Diabetes News:

Study: Higher Body Mass Index More Strongly Linked to Diabetes Than Inactivity

A higher body mass index (BMI) is more strongly linked to the development of diabetes than physical inactivity, according to a study reported in the September 8 issue of the Journal of the American Medical Association.

Amy R. Weinstein, M.D., formerly of Brigham and Women's Hospital, Boston, and her colleagues followed 37,878 women for an average of seven years to determine if increasing physical activity levels reduced the elevated risk of diabetes from obesity. The women were free of cardiovascular disease, cancer and diabetes at the beginning of the study.

Normal weight was defined as a BMI of less than 25; overweight, 25 to less than 30; and obese, 30 or higher. A 5'4" woman would have a BMI of 25 if she weighed 145 lbs. and a BMI of 30 if she weighed 174 lbs. Active was defined as expending more than 1,000 kilocalories on recreational activities per week.

The researchers found that BMI and physical activity were significant predictors of diabetes. Compared with normal-weight individuals, overweight individuals had a 3.2 times increased risk for diabetes, while the increased risk of diabetes soared to 9.1 times for obese individuals.

Compared to individuals among the least active 25 percent of participants, more active individuals had a decreased risk of diabetes that ranged from nine percent in the next active quartile to 18 percent in the most active quartile.

"We observed a modest reduction in the risk of diabetes with increasing physical activity level compared with a large increase in the risk with increasing BMI," the authors concluded. “Our study suggests that to further reduce the risk of diabetes with physical activity, it should be performed in conjunction with achieving weight loss.”

In an accompanying editorial, Steven N. Blair and Tim S. Church, M.D., of the Cooper Institute, Dallas, downplayed the fitness versus fatness issue, which they added has led to heated debate.

"In essence, physical activity is the common denominator for the clinical treatment of low fitness and excess weight, making the fitness versus fatness debate largely academic,” they wrote. “Thus, physicians, researchers and policymakers should spend less energy debating the relative health importance of fitness and obesity and more time focusing on how to get sedentary individuals to become active."

Source: Diabetes Week staff, September 18, 2004