Prevalence of Cognitive Impairment Without Dementia and Dementia in Tremembé, Brazil.

BACKGROUND: The prevalence of cognitive impairment is insufficiently determined in developing countries. The aim of this study was to ascertain the prevalence of cognitive impairment without dementia and dementia in community-dwelling elderly in Brazil. METHODS: This was a single-phase cross-sectional survey of the elderly (aged 60 years and above) living in the municipality of Tremembé, Brazil. Twenty percent of the households with elderly persons were randomly selected from urban and rural areas, to obtain a homogenous representation of all socioeconomic and cultural levels. RESULTS: We assessed 630 individuals [mean age, 71.3 y (±7.99); mean years of education, 4.9 (±4.54)] and found prevalence rates of 17.5% (95% confidence interval, 14.6-20.6) for dementia and 19.5% (95% confidence interval, 16.6-22.8) for cognitive impairment without dementia. These prevalence rates were influenced by age (P<0.001) and by educational level (P<0.001). There was no significant sex difference among diagnostic groups (P=0.166). The prevalence of dementia was higher in relatively younger individuals (below 70 y) when compared with other studies. Besides, dementia was associated with low socioeconomic status, stroke, previous psychiatric disorder, alcoholism, and epilepsy. CONCLUSIONS: The prevalence of dementia in this study was higher than in other studies, particularly among younger elderly.