Older people with unexplained weight loss may be an early sign of Alzheimer's disease, a recent study shows.

A study of more than 800 healthy nuns, priests and monks who were slightly overweight on average showed that those who lost about one unit of body mass index (BMI) a year -- a little more than five pounds (2 kg) or so -- had a 35 percent greater risk of developing Alzheimer's than those with no weight change.

Writing in the Sept. 27 issue of journal Neurology, Dr. Aron Buchman and colleagues at Rush University Medical Center in Chicago said they used information from an ongoing study of Catholic volunteers who undergo extensive health exams and who keep careful diaries.

"The most likely explanation is that there is something about these individuals or about this disease that affects body mass index before the clinical syndrome becomes apparent -- that loss of BMI reflects the disease process itself," study co-author Dr. David A. Bennett said in a prepared statement.

At the start of the study, none of the volunteers had dementia and their average BMI was 27 (for reference, overweight begins at a BMI of 25 or above, while obesity starts at 30).

During the follow-up period, 151 of the volunteers (18.4 percent) developed Alzheimer's disease.

"These findings suggest that subtle, unexplained body mass and weight loss in an older person may be an early sign of AD and can precede the development of obvious memory problems," said Dr. David Bennett.

Identifying Alzheimer's early will become more important, said Sam Gandy, a spokesman for the Alzheimer's Association. He believes that experimental drugs might soon be available to slow down the disease.

Such drugs do not yet exist, but Gandy said at-risk seniors should take charge of their affairs now before any sign of possible dementia takes hold.

Source: Xinhua/agencies