Racial Differences in Ischemic and Hemorrhagic Stroke: An Ecological Epidemiological Study.

Background:  This study aimed to evaluate racial differences in the incidence of stroke by conducting an ecological epidemiological study using UK Biobank and Korean nationwide data.

Methods:  This study used individual data from the Korean National Health Insurance Service-Health Screening and UK Biobank, which included participants who underwent health examinations between 2006 and 2010. We included 112,750 East Asians (50.7% men, mean age: 52.6 years) and 210,995 Caucasians (44.7% men, mean age: 55.0 years) who were not diagnosed with atrial fibrillation, cardiovascular diseases, chronic kidney disease, chronic obstructive pulmonary disease, or cancer. The primary outcome was defined as a composite of ischemic and hemorrhagic stroke.

Results:  East Asians tended to have a lower body mass index (23.7 vs. 26.4 kg/m,  < 0.001) and a higher proportion of participants who did not engage in moderate-to-vigorous physical activity (49.6% vs. 10.7%,  < 0.001) than Caucasians. During the follow-up, East Asians had higher 5-year incidence rates (presented as per 1,000 person-years) for primary outcome (1.73 vs. 0.50; IR ratio [IRR]: 3.48, 95% confidence interval [CI]: 3.13-3.88), ischemic stroke (1.23 vs. 0.33; IRR: 3.70, 95% CI: 3.25-4.21), hemorrhagic stroke (0.56 vs. 0.18; IRR: 3.20, 95% CI: 2.67-3.84), and atrial fibrillation-related stroke (0.19 vs. 0.09; IRR: 2.04, 95% CI: 1.55-2.68).

Conclusion:  Based on this ecological epidemiological study, racial differences in stroke incidence were robust to a variety of statistical analyses, regardless of the subtype. This suggests the need for region-specific approaches to stroke prevention.