Background: The lifetime risk of atrial fibrillation (AF) has been previously reported in whites, but not in African Americans. Moreover, we lack current estimates of lifetime risk of AF that take into account recent trends in the incidence of this arrhythmia. Lifetime risk of AF by socioeconomic status has not been investigated before.
Methods: We studied 15,343 whites and African Americans in the Atherosclerosis Risk in Communities study who were followed for an average of 21 years (maximum 27 years). Total family income was categorized as <$25,000, $25,000-$49,999, and ≥$50,000, and education as < high school graduate, high school graduate, and at least some college. Incident AF was ascertained from study electrocardiograms, hospital discharge records, and death certificates. Lifetime risk of AF was estimated by a modified Kaplan-Meier method that accounted for the competing risk of death.
Results: We identified 2760 AF cases during follow-up. Lifetime risk of AF was 36% (95% CI: 32-38%) in white men, 30% (26-32%) in white women, 21% (13-24%) in African American men, and 22% (16-25%) in African American women (Figure). Regardless of race and sex, incidence rates of AF decreased from the lowest to highest categories of income and education. In contrast, lifetime risk of AF increased in individuals with higher income and education in most sex-race groups. Cumulative incidence of AF was lower in those with higher income and education compared to their low socioeconomic status counterparts through earlier life, but was reversed after age 80.
Conclusion: Lifetime risk of AF in a contemporary cohort in the United States was approximately 1 in 3 among whites and 1 in 5 among African Americans. Socioeconomic status was inversely associated with cumulative incidence of AF before the last decades of life.