Estimated 10-year stroke risk by region and race in the United States: geographic and racial differences in stroke risk.

Objective: Black individuals younger than 75 years have more than twice the risk for stroke death than whites in the United States. Regardless of race, stroke death is approximately 50% greater in the "stroke belt" and "stroke buckle" states of the Southeastern United States. We assessed geographic and racial differences in estimated 10-year stroke risk.

Methods: The Reasons for Geographic and Racial Differences in Stroke study is a population-based cohort of men and women 45 years or older, recruited February 2003 to September 2007 at this report, with oversampling of stroke belt/buckle residents and blacks. Racial and regional differences in the Framingham Stroke Risk Score were studied in 23,940 participants without previous stroke or transient ischemic attack.

Results: The mean age-, race-, and sex-adjusted 10-year predicted stroke probability differed slightly across regions: 10.7% in the belt, 10.4% in the buckle, and 10.1% elsewhere (p <0.001). Geographic differences were largest for the score components of diabetes and use of antihypertensive therapy. Blacks had a greater age- and sex-adjusted mean 10-year predicted stroke probability than whites: 12.0 versus 9.2%, respectively (p <0.001). Race differences were largest for the score components of hypertension, systolic blood pressure, diabetes, smoking, and left ventricular hypertrophy.

Interpretation: Although blacks had a greater predicted stroke probability than whites, regional differences were small. Results suggest that interventions to reduce racial disparities in stroke risk factors hold promise to reduce the racial disparity in stroke mortality. The same may not be true regarding geographic disparities in stroke mortality.