Estimating the rates of dementia using administrative data linked to cohort studies.

Background: Current estimates of dementia and Alzheimer's disease incidence and prevalence are required to understand the health needs of the elderly.

Objective: We used two Australia cohort studies, administrative datasets, and data linkage techniques to estimate dementia rates in Australia.

Methods: The study used Australian Longitudinal Study on Women's Health and the Health in Men Cohort Study. Records of dementia were obtained from linked sources and incidence and prevalence estimates were produced. Capture-recapture methods were used to estimate numbers of dementia cases not identified through data linkage.

Results: There were 3399 (28.5%) men with dementia identified from any source and 3767 (34.8%) women. Rates of dementia incidence and prevalence were similar between sexes but were raised in men once estimates of unidentified cases were included.

Conclusions: Cohort studies and linked administrative data can be used together to produce current estimates of dementia prevalence and incidence comparable to other population estimates.