Regarding REGARDS: Does Inflammation Explain Racial and Regional Differences in Cardiovascular Disease Risk?

Abstract

Although black men and women residing in the US experience the highest rates of mortality from both stroke and coronary heart disease (CHD)1 (1), underlying reasons for these statistics remain uncertain. Although differential traditional risk factors, access to care, and sociodemographic and psychosocial variability between race/ethnic groups might undoubtedly account for some of the observed differences, other factors might be at play. For example, whereas both ischemic stroke and CHD often share atherosclerosis as a core pathogenic element, evidence suggests that in general blacks tend to have less atherosclerotic burden measured by coronary calcium score or angiography than whites (2). Additionally, autopsy results from blacks and whites who succumb to sudden cardiac death indicate that blacks have a higher preponderance of stable plaque than whites (3). Thus, from a pathological perspective, race/ethnic differences in cardiovascular risk require further elucidation. The REGARDS (Reasons for Geographic and Racial Differences in Stroke) study was instituted to examine causes for the excess stroke mortality among US blacks and people living in the stroke belt (4). Previous publications from the study examined individual traditional risk factors for stroke and CHD. Differences between blacks and whites and by region were demonstrated—including differences in the prevalence of blood pressure and antihypertensive use, diabetes, smoking, and left ventricular hypertrophy. The estimated predicted probability of stroke, reflecting a combination of risk factors, showed clear differences by race and sex: blacks had higher 10-year stroke risk than whites (11.3% vs 9.7%, P < 0.0001), largely driven by differences in diabetes and possibly hypertension in the 2 groups (4). The same studies, however, have not explained the differences in stroke by region. Whereas the prevalence of antihypertensive use was higher among both blacks and whites residing in the stroke belt (4), there was a trend toward better treatment and …