Weight loss precedes Alzheimer’s diagnosis in women

By Anthony J. Brown, MD

NEW YORK (Reuters Health) – 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.