Unexplained late-life weight loss may be early predictor of Alzheimer's disease

New findings show unexplained weight loss that precedes dementia by more than 10 years is associated with the severity of Alzheimer changes in the brain.

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 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.