Teens' faculties not harmed by low blood sugar

NEW YORK (Reuters Health) - Teenagers with type 1 diabetes who aim to keep their glucose levels under tight control may have frequent episodes of too-low blood sugar, but this apparently has no lasting effect on their cognitive function.

The finding comes from the Diabetes Control and Complications Trial (DCCT). Hypoglycemia -- a drop in blood sugar to abnormally low levels -- can cause confusion, seizures or even coma. There is concern that this may damage young brains that are still developing.

Dr. Gail Musen at Harvard Medical School in Boston and the research team reviewed cognitive outcomes among 175 patients with type 1 diabetes who were between 13 and 19 years old when they were enrolled in DCCT. The subjects underwent a comprehensive battery of cognitive tests when they were 29 to 41 years old.

The investigators found that 51 of the 82 subjects who were assigned to intensive diabetes therapy reported a total of 200 episodes of coma or seizure related to hypoglycemia; 94 similar episodes were reported by 36 of 93 subjects assigned to conventional treatment.

"Neither original treatment assignment nor cumulative number of hypoglycemic events influenced performance in any cognitive domain," the researchers report in the medical journal Diabetes Care.

On the other hand, higher A1C values -- indicating generally higher glucose levels over time -- were associated with declines in measures of mental ability.

Nonetheless, Musen's group writes: "We need to remain cognizant of the dangers of acute hypoglycemia, which can lead to comas, accidents, injuries, death, family stress, loss of school or work time, and loss of commitment to the goals of intensive treatment."

SOURCE: Diabetes Care, October 2008.