According to a new study from the American Academy of Neurology (AAN), having a larger BMI in your 60s could be linked to brain aging later in life. Carrying around excess weight at this point in one’s life could also accelerate brain aging by about a decade, the study shows.
“People with bigger waists and higher BMI were more likely to have thinning in the cortex area of the brain, which implies that obesity is associated with reduced gray matter of the brain,” said study author and AAN member Tatjana Rundek, MD, PhD, of the University of Miami Miller School of Medicine. “These associations were especially strong in those who were younger than 65, which adds weight to the theory that having poor health indicators in mid-life may increase the risk for brain aging and problems with memory and thinking skills in later life.”
The study, which involved 1,289 participants averagely aged 64, and two-thirds of whom were Latino, measured participants’ BMI and waist circumference. Then, about six years later, participants underwent MRI brain scans to measure the thickness of the cortex area of the brain, overall brain volume, and other brain-related factors.
The results, published in Neurology, showed that 346 of the participants had a BMI of less than 25, which is considered normal weight; 571 people had a BMI of 25 to 30 (overweight); and 372 people had a BMI of 30 or higher (obese).
When it came to waist circumference, which differs between men and women, the normal weight group, consisting of 54% women, had an average of 33 inches. The overweight group (56% women) had an average of 36 inches, and the obese group (73% women) had an average of 41 inches.
The higher the BMI, the thinner the cortex, even after researchers adjusted their findings for other factors that could affect the thinness of the cortex, like high blood pressure, alcohol use, and smoking. Furthermore, they found that those who were overweight experienced a 0.098 millimeter thinning of the cortex for every unit increase in BMI, and having a thinner cortex has been associated with an increased risk for Alzheimer’s disease.
What’s more is that also having a larger waist was also associated with a thinner cortex after adjusting for other factors.
Rundek noted, that the study does not prove that extra weight causes the cortex to get thinner. It only proves there is an association.
“In normal aging adults, the overall thinning rate of the cortical mantle is between 0.01 and 0.10 mm per decade, and our results would indicate that being overweight or obese may accelerate aging in the brain by at least a decade,” Rundek said.
“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 continued. “However, with the rising number of people globally who are overweight or obese and the difficulty many experience with losing weight, obviously this is a concern for public health in the future as these people age.”
By Olivia Harvey, Earth.com Staff Writer
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