Weight loss may be an early sign of dementia

Dementia-associated weight loss begins before the onset of the definite dementia symptoms and accelerates by the time of the diagnosis, according to a study in the January issue of Archives of Neurology.

Weight loss in old age is common and may be related to various diseases, according to background information in the article. “It has long been observed that weight loss is common in Alzheimer disease (AD), but this has been documented in people who already have dementia.”

Robert Stewart, M.D., From the Institute of Psychiatry, London, and colleagues analyzed data from 1,890 men (aged 77-98 years) who were participants in The Honolulu-Asia Aging Study. This population-based study of Japanese American men included 112 men with incident [new onset] dementia and 1,778 without dementia. The study participants were examined on six occasions over a period of up to 34 years. Weight was measured at each examination and dementia was ascertained at the three most recent examinations.

“Incident dementia was associated with significant previous weight loss, which was independent of a large number of potential confounding factors,” the researchers found. “A high proportion of men with dementia at examination 6 had lost at least 5 kg [about 11 pounds], which approaches 10 percent of average body weight for this cohort. This weight loss occurred in many cases over the two to four years prior to reaching the clinical threshold of dementia. The association was similar in AD and vascular dementia.”

In conclusion the authors write: “An important consideration arising from research in this area is the extent to which weight loss may be prevented or minimized in dementia. Poor nutrition and frailty frequently complicate later stages of dementia, causing falls, poor wound healing, and increased physical dependence. … The results presented here suggest that weight change and nutritional state in people with dementia should be taken seriously at least from the time of diagnosis if not at earlier stages of more mild cognitive impairment.”

In an accompanying editorial, Michael Grundman, M.D., M.P.H., from Elan Pharmaceuticals, San Diego, Calif., writes: “The article by Stewart et al in this issue of Archives of Neurology provide evidence that men who develop dementia (both AD and vascular dementia) tend to start losing weight at least several years prior to their clinical diagnoses.”

“Since it is already known that specific risk factors and genes are implicated in some patients who develop AD and other susceptibility genes are likely to be discovered, it may be too optimistic to suppose that nutritional approaches will necessarily have a huge impact on preventing AD or slowing cognitive decline. Nevertheless, even modest effects could have large public health implications. The degree to which treatment interventions directed toward maintaining optimal nutrition and preventing excess weight loss could slow the disease course requires more rigorous study.”