Body fat may be better predictor of diabetes risk than BMI

People who have a normal BMI, but a high body fat percentage, were more likely to have prediabetes or diabetes

Current guidelines call for adults with high body mass index, or BMI, to be screened for prediabetes and diabetes. But under these recommendations, physicians might be missing another high-risk group: people who have a BMI in the normal range, but a high percentage of body fat.

A new PHHP study finds that people who have a normal BMI, but a high body fat percentage, were more likely to have prediabetes or diabetes than people who have lower body fat, but a BMI that categorizes them as overweight. The findings appeared in the journal BMJ Open.

“Typically, normal BMI has been perceived as healthy, so people with normal BMI have been neglected in several preventive care guidelines. Yet, normal BMI does not necessarily mean healthy body composition,” said lead investigator Ara Jo, Ph.D., a clinical assistant professor in the department of health services research, management and policy.

The findings support previous research suggesting that people with healthy weight obesity, also known as “skinny fat,” may be at significant risk for some health problems that have traditionally been associated with high body weight, including diabetes and cardiovascular disease.

For the study, the UF researchers analyzed data for the years 1999 to 2006 from the National Health and Nutrition Examination Survey, a nationally representative study that uses a combination of interviews, physical examinations and laboratory tests. They focused on adults age 40 and older who had never received a diabetes diagnosis.

They found that 13.5 percent of people who had normal BMI and high body fat met the criteria for prediabetes or diabetes compared with 10.5 percent of people with an overweight BMI, but lower body fat.

The researchers encourage clinicians to integrate body fat measures with BMI to identify people who may need screening for prediabetes and diabetes.

“We hope these findings may inspire physicians and other health professionals to look more closely at the normal BMI population and provide preventive care on time for those who are at risk of developing diabetes,” Jo said.