Women destined to be diagnosed with Alzheimer's disease often show a reduction in body weight many years before symptom onset, new research shows. However, men who develop this neurologic disorder do not show any weight changes.
"Ten years before patients developed the expected symptoms of Alzheimer's disease, their weights were subtly dropping — a finding that has been seen in other studies. Our twist was that this was only observed in women, not men," lead author Dr. David Knopman, from the Mayo Clinic in Rochester, Minnesota, told Reuters Health.
The findings, which Knopman presented Sunday at the Alzheimer's Association International Conference on Alzheimer's Disease and Related Disorders in Madrid, are from a study of people living in Olmsted County, Minnesota, who were followed for up to 30 years. The researchers focused on 560 patients who developed Alzheimer's disease and a similar number of patients of the same age and sex without dementia.
Thirty years before dementia onset, the women diagnosed with Alzheimer's and the comparison group weighed roughly the same, 140 pounds on average. For those who remained dementia-free, weight remained relatively stable over the next three decades, whereas in Alzheimer's patients, the average weight fell to 136 pounds 10 years before diagnosis, and to 128 pounds when symptoms began.
As noted, no weight loss trends were observed among the men who developed Alzheimer's disease.
Knopman offers three possible explanations for these observations. First, "early Alzheimer's disease is associated with apathy and this could mean that affected patients are less likely to cook and eat." Second, the early brain changes may affect taste centers, making food less palatable and thereby decrease appetite. Third, early disease may have an effect on the satiety centers in the brain.
Exactly why men do not show similar changes in weight before disease onset is unclear, but may relate to changes in hormone levels with age, Knopman suggested.
Dr. Knopman added that his team is now conducting another study to identify other predictors of Alzheimer's disease.
