BALTIMORE – A man's waist size seems to be a stronger indicator of diabetes (search) risk than the body-mass index, new research suggests.
Johns Hopkins scientists reviewed data from 27,270 men tracked over 13 years and put them into five groups according to their waist size; 884 of the men had diabetes.
Compared to those in the group with the smallest waists, 29-34 inches, men with larger waist sizes were at least twice as likely to have diabetes. Those with the largest waist size — 40 inches and above — were up to 12 times more likely to have Type 2 diabetes (search), the kind associated with obesity.
When the men were divided into groups based on their body-mass index (search) — a formula based on weight and height — or waist-hip ratio, the level of risk wasn't as pronounced.
The study's lead author, Youfa Wang, an assistant professor with the Center for Human Nutrition at the Johns Hopkins Bloomberg School of Public Health, said waist size can indicate a strong risk for diabetes whether or not a man's BMI indicates he's overweight or obese.
"It's a better predictor for the risk of Type 2 diabetes," Wang said. "When we look at the association it's much stronger."
Wang also said the findings show the commonly used 40-inch waist circumference benchmark for diabetes risk should be lowered. Exactly how much has not been determined. "That's something we don't feel very comfortable about giving a concrete recommendation," Wang said.
Other studies have suggested about 37 1/2 inches, he said.
Alan Cherrington, president of the American Diabetes Association, said the results support previous research that has found waistline fat "is worse for you than other kinds of fat."
Researchers believe fat cells in that area may affect the liver differently, or there are signaling molecules in that type of fat cell that may affect diabetes, said Cherrington, who is also the chairman of the Department of Molecular Physiology and Biophysics at Vanderbilt University.
Cherrington said the results appear to show your waistline is a better predictor of diabetes risk and "if you combine BMI and waist circumference, you're getting the best of both worlds."
The findings are in the March issue of the American Journal of Clinical Nutrition.