Regional differences in mortality from dementia in Australia: an analysis of death certificate data.

Australian death certificate data were analysed to determine whether they can provide useful information on regional differences in the prevalence of dementia. Strong differences between the Australian states were found in the prevalence of dementing disorders at death. However, evidence indicated that death certification practices influenced the prevalence rates found: a) the reported prevalence of various dementing disorders at death has changed greatly over quite a short period; b) the prevalence of dementing disorders at death was more strongly influenced by place of death than by place of birth; and c) the differences between states were a result of very high rates in particular regions which, in one case, could be traced to the death certification practices of a single medical practitioner. It is concluded that death certificate data are not useful for investigating regional differences in the prevalence of dementia.