Functional MRI correlates high BMI and brain connectivity disorders in children

A large-scale study using structural and functional MRI data in American children with a high BMI showed changes in brain connectivity for this population. These results were presented at the Radiological Society of North America (RSNA) 2022 meeting.

Childhood obesity is a growing concern in the United States. According to the Centers for Disease Control and Prevention, approximately one in five American children is obese. It is in this context that a study dealing with the comparison of higher weight and body mass index (BMI) during preadolescence with poor brain health was presented at the RSNA 2022 congress.

A Large-Scale Study of the Impact of Obesity on the Brain Health of American Children

“We know that being obese in adulthood is associated with poor brain health,” says Dr. Simone Kaltenhauser, postgraduate researcher in radiology and biomedical imaging at the Yale School of Medicine in New Haven -Connecticut. However, previous studies of children have often focused on specific small populations or unique aspects of brain health. »

The work of Dr. Kaltenhauser and his team used imaging data from the Adolescent Brain Cognitive Development (ABCD) study that included 11,878 children ages 9 to 10 from 21 centers across the country to represent the diverse socio – demographics in the United States. “This dataset is unique in that it closely approximates the US population,” she continues.

After excluding children with eating disorders, neurodevelopmental and psychiatric illnesses, and traumatic brain injuries, the study group included 5,169 children (51.9% girls). According to the children’s BMI z-scores, the rates of overweight and obesity in the study group were 21% and 17.6%, respectively.

A study group subjected to structural and functional brain MRI explorations

To get a comprehensive view of brain health in the study group, the team assessed information from resting-state structural MRI and functional MRI (fMRI). The researchers also assessed data from diffusion tensor imaging and restriction spectrum imaging. After adjusting for age, gender, ethnicity, laterality, and socioeconomic status, the research team used linear models to determine associations between weight, BMI z-scores, and imaging parameters.

The researchers observed structural brain changes in children with higher weight and BMI z-scores, including significant impairment in white matter integrity. Areas of degradation included the white matter of the corpus callosum as well as connecting areas in the hemispheres that connect the lobes of the brain. “It is striking that these changes were visible from early childhood,” confirms Dr. Kaltenhauser.

The researchers also observed a thinning of the cortex, which has been associated with impaired executive function. “We expected a decrease in cortical thickness in children with high weight and BMI z-score, as previously seen in smaller subsamples of the ABCD study,” she notes. . However, we were surprised by the extent of white matter damage. »

Correlations found between high BMI z-scores and changes in brain connectivity

Resting-state fMRI images revealed that increased weight and BMI z-scores were associated with decreased connectivity in brain functional networks that involve cognitive control, motivation, and decision making. decision based on rewards. “Increased BMI and weight are not only associated with physical health consequences, but also brain health,” says Dr. Kaltenhauser. Our study showed that higher weight and BMI z-scores in 9- and 10-year-old children were associated with changes in macrostructures, microstructures, and functional connectivity that worsen brain health. »

The study’s lead author, Dr. Sam Payabvash, a neuroradiologist and assistant professor of radiology and biomedical imaging at the Yale School of Medicine, sees these findings as an important mechanistic explanation for other studies that show that a higher BMI high in children is associated with poor cognitive functioning and poor academic performance.

“The longitudinal ABCD study gives us the opportunity to observe all the changes that occur in children with higher weight and BMI z-scores,” he concludes. We will have to monitor them for the next 6 to 10 years. »

Bruno Benque with RSNA

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