Incidence of dementia in a Brazilian population: The Tremembé Epidemiologic Study.

Introduction: Few dementia incidence studies have been performed in Latin America. We aimed to provide the incidence of dementia in a Brazilian community-dwelling elderly population.

Methods: This study was conducted in urban and rural areas of Tremembé. The 520 participants without dementia at baseline were invited to participate in the follow-up.

Results: After a median follow-up of 5 years, the incidence rate of dementia was 26.1 per 1000 person-years (PY) (95% confidence interval  = 18.7-36.6/1000PY). This rate increased exponentially with age (8.3/1000PY for 60- to 64-year-olds to 110.2/1000PY for ≥80-year-olds) and lower education (10.5/1000PY for > 8 years of education to 59.2/1000PY for illiterates). Higher dementia risk was found among individuals with cognitive impairment no dementia at baseline.

Discussion: The dementia incidence rate found was higher than in other countries in people under 65 years. Higher incidence in younger individuals is expected in developing countries probably due to low education and a high burden of cardiovascular diseases.