Results of a recently published study show that type 2 diabetes in obese adolescents can affect their ability to learn by altering the amount of sugar that reaches their brains to fuel thinking.
The disease also can produce an observable decrease in the brain’s white matter, that part of the brain that carries messages between grey matter, where higher-order thinking originates.
The study, published in Diabetologia, sought to reveal in adolescents the same brain changes that had been observed in obese adults with type 2.
The researchers, from the New York University School of Medicine and the Maimonides Medical Center in New York City and from the University of Pittsburgh and the Nathan Kline Institute for Psychiatric Research in Pittsburgh, studied 36 obese adolescents, half of whom had type 2 diabetes.
The scientists closely matched the group with diabetes and the non-diabetic control group with regard to age, sex, grade in school, social class, body mass index, and other metrics.
Over the course of the study the researchers found that the young people with type 2 performed at a consistently and statistically significant lower cognitive level than their non-diabetic peers. There were decided differences in intellectual functioning, verbal memory, and psychomotor efficiency, as well as notable differences in reading and spelling scores.
While the type 2 adolescents’ grey matter volume remained unaffected, the volume of white matter dropped, and there was an enlargement of the brain space given over to cerebrospinal fluid. Instruments testing brain composition also found that the micro-structural integrity of both white and grey matter was reduced.
Based on what they saw, and given the controls that they had put in place, the researchers concluded that educational level or social class could not account for the brain disparities between adolescents who have diabetes and those who don’t. While the researchers were able to establish for the first time that type 2 diabetes may lead to the same brain abnormalities that have been detected in adults with diabetes, they were not ready to say exactly how the disease alters brain activity.
The theory for now is that because the brain uses glucose as an energy source, the insulin resistance associated with type 2 prevents the brain from receiving adequate “fuel”-a lack that eventually leads to the declines in function that the researchers noted.
The question remains as to whether increasing the youths’ insulin sensitivity can reverse the damage. The very next step, aside from further research with a bigger group over a longer period, will be to encourage obese young type 2s to step up their exercise routines. More exercise leads to weight loss and a more efficient uptake of insulin.
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