Being overweight may cause yet another health detriment — a deteriorating brain, a University of Miami study found.
The study found those with higher body mass indexes and larger waistlines were more likely to have thinning in the cortex of their brains — a phenomenon that has been linked to Alzheimer’s disease.
“On a public health level, this lends more evidence for the notion that maintaining a healthy weight may preserve brain health later in life,” said Michelle Caunca, a co-author of the study, published Thursday in the online edition of Neurology, the medical journal of the American Academy of Neurology. Caunca is a researcher and medical student with the Miller School’s Department of Neurology and Medical Scientist Training Program.
The thinning was particularly pronounced in people younger than 65, meaning those with greater BMIs and waistlines may be poised to face brain decay and a decrease in learning ability as they age.
The study’s 1,289 participants’ waistlines and BMI were measured at the start of the study, and again six years later.
Those who were overweight — characterized by a body mass index between 25 and 30 — had their brain cortex thin by a rate of 0.098 millimeters. Participants who were obese — with a BMI of 30 and higher — had a 0.207 millimeter thinning rate.
Having a thinner cortex has been tied to an increased risk of Alzheimer’s disease.
For people with a healthy BMI — from 18.5 to 24.9 — the normal cortex thinning rate is between 0.01 and 0.10 per decade.
The normal weight group had an average waist size of 33 inches; the overweight group had an average size of 36 inches, and the obese group had an average of 41 inches.
“Our results would indicate that being overweight or obese may accelerate aging in the brain by at least a decade,” said senior author Tatjana Rundek in a press release.
The researchers controlled for a number of factors often associated with obesity, including hypertension and diabetes, to ensure that the outcome wasn’t skewed.
Of the 1,289 participants in the study, two-thirds were Latino, a group typically underrepresented in medical studies. Participants were pulled from the Northern Manhattan Study, a research study that examines the population of Washington Heights in Manhattan.
Though the researchers discovered a correlation, more research is needed to come closer to discerning causation.
In the meantime, researchers pointed to a positive, that people can retain a level of control over brain degeneration as they age.
“These results are exciting because they raise the possibility that by losing weight, people may be able to stave off aging of their brains and potentially the memory and thinking problems that can come along with brain aging,” Rundek said in the press release.