By Nathan Seppa, Science News

A swath of the Deep South and Appalachia has emerged as the U.S. “diabetes belt,” researchers find. County-by-county mapping shows that the highest rates of diabetes cut two paths—one strung through Tennessee, Kentucky and West Virginia, and another running eastward from Louisiana through Mississippi, Alabama, Georgia and South Carolina.

The belt also touches parts of North Carolina, Virginia, Florida, Texas, Arkansas, Ohio and Pennsylvania, researchers at the Centers for Disease Control and Prevention report online March 7 in the American Journal of Preventive Medicine. High-diabetes pockets crop up in Oklahoma, Michigan, Arizona, the Dakotas and elsewhere. The data do not distinguish between types of diabetes, but nationally more than 90 percent of diabetes cases are type 2, also called adult-onset diabetes.

Study coauthor Lawrence Barker, a mathematical statistician at the Centers for Disease Control and Prevention in Atlanta, says people living in the diabetes belt have many characteristics in common, including higher-than-average likelihood of being obese, African-American and leading a sedentary lifestyle. The areas also had below-average education levels with 24 percent of people holding a college degree, compared with 34 percent in the rest of the country.

“It’s really important from a public health perspective for counties and regions to recognize the health problems for which they are at particular risk,” says endocrinologist Judith Fradkin of the National Institute of Diabetes and Digestive and Kidney Diseases in Bethesda, Md.

Some of these risk factors are modifiable. Delineation of a diabetes belt will enable public health officials to target communities for specific programs aimed at curbing the disease, Barker says. One useful community intervention to encourage walking would be to install sidewalks in residential areas where none exist, he says.

Other interventions can include taxes on high-calorie beverages or a requirement for restaurants to post calorie counts of their dishes, Fradkin says. To pull people out of a sedentary lifestyle, she suggests reduced rates for gymnasium memberships.

The new map overlaps considerably with the “stroke belt” identified decades ago. She says it’s not surprising that the diabetes belt and stroke belt overlap, in part because both conditions are linked to high blood pressure and have other similar risk factors.

But the belts aren’t identical. Indiana, which lies in the stroke belt, doesn’t have high rates of diabetes, Barker notes. Conversely, West Virginia lies firmly within the diabetes belt but not in the stroke belt.

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