Unexplained Late-life Weight Loss May Be Early Predictor Of Alzheimer's Disease

Using data from the Nun Study, a prospective study of the causes of dementia in Catholic sisters, University of South Florida researcher James Mortimer, PhD, reported today that the most likely cause of the unexplained weight loss is the severity of the Alzheimer changes in the brain rather than an eating disorder or other condition associated with declining cognition. Dr. Mortimer presented the findings at the Alzheimer's Association International Conference on the Prevention of Dementia in Washington, DC.

Although a previous study showed that individuals with lower weight for their height at the time of death had more Alzheimer brain changes at autopsy, this is the first study to show that lower weight up to 10 years earlier is specifically related to the severity of the disease.

"While weight one year or less prior to death was related to the amount of cognitive decline, this association could be explained by the severity of the Alzheimer process in the brain seen at autopsy," said Dr. Mortimer, professor of epidemiology at the USF College of Public Health.

"Given its very long duration prior to onset of dementia, it is likely that weight loss is specifically associated with the Alzheimer disease process and not to a restriction in food intake due to cognitive decline," he said. "There is considerable evidence that Alzheimer changes in the brain precede the first symptoms of this illness by decades."

Unexplained weight loss late in life, when coupled with other biomarkers, may help to identify those at risk of Alzheimer's disease more than a decade in the future. Identification of individuals who are at high risk of Alzheimer's long before cognitive decline becomes evident will be critical to its prevention once agents become available to slow the disease, Dr. Mortimer said.

The Nun Study, begun in 1992, is a study of 678 Catholic sisters, initially 75 to 102 years of age, who are evaluated yearly and who agreed to brain donation at the time of death. The Nun Study is directed by Dr. David Snowdon of the University of Kentucky. Dr. Snowdon is a co-author of the presentation as is Dr. William Markesbery, director of the Sanders-Brown Center on Aging at the University of Kentucky. Dr. Yougui Wu, the third coauthor, is an assistant professor of epidemiology and biostatistics at the USF College of Public Health

The Nun Study is funded by a grant from the National Institute on Aging.