.
      Social frailty predicts incident disability and mortality among community-dwelling japanese older adults.
      • Verver D.
      • Merten H.
      • de Blok C.
      • et al.
      A cross sectional study on the different domains of frailty for independent living older adults.
      • Makizako H.
      • Shimada H.
      • Tsutsumimoto K.
      • et al.
      Social frailty in community-dwelling older adults as a risk factor for disability.
      • Hayashi T.
      • Noguchi T.
      • Kubo Y.
      • et al.
      Social frailty and depressive symptoms during the COVID-19 pandemic among older adults in Japan: Role of home exercise habits.
      ,
      • Garre-Olmo J.
      • Calvó-Perxas L.
      • López-Pousa S.
      • et al.
      Prevalence of frailty phenotypes and risk of mortality in a community-dwelling elderly cohort.
      ,
      • Ono R.
      • Murata S.
      • Uchida K.
      • et al.
      Reciprocal relationship between locomotive syndrome and social frailty in older adults.
      ,
      • Miyata H.
      • Maruta M.
      • Makizako H.
      • et al.
      Association between satisfaction with meaningful activities and social frailty in community-dwelling Japanese older adults.
      ,
      • Bae S.
      • Lee S.
      • Lee S.
      • et al.
      The role of social frailty in explaining the association between hearing problems and mild cognitive impairment in older adults.
      • Chen Z.
      • Jiang X.
      • Shi G.
      • et al.
      Social frailty and longitudinal risk of depressive symptoms in a Chinese population: the Rugao Longevity and Aging Study.
      • Díaz-Alonso J.
      • Bueno-Pérez A.
      • Toraño-Ladero L.
      • et al.
      [Hearing loss and social frailty in older men and women].
      • Doi T.
      • Tsutsumimoto K.
      • Ishii H.
      • et al.
      Impact of social frailty on the association between driving status and disability in older adults.
      • Gobbens R.J.J.
      • van Assen M.
      Associations between multidimensional frailty and quality of life among Dutch older people.
      • Hirase T.
      • Makizako H.
      • Okubo Y.
      • et al.
      Chronic pain is independently associated with social frailty in community-dwelling older adults.
      • Hironaka S.
      • Kugimiya Y.
      • Watanabe Y.
      • et al.
      Association between oral, social, and physical frailty in community-dwelling older adults.
      • Huang C.H.
      • Okada K.
      • Matsushita E.
      • et al.
      The association of social frailty with intrinsic capacity in community-dwelling older adults: a prospective cohort study.
      ,
      • Ko H.
      • Jung S.
      Association of social frailty with physical health, cognitive function, psychological health, and life satisfaction in community-dwelling older Koreans.
      • Ko Y.
      • Lee K.
      Social frailty and health-related quality of life in community-dwelling older adults.
      • Kodama A.
      • Kume Y.
      • Lee S.
      • et al.
      Impact of COVID-19 Pandemic Exacerbation of Depressive Symptoms for Social Frailty from the ORANGE Registry.
      • Lee Y.
      • Chon D.
      • Kim J.
      • et al.
      The predictive value of social frailty on adverse outcomes in older adults living in the community.
      • Ma L.
      • Sun F.
      • Tang Z.
      Social frailty is associated with physical functioning, cognition, and depression, and predicts mortality.
      • Makizako H.
      • Kubozono T.
      • Kiyama R.
      • et al.
      Associations of social frailty with loss of muscle mass and muscle weakness among community-dwelling older adults.
      • Makizako H.
      • Shimada H.
      • Doi T.
      • et al.
      Social frailty leads to the development of physical frailty among physically non-frail adults: a four-year follow-up longitudinal cohort study.
      • Nagai K.
      • Tamaki K.
      • Kusunoki H.
      • et al.
      Physical frailty predicts the development of social frailty: a prospective cohort study.
      • Nakakubo S.
      • Doi T.
      • Makizako H.
      • et al.
      Association of sleep condition and social frailty in community-dwelling older people.
      • Noguchi T.
      • Nojima I.
      • Inoue-Hirakawa T.
      • et al.
      Association between social frailty and sleep quality among community-dwelling older adults: a cross-sectional study.
      ,
      • Park H.
      • Jang I.Y.
      • Lee H.Y.
      • et al.
      Screening value of social frailty and its association with physical frailty and disability in community-dwelling older koreans: aging study of pyeongchang rural area.
      • Renne I.
      • Gobbens R.J.
      Effects of frailty and chronic diseases on quality of life in Dutch community-dwelling older adults: a cross-sectional study.
      • Tsutsumimoto K.
      • Doi T.
      • Makizako H.
      • et al.
      Social frailty has a stronger impact on the onset of depressive symptoms than physical frailty or cognitive impairment: a 4-year follow-up longitudinal cohort study.
      • Tsutsumimoto K.
      • Doi T.
      • Makizako H.
      • et al.
      Association of social frailty with both cognitive and physical deficits among older people.
      • Tsutsumimoto K.
      • Doi T.
      • Nakakubo S.
      • et al.
      Impact of social frailty on Alzheimer's disease onset: a 53-month longitudinal cohort study.
      ,
      • Ye L.
      • Elstgeest L.E.M.
      • Zhang X.
      • et al.
      Factors associated with physical, psychological and social frailty among community-dwelling older persons in Europe: a cross-sectional study of Urban Health Centres Europe (UHCE).
      • Yoo M.
      • Kim S.
      • Kim B.S.
      • et al.
      Moderate hearing loss is related with social frailty in a community-dwelling older adults: the Korean Frailty and Aging Cohort Study (KFACS).
      • Zhang X.
      • Tan S.S.
      • Franse C.B.
      • et al.
      Association between physical, psychological and social frailty and health-related quality of life among older people.
      and 8 studies involved hospitalized older people.
      • Gobbens R.J.J.
      • Andreasen J.
      Multidimensional frailty and its determinants among acutely admitted older people: a cross-sectional study using the Tilburg Frailty Indicator.
      ,
      • Adachi T.
      • Tsunekawa Y.
      • Tanimura D.
      Association among mild cognitive impairment, social frailty, and clinical events in elderly patients with cardiovascular disease.
      ,
      • Inoue T.
      • Maeda K.
      • Satake S.
      • et al.
      Osteosarcopenia, the co-existence of osteoporosis and sarcopenia, is associated with social frailty in older adults.
      ,
      • Jujo K.
      • Kagiyama N.
      • Saito K.
      • et al.
      Impact of social frailty in hospitalized elderly patients with heart failure: a FRAGILE-HF registry subanalysis.
      ,
      • Okumura M.
      • Inoue T.
      • Melinda G.
      • et al.
      Social frailty as a risk factor for new-onset depressive symptoms at one year post-surgery in older patients with gastrointestinal cancer.
      ,
      • Ono R.
      • Makiura D.
      • Nakamura T.
      • et al.
      Impact of preoperative social frailty on overall survival and cancer-specific survival among older patients with gastrointestinal cancer.
      ,
      • Usui N.
      • Yokoyama M.
      • Nakata J.
      • et al.
      Association between social frailty as well as early physical dysfunction and exercise intolerance among older patients receiving hemodialysis.
      ,
      • Yamashita M.
      • Kamiya K.
      • Hamazaki N.
      • et al.
      Work status before admission relates to prognosis in older patients with heart failure partly through social frailty.
      Table 1Summary of the Included Studies on the Prevalence of Social Frailty (n = 43)
      Author, yearPopulation SourceSampling MethodsSettingCountryDesignAge, y, Mean (SD)/MedianSample SizeFemaleDefinition of Social FrailtyPrevalence of Frailty, %
      Sugie 2022Older people living in Nammoku villagePopulation surveyCommunityJapanCross-sectional81.5 (4.5)268147LSNS-68.20
      Miyata 2022Residents aged 65 years from Tarumizu cityPopulation surveyCommunityJapanCross-sectional74.2 (6.4)596379MSFI18.60
      Kume 2021General population of Akita prefecturePopulation surveyCommunityJapanCross-sectional75.0 (5.8)313213MSFI21.70
      Kodama 2022Older adults from 6 areas of Yokote city in Akita prefectureConvenience sampleCommunityJapanCohort study≥60161NAMSFI13.04
      Hayashi 2021Older people living in Minokamo cityPopulation surveyCommunityJapanCross-sectional81.1 (5.0)988520SFSI15.30
      Doi 2021Part study of NCGG-SGS; older adults living in Obu cityPopulation surveyCommunityJapanCohort study71.7 (5.3)46422330MSFI44.66
      Ye 2021Baseline data of Urban Health Centres Europe projectPopulation surveyCommunityEuropeCross-sectional79.7 (5.7)22891379TFI29.40
      Usui 2021Eligible older people from Kisen Hospital and Kisen ClinicConvenience sampleHospitalJapanCross-sectional74.1 (6.8)15845MSFI59.50
      Ono 2021Older adults from agricultural community located in Aizu region of Fukushima prefecturePopulation surveyCommunityJapanCohort study79.4 (3.5)748398MSFI23.26
      Ono 2021Patients with gastrointestinal cancerConvenience sampleHospitalJapanCohort study>6018142MSFI46.80
      Ko 2021Data from the 2017 National Survey of Older Koreans from 17 metropolitan cites and provincesNational sampleCommunityKoreaCross-sectional74.5 (6.2)10,0816035MSFI44.70
      Jujo 2021Older hospitalized people with heart failure from 15 hospitalsNational sampleHospitalJapanCohort study≥651240527MSFI66.50
      Huang 2021Older people from a community center in NagoyaConvenience sampleCommunityJapanCohort study69.5 (4.5)663376Bunt’s social frailty concept6.30
      Chen 2021Population-based study in Rugao, Jiangsu province; older adults from 31 communities of Jiang’an townshipPopulation surveyCommunityChinaCross-sectional75.3 (3.9)1764820Six questions3.60
      Okumura 2020Patients with gastrointestinal cancer form a single university hospitalConvenience sampleHospitalJapanCohort study714811MSFI27.00
      Nagai 2020Older people living in Tamba-Sasayama cityPopulation surveyCommunityJapanCross-sectionalNA625NASFSI7.70
      Zhang 2019Baseline data of Urban Health Centres Europe projectPopulation surveyCommunityEuropeCross-sectional79.7 (5.6)21671313TFI29.00
      Yoo 2019Older people from a national multicenter cohort study, living in urban and rural regionsNational sampleCommunityKoreaCross-sectional76.2 (3.93)1539815MSFI11.70
      Tsutsumimoto 2019Older people from Obu city, Aichi prefecturePopulation surveyCommunityJapanCohort study71.7 (5.3)37201918MSFI10.80
      Park 2019Older adults living in the rural area of PyeongchangPopulation surveyCommunityKoreaCross-sectional74.9 (6.0)408236MSFI20.50
      Nakakubo 2019Older people recruited from Obu cityPopulation surveyCommunityJapanCross-sectional71.91 (5.49)44272274MSFI11.20
      Makizako 2018Older people living in Tarumizu cityPopulation surveyCommunityJapanCross-sectional75.4 (6.5)353264MSFI14.70
      Hirase 2019Older people from Unzen city attending community-based exercise classesConvenience sampleCommunityJapanCross-sectional79.1 (6.0)248206MSFI22.20
      Yamada 2018Older people living in a city in Shiga prefecturePopulation surveyCommunityJapanCohort study75.2 (6.6)66033692SFSI18.00
      Tsutsumimoto 2018Older people from Obu cityPopulation surveyCommunityJapanCohort study71.3 (0.08)35381820MSFI29.90
      Makizako 2018Longitudinal data of older adults derived from first and second waves of OSHPEPopulation surveyCommunityJapanCohort study70.4 (4.1)1226633MSFI3.60
      Ma 2018Older adults from Beijing communityPopulation surveyCommunityChinaCohort study≥601697NAHALFT scale7.70
      Bae 2018Older people living in Obu cityPopulation surveyCommunityJapanCross-sectional72.5 (5.2)42512291MSFI10.37
      Tsutsumimoto 2017Data from Obu study of health promotion for elderly people; older people from Obu cityPopulation surveyCommunityJapanCross-sectional71.9 (5.5)44252274MSFI11.10
      Yamashita 2021Older hospitalized people with heart failure from 15 hospitalsNational sampleHospitalJapanCohort study811332574MSFI41.60
      Alonso 2020Noninstitutionalized adults aged 65 years or more from AsturiasPopulation surveyCommunitySpainCross-sectional76.2 (7.2)445255Accumulated functional deficits23.10
      Noguchi 2021Older people recruited at Togo public town hallPopulation surveyCommunityJapanCross-sectional73.0 (5.8)300153MSFI17.33
      Makizako 2015Older people from Obu study of health promotion for elderly people and living in ObuPopulation surveyCommunityJapanCohort study71.7 (5.3)43042207MSFI10.20
      Inoue 2022Participants in a frailty clinic of a general geriatric hospitalConvenience sampleHospitalJapanCross-sectional76.5 (7.2)495340SFSI12.30
      Gobbens 2021Participants at Aalborg University HospitalConvenience sampleHospitalNetherlandsCross-sectional76.8 (7.5)1267633TFI53.13
      Hironaka 2020Older adults residing in 9 towns in Itabashi ward in TokyoPopulation surveyCommunityJapanCross-sectional73.3 (6.6)682415MSFI23.20
      Renne 2018Older adults from small villages close to AmsterdamPopulation surveyCommunityNetherlandsCross-sectional76.5 (5.1)241116TFI32.78
      Gobbens 2017Dutch older people recruited via Web-based questionnaireConvenience sampleCommunityNetherlandsCross-sectional76.6 (4.7)671205TFI31.10
      Garre-Olmo 2013Older people living in 8 rural villagesPopulation surveyCommunitySpainCohort study81.7 (4.8)875509Accumulated functional deficits8.90
      Lee 2020Nationwide survey of older adults in KoreaNational sampleCommunityKoreaCohort study72.9 (6.7)11,2416711Bunt’s social frailty concept7.70
      Verver 2019Older adults in different regions of North-Holland provincePopulation surveyCommunityNetherlandsCross-sectional78.8 (6.4)1768546TFI18.40
      Adachi 2022Hospitalized older adults in cardiac rehabilitationConvenience sampleHospitalJapanCohort study7518462MSFI65.2
      Ko 2022Older people living in the communityNACommunityKoreaCross-sectional≥65735234MSFI48.4
      CFAI, Comprehensive Frailty Assessment Instrument; HALFT, acronym for the 5 components: Help, participation, Loneliness, Financial, and Talk; LSNS-6, Lubben Social Network Scale.
      MSFI, Makizako Social Frailty Index; NA, not applicable; NCGG-SGS, National Center for Geriatric and Gerontology-Study of Geriatric Syndromes; OSHPE, Obu Health Promotion for the Elderly Study; SFSI, Social Frailty Screening Index; TFI, Tilburg Frailty Indicator.

      Methodological Quality

      The studies included in our systematic review had a low to moderate risk of bias. Overall, 11 showed a low risk of bias, and 32 had a moderate risk. Their grades varied from 6 to 10 on a scale of 1 to 10 (Supplementary Table 2).

      Prevalence of Social Frailty

      The prevalence of social frailty in individual studies ranged from 3.6% to 66.5%. The pooled prevalence of social frailty was 23.9% (95% CI: 19.9%−27.9%, I2 = 99.66%, P < .001) (Figure 2).
      Figure thumbnail gr2
      Fig. 2Meta-analysis for the prevalence of social frailty among older adults.

      Subgroup Analyses

      Subgroup analyses based on country by excluding those studies from hospital settings

      The results showed that the pooled prevalence of social frailty in Japan and Korea was 16.2% (95% CI: 12.2%–20.3%) and 26.6% (95% CI: 7.1%–46.1%), respectively. The pooled prevalence of social frailty was lowest in China, at 4.9% (95% CI: 4.2%–5.7%). The pooled prevalence of social frailty was 11.6% (95% CI: 9.9%–13.3%) in Spain and 27.2% (95% CI: 16.9%–37.5%) in the Netherlands. Two studies were from the Urban Health Centres Europe project, covering 5 European countries, and the pooled prevalence of social frailty was 29.2% (95% CI: 27.9%–30.5%) (Table 2).
      Table 2Subgroup Analyses by Country, Age, Setting, Sample Size, Design, Gender, Definition for the Meta-analysis of Prevalence of Social Frailty
      VariablesNumber of StudiesPrevalence, %95% CII2, %P Value for Difference
      Country
      The subgroup analysis based on country was excluded in those studies that were conducted in a hospital setting.
      <.001
       European urban centers229.227.9%–30.5%0
       Japan2116.212.2%–20.3%99.35
       Korea526.67.1%–46.1%99.91
       China24.94.2%–5.7%0
       Spain211.69.9%–13.3%0
       Netherlands327.216.9%–37.5%0
      Age.40
       <751820.013.9%–26.1%99.77
       ≥752024.318.7%–29.9%99.31
      Setting<.001
       Community3518.814.9%–22.7%99.63
       Hospital847.332.2%–62.4%99.19
      Sample size.35
       ≤5001627.619.9%–35.2%97.38
       >5002722.217.4%–27.1%99.77
      Design.65
       Cohort study1725.419.1%–31.7%99.71
       Cross-sectional2622.917.4%–28.5%99.60
       Gender.55
       Male1923.516.7%–30.2%99.51
       Female1926.017.6%–34.3%99.67
      Definition for social frailty<.001
       Makizako Social Frailty Index2627.721.6%–33.8%99.71
       Social Frailty Screening Index413.48.4%–18.4%96.49
       Tilburg Frailty Indicator632.323.1%–41.5%98.84
       Others78.86.5%–11.1%95.60
      The subgroup analysis based on country was excluded in those studies that were conducted in a hospital setting.

      Subgroup analyses by age group

      We classified age into 2 groups (at least 75 years vs younger than 75 years). The pooled prevalence of social frailty was higher in those aged 75 years or older than those younger than 75 years (24.3%; 95% CI: 18.7%–29.9% vs 20.0%, 95% CI: 13.9%–26.1%). However, the difference was not statistically significant (P = .40) (Table 2).

      Subgroup analyses by study design and sample size

      The pooled prevalence of social frailty was 22.2% (95% CI: 17.4%–27.1 %) for studies with sample sizes greater than 500 and 27.6% (95% CI: 19.9%–35.2%) in studies with sample size of less than 500. In addition, the pooled prevalence of social frailty was 22.9% (95% CI: 17.4%–28.5%) in cross-sectional studies and 25.4% (95% CI: 19.1%–31.7%) in cohort studies. These differences were not statistically significant (P = .65 for study design and P = .35 for sample size) (Table 2).

      Subgroup analyses by setting

      Overall, 43 studies reported the setting, including 79,002 participants in the community and 4905 participants in hospital, with a higher prevalence of social frailty in hospital (47.3%, 95% CI: 32.2%–62.4% vs 18.8%, 95% CI: 14.9%–22.7%). The difference was statistically significant (P < .001) (Table 2). Regarding community settings, 27 studies were based on population surveys, 3 studies used national samples, and 4 studies used convenience samples. The subgroup analysis based on sampling methods showed no statistically significant difference in the pooled prevalence of social frailty among community-dwelling older adults (P = .94) (Supplementary Figure 1).

      Subgroup analyses by social frailty assessment tool

      Studies used several different social frailty assessment tools. Some used single-dimensional social frailty assessment tools but others used a multidimensional assessment. Overall, 26 studies used the Makizako Social Frailty Index and had a pooled prevalence of 27.7% (95% CI: 21.6%–33.8%). Four studies used the Social Frailty Screening Index, and had a prevalence of 13.4% (95% CI: 8.4%–18.4%), 6 studies used the Tilburg Frailty Indicator, with a prevalence of 32.3% (95% CI: 23.1%–41.5%), and 7 studies used other tools and had a pooled prevalence of 8.8% (95% CI: 6.5%–11.1%). Differences in the prevalence of social frailty between studies using different definitions were statistically significant (P < .001) (Table 2).

      Subgroup analysis by gender

      Only 19 studies reported the prevalence of social frailty by gender. The pooled prevalence of social frailty was higher in women than men (26.0%, 95% CI: 17.6%–34.3% vs 23.5%, 95% CI: 16.7%–30.2%). However, the difference was not statistically significant (P = .55) (Table 2).

      Publication bias

      The publication bias test found asymmetry across these studies (Supplementary Figure 2A), and the results of Begg’s test suggested a possible publication bias (P = .011) (Supplementary Figure 2B).

      Meta-regression

      The meta-regression on age showed that age did not affect the prevalence of social frailty, with a regression coefficient of 0.058 (95% CI: −0.0098 to 0.021), P = .45, 38 studies (Supplementary Figure 3).

      Sensitivity

      After omitting each study and pooling the remaining studies using sensitivity analysis, there were no statistically significant differences between the combined effect value and the total combined value, indicating that the results of this study were stable (Supplementary Figure 4).

      Discussion

      Our meta-analysis showed that the pooled prevalence of social frailty was 23.9% (95% CI: 19.9%−27.9%). Our subgroup analysis showed that the country, setting, and definition of social frailty affected the prevalence of social frailty among older adults. However, age, gender, and study design had no effect. To the best of our knowledge, this is the first meta-analysis to summarize the evidence of the prevalence of social frailty among older adults.
      This study found statistically significant differences in social frailty prevalence by country. Social frailty was lowest in China (4.9%), followed by Spain (11.6%), Japan (16.2%), Korea (26.6%), 5 European countries (29.2%), and the Netherlands (27.2%) among community-dwelling older adults. These differences may reflect differences in sampling, measurement tools, and/or differences in social structures, cultures,
      • Chen Z.
      • Jiang X.
      • Shi G.
      • et al.
      Social frailty and longitudinal risk of depressive symptoms in a Chinese population: the Rugao Longevity and Aging Study.
      and economics within each country. Most of the included studies in this review were conducted in Japan; only 2 studies were from China.
      • Chen Z.
      • Jiang X.
      • Shi G.
      • et al.
      Social frailty and longitudinal risk of depressive symptoms in a Chinese population: the Rugao Longevity and Aging Study.
      ,
      • Ma L.
      • Sun F.
      • Tang Z.
      Social frailty is associated with physical functioning, cognition, and depression, and predicts mortality.
      More studies from different countries, such as China, Spain, and the Netherlands, are needed to fully explore this topic.
      The subgroup analysis based on study design showed that the prevalence of social frailty was 22.9% (95% CI: 17.4%–28.5%) for cross-sectional studies and 25.4% (95% CI: 19.1%–31.7%) for cohort studies. The most likely explanation for this difference is methodology: cross-sectional and cohort studies have different inclusion and exclusion criteria. Generally, most of the cross-sectional studies of older community-dwelling people recruited participants who could walk independently and could communicate with the investigator.
      • Sugie M.
      • Harada K.
      • Nara M.
      • et al.
      Prevalence, overlap, and interrelationships of physical, cognitive, psychological, and social frailty among community-dwelling older people in Japan.
      ,
      • Ono R.
      • Murata S.
      • Uchida K.
      • et al.
      Reciprocal relationship between locomotive syndrome and social frailty in older adults.
      ,
      • Hirase T.
      • Makizako H.
      • Okubo Y.
      • et al.
      Chronic pain is independently associated with social frailty in community-dwelling older adults.
      ,
      • Park H.
      • Jang I.Y.
      • Lee H.Y.
      • et al.
      Screening value of social frailty and its association with physical frailty and disability in community-dwelling older koreans: aging study of pyeongchang rural area.
      ,
      • Renne I.
      • Gobbens R.J.
      Effects of frailty and chronic diseases on quality of life in Dutch community-dwelling older adults: a cross-sectional study.
      ,
      • Ye L.
      • Elstgeest L.E.M.
      • Zhang X.
      • et al.
      Factors associated with physical, psychological and social frailty among community-dwelling older persons in Europe: a cross-sectional study of Urban Health Centres Europe (UHCE).
      However, the cohort studies usually featured additional exclusion criteria, such as depression
      • Kodama A.
      • Kume Y.
      • Lee S.
      • et al.
      Impact of COVID-19 Pandemic Exacerbation of Depressive Symptoms for Social Frailty from the ORANGE Registry.
      and decline in activities of daily living scores
      • Huang C.H.
      • Okada K.
      • Matsushita E.
      • et al.
      The association of social frailty with intrinsic capacity in community-dwelling older adults: a prospective cohort study.
      at the baseline survey. In addition, 7 cohort studies provided baseline data on social frailty (which were extracted for our data analysis) at the beginning of the survey, and therefore were not true cohort studies. In addition, 6 studies excluded from their final analysis data for some older people who did not complete the follow-up. Therefore, missing data owing to noncompletion of follow-up may have led to differences in the prevalence of social frailty.
      The common tools used to assess social frailty are the Makizako Social Frailty Index, Social Frailty Screening Index, and Tilburg Frailty Indicator. The pooled prevalence of social frailty measured by the 3 instruments respectively was 27.7%, 13.4%, and 32.3% (P < .001). The most common assessment tool was the Makizako Social Frailty Index, which was used in 26 studies. The highest prevalence was with the use of Tilburg Frailty Indicator. Bessa et al.
      • Bessa B.
      • Coelho T.
      • Ribeiro Ó.
      Social frailty dimensions and frailty models over time.
      also found different results for alternative measures of social frailty. The higher social frailty prevalence when using the Tilburg Frailty Indicator may be because the studies using this scale had a higher mean age, all ≥75 years. In addition, there are also other differences between the Makizako Social Frailty Index and Tilburg Frailty Indicator. Tilburg Frailty Indicator has been used to assess social frailty,
      • Bunt S.
      • Steverink N.
      • Olthof J.
      • et al.
      Social frailty in older adults: a scoping review.
      but it also contains items across 2 other domains of frailty, physical and psychological frailty.
      • Gobbens R.J.
      • van Assen M.A.
      • Luijkx K.G.
      • et al.
      The Tilburg Frailty Indicator: psychometric properties.
      The Tilburg Frailty Indicator may also be more sensitive because it contains only 3 items on social frailty. The Makizako Social Frailty Index, however, was specifically designed to assess social frailty, and it contains 5 items. Participants are classified into socially frail, pre-frail, and robust.
      • Tsutsumimoto K.
      • Doi T.
      • Nakakubo S.
      • et al.
      Impact of social frailty on Alzheimer's disease onset: a 53-month longitudinal cohort study.
      No consensus has been reached on the most appropriate tools for assessing social frailty. The Tilburg Frailty Indicator is usually chosen in Europe, and the Makizako Social Frailty Index and Social Frailty Screening Index were more likely to be used in Japan and South Korea. This suggests that there are some challenges in measuring social frailty across cultures, especially in validating the efficacy, applying assessment tools in other countries, and establishing a standardized method for social frailty screening.
      The subgroup analysis by setting showed that the prevalence of social frailty was lower among people in the community than in hospital (18.8% vs 47.3%; P < .001). This is similar to the result of another meta-analysis, in which the overall prevalence of frailty in older adult individuals in hospitals was 41.4%.
      • Gómez Jiménez E.
      • Avendaño Céspedes A.
      • Cortés Zamora E.B.
      • et al.
      [Frailty prevalence in hospitalized older adults. A systematic review].
      This may be because older adult patients in hospital tended to do fewer social activities because of their illness or condition, and were in poorer physical condition than people living in the community. Hospitalized older adults are also more likely to have negative emotions.
      • Ciro C.A.
      • Ottenbacher K.J.
      • Graham J.E.
      • et al.
      Patterns and correlates of depression in hospitalized older adults.
      In addition, hospitalized patients may be taking more drugs and medication, and the side effects of these could have a negative impact on social frailty. Some studies have suggested that depression,
      • Chen Z.
      • Jiang X.
      • Shi G.
      • et al.
      Social frailty and longitudinal risk of depressive symptoms in a Chinese population: the Rugao Longevity and Aging Study.
      medication risk,
      • Park H.
      • Jang I.Y.
      • Lee H.Y.
      • et al.
      Screening value of social frailty and its association with physical frailty and disability in community-dwelling older koreans: aging study of pyeongchang rural area.
      physical activity, and weakness are factors affecting social frailty.
      • Nagai K.
      • Tamaki K.
      • Kusunoki H.
      • et al.
      Physical frailty predicts the development of social frailty: a prospective cohort study.
      Hospitalized patients are therefore more likely to experience social frailty. It may be helpful for hospital staff to assess the social frailty of hospitalized older adults in a timely manner, conduct individualized assessments, and develop intervention measures to delay or prevent the occurrence of social frailty.
      Our results showed that the pooled prevalence of social frailty was higher in adults aged 75 years or older than in those younger than 75 years (24.3% vs 20.0%). Surprisingly, however, this result was not statistically significant (P = .40), and the meta-regression did not suggest that age influenced the prevalence of social frailty. However, we still think this is a possibility. A previous study found that age was a risk factor for social frailty.
      • Gobbens R.J.J.
      • Andreasen J.
      Multidimensional frailty and its determinants among acutely admitted older people: a cross-sectional study using the Tilburg Frailty Indicator.
      It is likely that the most common reason why social frailty increases with age is death of a spouse.
      • Ofori-Asenso R.
      • Chin K.L.
      • Mazidi M.
      • et al.
      Global incidence of frailty and prefrailty among community-dwelling older adults: a systematic review and meta-analysis.
      Older age is associated with living alone, which is a component of social frailty. In addition, aging causes natural deterioration of bodily functions. A study showed that after controlling for confounding factors, hearing loss was associated with social frailty (odds ratio 2.17; 95% CI: 1.43–3.30).
      • Yoo M.
      • Kim S.
      • Kim B.S.
      • et al.
      Moderate hearing loss is related with social frailty in a community-dwelling older adults: the Korean Frailty and Aging Cohort Study (KFACS).
      Hearing loss is more likely to increase with age, leading to lower social participation.
      • Shukla A.
      • Cudjoe T.K.M.
      • Lin F.R.
      • et al.
      Functional hearing loss and social engagement among medicare beneficiaries.
      In the age subgroup analysis, our results were similar to another meta-analysis of frailty, which also found that the prevalence of frailty increased with age, although the correlation was weak.
      • O'Caoimh R.
      • Sezgin D.
      • O'Donovan M.R.
      • et al.
      Prevalence of frailty in 62 countries across the world: a systematic review and meta-analysis of population-level studies.
      This indicates that the prevalence of social frailty may vary with age, and therefore may be age-related.
      Our meta-analysis had several strengths. First, to our knowledge, this meta-analysis is the first to have analyzed the prevalence of social frailty, and therefore provides an overall picture of social frailty among older adults. It highlights the importance of early screening and intervention to reduce the impact of social frailty on older people. Second, the analysis included a large number of studies from different countries around the world, and the sample size was large, with two-thirds of studies including more than 500 people. Third, we used comprehensive analyses, including various subgroup analyses, sensitivity analyses, meta-regression, and tests of publication bias, to identify whether the study results were stable and reliable.
      Our meta-analysis also had some limitations. First, the review did not cover any particular population groups, such as older nursing home residents. Second, the international sample was uneven, with significantly more studies from Japan than other countries. Third, not all the articles were of high quality and there might be some publication bias. Fourth, we did not search any gray literature, which may have biased our findings to the degree of uncertainty. Fifth, our results should be taken with caution because there is considerable heterogeneity. However, this is often unavoidable in meta-analyses of observational studies and does not necessarily negate the findings.
      • Zhang T.
      • Ren Y.
      • Shen P.
      • et al.
      Prevalence and associated risk factors of cognitive frailty: a systematic review and meta-analysis.
      We performed sufficient analyses to investigate potential sources of heterogeneity, including subgroup, random-effects meta-regression and sensitivity analyses. The results show that country, setting, and definition of social frailty make significant contributions to heterogeneity. Sixth, one subgroup analysis showed very large CIs. The 95% CI was between 7.1% and 46.1% for people in Korea. Finally, the different assessment tools arrive at very different estimates, and therefore our meta-analysis results should be used with caution and especially across different measurement tools.

      Conclusion and Implications

      The prevalence of social frailty is high in the older adult population. Our study found that it was influenced by country, settings, and the assessment tools for social frailty. However, it is clear that public health professionals and policymakers need to take social frailty among older adults seriously. Future clinical trials or cohort studies are needed to evaluate the best intervention and strategies for reducing the prevalence of social frailty.

      Acknowledgments

      We thank Melissa Leffler, MBA, from Liwen Bianji (Edanz) (www.liwenbianji.cn) for editing the English text of a draft of this manuscript.
      Author contributions: X.M.Z. and S.M.C. were responsible for drafting, revising, and finalizing the manuscript. X.H.X. and X.J.W. initiated the study concept and design. X.M.Z. and S.M.C. were responsible for determining the research strategy and screening. S.Y.X., M.F.G., and S.M.C. were responsible for data extraction, data analysis, and quality bias assessment.

      Supplementary File 1. Search Strategy

      PubMed:

      #1: Search: "social frailty" Sort by: Most Recent
      #2: Search: "social vulnerability" Sort by: Most Recent
      #3: Search: "social frail∗" Sort by: Most Recent
      #4: Search: elder∗ OR "older people∗" OR "older adult∗" OR aged OR senior∗ Sort by: Most Recent
      #5: Search: (Prevalence OR Epidemiology∗). Sort by: Most Recent
      #6: Search: (("social frailty") OR ("social vulnerability")) OR ("social frail∗") Sort by: Most Recent
      #7: Search: (((("social frailty") OR ("social vulnerability")) OR ("social frail∗")) AND ((Prevalence OR Epidemiology∗).)) AND (elder∗ OR "older people∗" OR "older adult∗" OR aged OR senior∗) Sort by: Most Recent

      Embase:

      #1('social frailty' OR 'social vulnerability'/exp OR 'social frail∗')
      #2:('older adults' OR 'older people' OR 'aged'/exp OR 'aged' OR 'aged patient' OR 'aged people' OR 'aged person' OR 'aged subject' OR 'elderly' OR 'elderly patient' OR 'elderly people' OR 'elderly person' OR 'elderly subject' OR 'senior citizen' OR 'senium')
      #3: ('prevalence'/exp OR 'epidemiology'/exp OR 'clinical epidemiology' OR 'confounding factors (epidemiology)' OR 'confounding factors, epidemiologic' OR 'controlled before after studies' OR 'controlled before and after studies' OR 'controlled before and after study' OR 'controlled before-after studies' OR 'effect modifier, epidemiologic' OR 'effect modifiers (epidemiology)' OR 'effect modifiers (psychology)' OR 'environmental epidemiology' OR 'epidemiologic confounding factors' OR 'epidemiologic effect modifier' OR 'epidemiologic factors' OR 'epidemiologic methods' OR 'epidemiologic research' OR 'epidemiologic research design' OR 'epidemiologic studies' OR 'epidemiologic study characteristics' OR 'epidemiologic study characteristics as topic' OR 'epidemiologic survey' OR 'epidemiological research' OR 'epidemiology' OR 'epidemiometry' OR 'historically controlled study' OR 'interrupted time series analysis' OR 'precipitating factors' OR 'sampling studies')
      #4: #1 AND #2 AND #3

      Supplementary File 2. PRISMA Checklist

      Tabled 1
      Section/topic#Checklist itemReported on page #
      Title
       Title1Identify the report as a systematic review, meta-analysis, or both.Page 1
      Abstract
       Structured summary2Provide a structured summary including, as applicable: background; objectives; data sources; study eligibility criteria, participants, and interventions; study appraisal and synthesis methods; results; limitations; conclusions and implications of key findings; systematic review registration number.Page 1–2
      Introduction
       Rationale3Describe the rationale for the review in the context of what is already known.Pages 3–4
       Objectives4Provide an explicit statement of questions being addressed with reference to participants, interventions, comparisons, outcomes, and study design (PICOS).Pages 4–5
      Methods
       Protocol and registration5Indicate if a review protocol exists, if and where it can be accessed (eg, Web address), and, if available, provide registration information including registration number.Page 5 line 92
       Eligibility criteria6Specify study characteristics (eg, PICOS, length of follow-up) and report characteristics (eg, years considered, language, publication status) used as criteria for eligibility, giving rationale.Page 5 lines 101–107
       Information sources7Describe all information sources (eg, databases with dates of coverage, contact with study authors to identify additional studies) in the search and date last searched.Page 4 lines 98–99
       Search8Present full electronic search strategy for at least 1 database, including any limits used, such that it could be repeated.Page 5 lines 96–98

      Supplementary File 1
       Study selection9State the process for selecting studies (ie, screening, eligibility, included in systematic review, and, if applicable, included in the meta-analysis).Pages 5–6 lines 101–111

      Figure 1
       Data collection process10Describe method of data extraction from reports (eg, piloted forms, independently, in duplicate) and any processes for obtaining and confirming data from investigators.Page 6 lines 111–120
       Data items11List and define all variables for which data were sought (eg, PICOS, funding sources) and any assumptions and simplifications made.Page 6 lines 114–120
       Risk of bias in individual studies12Describe methods used for assessing risk of bias of individual studies (including specification of whether this was done at the study or outcome level), and how this information is to be used in any data synthesis.Page 6 lines 121–131
       Summary measures13State the principal summary measures (eg, risk ratio, difference in means).Page 7 lines 133–134
       Synthesis of results14Describe the methods of handling data and combining results of studies, if done, including measures of consistency (eg, I2) for each meta-analysis.Page 7 lines 134–140
      Section/topic#Checklist itemReported on page #
      Risk of bias across studies15Specify any assessment of risk of bias that may affect the cumulative evidence (eg, publication bias, selective reporting within studies).Page 7 line 140
      Additional analyses16Describe methods of additional analyses (eg, sensitivity or subgroup analyses, meta-regression), if done, indicating which were prespecified.Page 7 lines 140–145
      Results
       Study selection17Give numbers of studies screened, assessed for eligibility, and included in the review, with reasons for exclusions at each stage, ideally with a flow diagram.Pages 7–8 lines 149–156 Figure 1
       Study characteristics18For each study, present characteristics for which data were extracted (eg, study size, PICOS, follow-up period) and provide the citations.Page 8 lines 157–171

      Table 1
       Risk of bias within studies19Present data on risk of bias of each study and, if available, any outcome level assessment (see item 12).Page 8 lines 172–175 Supplementary Table 2
       Results of individual studies20For all outcomes considered (benefits or harms), present, for each study: (1) simple summary data for each intervention group, (2) effect estimates and confidence intervals, ideally with a forest plot.Pages 8–9 lines 176–179
       Synthesis of results21Present results of each meta-analysis done, including confidence intervals and measures of consistency.Pages 8–9 lines 176–179 Figure 2
       Risk of bias across studies22Present results of any assessment of risk of bias across studies (see Item 15).Supplementary Table 2
       Additional analysis23Give results of additional analyses, if done [eg, sensitivity or subgroup analyses, meta-regression (see Item 16)].Pages 9–11 lines 180–238

      Table 2 and Supplementary Fig. 1, Supplementary Fig. 2, Supplementary Fig. 3
      Discussion
       Summary of evidence24Summarize the main findings including the strength of evidence for each main outcome; consider their relevance to key groups (eg, healthcare providers, users, and policy makers).Pages 11–15 lines 241–328
       Limitations25Discuss limitations at study and outcome level (eg, risk of bias), and at review-level (eg, incomplete retrieval of identified research, reporting bias).Pages 15–16 lines 329–344
       Conclusions26Provide a general interpretation of the results in the context of other evidence, and implications for future research.Page 16 lines 346–352
      Funding
       Funding27Describe sources of funding for the systematic review and other support (eg, supply of data); role of funders for the systematic review.Title page

      Supplementary Data

      Supplementary Table 1Different Definitions of Social Frailty
      ItemsYesNo
      Going out less frequently than last year
      Visiting friends sometimes
      Feeling like helping friends or family
      Living alone
      Talking with someone every day
      Note: A total score of more than 2 points indicates social frailty.
      Tabled 1Social Frailty Screening Index: The measure includes 4 questions.
      Items0 point1 point
      Are you satisfied with your economic condition?Very satisfied, satisfiedUnsatisfied, very unsatisfied
      Do you live alone?NoYes
      How often do you participate in the following groups: volunteer, sports, hobby, learning or cultural, nursing care prevention, senior citizens, or residents’ associations?“Four or more times a week,” “Two or 3 times a week,” “Once a week,” “One to 3 times a month,” “A few times in a year”Never
      How do you get along with your neighbors?“I have a neighbor who comes and goes to each house,” “I have a neighbor to chat with on the street,” “I have a neighbor to say hello to,” and “I do not communicate with neighbors”“I have a neighbor to say hello to” or “I do not communicate with neighbors”
      Note: Scores of 2 or more as social frailty, 1 as pre-social frailty, and 0 as non-social frailty.
      Tabled 1Tilburg Frailty Indicator (TFI): The TFI is a questionnaire based on a multidimensional approach to frailty and was made and validated for use in primary care. Part B consists of 15 self-reported questions covering 3 domains: physical (8 items, score range 0–8), psychological (4; 0–4) and social frailty (3; 0–3). Items have answer categories 0 (no) and 1 (sometimes or yes). Participants with total score of at least 5 were diagnosed as being frail. The cut points for physical, psychological, and social frailty were 3, 2, and 2, respectively.
      ItemsYesNo
      Living alone
      Lack of social relations (loneliness)
      Lack of social support
      Note: The cut points for social frailty were 2.
      Tabled 1Lubben Social Network Scale (LSNS-6): The LSNS-6 is an extremely rapid measure of social isolation in a clinical setting. The total scale score is an equally weighted sum of scores on the six 5-point items.
      Items0–5 points
      How many relatives do you see or hear from at least once a month?
      How many relatives do you feel close to such that you could call on them for help?
      How many relatives do you feel at ease with that you can talk about private matters?
      How many friends do you see or hear from at least once a month?
      How many friends do you feel close to such that you could call on them for help?
      How many friends do you feel at ease with that you can talk about private matters?
      Note: Total scores range from 0 to 30. Social frailty (n = 22) as LSNS-6 scores <12.
      Tabled 1Bunt’s social frailty concept: A validated 4-item questionnaire derived from Bunt’s social frailty concept (general resources, social resources, social behavior, and fulfillment of basic social needs) was used to assess social frailty.
      Items1 point0 point
      Financial difficultyNeed financial supportNo need for financial support
      Household statusLiving aloneNot living alone
      Social activityNonparticipation in social activitiesRegular participation in social activities
      Regular contact with othersTotal scores of the Lubben Social Network Scale: <12 pointsTotal scores of the Lubben Social Network Scale: ≥12 points
      Note: Social frailty (2–4 points), social prefrailty (1 point), and social robustness (0 points).
      Tabled 1Six questions: Three questions (questions 2, 3, and 4) were based on Makizako et al.
      • Makizako H.
      • Shimada H.
      • Tsutsumimoto K.
      • et al.
      Social frailty in community-dwelling older adults as a risk factor for disability.
      , Tsutsumimoto et al.
      • Tsutsumimoto K.
      • Doi T.
      • Makizako H.
      • et al.
      Association of social frailty with both cognitive and physical deficits among older people.
      , and Yamada et al.
      • Yamada M.
      • Arai H.
      Social frailty predicts incident disability and mortality among community-dwelling japanese older adults.
      ; 1 question (question 5) was based on Ma et al.
      • Ma L.
      • Sun F.
      • Tang Z.
      Social frailty is associated with physical functioning, cognition, and depression, and predicts mortality.
      ; and 2 questions (questions 1 and 6) were based on Bunt et al.
      • Bunt S.
      • Steverink N.
      • Olthof J.
      • et al.
      Social frailty in older adults: a scoping review.
      and Teo et al.
      ItemsYesNo
      Is your family in harmony?
      Are you living alone now?
      When faced with troubles, do you have anyone to talk to?
      In the past week, have you visited your friends, or have your friends come to visit you?
      Do you feel lonely?
      Financial difficulty
      Note: Participants showing none or 1 of these components were considered non-socially frail. those showing 2 or 3 components were considered pre-socially frail; and those showing 4 or more components were considered socially frail.
      Tabled 1HALFT scale: The HALFT scale comprises 5 items in Chinese.
      ItemsYes (1 point)No (0 point)
      Inability to help others within the past 12 months
      Limited social participation in the previous 12 months
      Loneliness in the past week
      Financial difficultly over the past 12 months
      Not having anyone to talk to every day
      Note: The HALFT scale score ranges from 0–5 points: a score of 0 was considered non-socially frail; 1–2 was considered pre-socially frail, and a score of ≥3 indicated social frailty.
      Tabled 1Accumulated functional deficits:
      ItemsYesNo
      Living alone
      People without help
      Not having regular contact with family
      Not having regular contact with friends neighbors
      Low self-confidence
      Lack of help in daily activities in the past 3 months
      Note: People who exhibit 1 of the 6 traits are considered pre-social frailty, and those who exhibit 2 or more are considered social frailty.
      Supplementary Table 2Risk of Bias of Included Studies (n = 42)
      Author, yearExternal Validity ItemsInternal Validity ItemsOverall ScoreOverall Risk of Bias
      12345678910
      Sugie 202200011111117Moderate
      Miyata 202200101111117Moderate
      Kume 202100011111117Moderate
      Kodama 202200011111117Moderate
      Hayashi 202100101111117Moderate
      Doi 202101111111108Moderate
      Ye 202110111111108Moderate
      Usui 202101101111107Moderate
      Ono 202101101111107Moderate
      Ono 202100011111117Moderate
      Ko 2021111111111110Low
      Jujo 2021111111111110Low
      Huang 202101111111119Low
      Chen 202101111001117Moderate
      Okumura 202001111111119Low
      Nagai 202000001111116Moderate
      Zhang 201911011011118Low
      Yoo 201911111011119Low
      Tsutsumimoto 201910101111118Moderate
      Park 201911011111119Low
      Nakakubo 201910111001117Moderate
      Makizako 201811111001118Moderate
      Hirase 201901011011117Moderate
      Yamada 201801111011118Moderate
      Tsutsumimoto 201811101001117Moderate
      Makizako 201811101111119Low
      Ma 201801111111119Low
      Bae 201801101111118Moderate
      Tsutsumimoto 2017111111111110Low
      Yamashita 202101111011107Moderate
      Alonso 202001111001117Moderate
      Noguchi 202101111001117Moderate
      Makizako 201511111001118Moderate
      Inoue 202201010111117Moderate
      Gobbens 202101111011118Moderate
      Hironaka 202001101111118Moderate
      Renne 201801101011117Moderate
      Gobbens 201711101011118Moderate
      Garre-Olmo 201301101011117Moderate
      Lee 202011111001017Moderate
      Adachi 202201011111118Moderate
      Ko 202211000111117Moderate
      Verver 201911101111119Low
      Note: 0: no, 1: yes, overall risk of bias: low (score >8), moderate (score 6–8), or high (score ≤5). Items scored: (1)Was the study's target population a close representation of the national population in relation to relevant variables (eg, age, sex)? (2) Was the sampling frame a true or close representation of the target population? (3) Was some form of random selection used to select the sample, OR, was a census undertaken? (4) Was the likelihood of nonresponse bias minimal? (5) Were data collected directly from the subjects (as opposed to a proxy)? (6) Was an acceptable case definition used in the study? (7) Had the study instrument that measured the parameter of interest (eg, prevalence of comorbidity) been tested for reliability and validity (if necessary)? (8)Was the same mode of data collection used for all subjects? (9) Was the length of the shortest prevalence period for the parameter of interest appropriate? (10) Were the numerator(s) and denominator(s) for the parameter of interest appropriate?
      Figure thumbnail fx1
      Supplementary Fig. 1Subgroup analysis based on sampling methods for the pooled prevalence of social frailty among community-dwelling older adults.
      Figure thumbnail fx2
      Supplementary Fig. 2(A) Publication bias. (B) Publication bias by Begg’s test.
      Figure thumbnail fx3
      Supplementary Fig. 3Meta-regression of the effect of age on the prevalence of social frailty.

      References

        • Lin T.
        • Zhao Y.
        • Xia X.
        • et al.
        Association between frailty and chronic pain among older adults: a systematic review and meta-analysis.
        Eur Geriatr Med. 2020; 11: 945-959
        • Vetrano D.L.
        • Palmer K.
        • Marengoni A.
        • et al.
        Frailty and multimorbidity: a systematic review and meta-analysis.
        J Gerontol A Biol Sci Med Sci. 2019; 74: 659-666
        • Kehler D.S.
        • Hay J.L.
        • Stammers A.N.
        • et al.
        A systematic review of the association between sedentary behaviors with frailty.
        Exp Gerontol. 2018; 114: 1-12
        • Morley J.E.
        • Vellas B.
        • van Kan G.A.
        • et al.
        Frailty consensus: a call to action.
        J Am Med Dir Assoc. 2013; 14: 392-397
        • Pek K.
        • Chew J.
        • Lim J.P.
        • et al.
        Social frailty is independently associated with mood, nutrition, physical performance, and physical activity: insights from a theory-guided approach.
        Int J Environ Res Public Health. 2020; 17: 4239
        • Sugie M.
        • Harada K.
        • Nara M.
        • et al.
        Prevalence, overlap, and interrelationships of physical, cognitive, psychological, and social frailty among community-dwelling older people in Japan.
        Arch Gerontol Geriatr. 2022; 100: 104659
        • Qiu Y.
        • Li G.
        • Wang X.
        • et al.
        Prevalence of cognitive frailty among community-dwelling older adults: a systematic review and meta-analysis.
        Int J Nurs Stud. 2022; 125: 104112
        • O'Caoimh R.
        • Sezgin D.
        • O'Donovan M.R.
        • et al.
        Prevalence of frailty in 62 countries across the world: a systematic review and meta-analysis of population-level studies.
        Age Ageing. 2021; 50: 96-104
        • Gobbens R.J.
        • van Assen M.A.
        • Luijkx K.G.
        • et al.
        Determinants of frailty.
        J Am Med Dir Assoc. 2010; 11: 356-364
        • Bunt S.
        • Steverink N.
        • Olthof J.
        • et al.
        Social frailty in older adults: a scoping review.
        Eur J ageing. 2017; 14: 323-334
        • Kume Y.
        • Kodama A.
        • Takahashi T.
        • et al.
        Social frailty is independently associated with geriatric depression among older adults living in northern Japan: a cross-sectional study of ORANGE registry.
        Geriatr Gerontol Int. 2022; 22: 145-151
        • Yamada M.
        • Arai H.
        Social frailty predicts incident disability and mortality among community-dwelling japanese older adults.
        J Am Med Dir Assoc. 2018; 19: 1099-1103
        • Verver D.
        • Merten H.
        • de Blok C.
        • et al.
        A cross sectional study on the different domains of frailty for independent living older adults.
        BMC Geriatr. 2019; 19: 61
        • Makizako H.
        • Shimada H.
        • Tsutsumimoto K.
        • et al.
        Social frailty in community-dwelling older adults as a risk factor for disability.
        J Am Med Dir Assoc. 2015; 16: 1003.e7-1003.e11
        • Hayashi T.
        • Noguchi T.
        • Kubo Y.
        • et al.
        Social frailty and depressive symptoms during the COVID-19 pandemic among older adults in Japan: Role of home exercise habits.
        Arch Gerontol Geriatr. 2022; 98: 104555
        • Ragusa F.S.
        • Veronese N.
        • Smith L.
        • et al.
        Social frailty increases the risk of all-cause mortality: a longitudinal analysis of the English Longitudinal Study of Ageing.
        Exp Gerontol. 2022; 167: 111901
        • Ge L.
        • Yap C.W.
        • Heng B.H.
        Associations of social isolation, social participation, and loneliness with frailty in older adults in Singapore: a panel data analysis.
        BMC Geriatr. 2022; 22: 26
        • Rapolienė G.
        • Aartsen M.
        Lonely societies: low trust societies? Further explanations for national variations in loneliness among older Europeans.
        Eur J Ageing. 2022; 19: 485-494
        • Garre-Olmo J.
        • Calvó-Perxas L.
        • López-Pousa S.
        • et al.
        Prevalence of frailty phenotypes and risk of mortality in a community-dwelling elderly cohort.
        Age Ageing. 2013; 42: 46-51
        • Ono R.
        • Murata S.
        • Uchida K.
        • et al.
        Reciprocal relationship between locomotive syndrome and social frailty in older adults.
        Geriatr Gerontol Int. 2021; 21: 981-984
        • Gobbens R.J.J.
        • Andreasen J.
        Multidimensional frailty and its determinants among acutely admitted older people: a cross-sectional study using the Tilburg Frailty Indicator.
        Eur Geriatr Med. 2021; 12: 151-160
        • Miyata H.
        • Maruta M.
        • Makizako H.
        • et al.
        Association between satisfaction with meaningful activities and social frailty in community-dwelling Japanese older adults.
        Arch Gerontol Geriatr. 2022; 100: 104665
        • Liberati A.
        • Altman D.G.
        • Tetzlaff J.
        • et al.
        The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration.
        Ann Intern Med. 2009; 151: W65-W94
        • Hoy D.
        • Brooks P.
        • Woolf A.
        • et al.
        Assessing risk of bias in prevalence studies: modification of an existing tool and evidence of interrater agreement.
        J Clin Epidemiol. 2012; 65: 934-939
        • Adachi T.
        • Tsunekawa Y.
        • Tanimura D.
        Association among mild cognitive impairment, social frailty, and clinical events in elderly patients with cardiovascular disease.
        Heart Lung. 2022; 55: 82-88
        • Bae S.
        • Lee S.
        • Lee S.
        • et al.
        The role of social frailty in explaining the association between hearing problems and mild cognitive impairment in older adults.
        Arch Gerontol Geriatr. 2018; 78: 45-50
        • Chen Z.
        • Jiang X.
        • Shi G.
        • et al.
        Social frailty and longitudinal risk of depressive symptoms in a Chinese population: the Rugao Longevity and Aging Study.
        Psychogeriatrics. 2021; 21: 483-490
        • Díaz-Alonso J.
        • Bueno-Pérez A.
        • Toraño-Ladero L.
        • et al.
        [Hearing loss and social frailty in older men and women].
        Gac Sanit. 2021; 35: 425-431
        • Doi T.
        • Tsutsumimoto K.
        • Ishii H.
        • et al.
        Impact of social frailty on the association between driving status and disability in older adults.
        Arch Gerontol Geriatr. 2022; 99: 104597
        • Gobbens R.J.J.
        • van Assen M.
        Associations between multidimensional frailty and quality of life among Dutch older people.
        Arch Gerontol Geriatr. 2017; 73: 69-76
        • Hirase T.
        • Makizako H.
        • Okubo Y.
        • et al.
        Chronic pain is independently associated with social frailty in community-dwelling older adults.
        Geriatr Gerontol Int. 2019; 19: 1153-1156
        • Hironaka S.
        • Kugimiya Y.
        • Watanabe Y.
        • et al.
        Association between oral, social, and physical frailty in community-dwelling older adults.
        Arch Gerontol Geriatr. 2020; 89: 104105
        • Huang C.H.
        • Okada K.
        • Matsushita E.
        • et al.
        The association of social frailty with intrinsic capacity in community-dwelling older adults: a prospective cohort study.
        BMC Geriatr. 2021; 21: 515
        • Inoue T.
        • Maeda K.
        • Satake S.
        • et al.
        Osteosarcopenia, the co-existence of osteoporosis and sarcopenia, is associated with social frailty in older adults.
        Aging Clin Exp Res. 2022; 34: 535-543
        • Jujo K.
        • Kagiyama N.
        • Saito K.
        • et al.
        Impact of social frailty in hospitalized elderly patients with heart failure: a FRAGILE-HF registry subanalysis.
        J Am Heart Assoc. 2021; 10: e019954
        • Ko H.
        • Jung S.
        Association of social frailty with physical health, cognitive function, psychological health, and life satisfaction in community-dwelling older Koreans.
        Int J Environ Res Public Health. 2021; 18: 818
        • Ko Y.
        • Lee K.
        Social frailty and health-related quality of life in community-dwelling older adults.
        Int J Environ Res Public Health. 2022; 19: 5659
        • Kodama A.
        • Kume Y.
        • Lee S.
        • et al.
        Impact of COVID-19 Pandemic Exacerbation of Depressive Symptoms for Social Frailty from the ORANGE Registry.
        Int J Environ Res Public Health. 2022; 19: 986
        • Lee Y.
        • Chon D.
        • Kim J.
        • et al.
        The predictive value of social frailty on adverse outcomes in older adults living in the community.
        J Am Med Dir Assoc. 2020; 21: 1464-1469.e2
        • Ma L.
        • Sun F.
        • Tang Z.
        Social frailty is associated with physical functioning, cognition, and depression, and predicts mortality.
        J Nutr Health Aging. 2018; 22: 989-995
        • Makizako H.
        • Kubozono T.
        • Kiyama R.
        • et al.
        Associations of social frailty with loss of muscle mass and muscle weakness among community-dwelling older adults.
        Geriatr Gerontol Int. 2019; 19: 76-80
        • Makizako H.
        • Shimada H.
        • Doi T.
        • et al.
        Social frailty leads to the development of physical frailty among physically non-frail adults: a four-year follow-up longitudinal cohort study.
        Int J Environ Res Public Health. 2018; 15: 490
        • Nagai K.
        • Tamaki K.
        • Kusunoki H.
        • et al.
        Physical frailty predicts the development of social frailty: a prospective cohort study.
        BMC Geriatr. 2020; 20: 403
        • Nakakubo S.
        • Doi T.
        • Makizako H.
        • et al.
        Association of sleep condition and social frailty in community-dwelling older people.
        Geriatr Gerontol Int. 2019; 19: 885-889
        • Noguchi T.
        • Nojima I.
        • Inoue-Hirakawa T.
        • et al.
        Association between social frailty and sleep quality among community-dwelling older adults: a cross-sectional study.
        Phys Ther Res. 2021; 24: 153-162
        • Okumura M.
        • Inoue T.
        • Melinda G.
        • et al.
        Social frailty as a risk factor for new-onset depressive symptoms at one year post-surgery in older patients with gastrointestinal cancer.
        J Geriatr Oncol. 2020; 11: 904-907
        • Ono R.
        • Makiura D.
        • Nakamura T.
        • et al.
        Impact of preoperative social frailty on overall survival and cancer-specific survival among older patients with gastrointestinal cancer.
        J Am Med Dir Assoc. 2021; 22: 1825-1830.e1
        • Park H.
        • Jang I.Y.
        • Lee H.Y.
        • et al.
        Screening value of social frailty and its association with physical frailty and disability in community-dwelling older koreans: aging study of pyeongchang rural area.
        Int J Environ Res Public Health. 2019; 16: 2809
        • Renne I.
        • Gobbens R.J.
        Effects of frailty and chronic diseases on quality of life in Dutch community-dwelling older adults: a cross-sectional study.
        Clin Interv Aging. 2018; 13: 325-334
        • Tsutsumimoto K.
        • Doi T.
        • Makizako H.
        • et al.
        Social frailty has a stronger impact on the onset of depressive symptoms than physical frailty or cognitive impairment: a 4-year follow-up longitudinal cohort study.
        J Am Med Dir Assoc. 2018; 19: 504-510
        • Tsutsumimoto K.
        • Doi T.
        • Makizako H.
        • et al.
        Association of social frailty with both cognitive and physical deficits among older people.
        J Am Med Dir Assoc. 2017; 18: 603-607
        • Tsutsumimoto K.
        • Doi T.
        • Nakakubo S.
        • et al.
        Impact of social frailty on Alzheimer's disease onset: a 53-month longitudinal cohort study.
        J Alzheimer's Dis. 2019; 70: 587-595
        • Usui N.
        • Yokoyama M.
        • Nakata J.
        • et al.
        Association between social frailty as well as early physical dysfunction and exercise intolerance among older patients receiving hemodialysis.
        Geriatr Gerontol Int. 2021; 21: 664-669
        • Yamashita M.
        • Kamiya K.
        • Hamazaki N.
        • et al.
        Work status before admission relates to prognosis in older patients with heart failure partly through social frailty.
        J Cardiol. 2022; 79: 439-445
        • Ye L.
        • Elstgeest L.E.M.
        • Zhang X.
        • et al.
        Factors associated with physical, psychological and social frailty among community-dwelling older persons in Europe: a cross-sectional study of Urban Health Centres Europe (UHCE).
        BMC Geriatr. 2021; 21: 422
        • Yoo M.
        • Kim S.
        • Kim B.S.
        • et al.
        Moderate hearing loss is related with social frailty in a community-dwelling older adults: the Korean Frailty and Aging Cohort Study (KFACS).
        Arch Gerontol Geriatr. 2019; 83: 126-130
        • Zhang X.
        • Tan S.S.
        • Franse C.B.
        • et al.
        Association between physical, psychological and social frailty and health-related quality of life among older people.
        Eur J Public Health. 2019; 29: 936-942
        • Bessa B.
        • Coelho T.
        • Ribeiro Ó.
        Social frailty dimensions and frailty models over time.
        Arch Gerontol Geriatr. 2021; 97: 104515
        • Gobbens R.J.
        • van Assen M.A.
        • Luijkx K.G.
        • et al.
        The Tilburg Frailty Indicator: psychometric properties.
        J Am Med Dir Assoc. 2010; 11: 344-355
        • Gómez Jiménez E.
        • Avendaño Céspedes A.
        • Cortés Zamora E.B.
        • et al.
        [Frailty prevalence in hospitalized older adults. A systematic review].
        Rev Esp Salud Publica. 2021; : 95
        • Ciro C.A.
        • Ottenbacher K.J.
        • Graham J.E.
        • et al.
        Patterns and correlates of depression in hospitalized older adults.
        Arch Gerontol Geriatr. 2012; 54: 202-205
        • Ofori-Asenso R.
        • Chin K.L.
        • Mazidi M.
        • et al.
        Global incidence of frailty and prefrailty among community-dwelling older adults: a systematic review and meta-analysis.
        JAMA Netw Open. 2019; 2: e198398
        • Shukla A.
        • Cudjoe T.K.M.
        • Lin F.R.
        • et al.
        Functional hearing loss and social engagement among medicare beneficiaries.
        J Gerontol B Psychol Sci Soc Sci. 2021; 76: 195-200
        • Zhang T.
        • Ren Y.
        • Shen P.
        • et al.
        Prevalence and associated risk factors of cognitive frailty: a systematic review and meta-analysis.
        Front Aging Neurosci. 2021; 13: 755926