Too Much Insulin May Cause Memory Problems
Nov. 16, 1999 (New York) - Children with type 1 diabetes who must take large doses of insulin may develop serious memory problems as a result of treatment, researchers have found. The results of a study published in a recent issue of Diabetes Care suggest that the kind of insulin therapy now recommended by the American Diabetes Association may cause memory deficits as serious as those associated with the effects of severe hypoglycemia -- a condition caused by dangerously low blood sugar levels. Other parts of the brain may also be affected by regular large doses of insulin, according to the researchers.
In diabetes, blood glucose (sugar) levels are abnormally high because the body doesn't produce enough insulin. People with diabetes must take insulin as medication in order to control their blood glucose levels.
Researcher Tamara Hershey, PhD, tells WebMD that until recently, scientists haven't looked at the possible relationship between severe hypoglycemia and learning or memory problems in children with type 1 diabetes. The study -- conducted by scientists at Washington University School of Medicine in St. Louis -- evaluated how well children with type 1 diabetes who required large doses of insulin performed certain memory functions, such as recalling important stories and remembering the shapes of objects they had seen and the way the objects were placed. The children not only showed memory problems but also had difficulty performing tasks requiring small, precise movements.
Hershey cautions, however, that more studies are needed to determine whether the memory problems are serious enough to call for changing the insulin treatment -- presuming that that can be done safely. Intensive [large-dose] insulin therapy "is clearly beneficial for type 1 diabetic teenagers and adults, and without a clear demonstration of the relationship between severe hypoglycemia and memory deficits in children, I would hesitate recommending withholding or modifying [therapy] based only on these results," she says.
Christopher M. Ryan, PhD, also urges caution in modifying insulin dosage based solely on the study?s results. In a separate article published in the same journal, Ryan -- associate professor of psychiatry at the University of Pittsburgh School of Medicine, Pennsylvania -- writes that while the results "are certainly chilling" given the importance of memory ability in school-age children, the study does not provide enough evidence to support physicians' reducing children's insulin intake.