Unfit, Heavy Teens on Path to Diabetes
Physical Fitness May Protect Against Insulin Resistance
March 7, 2003 -- An overweight teenager who rarely exercises already may be well on the way to developing type 2 diabetes. Although it's no surprise that overweight children face a greater risk of diabetes, a new study suggests that physical fitness may also play an important role in the development of the disease.
Researchers found teens who were unfit had a higher risk of having insulin resistance, a condition that often precedes diabetes, which was independent of the increase in diabetes risk they faced for being overweight.
Insulin resistance, also known as low insulin sensitivity, occurs when the body is unable to use insulin efficiently to convert glucose (blood sugar) into energy. The condition often leads to diabetes due to the increasing demands placed on the pancreas to produce insulin. When the pancreas can't keep up with this rising demand, glucose levels climb into the diabetic range.
Researchers studied 289 teens from high schools in the Augusta, Ga. area and evaluated their insulin sensitivity, cardiovascular fitness level, body composition (amount of fat versus other body mass), and waist circumference (a measure of abdominal fat).
When the researchers controlled for race and gender, they found that teens with a higher level of cardiovascular fitness and lower body fat were less likely to have insulin resistance.
"This is an important finding because some people think that body fat is the critical factor in the development of diabetes," says researcher Bernard Gutin, PhD, professor of pediatrics and physiology at the Medical College of Georgia in Augusta, in a news release. "We found it was certainly important, but that even after adjusting for it, fitness still made an independent contribution."
Gutin presented the study this week at American Heart Association's 43rdAnnual Conference on Cardiovascular Disease Epidemiology and Prevention, in Miami, Fla.
He says these results suggest that improving physical fitness and losing body fat early in life might be a way to protect children at high risk of developing diabetes due to a family history of the disease, or other risk factors.
The study also found that insulin resistance was most common among black girls, and white girls had the highest levels of insulin sensitivity. In addition, boys were more likely to have higher fitness levels than girls as well as lower body fat.
SOURCE: American Heart Association's 43rdAnnual Conference on Cardiovascular Disease Epidemiology and Prevention, Miami, Fla. News release, American Heart Association.