A new study, which appears in the October issue of the journal Diabetes Care, demonstrates that high frequency of and early exposure to severe hypoglycemia during development negatively affects spatial long-term memory performance.
Severe hypoglycemia is a significant and relatively common complication of insulin treatment in children with type 1 diabetes. Repeated severe hypoglycemia has been reported to reduce long-term spatial memory in children with type 1 diabetes. Early exposure to hypoglycemia may be more damaging to cognitive function than later exposure.
Researchers from the Washington University School of Medicine, and St. Louis Children's Hospital, St. Louis, Missouri set out to determine whether the age at which severe hypoglycemia occurs modulates the impact of severe hypoglycemia frequency on long-term spatial memory.
To achieve the goal, they combined data from three independent studies to obtain a sample of children aged 6-18 years with type 1 diabetes and nondiabetic control subjects. Each study evaluated previous severe hypoglycemia and tested short and long delay spatial memory with the spatial delayed response task.
Type 1 diabetic participants were categorized as having zero, one to two, or three or more severe hypoglycemic episodes and as having their first severe hypoglycemic episode before or after 5 years of age. Information on chronic hyperglycemia (HbA1c values) was also collected.
It was found that repeated severe hypoglycemia (more than three episodes) reduced long-delay spatial delayed response performance, particularly when severe hypoglycemic episodes began before the age of 5 years. The age of type 1 diabetes onset and estimates of chronic hyperglycemia did not influence performance.
The authors suggest that this information should be used in assessing the benefits and risks of tight glycemic control of type 1 diabetes at very young ages. Linking the cognitive effects to changes in brain structure or function and everyday behavior would be useful in predicting the ultimate functional outcome of children with type 1 diabetes as well as in weighing the risks and benefits of treatment strategies for diabetes in childhood.