Weight loss precedes dementia in community-dwelling older adults

To determine whether the weight loss associated with Alzheimer's disease precedes or follows the dementia.

Older community-dwelling men (n = 134) and women (n = 165) were followed for 20 years before they were diagnosed as cognitively intact or demented. A repeated measures analysis was used to compare weight change in those who developed Alzheimer's Disease (AD) with those who remained cognitively intact.

Weight was measured at three clinic visits between 1972-74, 1984-87, and 1990-93. Participants were classified as having probable or possible AD or being cognitively intact at the 1990-93 evaluation. Diagnoses were made by two neurologists and a neuropsychometrist, based on neuropsychological tests and physical examination, using NINCDS-ADRDA criteria.

There were 36 men and 24 women diagnosed with probable or possible AD; they were considered to have mild to moderate dementia based on their test scores and community-dwelling status. Those who developed dementia were older than those diagnosed as cognitively intact. In age-adjusted analyses, both men and women who were later diagnosed with AD had a significant decrease in weight after the baseline visit (P < .001 and P < .003, respectively), but there was no significant weight loss in the men and women who remained cognitively intact. These differences were not explained by lifestyle, depression, or other illness.

Weight loss precedes mild to moderate dementia; early weight loss is, therefore, unlikely to be a consequence of AD patients being unable or unwilling to eat.