Self-rated health and incident dementia over two decades: Replication across two cohorts

This prospective study examined the association between self-rated health and incident dementia in two large cohorts of middle-aged and older adults. Participants were drawn from the Health and Retirement Study (HRS, N = 13,839, Mean Age = 64.32, SD = 9.04) and the English Longitudinal Study of Ageing (ELSA, N = 4649, Mean Age = 64.44, SD = 9.97). Self-rated health and covariates were assessed at baseline in 1998 and 2002, and cognitive status was tracked for up to 21 years in HRS and 17 years in ELSA, respectively. Controlling for demographic factors, poorer self-rated health was associated with higher risk of incident dementia in HRS (HR: 1.18, 95%CI: 1.12-1.24, p < .001) and ELSA (HR: 1.38, 95%CI: 1.23-1.55, p < .001). These associations remained significant when diabetes, hypertension, smoking, physical inactivity, depressive symptoms, personality, and polygenic risk for Alzheimer's Disease were included as additional covariates or when cases occurring within the first ten years of follow-up were excluded from the analyses. There was no replicable evidence that age, sex, education, race or ethnicity moderated the association. Self-rated health is a long-term, replicable predictor of incident dementia that is independent of genetic, clinical, and behavioral risk factors.