Rapid Weight Loss in Seniors Signals Higher Dementia Risk

ByABC News
May 19, 2009, 2:52 PM

May 20 -- TUESDAY, May 19 (HealthDay News) -- Losing weight rapidly late in life seems to signal a greater risk of experiencing some form of dementia, new research suggests.

For older adults, "basically, we saw that if you are thinner or are losing weight at a faster rate, then you are at a higher risk of developing dementia," said study author Tiffany F. Hughes, a postdoctoral fellow in the department of psychiatry at the University of Pittsburgh School of Medicine.

"This is in contrast to other studies that have shown higher BMI in middle age to increase risk of dementia," she acknowledged. "What is likely going on is that higher BMI in middle age is a true risk factor for dementia, while being thinner or losing weight more quickly in old age is a result of dementia that has not been detected yet."

Hughes, who conducted her research while a doctoral student at University of South Florida, published the findings in the May 19 issue of Neurology.

To assess the association, the study authors focused on a group of just over 1,800 Japanese Americans living in Washington state.

At the launch of the study in 1992, the participants were about 72 years old, on average, at which point all were free of dementia.

Over a period of eight years, Hughes and her colleagues tracked changes in body mass index (BMI), waist circumference and waist-to-hip ratio among the members of the study group, and then lined up those statistics against diagnoses of various forms of dementia, including Alzheimer's disease.

The team found that regardless of smoking history, exercise habits and gender, having a higher BMI late in life actually appeared to be associated with having a lower risk for developing Alzheimer's.

Looked at in reverse, the study authors observed that those participants who had a lower BMI at the study's launch actually faced a 79 percent greater risk for developing dementia.

In addition, participants of any weight who went on to lose pounds during the study period at a relatively fast rate had a three times higher risk for developing dementia than those who lost weight more slowly.