BACKGROUND: The increasing prevalence of atrial fibrillation (AF) requires efforts to understand racial differences in disease distribution and risk factors. OBJECTIVE: We aimed to compare associations between risk factors and AF in White Europeans from the UK Biobank and Asians from the Korean National Health Insurance Service-Health Screening (NHIS-HEALS) study. METHODS: This study included participants from the Korean NHIS-HEALS and UK Biobank. After matching for age and sex, 206,704 participants in the Korean NHIS-HEALS and 206,704 participants in the UK Biobank were enrolled in the study. The incidence of AF, its associations with biomarkers, prevalent cardiovascular disease, and population attributable risk by race were examined. RESULTS: During a median follow-up of 7.1 years in the Korean NHIS-HEALS and 11.9 years in the UK Biobank, those in the UK Biobank showed a higher incidence and risk of AF (3.99 vs 3.41 per 1000 person-years
hazard ratio, 1.20
95% confidence interval [CI], 1.15-2.25) compared with the population in the Korean NHIS-HEALS. Body mass index (BMI), systolic blood pressure, alcohol, heart failure, myocardial infarction, and stroke were associated with an increased risk of new-onset AF in both cohorts. Higher BMI and smoking were more strongly related to the increased risk of new-onset AF in the UK Biobank compared with the Korean NHIS-HEALS, with a relative risk ratio of 1.21 (95% CI, 1.17-1.25) and 1.12 (95% CI, 1.02-1.21), respectively. CONCLUSION: In this first large-scale comparison of White and Asian populations, the cumulative risk for development of AF was higher in the United Kingdom than in Korea. Higher BMI and smoking were associated with a higher risk of AF in the United Kingdom than in Korea.