Preteens with obesity display significant differences in cognitive performance, brain structure, and brain circuitry compared to those with normal body-mass index. The corresponding study was published in the International Journal of Obesity.
The prevalence of overweight and obesity among children and adolescents aged 5- 19 years old rose from 4% in 1975 to over 18% in 2016. In the same time frame, obesity alone rose from 1% of 5- 19 year olds to 6% of girls and 8% of boys.
Obesity is a known risk factor for a range of neurological disorders, including Alzheimer's disease, schizophrenia, and carpal tunnel syndrome. However, its effects in neurodevelopmentally vulnerable periods remain unclear.
In the present study, researchers investigated how BMI relates to high-level cognition and its underlying brain structures in pre-adolescence. To do so, they analyzed data from 4922 9- 10-year-olds, including their BMI's, cross-sectional resting-state fMRI's, structural sMRI's, and neurocognitive task scores.
Altogether, 15% of the youth were overweight, and 13.7% were obese. The researchers found that the brain circuits of children with higher BMI's that support higher-level cognitive functions, reward, emotional processing, and attention were less efficiently organized, less well connected, and less resilient than their peers with normal BMIs.
They further found that preteens with higher BMIs scored lower in logical thinking and problem-solving in new settings. The findings remained after adjusting for factors including sleep duration, screen time, depression, physical activity levels and self-worth related to weight.
While the findings do not prove a causative link between obesity and structural and cognitive changes in the brain, the researchers noted that as preteens' brains are still developing, interventions may make a difference. Interventions may include mental health screenings, improving sleep quantity and quality, increasing physical activity, and reducing screen time.
The researchers now plan to assess two-year follow-up data to observe the brains of children with excess BMI over a longer period of time. They also hope to include genetic and nutritional data in their analyses.