Cognitive Impairment: A Hidden Consequence of the Childhood Obesity Epidemic

Research at NYU Langone Medical Center Unravels Obesity’s Effects on the Brain

Antonio Convit, MD, professor of psychiatry and medicine, and director of the BODyLab, analyzes MRI brain scans of obese children with metabolic syndrome.

Translational research taking place in the Brain, Obesity, and Diabetes Laboratory (BODyLab) of NYU Langone Medical Center is helping scientists gain a better understanding of one of the most underappreciated consequences of the child obesity epidemic in the United States—the effects of obesity and the metabolic syndrome on the brain.

Antonio Convit, MD, professor of psychiatry and medicine, and director of BODyLab, and colleagues are quantifying physiologic brain changes seen on magnetic resonance imaging (MRI) scans of obese children with metabolic syndrome. So far, they have noted hippocampal shrinkage and changes in the white matter, which may be associated with the cognitive impairments that they have documented in this population.

Dr. Convit’s research, recently published in Pediatrics, found that such children perform worse on memory and spelling tasks and on tests of their overall intellectual functioning. “Their brains are not firing on all pistons,” Dr. Convit says. “The more overweight that youth are, the more they experience the medical consequences of obesity, and the greater the difficulties they have in all these areas of cognitive functioning.”

The stakes are high. One out of three children in the United States is considered overweight or obese. “If a child is obese, there is a 35 percent chance that he or she will have metabolic syndrome,“ Dr. Convit says. “This is a huge number of kids at risk.”

Inflammation may play a role in the brain abnormalities and the cognitive impairments, he says. “Another possibility is problems with vascular reactivity. The endothelial cells may not work as effectively in obese children with metabolic syndrome or prediabetes,” Dr. Convit says. “We want to understand how the brain is affected by a whole spectrum of metabolic diseases, from uncomplicated obesity to metabolically complicated obesity that’s just short of diabetes to type 2 diabetes.” The more severe the metabolic disease, the more significant the cognitive impairments, he adds. 

The team is conducting experiments that are looking at how the vasculature reacts to carbon dioxide, which should yield important insights. 

Another major player in this area is brain-derived neurotropic factor (BDNF). “BDNF is essential for the maintenance and repair of the brain, and we know that BDNF is lower in people who are obese and have metabolic syndrome,“ Dr. Convit explains. “The brain makes more BDNF when you exercise. BDNF helps regulate glucose metabolism, and when you improve insulin function, you can improve cognition. The catch is that when you stop exercising, you lose these benefits. Getting this population to comply with lifestyle changes over the long haul is a challenge,” he says. “Once you gain weight, your body is working against you. It’s a real struggle to lose it.”

While the research in the lab continues, Dr. Convit is also taking his findings into New York City public schools to help identify earlier children at risk of type 2 diabetes, as part of The BODY Project (Banishing Obesity and Diabetes in Youth). At-risk kids receive user-friendly reports of their medical results along with information for the whole family about how to turn things around before the child develops type 2 diabetes. “The MRI studies should also help elucidate some of the pathways affected by insulin resistance and obesity, and lead to new treatments to help mitigate these risks,” Convit says.

Charles Marmar, MD, the Lucius N. Littauer Professor of Psychiatry and chair of the Department of Psychiatry at NYU Langone, lauds this population health-based approach. “As psychiatrists, we need to work with others to get kids eating less and moving more and work together with primary care doctors, politicians, and government,” he says. “We need to take psychiatry outside of the clinic because psychiatrists studying mind, brain, and behavioral issues can make a major contribution to population health.”