Self-rated health and risk of incident dementia: a community-based elderly cohort, the 3C study.

OBJECTIVES: We examined the relationship between self-rated health and incident dementia, and investigated the impact of cognitive complaints, depressive symptoms, and functional status on this relationship.
METHODS: Participants of the 3C Study, a prospective cohort study composed of 8,169 community-dwelling persons aged ≥65 years, were asked to rate their health at the baseline examination in 1999-2001. They were followed for a median of 6.7 years during which dementia was screened and diagnosed. Hazard ratios (HR) of dementia according to baseline self-rated health (good, fair, or poor) were estimated with a Cox model adjusted for potential confounders.
RESULTS: During the 46,990 person-years of follow-up, 618 participants developed dementia. Risk of dementia was increased in participants with poor (adjusted HR 1.70, 95% confidence interval [CI] 1.22-2.37) or fair (adjusted HR 1.34, 95% CI 1.13-1.59) self-rated health compared to those with good self-rated health. Poor self-rated health was associated with both AD (1.48, 1.00-2.24) and vascular dementia (3.38, 1.25-9.17). Self-rated health was a stronger predictor of dementia in participants without cognitive complaints (risk of dementia in subjects without cognitive complaints rating their health as poor: 1.96 [1.24-3.09], p = 0.004) and in those without functional disability.
CONCLUSIONS: Participants rating their health as poor or fair at baseline were at increased risk of incident dementia during follow-up. Self-rated health could help raise awareness of medical doctors about a patient's risk of dementia, especially in those without conditions indicative of potential cognitive impairment.