Study: Duration of obesity linked to increased risk of diabetes

ANN ARBOR, Mich. — The longer a person maintains a body mass index qualifying him or her as "obese," the greater risk he or she incurs in developing diabetes, a new study released Tuesday found.

"Our study finds that the relationship between weight and Type 2 diabetes is similar to the relationship between smoking and the risk of lung cancer,” stated study lead author Joyce Lee,  a pediatric endocrinologist at University of Michigan’s C.S. Mott Children’s Hospital. “The amount of excess weight that you carry, and the number of years for which you carry it, dramatically increase your risk of diabetes," she said. “We know that, due to the childhood obesity epidemic, younger generations of Americans are becoming heavier much earlier in life, and are carrying the extra weight for longer periods over their lifetimes. … When you add the findings from this study, rates of diabetes in the United States may rise even higher than previously predicted.”

Researchers found that a measure of degree and duration of excess weight — based on the number of years a person maintained a body mass index of 25 or higher — was a better predictor of diabetes risk than a single measurement of excess weight.

Lee and colleagues also found that black and Hispanic individuals compared with white individuals had a higher risk for diabetes, for the same amount of excess weight over time. For example, individuals with a BMI of 35 (10 points higher than healthy weight) for 10 years would be considered to have 100 years of excess BMI. Hispanics in this group were twice as likely to develop diabetes compared to whites, while blacks in this group had 1.5 times greater risk than whites.

Based on the latest findings, Lee suggested obesity prevention and treatment efforts should focus on adolescents and young adults, especially racial minorities.

In addition, she believed that measuring and following BMI and the cumulative “dose” of excess BMI may be helpful for clinicians and patients in understanding risk of diabetes in the future.

The new University of Michigan Health System study surveyed 8,000 adolescents and young adults. The study appeared online ahead of print in the September issue of the Archives of Pediatric & Adolescent Medicine.