A study of elderly volunteers has revealed that their average rate of weight loss doubles in the year before symptoms of Alzheimer's-type dementia first become detectable. The surprising finding may be useful in detecting and treat Alzheimer's before it can cause irreversible brain damage. A link between weight loss and dementia was identified nearly a decade ago, but it wasn't until this new study that the effect was quantified. The new study, appearing in the Archives of Neurology, found that one year before the onset of dementia, the rate of weight loss in the volunteer subjects doubled from 0.6 pounds per year to 1.2 pounds per year. "A person's weight can vary substantially in a given year, so weight loss alone can't serve as a definite indicator for physicians," said researcher David K. Johnson. "But it's interesting from a biochemical perspective - we don't know why these two phenomena are linked."
The researchers, from the Washington University School of Medicine in St. Louis, based the study on participants who were all cognitively normal at the beginning of the study, but where one-quarter were eventually diagnosed with mild dementia. "Interestingly, the group of volunteers who did become demented started the study weighing about eight pounds less on average than the patients who did not develop dementia," Johnson said. "The two groups lost weight at the same rate for four to five years, and then one year before the detection of even the mildest cognitive symptoms, weight loss increased in the group that would eventually be diagnosed with mild dementia."
The study didn't establish why the group that developed dementia began the study at a lower average weight. Johnson speculates that a process somehow related to Alzheimer's might have become active earlier in the participants' lives and started to drive their weight down. "Sometime between the last evaluation when they were healthy and this first evaluation when they had mild dementia, a metabolic process kicked in, or kicked into higher gear, and made their Alzheimer's detectable. And [an] increased weight loss went hand-in-hand with that change," he concluded.
Source: Washington University School of Medicine
