COLUMBUS, Ohio – A study led by researchers at The Ohio State University Wexner Medical Center and College of Medicine found that measuring Black adults' waist circumferences can be a simple and inexpensive way to predict if they'll develop diabetes in the future.
Study findings published online today in the Journal of the American Heart Association.
Researchers compared a variety of tests to try to predict which patients would develop diabetes, including measuring waist circumference, along with visceral adipose (fat) tissue that surrounds internal organs and liver fat. They also used measured fasting glucose (blood sugar) levels and hemoglobin A1C blood tests.
"We found that waist circumference, as well as the visceral fat tissue and liver fat, were much better predictors of development of diabetes than the hemoglobin A1C test in people with normal blood sugar levels. But for those with pre-diabetes, we found that the hemoglobin A1C test is the best predictor for developing diabetes," said the study's lead author Dr. Joshua J. Joseph, assistant professor of medicine in the Division of Endocrinology, Diabetes and Metabolism at Ohio State Wexner Medical Center.
More than 34 million Americans have diabetes, but Black populations have a higher risk of developing the disease, according to the American Diabetes Association.
Although the study did not evaluate specific targets for waist circumference – measured around the waist at the belly button – previous work in metabolic syndrome has shown that a waist circumference of 35 inches or more for women or 40 inches or more for men increases – was a risk of diabetes. Body mass index (BMI), was not as strong of a predictor as waist circumference in this study.
Researchers studied almost 4,000 participants of the long-term Jackson Heart Study at the University of Mississippi Medical Center in Jackson, Miss. They fell into two groups: either normal fasting glucose (blood sugar) or had been diagnosed with pre-diabetes because of elevated blood sugar levels.
The hemoglobin A1C test measures the percentage of your red blood cells that have sugar-coated hemoglobin, which is a protein in your blood. A normal A1C level is below 5.7%, a level of 5.7% to 6.4% indicates prediabetes, and a level of 6.5% or more indicates diabetes, according to the Centers for Disease Control and Prevention.
A fasting blood sugar test measures blood sugar after an overnight fast of not eating. A fasting blood sugar level of 99 mg/dL or lower is normal, 100 to 125 mg/dL indicates prediabetes, and 126 mg/dL or higher indicates diabetes, according to the CDC.
"Visceral fat and liver fat are measured with CT scans, which are costly and expose individuals to radiation. But measuring waist circumference is simple and free," said Joseph, who collaborated with researchers at the University of Mississippi and Johns Hopkins University. "We encourage primary care physicians to measure waist circumference during annual physicals, and if needed, suggest healthy lifestyle modifications to help patients improve their waist sizes."
These lifestyle modifications could include eating more fruits and vegetables, limiting sugar-sweetened beverages, increasing fiber, engaging in 150 minutes of moderate intensity physical activity each week, getting enough sleep and lowering sodium intake to less than 1,500 mg daily, Joseph said.
Doctors also could prescribe exercise classes such as Exercise is Medicine or nutritious cooking classes to their patients, Joseph said.
"With this study, we're trying to see if we could think about diabetes prevention even earlier. Instead of waiting until someone has already been diagnosed with pre-diabetes and is knocking on the door of diabetes, could we try to intervene sooner, and encourage them to adopt healthier lifestyle modifications to limit their risk of developing diabetes over time," Joseph said.
