Inflammation, one of the body’s principal defensive reactions to injury or infection, also may be a sign of risk for diabetes, researchers are reporting here at the annual research conference of the American Diabetes Association (ADA).
Investigators have concluded in recent years that heart disease may be linked to inflammation, and they are trying to determine the cause. Now there is increasing evidence that type 2 diabetes, which is strongly linked to heart disease, may be related to inflammation, too.
When you get hurt or get an infection, your body produces cells that help to fight off the disease or repair the injury. When this occurs, a variety of protein types and other substances collect in the bloodstream. Inflammation can be measured by looking for these substances in the blood, just as you can look for smoke to find fire. These substances are called “markers” of inflammation. Examples include C-reactive protein, homocysteine and sialic acid.
Higher levels of several of these markers have been found in people with heart disease, and their presence seems to predict development of heart disease in people who don’t have it yet.
More recent research indicates there may be a similar relationship between inflammation markers and type 2 diabetes. In some ways, this is not surprising because diabetics have a very high risk of developing heart disease and dying of a heart attack or stroke. Inflammation may be another link between the two diseases.
Type 2 diabetes, by far the most common form of the disease, develops when the body gradually loses its ability to make efficient use of the insulin it produces. Insulin makes it possible for the body’s cells to turn sugar (glucose) into energy.
Two studies presented June 15 at the ADA meeting point out commonly prescribed drugs that appear to both reduce inflammation and improve diabetes control. The link between diabetes and inflammation may not be a coincidence, researchers suggest.
“I personally believe that given the number of studies we have, … the weight of the evidence is that there is an association where inflammatory markers predict the development of diabetes,” said Bruce Duncan, M.D., Ph.D.
Dr. Duncan, an associate professor in the medical school at the Federal University of Rio Grande del Sul, Brazil, was among those presenting research on inflammatory markers at the conference.
One study presented here found that rosiglitazone (Avandia), a drug that many diabetics take to reduce their blood-sugar levels, also significantly reduced levels of several blood markers of inflammation. The study involved 11 diabetic patients who were given the drug for six weeks by investigators at the State University of New York at Buffalo medical school.
Paresh Dandona, M.D., Ph.D., head of the Division of Endocrinology, Diabetes and Metabolism at the medical school, said his research team previously had demonstrated a similar effect with Rezulin, another drug in the class known as thiazolidinediones. Rezulin since been withdrawn from the market for unrelated reasons.
In the other study related to inflammation, the effect of cholesterol-lowering drugs on diabetes was examined. Cholesterol-lowering drugs in the class known as “statins” had previously been credited for limiting inflammation.
Researchers in Canada examined the prescription drug records of nearly 11,000 patients with type 2 diabetes who began taking drugs to lower their blood sugar between 1991 and 1996. After keeping track of the patients for an average of five years, researchers found that it took longer for patients’ diabetes to get worse if they were taking statins.
About 11 percent of each group eventually had to start taking insulin because the glucose-lowering drugs did not do enough to control their condition, said Jeffrey A. Johnson, Ph.D., associate professor of public health sciences at the University of Alberta, Canada. It was remarkable that those who used statins needed insulin nearly a year later than the other group, he said.
Previous studies have shown that people who take statins have a 33 percent lower risk of developing diabetes. Also, Dandona said, large studies of statins also have shown that statins help diabetics even more than they help non-diabetics in preventing heart disease.
Johnson said more research is needed to determine whether statins should be used even when they are not needed for high cholesterol.