Whereas researchers previously used body mass index (BMI) or waist-to-hip ratio to predict disease in obese and overweight patients, new studies suggest that the size of a person's waistline is a better predictor. Until now, if a person had a BMI of 25 to 30, he or she was considered overweight; if the BMI was higher than 30, he or she was considered obese and at risk for a variety of illnesses, including heart disease and diabetes. Recent studies in the American Journal of Clinical Nutrition use the waistline as a determining marker for health status. Researchers utilized data from more than 10,000 people taking part in a government health survey between 1988 and 1994 and found that, across race and gender, waist size correlated better with cholesterol, blood pressure, and blood glucose levels than BMI. The most recent study from the Johns Hopkins Bloomberg School of Public Health compared men's waist sizes with their relative risk of diabetes and found that the risk increased when the waist was larger than 35 inches, and that 80% of type 2 diabetes cases occurred in men with waists larger than 37 inches. Those data were based on the 13-year Harvard Health Professionals Followup Study of 27,270 men. The study also found that men with a waist larger than 40 inches were 12 times more likely than men with waists smaller than 34 inches to develop the kind of diabetes in which the pancreas is unable to create enough insulin.
Ms. Farley is a freelance medical writer based in Wakefield, RI.