Air Pollution Could Cause Problems for Diabetics

Persons with diabetes may be at higher risk for cardiovascular problems when air pollution levels are higher, according to a new study published in the medical journal circulation.

Diabetes is a metabolic disorder characterized by a failure to secrete enough insulin, or, in some cases, the cells do not respond appropriately to the insulin that is produced. Because insulin is needed by the body to convert glucose into energy, these failures result in abnormally high levels of glucose accumulating in the blood.

Diabetes is widely recognized as one of the leading causes of death and disability in the US, affecting more than 13 million Americans.

Pollution Impairs Blood Vessels

A study of Boston-area residents found that the ability of the blood vessels to control blood flow was impaired in adults with diabetes on days with elevated levels of particles from traffic and coal-burning power plants.

The researchers evaluated several kinds of fine particles found in urban air pollution. These included sulfate particles, which come mainly from coal-burning power plants, as well as ultra-fine particles and black carbon soot, which are generated primarily by diesel- and gasoline-powered vehicles.

"Our strongest finding was that blood vessel reactivity was impaired in people with diabetes on days when concentrations of sulfate particles and black carbon were higher," says Marie O'Neill, PhD, an epidemiologist at the Robert Wood Johnson Health and Society Scholars program at the University of Michigan.

"Impaired vascular reactivity has been associated with an increased risk of heart attack, stroke and other heart problems," says Dr. O'Neill, lead author on the study.

"Previous studies have shown that when air pollution levels are higher, people with diabetes have higher rates of hospitalization and death related to cardiovascular problems," says David Schwartz, MD, director of the National Institute of Environmental Health Sciences.

"These changes in blood vessel reactivity may help explain this phenomenon," he says.

"We don't really understand why fine particles may cause this decrease in vascular reactivity," says Dr. O'Neill. "Further research is needed to confirm this association between air pollution and vascular health and to understand what causes people with diabetes to be especially sensitive."

Comparison of Diabetics and Non-Diabetics

Researchers recruited 270 greater Boston metropolitan residents and divided them into two groups.

The first group consisted of persons with a positive diagnosis of type I or type II diabetes. The second group included individuals who were not diabetic, but who had a family history of diabetes or blood sugar levels slightly higher than normal.

The investigators used a technique called brachial artery ultrasound to assess blood vessel response in the study subjects.

The measurement was obtained by applying a pressure cuff to the persons upper arm and cutting off the blood flow through the arm's main artery. Researchers then released the cuff, allowing the blood to rush through.

The researchers then evaluated changes in the diameter of the main artery as a result of the physical stress placed on the vessel.

"We observed an 11 percent decrease in diabetics' vascular reactivity on days when sulfate particle concentrations were higher than normal," remarks Dr. O'Neill. "We also noted a 13 percent decrease in their vascular reactivity on days with higher-than-normal black carbon concentrations.

"We hope our study will remind people that reducing air pollution is important for everyone's health, but especially for vulnerable members of our population, including the elderly and people with chronic health problems such as diabetes," she says.

Warning Signs of a Heart Attack

BY THE AMERICAN DIABETES ASSOCIATION

What is a heart attack?

A heart attack occurs when the blood vessels that go to your heart become partially or totally blocked by fatty deposits and the blood supply is reduced or cut off. Then oxygen and other needed materials aren't carried to the heart and heart muscle dies. Another name for a heart attack is myocardial infarction, or MI. If you have diabetes, you're at risk for a heart attack.

Are the signs of a heart attack different for people with diabetes? Diabetes can affect your nerves and, therefore, make heart attacks painless or "silent." A silent heart attack means that you may not have any warning signs, or they may be very mild. Special tests may be needed to help your doctor make a diagnosis.

What are the warning signs of a heart attack?

Become familiar with these signs and call 911 right away if they occur:

• chest pain or discomfort

• pain or discomfort in your arms, back, jaw, neck, or stomach

• shortness of breath

• sweating or light-headedness

• indigestion or nausea

• tiredness

You may not experience all of these signs, and they may come and go. Chest pain that doesn't go away after resting a few minutes may signal a heart attack.

Why is it important to call 911 right away if I'm having warning signs of a heart attack?

After a heart attack, early intervention such as getting clot-busting drugs is imperative-doing so can save your life. Health care providers can also use special procedures that open up blood vessels, preventing further damage to the heart. These steps work best within an hour of the first symptoms of a heart attack. It's wise to review the symptoms of a heart attack with family and friends and to tell them about the importance of calling 911.

Diabetes, Heart Disease and Stroke is an initiative of the American Diabetes Association and the American College of Cardiology, aimed at increasing awareness of the link between diabetes and heart disease.