To quantify the dose-response associations between tooth loss and risk of cognitive impairment and dementia.
Longitudinal studies that examined the association between tooth loss and cognitive function were systematically searched on 6 databases through March 1, 2020. The study adhered to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines. Risk estimates were pooled using random-effects models. The dose-response associations were assessed using generalized least squares spline models.
Setting and Participants
Adults from community, institution, outpatient or in-hospital were included in the meta-analysis.
Cognitive impairment and dementia were defined by neuropsychological tests, diagnostic criteria, or medical records. Tooth loss was self-reported or assessed by clinical examinations.
Fourteen studies were entered into the meta-analysis, including 34,074 participants and 4689 cases with diminished cognitive function. Participants with more tooth loss had a 1.48 times higher risk of developing cognitive impairment [95% confidence interval (CI) 1.18–1.87] and 1.28 times higher risk of being diagnosed with dementia (95% CI 1.09–1.49); however, the association was nonsignificant for participants using dentures (relative risk = 1.10, 95% CI 0.90–1.11). Eight studies were included in the dose-response analysis, and data supported the use of linear models. Each additional tooth loss was associated with a 0.014 increased relative risk of cognitive impairment and 0.011 elevated relative risks of dementia. Edentulous participants faced a 1.54 times higher risk of cognitive impairment and a 1.40 times higher risk of being diagnosed with dementia.
Conclusions and Implications
Moderate-quality evidence suggested tooth loss was independently associated with cognitive impairment and dementia; risk of diminished cognitive function increased with incremental numbers of teeth lost. Furthermore, timely prosthodontic treatment with dentures may reduce the progression of cognitive decline related to tooth loss.
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- Estimating the global mortality from Alzheimer’s disease and other dementias: A new method and results from the Global Burden of Disease study 2019: Epidemiology/prevalence, incidence, and outcomes of MCI and dementia.Alzheimers Dement. 2020; 16: e042236
- Racial and ethnic estimates of Alzheimer’s disease and related dementias in the United States (2015–2060) in adults aged ≥65 years.Alzheimers Dement. 2019; 15: 17-24
- Potentially modifiable risk factors for dementia in identical twins.Alzheimers Dement. 2006; 2: 110-117
- Mild cognitive impairment as a clinical entity and treatment target.Arch Neurol. 2005; 62: 1160
- Mild cognitive impairment: Conceptual, assessment, ethical, and social issues.Clin Interv Aging. 2008; 3: 413-420
- Burden of oral disease among older adults and implications for public health priorities.Am J Public Health. 2012; 102: 411-418
- Oral hygiene and oral health in older people with dementia: A comprehensive review with focus on oral soft tissues.Clin Oral Investig. 2018; 22: 93-108
- Twenty-year trends in dependency in residential aged care in Auckland, New Zealand: A descriptive study.J Am Med Dir Assoc. 2011; 12: 535-540
- Tooth loss increases the risk of diminished cognitive function: A systematic review and meta-analysis.JDR Clin Transl Res. 2016; 1: 10-19
- Evidence summary: The relationship between oral health and dementia.Br Dent J. 2017; 223: 846-853
- Tooth loss as a risk factor for dementia: Systematic review and meta-analysis of 21 observational studies.BMC Psychiatry. 2018; 18: 345
- Association between residual teeth number in later life and incidence of dementia: A systematic review and meta-analysis.BMC Geriatr. 2018; 18: 48
- Association between tooth loss and dementia among older people: A meta-analysis: Association between tooth loss and dementia among older people.Int J Geriatr Psychiatry. 2016; 31: 953-955
- Periodontal disease, tooth loss and dementia: Is there a link? A systematic review.Gerodontology. 2017; 34: 151-163
- Association between oral health and cognitive status: A systematic review.J Am Geriatr Soc. 2016; 64: 739-751
- Tooth loss is associated with increased risk of dementia and with a dose-response relationship.Front Aging Neurosci. 2018; 10: 415
- Tooth loss is associated with accelerated cognitive decline and volumetric brain differences: A population-based study.Neurobiol Aging. 2018; 67: 23-30
- Influence of lack of posterior occlusal support on cognitive decline among 80-year-old Japanese people in a 3-year prospective study: Influence of occlusion on cognition.Geriatr Gerontol Int. 2018; 18: 1439-1446
- Association between tooth loss and cognitive impairment in community-dwelling older Japanese adults: A 4-year prospective cohort study from the Ohasama study.BMC Oral Health. 2018; 18: 142
- Preferred reporting items for systematic reviews and meta-analyses: The PRISMA Statement.PLoS Med. 2009; 6: e1000097
- Critical evaluation of the Newcastle-Ottawa Scale for the assessment of the quality of non-randomized studies in meta-analyses.Eur J Epidemiol. 2010; 25: 603-605
- GRADE: An emerging consensus on rating quality of evidence and strength of recommendations.BMJ. 2008; 336: 924-926
- Cochrane Handbook for Systematic Reviews of Interventions. 2nd. John Wiley & Sons, Chichester (UK)2019
- Methods for trend estimation from summarized dose-response data, with applications to meta-analysis.Am J Epidemiol. 1992; 135: 1301-1309
- Regression models in clinical studies: Determining relationships between predictors and response.J Natl Cancer Inst. 1988; 80: 1198-1202
- Oral health condition of French elderly and risk of dementia: A longitudinal cohort study: Elderly’s oral health and risk of dementia.Community Dent Oral Epidemiol. 2012; 40: 230-238
- Oral disease in relation to future risk of dementia and cognitive decline: Prospective cohort study based on the action in diabetes and vascular disease: Preterax and Diamicron Modified-Release Controlled Evaluation (Advance) Trial.Eur Psychiatry. 2013; 28: 49-52
- Dentition, dental health habits, and dementia: The Leisure World Cohort Study.J Am Geriatr Soc. 2012; 60: 1556-1563
- Association between tooth loss and the development of mild memory impairment in the elderly: The Fujiwara-kyo Study.J Alzheimers Dis. 2015; 44: 777-786
- Influence of dentition status on physical disability, mental impairment, and mortality in institutionalized elderly people.J Dent Res. 2001; 80: 340-345
- Tooth loss, dementia and neuropathology in the Nun Study.J Am Dent Assoc. 2007; 138: 1314-1322
- Associations between oral health and risk of dementia in a 37-year follow-up study: The prospective population study of women in Gothenburg.J Am Geriatr Soc. 2015; 63: 100-105
- Tooth loss and risk of dementia in the community: The Hisayama Study.J Am Geriatr Soc. 2017; 65: e95-e100
- Association between self-reported dental health status and onset of dementia: A 4-year prospective cohort study of older Japanese adults from the Aichi Gerontological Evaluation Study (AGES) Project.Psychosom Med. 2012; 74: 241-248
- Dental health, nutritional status and recent-onset dementia in a Korean community population.Int J Geriatr Psychiatry. 2007; 22: 850-855
- Tooth loss, denture use, and cognitive impairment in Chinese older adults: A community cohort study.J Gerontol A Biol Sci Med Sci. 2021 Mar 1.; ([E-pub ahead of print])
- Rehabilitation of lost teeth related to maintenance of cognitive function.Oral Dis. 2019; 25: 290-299
- Cognitive status of edentate elders wearing complete denture: Does quality of denture matter?.J Dent. 2015; 43: 1071-1075
- Masticatory function and cognitive function.Okajimas Folia Anat Jpn. 2010; 87: 135-140
- Chewing maintains hippocampus-dependent cognitive function.Int J Med Sci. 2015; 12: 502-509
- Hard-diet feeding recovers neurogenesis in the subventricular zone and olfactory functions of mice impaired by soft-diet feeding.PLoS One. 2014; 9: e97309
- Effect of bite-raised condition on the hippocampal cholinergic system of aged SAMP8 mice.Neurosci Lett. 2012; 520: 77-81
- Vitamin D inhibits the expression of interleukin-8 in human periodontal ligament cells stimulated with Porphyromonas gingivalis.Arch Oral Biol. 2013; 58: 397-407
- Vitamin D status and risk of dementia and Alzheimer’s disease: A meta-analysis of dose-response.Nutr Neurosci. 2019; 22: 750-759
- Are Porphyromonas gingivalis outer membrane vesicles microbullets for sporadic Alzheimer’s disease manifestation?.J Alzheimers Dis Rep. 2018; 2: 219-228
- Porphyromonas gingivalis infection induces amyloid-β accumulation in monocytes/macrophages.J Alzheimers Dis. 2019; 72: 479-494
- Porphyromonas gingivalis in Alzheimer’s disease brains: Evidence for disease causation and treatment with small-molecule inhibitors.Sci Adv. 2019; 5: eaau3333
- Tooth loss and periodontal disease predict poor cognitive function in older men: Periodontal disease and cognitive function.J Am Geriatr Soc. 2010; 58: 713-718
- Serum IgG antibody levels to periodontal microbiota are associated with incident Alzheimer disease.PLoS One. 2014; 9: e114959
- Association between periodontitis and Alzheimer′s disease.North Am J Med Sci. 2015; 7: 241
- Mind your teeth—the relationship between mastication and cognition.Gerodontology. 2019; 36: 2-7
- Parental education and late-life dementia in the United States.J Geriatr Psychiatry Neurol. 2009; 22: 71-80
- Tooth loss and dementia: A critical examination.J Dent Res. 2021; 100: 226-231
- Cognitive decline and oral health in middle-aged adults in the ARIC study.J Dent Res. 2013; 92: 795-801
- Cognitive function and oral health among ageing adults.Community Dent Oral Epidemiol. 2019; 47: 259-266
- Longitudinal studies.J Thorac Dis. 2015; 7: E537-E540
- Testing the Newcastle Ottawa Scale showed low reliability between individual reviewers.J Clin Epidemiol. 2013; 66: 982-993
Published online: July 08, 2021
XQ and ZZ contributed equally to this study and shared first authorship.
This study is partially supported by the National Institutes of Health (1R56AG067619 and U01DE027512).
The authors declare no conflicts of interest.
© 2021 AMDA - The Society for Post-Acute and Long-Term Care Medicine.