Study Compares Driving Records With Type 2 Diabetics, Others

Drivers with type 1 diabetes may be more prone to car accidents than people without diabetes or those with type 2 diabetes, according to a report in the medical journal Diabetes Care.

The study, by researchers at the University of Virginia Health System, looked at whether or not diabetes treatments to  control blood sugar level are linked with increased risk for driving mishaps.

The researchers also report that people with type 2 diabetes are not accident prone, even if they are taking insulin.

The drivers with type 1 diabetes reported significantly more crashes, moving violations, and hypoglycemic episodes than did patients with type 2 diabetes regardless of whether they used insulin, according to Dr. Daniel J. Cox, a researcher on the study.

Blood Sugars May Rise or Fall Too Quickly

According to the American Diabetes Association, Type 1 diabetes is usually diagnosed in children and young adults, and was previously known as juvenile diabetes.

Type 1 diabetes develops when the pancreas can no longer manufacture insulin, the hormone necessary to move sugar out of the blood and into tissues where it supplies energy. To compensate, those with type 1 diabetes must rely on an outside source of insulin, usually in the form of injections several times a day.

Type 2 diabetes is the most common form of diabetes. In type 2 diabetes, either the body does not produce enough insulin or the cells ignore the insulin. 

Insulin is necessary for the body to be able to use sugar.  Sugar is the basic fuel for the cells in the body, and insulin takes the sugar from the blood into the cells. When glucose builds up in the blood instead of going into cells, it can cause two problems: Your cells may be starved for energy, and over time, high blood glucose levels may hurt your eyes, kidneys, nerves, or heart.

Treatment involves medications that increase insulin sensitivity or, in some instances, supplemental insulin.

Experts say when insulin levels are not well-controlled, there is the potential for blood sugar levels to either rise too high or drop too low. And they strongly infer that the drop in blood sugar more commonly seen in type 1 diabetes may precipitate the driving dangers.

"There's always the concern that patients who experience low blood sugar - hypoglycemia - may be at greater risk when driving or performing other tasks that require mental concentration and high performance," says Dr. Kenneth Hupart, chief of endocrinology, metabolism, and diabetes at Nassau University Medical Center.

"If you're driving during a period of hypoglycemia, for example, your reaction time and judgment might be impaired," Dr. Hupart explains.

Although people with type 2 diabetes are also prone to episodes of low blood sugar, Dr. Hupart says it happens far less frequently, and usually to a lesser degree. This is one possible reason why this group did not appear to have any greater increase in driving risks.

The study involved 1,036 participants from seven diabetes specialty-care centers across the US, as well as four centers in major European cities. At each center, people with either type 1 or type 2 diabetes, as well as their non-diabetic spouses, were asked to fill out an anonymous questionnaire concerning both their driving record and their diabetes history for the two years prior to the survey.

According to Dr. Cox, the questions included the number of automobile accidents and moving violations, the number of times driving assistance was required due to low blood sugar, and how often the patient drove while experiencing severe low blood sugar.

Also included were questions testing the patients knowledge of low blood sugar levels, and whether they routinely tested their blood sugar levels before getting behind the wheel.

The final analysis: When compared to drivers with type 2 diabetes, as well as non-diabetic drivers, people with type 1 diabetes were at what the researchers called "significant risk" for driving accidents.

Study Points to Steps to Prepare Drivers

Dr. Hupart says the study results could be instrumental in developing guidelines to reduce risks on the road.

He says it can offer a road map for improved patient counseling, wherein physicians can help those patients at highest risk of accidents alter their behaviors in such a way that this risk can decrease.

For example, Dr. Hupart says, physicians could point out levels of blood glucose that would be considered dangerous or unsafe when driving, and then encourage patients who are at risk to pay attention to their own sugar levels before getting behind the wheel.

At the same time, however, he cautions against this or other similar studies being used to discriminate against those with diabetes.

"We don't want to promote unjustified discrimination against diabetics in our society, when it may not be appropriate, and when there may be a way of identifying the risk and lowering that risk," Dr. Hupart says.

Always consult your physician for more information.

September 2003

Drivers With Type 1 Diabetes Report More Car Accidents

Blood Sugars May Rise or Fall Too Quickly

Study Points to Steps to Prepare Drivers

What Is Hypoglycemia?

Online Resources

What Is Hypoglycemia?

Hypoglycemia is a condition characterized by a glucose (blood sugar) level that is too low to effectively fuel the body's blood cells.

Glucose is the main source of fuel for the body. According to the National Institute for Diabetes and Digestive and Kidney Diseases (NIDDK), the good range of blood sugar is approximately 60 to 120 mg/dL (milligrams of glucose per deciliter of blood). Blood sugar levels under 60 mg/dL are too low and are considered unhealthy.

Hypoglycemia may be a condition by itself, or may be a complication of diabetes or another disorder. It is most often seen as a complication of diabetes, which is sometimes referred to as insulin reaction.

Causes of hypoglycemia in people with diabetes may include the following:

Other causes of hypoglycemia are rare, but may occur in early pregnancy, after strenuous exercise, or during prolonged fasting. Hypoglycemia may also result from taking certain medications, abusing alcohol, or other rare causes.

The following are the most common symptoms of hypoglycemia. However, each individual may experience symptoms differently. The symptoms include:

The symptoms of hypoglycemia may resemble other conditions or medical problems. Always consult your physician for a diagnosis.

In addition to a complete medical history and physician examination, certain blood tests are used to diagnose hypoglycemia.

When a person with diabetes has symptoms of hypoglycemia, then the cause is usually diagnosed as a complication of diabetes, or insulin reaction. It is often the result of the causes listed above.

Always consult your physician for more information.

Online Resources

(Our Organization is not responsible for the content of Internet sites.)

American Diabetes Association

Centers for Disease Control and Prevention (CDC)

Diabetes Care

National Diabetes Education Program

National Institute of Diabetes & Digestive & Kidney Diseases (NIDDKD)

National Insitutes of Health (NIH)