Marital status and risk of Alzheimer’s disease

OBJECTIVE: To analyze the relationship between marital status and risk of AD or dementia. METHODS: This study was carried out from the Personnes Agées QUID (PAQUID) cohort, an epidemiologic study on normal and pathologic aging after age 65 years. The PAQUID cohort began in 1988. Individuals were followed up at 1, 3, and 5 years, with an active detection of dementia. Marital status was divided into four categories: widowed, never married, divorced or separated, and the reference category, married or cohabitant. The longitudinal relationship between marital status and risk of incident AD or dementia was analyzed by a Cox model with delayed entry. RESULTS: Among the 3,675 individuals initially not demented, 2,106 were married or cohabitants, 1,287 were widowers, 179 were never married, and 103 were divorced or separated. Among the 2,881 individuals reevaluated at least once for the risk of dementia during the 5-year follow-up, 190 incident cases of dementia were identified, including 140 with AD. The relative risks (RRs) of dementia (RR = 1.91, p = 0.018) and of AD (RR = 2.68, p<0.001) were increased for the never-married individuals compared with those who were married or cohabitants. This excess of risk was specifically associated with AD. Adjustment for other risk factors of dementia (education, wine consumption), or for factors reflecting social environment, leisure activities, and depression, did not modify the risk of AD for never-married individuals (RR = 2.31, p = 0.02). CONCLUSIONS: We confirmed an association between marital status and AD, with an excess risk observed among never-married individuals. This association may provide clues about the pathogenesis of AD.