Objective: To determine whether the weight loss associated with Alzheimer's disease precedes or follows the dementia.
Design: 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.
Measurements: 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.
Results: 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.
Conclusion: 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.