Too-Strict Blood Sugar Control May Lead to Car Crashes

ByABC News
December 8, 2009, 4:23 PM

Dec. 9 -- TUESDAY, Dec. 8 (HealthDay News) -- Diabetics who keep their blood sugar tightly controlled run the risk of having traffic accidents due to low blood sugar, Canadian researchers report.

Controlling blood sugar is the cornerstone of managing diabetes. By keeping blood sugar under control, diabetics can ward off many of the complications associated with the condition, including heart and kidney disease. However, blood sugar that is too low -- known as hypoglycemia -- can cause dizziness and loss of consciousness, the researchers say.

"Diabetes is a common disease that may impair an adult's ability to drive," said lead researcher Dr. Donald A. Redelmeier, a professor of medicine at the University of Toronto.

Worldwide, Redelmeier said, diabetics are required to produce proof of good blood-sugar control to keep their driver's license. The United States, United Kingdom, Canada, Germany, Holland, Australia and other countries all have such laws, but they're "based on theory rather than science," he said.

And contrary to the prevailing theory, people with good blood-sugar control were found to have a higher risk for crashing, Redelmeier said of his study's results. The risk was substantial, accounting for almost 50 percent of the accidents, he said.

The accidents were mostly related to severe hypoglycemia in association with strict blood sugar control, he noted. The findings were published online Dec. 8 in PLoS Medicine.

For the study, Redelmeier's team collected data on 795 diabetic drivers. They found that one in 14 of the drivers had been involved in car accidents. Those with low blood sugar were more likely to have had an accident than were diabetics whose blood sugar was not as well controlled.

Moreover, the risk for having a car accident increased fourfold if the person had a history of hypoglycemia, the researchers found.

"This finding calls into question laws that restrict driver's licenses on the basis of this measure of diabetes control," Redelmeier said.