In the so-called stroke belt in the Southeast, cardiovascular disease rates are much higher than in the rest of the country. Scientists generally believe that is because people in the region have higher rates of such risk factors as smoking, obesity and diabetes.
Now a large study, published in the November issue of PLoS One, suggests that there may be more to it than that. Using nationwide data on 26,029 healthy women whose average age was 53, researchers found significant geographical variations in inflammation as measured by blood levels of C-reactive protein and two other markers that significantly increase the risk for heart problems in women.
Women in the Southeast and Appalachia had the highest levels, but none of the clinical and lifestyle risk factors for cardiovascular disease could account for the finding. Even after controlling for race, ethnicity, obesity, smoking, diabetes, exercise, cholesterol levels and blood pressure, the geographic variation in the inflammatory markers persisted.
“Our research doesn’t answer why, but my guess is that it has something to do with economic differences between places,” said the lead author, Dr. Cheryl R. Clark, an assistant professor of medicine at Harvard University.
“Place matters in questions of health,” she added, “and we’re trying to understand what some states might be doing differently from other states that might affect heart disease risk.”