Factors associated with reduced survival were investigated in elderly people diagnosed as having Alzheimer's disease (AD) and in those free of dementia at diagnosis. The study population comprised 155 people free of dementia and 222 with AD; all were aged 75 years and over and were part of a two-stage prevalence study of dementia during 1988 in Melton Mowbray, Leicestershire. An increased risk of death was found for those with a history of heavy alcohol use, lower cognitive function, a history of heart failure and those in institutional care, these factors acting in the same manner for persons free of dementia and those with AD. For the non-demented group a greater risk of death was found with increasing age and for those with a history of cancer. A greater risk of death was found for males with AD compared to females with the risk increasing over time. The longer survival of women over men may explain the sex differences found in the prevalence of AD without accompanying differences in incidence.