Stroke Incidence and Survival in American Indians, Blacks, and Whites: The Strong Heart Study and Atherosclerosis Risk in Communities Study

Background: American Indians (AIs) have high stroke morbidity and mortality. We compared stroke incidence and mortality in AIs, blacks, and whites. Methods and Results: Pooled data from 2 cardiovascular disease cohort studies included 3182 AIs from the SHS (Strong Heart Study), aged 45 to 74 years at baseline (1988–1990) and 3765 blacks and 10 413 whites from the ARIC (Atherosclerosis Risk in Communities) Study, aged 45 to 64 years at baseline (1987–1989). Stroke surveillance was based on self-report, hospital records, and death certificates. We estimated hazard ratios for incident stroke (ischemic and hemorrhagic combined) through 2008, stratified by sex and birth-year tertile, and relative risk for poststroke mortality. Incident strokes numbered 282 for AIs, 416 for blacks, and 613 for whites. For women and men, stroke incidence among AIs was similar to or lower than blacks and higher than whites. Covariate adjustment resulted in lower hazard ratios for most comparisons, but results for these models were not always statistically significant. After covariate adjustment, AI women and men had higher 30-day poststroke mortality than blacks (relative risk=2.1 [95% CI=1.0, 3.2] and 2.2 [95% CI=1.3, 3.1], respectively), and whites (relative risk=1.6 [95% CI=0.8, 2.5] and 1.7 [95% CI=1.1, 2.4]), and higher 1-year mortality (relative risk range=1.3–1.5 for all comparisons). Conclusions: Stroke incidence in AIs was lower than for blacks and higher than for whites; differences were larger for blacks and smaller for whites after covariate adjustment. Poststroke mortality was higher in AIs than blacks and whites.