Numerous past studies have long found a correlation between
obesity in
children and decreased executive function. A New research published in
JAMA Pediatrics, based on data mined from a massive national research study, suggests that a change in
brain structure: a thinner prefrontal cortex,may help explain that interrelationship.
Dr Jennifer Laurent, an associate professor in the Department of Nursing at the University of Vermont and lead author of the study told
Thailand Medical News,"Our results show an important connection; that kids with higher BMI tend to have a thinner cerebral cortex, especially in the prefrontal area."
The study findings are based on data retrieved from a National Institutes of Health-funded research project, the Adolescent
Brain Cognitive Development study, or ABCD, which is following 10,000 teens over a 10 year period. Every two years, study subjects are interviewed, take a battery of tests, give blood samples and undergo
brain scans.
The new study analyzed results from 3,190 nine- and 10-year-olds recruited at 21 ABCD sites in 2017.
The detailed study confirmed the findings of its predecessors; that subjects with higher BMI tended to have lower working memory, as measured by a list sorting test.
It also added an important component to that insight, a physiological correlate in the
brain that might help explain the connection.
Dr Laurent added, "Our hypothesis going into the study was that the thickness of the cerebral cortex would 'mediate' or serve as an explanatory link for the relationship between BMI and executive function."
The study findings did confirm the relationship, according to the study's senior author, Dr Scott Mackey, an assistant professor of Psychiatry in the University of Vermont's Larner College of Medicine.
Dr Mackey said, "We found widespread thinning of cerebral cortex" among research subjects with higher BMI, but especially so in the prefontal area. That's significant because we know that executive function, things like memory and the ability to plan, are controlled in that area of the
brain.”
Further research is needed to determine the nature of the link between the three variables.
Dr Laurent further added, "It could be that a thinner prefrontal cortex is affecting decision-making in some
children, and they make unhealthy dietary choices as a result, which could lead to
obesity. Or the causal relationship could work in the opposite direction. We know from rodent models and adult studies that
obesity can induce low grade inflammatory effects, which actually do alter cellular structure" and can lead to cardiovascular disease. With prolonged exposure to
obesity, it is possible that
children have chronic inflammat
ion, and that may actually be affecting their
brain in the long term. If that were the case, there would be significant public health implications. We would want to proactively encourage changes in kids' diets and exercise levels at a young age with the understanding that it's not only the heart that is being affected by
obesity, it is perhaps also the
brain."
The decrease in working memory was a statistical observation, Laurent said, not a clinical one.
She added, "We did not look at behavior. It's very important that this work not further stigmatize people who are
obese or overweight. What we're saying is that, according to our measures, we are seeing something that bears watching. How and if it translates to behavior is for future research to determine."
Detailed data analysis for the study was done at the University of Vermont and Yale University. Dr Richard Watts, director at the FAS
Brain Imaging Center and research associate professor of radiology at Yale, was a co-author of the study.
Reference: Jennifer S. Laurent et al, Associations Among Body Mass Index, Cortical Thickness, and Executive Function in Children, JAMA Pediatrics (2019). DOI: 10.1001/jamapediatrics.2019.4708
