Overall Obesity, measured by high body mass index (BMI) - the height-to-weight ratio, and abdominal obesity, measured by a large waist circumference, each strongly and independently predict the risk of type 2 diabetes in men, but abdominal obesity appears to be the better predictor, new research shows.

“Both BMI and waist circumference are useful for assessing health risk and should be measured in clinical settings…whenever possible,” the investigators say. But abdominal fat measured by waist circumference “can indicate a strong risk for diabetes whether or not a man is considered overweight or obese according to his BMI,” lead author Dr. Youfa Wang added in a statement.

In the study, investigators compared the predictive power of BMI, waist circumference, and waist-to-hip ratio for the development of type 2 diabetes in 27,270 men participating in the Health Professionals Follow-up Study.

During 13 years of follow-up, a total of 884 men developed type 2 diabetes, Wang, from Johns Hopkins Bloomberg School of Public Health in Baltimore, and colleagues report in the American Journal of Clinical Nutrition.

According to the team, as waist circumference increased, so did the risk of developing diabetes, with the risk in men with the highest waist circumference (up to 158 centimeters) increasing by 12-fold, they report.

A similar graduated risk was seen for waist-to-hip ratio and BMI, with the largest values associated with a 7-fold and 8-fold increased risk, respectively.

“Our findings support the contention that the measurement of waist circumference should be used in clinical practice instead of waist-to-hip ratio,” the investigators write.

The study findings also suggest that the currently recommended cutoff for high waist circumference of 102 cm (40 inches) for men may need to be lowered to 95 cm.

“Many of the men who developed type 2 diabetes had measurements lower than the cutoff, Wang said, “and the risk associated with the waist circumference increased at a much lower level.”

SOURCE: American Journal of Clinical Nutrition, March 2005.