Socioeconomic disparities in six-year incident dementia in a nationally representative cohort of U.S. older adults: an examination of financial resources

BACKGROUND: Less educational training is consistently associated with incident dementia among older adults, but associations between income and financial strain with incident dementia have not been well tested in national samples. This is an important gap because, like education, financial resources are potentially modifiable by policy change and strengthening the social safety net. This study tested whether financial resources (income and financial strain) predict six-year incident dementia independent of education and occupation. METHODS: The National Health and Aging Trends Study is a prospective cohort study that recruited a nationally representative sample of U.S. Medicare beneficiaries aged ≥65 years. Incident dementia (2013 to 2018) was classified based on diagnosis, cognitive test scores or proxy-reported changes among participants dementia-free in 2012 (n = 3785). Baseline socioeconomic measures included income to poverty ratio (analyzed separately for those < 500% vs. ≥500% poverty threshold), financial strain, education and history of professional occupation. Discrete time survival analysis applied survey weights to account for study design and nonresponse. Coefficients were standardized to compare the strength of associations across the four socioeconomic measures. RESULTS: Adjusting for socioeconomic measures, demographic characteristics, home ownership, retirement, chronic conditions, smoking, BMI and depressive symptoms, higher income (hazard OR = 0.84, 95% CI: 0.74, 0.95 among those < 500% poverty) and higher education (hOR = 0.73, 95% CI: 0.65, 0.83) were associated with lower odds, and financial strain with higher odds (hOR = 1.20, 95% CI: 1.09, 1.31), of incident dementia. CONCLUSION: Low income and greater financial strain predict incident dementia among older adults and associations are comparable to those of low education among U.S. older adults. Interventions to mitigate financial strain through improving access to economic opportunity and strengthening safety net programs and improving access to them in low income groups may complement other ongoing efforts to prevent dementia.