Low blood sugar may impair diabetics' driving

A vehicle drives on a road in Tokyo July 12, 2009.

NEW YORK (Reuters Health) - Bouts of low blood sugar can lead to unsafe driving among people with diabetes, new research shows.

In 452 adult drivers with diabetes, 52 percent reported at least one driving mishap when their blood sugar was low, Dr. Daniel J. Cox, at University of Virginia Health Sciences Center in Charlottesville, and colleagues found.

Just as one would pull over to deal with a flat tire, Cox commented in an email to Reuters Health, diabetics with low blood sugar "need to immediately stop driving, eat fast-acting sugar, and wait for blood sugar to rise," before driving on.

Cox's team tallied driving mishaps reported over 12 months by men and women who had type 1 or "insulin-dependent" diabetes for an average of 26 years.

The study participants were about 42 years old on average, and drove about 16,000 miles annually in and around central Virginia, Boston, Massachusetts, and Minneapolis, Minnesota.

Driving with low blood sugar did not appear to cause a large number of collisions in this study. Overall, 22 percent of the drivers reported some sort of collision during the year, but just 2.4 percent were said to be related to bouts of low blood sugar.

Nonetheless, about 35 percent of the time drivers said they had checked their blood sugar 30 minutes prior to having some sort of driving mishap. In 78 percent of these times, blood sugar readings were low-to-normal (less than 90 milligrams per deciliter of blood). In 48 percent of these times readings were even lower, less than 70 milligrams per deciliter.

Moreover, in addition to the half who reported at least one low-blood-sugar-related driving mishap, such as zoning out or becoming disoriented, being stopped by police, or having someone else take over driving, 32 percent reported 2 or more and 5 percent reported 6 or more such mishaps.

Therefore, Cox and colleagues suggest healthcare providers encourage those reporting such events strive for blood sugar levels greater than 90 milligrams per deciliter before beginning to drive.

SOURCE: Diabetes Care, December 2009