Turns out there’s more to worry about middle age spread
other than creeping numbers on the scale: A recent article in Molecular Psychiatry says that those who
pack on the pounds in middle age face a higher risk of earlier onset and
greater severity of Alzheimer’s disease.
Obesity and Alzheimer’s disease have reached epidemic
proportions. In 2014, about 13 percent and 39 percent of the world’s adult
population were obese and overweight, respectively, according to the World
Health Organization. About 46 million people worldwide currently suffer from
Alzheimer’s disease—a number that is projected to double in the next 20 years,
according to the recently published “World Alzheimer’s Report” by Alzheimer’s
Disease International.
Although previous studies have hinted at a link between
midlife obesity and increased risk for Alzheimer’s, the current study delves
further into how midlife obesity impacts the age of onset.
The study authors searched through records from the
Baltimore Longitudinal Study of Aging, one of the largest and longest-running
ongoing studies of aging in the United States, as well as autopsy data. They
found that study participants who were overweight or obese in midlife developed
Alzheimer’s an average of 6.7 months earlier than those of a healthy weight.
Additionally those with a high body mass index (BMI, a
common medical term that describes the ratio of a person’s weight to height; a
BMI greater than 25 is considered overweight, while one greater than 30 is
considered obese) and the disease had greater neurofibrillary tangles and
plaques at autopsy. These hallmarks of the disease also tended to accumulate in
a region of the brain called the precuneus, an area linked to episodic memory,
visuospatial processing, reflections upon self, and aspects of consciousness,
and found to be an early deposit site for these pernicious proteins.
“This study…adds to a substantial body of knowledge of how
obesity affects Alzheimer’s disease,” said primary author Madhav Thambisetty, MD,
at the National Institutes of Aging’s Laboratory of Behavioral Neuroscience in
a video released by the agency. “It indicates that if we can maintain a healthy
body mass even as early as midlife, it may have long-lasting effects toward
delaying Alzheimer’s disease decades later.”
Inexpensive, noninvasive interventions such as diet and
exercise, Thambisetty and his group suggest in their paper, could
“substantially alter the trajectory of Alzheimer’s disease, reducing its global
public health and economic impact.”
Larger studies are needed to see if the opposite is
true—that keeping fit and trim at 50 will stall Alzheimer’s development. But a
closer eye on the scale certainly wouldn’t do any harm.
Jackie Oberst is Provider’s managing editor. Email
her at joberst@providermagazine.com. Follow the magazine on Twitter
@ProviderMag and @ProviderMyers.