The Canadian Study of Health and Aging (CSHA) was planned in 1989 as a national longitudinal study to provide accurate statistics on the number of people who have dementia, including Alzheimer's disease, in Canada. The study also covers a range of other health topics. The CSHA involved 10,263 people aged 65 or over, sampled from 36 communities across Canada. Representative samples were drawn from the community and from institutions, and participants were assessed at 5-yearly intervals: in 1991, 1996, and for a final time in 2001. The objectives initially focused on the epidemiology of dementia, and the study has provided estimates of prevalence, incidence and risk factors for dementia, and the burden it places on family caregivers. The CSHA has also described patterns of disability, frailty and healthy aging, and has recorded utilization of health services for different diagnostic groups.