Hypoglycemia May Not Impair Thinking
Poorly controlled blood sugar may be greater risk to brain function

(HealthDay News) -- A bout or two of severely low blood sugar doesn't appear to affect brain function later in life, but poorly controlled diabetes might.

That finding, published in the New England Journal of Medicine , offered reassurance to diabetics, who must combat low blood sugar levels, known as hypoglycemia.

"Of course, it goes without saying that hypoglycemia can be a serious problem. But, if you've had a more severe hypoglycemia event, at least it appears that you don't have to worry that 10 years later you may have trouble doing your job or thinking," the study's lead author, Dr. Alan Jacobson, director of behavioral and mental health research at the Joslin Diabetes Center in Boston, told HealthDay .

However, the researchers did find that people who didn't manage their diabetes well -- which was defined as having a hemoglobin A1C level (a long-term measure of blood sugar levels) of 8.8 or higher -- had a subtle decrease in certain measures of cognitive function.

Hypoglycemia can be potentially life threatening for people with type 1 diabetes. It can occur if a person takes too much insulin, eats too little food or exercises more than normal. Symptoms of hypoglycemia include shakiness, dizziness, sweating, hunger, headache, pale color, sudden mood changes and confusion and, when severe, seizures and coma, according to the American Diabetes Association.

People with type 1 diabetes have to try to lower their blood glucose levels to near normal, but that can be difficult to do without dropping too low. That's the main reason type 1 diabetics experience hypoglycemia.

Repeated episodes of severe hypoglycemia can cause nerve cell death, and some experts had expressed concern that such episodes might also affect brain function.

Jacobson and his colleagues tested the cognitive abilities of more than 1,100 people between the ages of 13 and 39 who had type 1 diabetes. Cognitive performance was measured at the start of the study and again about 18 years later.

During that time span, 1,355 episodes of coma and seizure caused by hypoglycemia were recorded. Three people died due to severely low blood sugar levels.

However, "hypoglycemia did not seem to predict the advent of worsening cognitive function," Jacobson said. Small decreases in cognitive function were associated only with those who had not controlled their blood sugar levels, the study found.

The finding should be "reassuring for people with type 1 diabetes," Dr. Maria Ramos-Roman, a diabetes specialist and an assistant professor of internal medicine at the University of Texas Southwestern Medical Center, told HealthDay .

On the Web

To learn more about hypoglycemia, visit the National Institute of Diabetes and Digestive and Kidney Diseases.

SOURCES: HealthDay News ; Alan Jacobson, M.D., professor of psychiatry, Harvard Medical School, and director, Behavioral and Mental Health Research Program, Joslin Diabetes Center, Boston; Maria Ramos-Ramon, M.D., assistant professor of internal medicine, University of Texas Southwestern Medical Center, Dallas; May 3, 2007, New England Journal of Medicine ; American Diabetes Association (www.diabetes.org)
Author: Serena Gordon
Publication Date: May 31, 2008
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