Cardio-metabolic risk can occur at normal BMIs

By Martha Kerr

CHICAGO (Reuters Health) - Patients with a normal body mass index (BMI) can still have a high body fat content, which increases the risk of cardiovascular disease, a Mayo Clinic team announced here during the American College of Cardiology's 57th Annual Scientific Session.

Investigator Dr. Francisco Lopez-Jimenez presented the Rochester, Minnesota group's findings on so-called "normal weight obesity" from a study of 2,127 subjects with a BMI in the normal range. BMI is the ratio of weight to height, which classifies people within a range from underweight to morbidly obese.

The study participants' body composition was measured and a full assessment was made of body size variables and cardiovascular risk factors. Normal weight obesity was defined as a body fat content higher than 20 percent for men and 30 percent for women.

"Normal weight obesity appears to be highly prevalent," Lopez-Jimenez noted, "constituting more than half of the patients with a normal weight as defined by the BMI." Of the total 2,127 subjects in the study, 1,321 had normal weight obesity, while 806 had a normal body fat content.

The investigators also found that 13.6 percent of the normal weight obese individuals met the criteria for metabolic syndrome compared with 5.3 percent of those who had a normal weight without a high body fat content.

The metabolic syndrome is a cluster of risk factors for cardiovascular disease, including high blood sugar, high levels of the "bad" LDL cholesterol and triglyceride levels, low levels of the "good" HDL cholesterol, high blood pressure and excess belly fat.

Specifically, significantly more of the normal weight obese had a high waist circumference, elevated triglyceride levels, elevated fasting blood sugar levels or a diagnosis of diabetes, and other metabolic markers associated with an increased risk of cardiovascular disease.

"Instead of tracking weight and BMI only, public health measures to prevent heart disease might benefit more from measuring the belly or by assessing percentage of body fat as more reliable risk factors of heart disease," Lopez-Jimenez concludes.