A Surprising Sign of Dementia

We all know that being obese ratchets up your risk for a number of diseases, including heart disease, some cancers and diabetes, right? You may also know that it may be a contributing factor in the development of dementia. But here's some surprising news about weight. Research published in the journal Neurology, finds that being too thin in later years-especially for those who lose weight rapidly or who had been overweight-may well be an early sign of dementia.

Researchers followed 1,836 Japanese Americans-with an average age of 72-for eight years. During that time, 129 people developed dementia. Those subjects with lower body mass index (BMI) scores at the beginning of the study were 79 percent more likely to develop dementia than those with higher BMI scores.

In addition, those who lost weight over the study period at a faster rate were nearly three times more likely to develop dementia than those who lost weight more slowly over time. This result was more pronounced in those who were overweight or obese to start; subjects with a BMI of 23 or higher had an 82-percent reduced risk of developing the disease compared to those who were normal or underweight. The results were the same after testing for other health risk factors such as smoking, exercise and gender.

"Our finding suggests that losing weight quickly in older age may be an early sign of dementia," said study author Tiffany Hughes, PhD, MPH, who is with the University of Pittsburgh School of Medicine but conducted the research while she was a doctoral student at the University of South Florida. "This doesn't mean that being obese or overweight is healthy for the mind or body, but losing weight may be a sign of emerging brain disease."

Hughes says other current research shows that, in contrast, a larger belly in midlife may be a risk factor for dementia.

"Dementia has been shown to develop in the brain decades before any symptoms develop," Hughes said. "These findings likely reflect that process. In middle age, obesity may be a risk factor for dementia, while declining weight in late life may be considered one of the first changes from the disease that occurs before it actually affects a person's memory."