***EMBARGOED FOR RELEASE UNTIL FRIDAY, JUNE 22, 2001
CONTACT: Catherine SeigermanU.Va. Health System Media Relations804-924-5679
TOO MUCH BLOOD SUGAR SLOWS BRAIN FUNCTION IN TYPE 1 DIABETES PATIENTS, U.VA. STUDY SHOWS
CHARLOTTESVILLE, Va., June 22 --A new study by University of Virginia researchers shows that insulin-dependent (type 1) diabetes patients experience slower brain function and other short-term symptoms from too much blood sugar, or hyperglycemia. Daniel J. Cox, head of the U.Va. Center for Behavioral Medicine Research and principal investigator of the study, will present the findings at a poster session starting today at the annual meeting of the American Diabetes Association.
"For the first time, we can demonstrate that performance of the brain is impaired in the short term when a patient has too much blood sugar," Cox said. "Once you get above a blood glucose level of about 270, the brain starts to show evidence of slowing down. A similar thing happens when you get to a level of less than 80. The brain works optimally between those levels."
The study included 105 adults with type 1 diabetes, who rated four symptoms: being tired or sleepy; having dry eyes, nose or mouth; having a sweet taste in their mouths; and needing to urinate. The subjects performed mental subtractions and were tested on their verbal fluency and multiple choice reaction times tests. They then measured and entered their blood glucose levels on a hand-held computer 82 times over four weeks.
All four symptoms steadily increased as blood glucose levels rose. Verbal fluency and mental arithmetic ability slowed as blood glucose rose above 270, Cox said.
"Many patients feel symptoms as blood glucose goes higher, but they may not know their cause. They might not even be aware that their cognitive efficiency is slowing down," Cox said.
Little research exists on the short-term effects of high blood sugar, Cox said. "Traditionally, we thought that hyperglycemia had only long-term effects, such as eye problems, heart disease and poor circulation. We didn't think it had acute effects. In contrast, hypoglycemia -- low blood sugar -- has always been thought of as having short-term effects, but not long-term effects. Now we're starting to recognize that both high and low blood sugar levels have both short- and long-term effects," he said.
Hyperglycemic peaks, as well as hypoglycemic valleys (too little blood sugar), can be commonly experienced by people with diabetes. The American Diabetes Association estimates that 15.7 million Americans have diabetes, the nation's sixth leading cause of death by disease. These and other effects of diabetes--including a significant increase in heart disease, kidney and eye disease and other health problems--can be prevented by maintaining good blood glucose control, as well as a healthy weight, a low-fat diet and regular exercise.
The U.Va. study was funded by the National Institute of Diabetes, Digestive and Kidney Disease, one of the National Institutes of Health, and by Eli Lilly and Company. Cox and his colleagues plan to continue researching the effects of hyperglycemia in type 2 diabetes patients, who comprise approximately 90 percent of all persons with diabetes.
# # #June 18, 2001
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