Vehicle exhaust level at home and incidence of diagnosed dementia

Background Vehicle exhaust has proven to be a risk factor for several chronic diseases. Recent years a few studies have suggested an association also between ambient air pollutants and mental decline. Aims We investigate traffic related air pollution and dementia diagnosis in a detailed longitudinal study, Betula, in Umea, Sweden. Metods At the first data collection in Betula 1988-90, 1000 participants from ten age cohorts (35-80 yrs) were included. In the first 5-yr follow-up, 1993-95, two new samples were added; one with the same age distribution as the first sample had at inclusion, and one with persons born the same year as in the first sample. Information on deaths is matched from the cause of death register. The social variables of Betula include socio-economic variables, marital status, type of dwelling, living conditions, education, leisure activities, current daily activities, smoking, occupation, children, parents, childhood and adolescence, as well as availablity of friends. We used a high reso...