Atrial Fibrillation and Ethnicity

To the Editor: Benjamin et al1 address the risk of atrial fibrillation (AF) in the Framingham Study with a longitudinal population design, which overcomes the common problem of selection bias. However, the study sample was predominantly white, and the one epidemiological question that remains unanswered is the relationship between race and the incidence of AF.Although there are recognized ethnic differences in cardiovascular disease and stroke, the world literature on the clinical epidemiology of AF in nonwhite groups is scarce. We are only aware of small surveys on the prevalence of AF in nonwhites from Africa,2 Japan,3 and Hong Kong,4 in addition to our work in a multiethnic population in Birmingham, England.5 For example, Maru2 reported 136 Ethiopian cardiac outpatients with AF, in whom the mean age was 41 years, and the commonest causes were rheumatic heart disease (66%), hypertension (10%), cardiomyopathy (9%), and ischemic heart disease (7%). A Japanese report3 of secular trends in the prevalence and incidence …