The increased prevalence of atrial fibrillation (AF) in White individuals may relate to their having larger left atrial diameters relative to Blacks

Analysis of data from three prospective cohort studies confirmed that the prevalence of electrocardiographically proven AF is higher in White than African–American people; comparison of echocardiographic characteristics in one cohort showed that left atrial diameter was significantly larger in Whites. Analysis revealed that significantly more White participants had AF than did all other races combined, while fewer African Americans had AF than all other races combined, whereas Asian and Latin–American individuals had no difference in prevalence versus all other groups combined. The largest difference in AF prevalence was seen when White and African–American groups were compared: 251 (5%) of Whites versus 6 (1%) of African Americans had AF. After adjusting for potential confounders including age, gender, body mass index, heart failure, statin use, and ACE inhibitor or angiotensin receptor blocker use, White individuals had a 3.8-fold higher odds of AF compared with African Americans (p=0.002), and a 2.4-fold higher odds compared with any other race (p=0.001). African Americans had a 72% lower odds of AF compared with all other races (p=0.003). Further analysis of echocardiographic findings from the Heart and Soul Study indicated that White individuals had an average 2-mm greater left atrial diameter compared with African Americans after adjusting for confounders including age, hypertension, BMI, and ventricular septal thickness.