Aug. 20, 2007 -- Weight loss among middle-aged and older women may be an early warning sign of dementia.
Researchers found that middle-aged women who went on to develop dementia started losing weight up to 20 years before the disease was diagnosed and weighed about 12 pounds less than those without the disease by the time of diagnosis.
"One explanation for the weight loss is that, in the very early stages of dementia, people develop apathy, a loss of initiative, and also losses in the sense of smell," says researcher David Knopman, MD, of the Mayo Clinic in Rochester, Minn., in a news release. "When you can't smell your food, it won't have much taste, and you might be less inclined to eat it. And, apathy and loss of initiative may make women less likely to prepare nutritious meals and more likely to skip meals altogether."
Researchers say the results contradict previous studies that have suggested that obesity in middle age may raise the risk of dementia. Obesity is also associated with diabetes, hypertension, and heart disease, which are known risk factors for dementia.
Weight Loss May Signal Dementia
In the study, researchers reviewed the medical records for 30 or more years of people diagnosed with dementia in Rochester, Minn., from 1990 to 1994 and a group of healthy people matched for sex and age.
The results, published in Neurology, showed that there were no differences in weight between those diagnosed with dementia and the others 20 to 30 years before the memory-robbing disease was detected. But women with dementia weighed less than the healthy people 11 to 20 years before the disease emerged -- and those weight differences grew over time.
In fact, researchers found an increasing risk of dementia with decreasing weight in women for up to 10 years before dementia was diagnosed.
However, men who later developed dementia did not lose weight in the years prior to diagnosis, which researchers attribute to hormonal or social reasons.
"Middle-aged and elderly men are less likely to be preparing their own meals," Knopman says. "Their spouses or adult children were more likely making meals for them, which would lessen the effect of the apathy, loss of initiative, and loss of sense of smell."