Abstract
Objectives
There is limited research on long-term changes in functional capacity among older
Japanese, who differ significantly from their counterparts in Western, developed nations.
This study aimed to identify distinct trajectories of functional capacity over a 25-year
period and to explore socioeconomic differences in trajectory-group membership probabilities,
using a national sample of older Japanese.
Design
Longitudinal panel study with 8 observation points from 1987 to 2012.
Setting and Participants
The data came from the National Survey of the Japanese Elderly, which consisted of
6193 samples of community-dwelling Japanese aged 60 years and older at baseline.
Methods
Functional capacity measure included basic and instrumental activities of daily living.
Group-based mixture models were used for data analysis.
Results
Among participants aged 60 to 74 years at baseline, 4 trajectories were identified:
minimal disability (80.3%), late-onset disability (11.6%), early-onset disability
(6.2%), and moderate disability (1.9%). Those aged ≥75 years at baseline experienced
higher levels of disability but somewhat parallel trajectories, including minimal
disability (73.3%), early-onset disability (11.2%), moderate disability (11.3%), and
severe and worsening disability (4.2%). Lower socioeconomic status, including education
and household income, was associated with a higher risk of experiencing trajectories
of poorer functional capacity among those aged 60 to 74 years, but no such association
existed among those aged ≥75 years.
Conclusions and Implications
We found that approximately 70% to 80% of older Japanese maintained healthy functional
capacity over time. Although we could not follow those who dropped out during the
observation period, this study provided useful evidence that socioeconomic disparities
in functional health converge with age. Our findings inform the design of health policies
and interventions aiming to maintain functional health among older adults with diverse
socioeconomic backgrounds. In particular, public policies aiming to reduce socioeconomic
disparities should be emphasized to promote healthy aging.
Keywords
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References
- The World report on ageing and health: A policy framework for healthy ageing.Lancet. 2016; 387: 2145-2154
- Low socioeconomic status and disability in old age: Evidence from the InChianti study for the mediating role of physiological impairments.J Gerontol A Biol Sci Med Sci. 2006; 61: 86-91
- Socioeconomic status and the expectation of disability in old age: Estimates for England.J Epidemiol Community Health. 2000; 54: 286-292
- Risk factors for functional status decline in community-living elderly people: A systematic literature review.Soc Sci Med. 1999; 48: 445-469
- Education, age, and the cumulative advantage in health.J Health Soc Behav. 1996; 37: 104-120
- Continuity and change in the social stratification of aging and health over the life course: Evidence from a nationally representative longitudinal study from 1986 to 2001/2002 (Americans' Changing Lives Study).J Gerontol B Psychol Sci Soc Sci. 2005; 60: 15-26
- Socioeconomic stratification and multidimensional health trajectories: Evidence of convergence in later old age.J Gerontol B Psychol Sci Soc Sci. 2015; 70: 661-671
Kitao S, Yamada T. Dimensions of inequality in Japan: Distributions of earnings, income, and wealth between 1984 and 2014. CAMA Working Paper No. 36/2019. Centre for Applied Macroeconomic Analysis, The Australian National University. 2019. Available at: https://crawford.anu.edu.au/sites/default/files/publication/cama_crawford_anu_edu_au/2019-06/36_2019_kitao_yamada.pdf. Accessed June 1, 2019.
- Inequalities in household wealth across OECD countries: Evidence from the OECD Wealth Distribution Database.(OECD Statistics Working Paper No. 2018/01) Paris: OECD Publishing, 2018
- Socioeconomic status and health in the Japanese population.Soc Sci Med. 2009; 68: 2152-2160
- What has made the population of Japan healthy?.Lancet. 2011; 378: 1094-1105
- Cognitive domains and trajectories of functional independence in nondemented elderly persons.J Gerontol A Biol Sci Med Sci. 2006; 61: 1330-1337
- Trajectory of functional status among older Taiwanese: Gender and age variations.Soc Sci Med. 2010; 71: 1208-1217
- Transitions in functional status among older people in Wuhan, China: Socioeconomic differentials.J Clin Epidemiol. 2001; 54: 1126-1138
- Ethnicity and changing functional health in middle and late life: A person-centered approach.J Gerontol B Psychol Sci Soc Sci. 2010; 65: 470-481
- Gender differences in functional status in middle and older age: Are there any age variations?.J Gerontol B Psychol Sci Soc Sci. 2008; 63: S282-S292
- Understanding how race/ethnicity and gender define age-trajectories of disability: An intersectionality approach.Soc Sci Med. 2011; 72: 1236-1248
- Capturing transitions and trajectories: The role of socioeconomic status in later life disability.J Gerontol B Psychol Sci Soc Sci. 2010; 65: 733-743
- Short portable mental status questionnaire for assessment of organic brain deficit in elderly patients.J Am Geriatr Soc. 1975; 23: 433-441
- Transitions in cognitive status among the aged in Japan.Soc Sci Med. 1996; 43: 325-337
- Modeling intraindividual change in personality traits: Findings from the normative aging study.J Gerontol B Psychol Sci Soc Sci. 2003; 58: P153-P165
- Population inference with mortality and attrition in longitudinal studies on aging: A two-stage multiple imputation method.Exp Aging Res. 2007; 33: 187-203
- A SAS procedure based on mixture models for estimating developmental trajectories.Sociol Method Res. 2001; 29: 374-393
- Group-Based Modeling of Development.Harvard University Press, Cambridge, MA2005
- Changes in functional status among older adults in Japan: Successful and usual aging.Psychol Aging. 2003; 18: 684-695
- Cohort differences and chronic disease profiles of differential disability trajectories.J Gerontol B Psychol Sci Soc Sci. 2011; 66: 729-738
- Trends in old-age functioning and disability in Japan, 1993-2002.Popul Stud. 2006; 60: 39-53
- Do functional health inequalities decrease in old age? Educational status and functional decline among the 1931-1941 birth cohort.Res Aging. 2006; 28: 375-392
- Do socioeconomic effects on health diminish with age? A Singapore case study.J Cross Cult Gerontol. 2007; 22: 287-301
- Socioeconomic position and health: The differential effects of education versus income on the onset versus progression of health problems.J Health Soc Behav. 2007; 48: 223-238
- Socioeconomic status and health.in: Berkman L.F. Kawachi I. Glymour M.M. Social Epidemiology. 2nd ed. Oxford University Press, New York, NY2012: 17-62
- Vital Statistics 2018.(Available at:)https://www.mhlw.go.jp/toukei/saikin/hw/jinkou/geppo/nengai18/index.htmlDate accessed: June 1, 2019
- Aging and the elapse of time: A comment on the analysis of change.J Gerontol B Psychol Sci Soc Sci. 2007; 62: S198-S202
- Association of trajectories of higher-level functional capacity with mortality and medical and long-term care costs among community-dwelling older Japanese.J Gerontol A Biol Sci Med Sci. 2019; 74: 211-218
Article info
Publication history
Published online: April 18, 2020
Footnotes
Funding: This work was supported by the National Institute on Aging (R01 AG031109, P60 AG024824) at the National Institutes of Health and by JSPS KAKENHI (17H01555 and 23243062).
The authors declare no conflicts of interest.
Identification
Copyright
© 2020 Published by Elsevier Inc. on behalf of AMDA - The Society for Post-Acute and Long-Term Care Medicine.
