Data collected as part of the Canadian Study of Health and Aging were analyzed to determine whether physiological changes associated with Alzheimer's disease are common to other types of dementia and are related more to the severity of cognitive impairment. We found that blood pressure and body mass index decreased with increasing dementia severity in both probable Alzheimer's disease and vascular dementia. There were no differences in mean random blood glucose levels or serum osmolarities between types or stages of dementia. We conclude that certain 'hypometabolic' features are associated with dementia severity and are not unique to Alzheimer's disease.