January 10, 2005
Unexpected weight loss in elderly men and women may be an early harbinger of Alzheimer's disease, a new study reports. The weight loss may develop several years before the memory begins to fade, and well before most cases of Alzheimer's are even diagnosed. Nevertheless, many elderly people who lose weight do not go on to develop Alzheimer's disease.
Researchers at the Institute of Psychiatry in London tracked the long-term progress of 1,890 men, aged 77 to 98, who were enrolled in The Honolulu-Asia Aging Study. Japanese-American men enrolled in the study were examined on six occasions over a period of up to 34 years. Weight was measured at each examination, and memory tests were given at the three most recent doctor visits. During the course of the study, 112 men were recently diagnosed with Alzheimer's disease or other forms of dementia.
On average, men who developed Alzheimer's or other forms of dementia did not weigh any more or less during middle age than those who did not develop the disease. However, in the six years prior to their diagnosis, men who developed dementia tended to lose more weight compared with mentally intact men. Weight loss accelerated during the final three years before diagnosis. A high proportion of the men with dementia lost about 11 pounds, which was close to 10 percent of the average body weight for this group.
Weight loss is a common problem in the elderly and may be due to many factors, including general frailty, physical illness, depression, and the side effects of medications. It has long been observed that people with Alzheimer's tend to be thinner than their healthy peers, and as the disease progresses, weight loss can become dramatic. Poor appetite, disorientation, problems with vision and perception, and an inability to feed oneself or remember to eat can all contribute to poor nutrition in those with the disease.
Close Monitoring Needed
This current study, published in the Archives of Neurology, reveals that weight loss may begin years before memory lapses and other clear symptoms of Alzheimer's arise. Before Alzheimer's disease is diagnosed, it is often preceded by a period of more subtle memory loss, a condition known as mild cognitive impairment, or MCI. Defects in the brain and thinking may contribute to appetite defects and poor meal planning in those with MCI. Recent studies suggest that people with memory problems are also more likely to become irritable, anxious, depressed, or apathetic, which could also affect appetite and meal preparation. Many other factors likely play a role in the eating and nutritional problems among people with Alzheimer's disease.
The investigators in the current study note that any changes in weight or nutritional status should be carefully monitored and assessed in the elderly. Weight changes may have serious consequences for those suffering from Alzheimer's disease. Poor nutrition and frailty, for example, often lead to falls (and consequent broken bones), slow healing of wounds, and increased physical dependence during the later stages of the illness.
The symptoms of Alzheimer's disease, even during its early stages, may be made worse when an individual does not receive adequate nourishment. In addition to careful monitoring, some simple caregiving measures may help. For example, researchers report that using brightly colored tableware may make it easier for those with advanced Alzheimer's disease to see the food and beverages in front of them, leading them to eat and drink more at mealtimes. [See the article "Brighten Mealtimes to Enhance Alzheimer's Care."]
"This article provides evidence that men who develop dementia tend to start losing weight at least several years prior to their clinical diagnoses," writes public health expert Michael Grundman, M.D., M.P.H., in an editorial accompanying the study. He points out that various genes and lifestyle factors likely play a role in who develops Alzheimer's, and that providing extra food or nutrients to susceptible seniors is not likely to have a big impact on preventing the disease or slowing cognitive decline. "Nevertheless," he continues, "even modest effects could have large public health implications." He calls for more rigorous study to examine the potential effects of good nutrition on the course of the illness.
Robert Stewart, Kamal Masaki, Qian-Li Xue, et al: "A 32-Year Prospective Study of Change in Body Weight and Incident Dementia: The Honolulu-Asia Aging Study." Archives of Neurology, January 2005; Volume 62: pages 55 -- 60
Michael Grundman, "Weight Loss in the Elderly May Be a Sign of Impending Dementia" (editorial). Archives of Neurology, January 2005; Volume 62, pages 20 -- 22.