Aug. 3, 2010 -- Obese adolescents with type 2 diabetes may experience changes in their brains that affect how well they are learning in school, according to a new study published online in Diabetologia.
Childhood obesity is an epidemic in the U.S, and as a result diseases that were previously seen only in adults are now increasingly being diagnosed in children. These diseases include high blood pressure and type 2 diabetes.
"This is the first report to show that the brain is a site of complications among kids with type 2 diabetes," says Antonio Convit, MD, professor of psychiatry and medicine at the New York University Langone Medical Center in New York City. "Obesity in adolescents can lead to type 2 diabetes, which increases risk of mortality, but now we know that these children's brains are not working as effectively as they should be either and their ability to do well in school is also impaired."
What is not known, however, is whether or not this damage is reversible, he says.
Eighteen obese children with type 2 diabetes and their counterparts who were obese, but had no evidence of diabetes or pre-diabetes, underwent extensive testing. The children with diabetes performed worse on memory and spelling tasks as well as on tests of their overall intellectual functioning.
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Exactly how type 2 diabetes affects children's ability to think and learn is not fully understood, but "we know the brain uses sugar as a source of metabolism, and insulin resistance interferes with the body's ability to get more juice or sugar into the brain," Convit says. Similar findings have been seen in adults with diabetes, but the cognitive changes were thought to be the result of vascular disease in their brains.
The next step is to try to determine if this damage can be reversed by treating the insulin resistance.
"Years ago, we started predicting that obese kids would start getting type 2 diabetes, and now we are seeing the effects of insulin resistance on cognition, and a child's education and ability to learn may be impacted," says Gail Musen, PhD, an assistant investigator in the section on behavioral and mental health at the Joslin Diabetes Center and an instructor in psychiatry at Harvard Medical School in Boston.
Musen says that she was surprised to learn that these early brain changes were affecting a child's ability to learn. "Brain changes usually occur before cognition changes," she says.
Children's brains are still developing, and their body weight and its complications are affecting the brain structure, she says. "The brain is very resilient," she says. If the structural changes are permanent, "other brain areas can come in and take over for the affected parts."
"We don't know for sure yet, but it is possible that if we can treat insulin resistance, we can ameliorate these changes," she says. Children who are obese or overweight should be given glucose tests to identify insulin resistance early.
In addition, "parents need to set a good example with healthy eating and exercise," she says.