Differential impact of race and risk factors on incidence of atrial fibrillation

Abstract

Despite some common risk factors for AF being more prevalent amongst blacks, AfricanAmericans are increasingly being reported with lower prevalence and incidence of atrial fibrillation (AF) compared to Caucasians or whites. Contemporary studies have not provided a complete explanation for this apparent AF paradox in African Americans. Although many traditional and novel risk factors for AF have been identified, the role of ethnic-specific risk factors has not been examined. Whereas hypertension has been the most common risk factor associated with AF, coronary artery disease (CAD) also plays an important role in AF pathophysiology in whites. Thereby, elucidating the role of ethnic-specific risk factors for AF may provide important insight into why African Americans are protected from AF or why whites are more prone to develop the arrhythmia. The link between AF susceptibility and genetic processes has only been recently uncovered. Polymorphisms in renin-angiotensin system genes have been characterized as predisposing to AF under certain environmental conditions. A number of ion channel genes, signaling molecules and several genetic loci have been linked with AF. Thereby, studies investigating genetic variants contributing to the differential AF risk in individuals of African American versus European ancestry may also provide important insight into the etiology of the AF paradox in blacks.

Lifetime Risk of Atrial Fibrillation by Race and Socioeconomic Status

“…8 The same results have been found in different cohorts. [22][23][24][25][26][27][28] Complementing previous studies, we now show that AAs have lower lifetime risk of AF than whites, despite higher prevalence of AF risk factors. However, notwithstanding their lower lifetime risk, still 1 in 5 AAs in ARIC were estimated to develop AF during their lifetime, certainly not a trivial figure.…”

Evidence for reduced susceptibility to cardiac bradycardias in South Asians compared with Caucasians

“…While we are not aware of demonstration of such differences specifically between South Asian and white European populations, it is possible that the presence of ethnic-specific variants contribute to the relative protection of South Asians from bradycardias. Interestingly, the incidence and prevalence of atrial fibrillation (AF) has also been reported to be higher in Caucasians when compared with other ethnic groups, even when ascertainment bias has been overcome, suggesting lower susceptibility to AF in non-white ethnic groups 30. Indeed, we observed lower AF prevalence in South Asians in this report and previously in patients hospitalised with heart failure 21.…”

Global Burden of Thrombosis

“…13 Within the United States, the prevalence of atrial fibrillation is higher among whites than blacks, 39 even when controlling for modifiable risk factors, such as hypertension, diabetes mellitus, obesity, and tobacco use. 40 Increasing age is associated with increased risk of atrial fibrillation; specifically, the risk increases from 0.1% in those aged <55 years to 9% in those aged ≥80 years. 41 Men aged 75 to 79 years have twice the prevalence as men aged 65 to 69 years and >5× the prevalence of men aged 55 to 59 years.…”