Insulin Resistance a Marker of Heart Risk for Teens

Increased chance of diabetes, cardiovascular disease found, report says

MONDAY, Aug. 21, 2006 (HealthDay News) -- Insulin resistance in adolescence might be a powerful predictor of both diabetes and heart disease in adulthood, researchers report.

"We wanted to compare the predictability of body-mass index and insulin resistance on future risk factors," explained Dr. Alan R. Sinaiko, a professor of pediatrics at the University of Minnesota Medical School, and lead author of a report in the Aug. 22 issue of Hypertension. "We found that insulin resistance itself, independent of body-mass index, was an indicator of increased risk."

Body-mass index is the primary measurement of obesity; a reading of 30 or higher indicates obesity.

"Everyone today is tuned into fatness," Sinaiko said. "If you can keep people from gaining weight in childhood and adolescence, it will have a positive impact on risk as a young adult. Since insulin resistance is important independent of body-mass index, this suggests attention should be paid to trying to develop strategies against it."

Those strategies are pretty much the same as those aimed at obesity, he said, and they include exercise and eating the proper amount of the proper foods.

"At the present time, there is not enough data about possible drug therapy, but that may come from future clinical studies," Sinaiko said.

The study followed 357 students in Minneapolis public schools who were given thorough physical examinations and blood tests at the age of 13. Their ability to manage insulin was measured by a sophisticated test, the insulin clamp, in which glucose and insulin are infused into the blood. Lower uptake of glucose into cells was a marker of insulin resistance.

The tests were repeated at age 15, and again at age 19. Insulin resistance at age 13 predicted high blood pressure and high levels of blood fats at age 19, both risk factors for heart disease and stroke, the researchers reported.

The issue of insulin resistance "is becoming increasingly more on the radar screen for pediatricians," said Dr. Stephen Daniels, chairman of the department of pediatrics at the University of Colorado, and a spokesman for the American Heart Association, but "one of the difficulties is how to check for it."

The clamp test done in the Minneapolis study is "complex and time-consuming," beyond the ability of a pediatrician in family practice, Daniels said.

"In a clinical setting, you can use the fasting insulin level to help get an idea of insulin resistance," he said. "But it is a bit complicated there, because measurements for insulin are not standardized."

So, for the time being, "the first focus has to be on the issue of obesity," Daniels said. "I view this study as a better way to understand what the effects of obesity are. For the average family and pediatrician, the focus should be on preventing obesity."

The insulin resistance study is an example of "how we are starting to explore the relationship between obesity and blood pressure, and how it works," Daniels said. "We are learning more about how to predict which child is at higher risk for obesity, but we're not there yet."

More information

Insulin resistance is explained by the National Institute of Diabetes and Digestive and Kidney Diseases.

SOURCES: Alan R. Sinaiko, M.D., professor, pediatrics, University of Minnesota, Minneapolis; Stephen Daniels, M.D., chairman, department of pediatrics, University of Colorado, Denver; Aug. 22, 2006, Hypertension
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