Race-Specific Impact of Atrial Fibrillation Risk Factors in Blacks and Whites in the Southern Community Cohort Study

Abstract

Despite a greater burden of traditional risk factors, atrial fibrillation (AF) is less common among black than whites for reasons that are unclear. We have examined race- and gender-specific influences of demographic, lifestyle, anthropometric and medical factors on AF in a large cohort of blacks and whites. Among white and black participants in the Southern Community Cohort Study age 65 and older receiving Medicare coverage from 1999–2008 (n=8,836), we ascertained diagnoses of AF (ICD-9 CM 427.3). Multivariate logistic regression was used to compute AF odds ratios (ORs) associated with participant characteristics, including histories of hypertension, diabetes, stroke and myocardial infarction/coronary artery bypass graft surgery, ascertained at cohort entry. Over an average of 5.7 years of Medicare coverage, AF was diagnosed among 1,062 participants. AF prevalence was significantly lower among blacks (11%) than whites (15%; P<.0001). ORs for AF rose with age, were higher among men, the tall and obese, and among persons with each of the comorbid conditions, but the AF deficit among blacks compared with whites persisted upon adjustment for these factors (OR=0.64, 95% CI 0.55–0.73). The patterns of AF risk were similar for blacks and whites, although associations with hypertension, diabetes and stroke were somewhat stronger among blacks. In conclusion, these findings confirm the lower prevalence of AF among blacks than whites and suggest that traditional risk factors for AF apply similarly to both groups and thus do not appear to explain the AF paradox in blacks.

Atrial fibrillation incidence and risk factors in relation to race-ethnicity and the population attributable fraction of atrial fibrillation risk factors: the Multi-Ethnic Study of Atherosclerosis

“…PAF estimates of AF risk factors have been previously noted to be higher for NHBs than for NHWs [38]. However, in our study and others [7,8], the race–ethnic differential distribution of AF risk factors does not explain the lower incidence of AF among nonwhite participants. Because there appears to be a genetic predisposition among NHWs for AF [28], our results support continued investigation for unexplained AF risk factors among NHWs and/or protective factors among nonwhite populations.…”

“…Although debatable [8], several explanations have been suggested to explain differences in AF incidence among NHBs and NHWs such as under ascertainment of events because of poorer access to care among NHBs, differential mortality, or under ascertainment of events because of a higher incidence of paroxysmal AF in NHBs [27]. In a population of NHBs and NHWs, ECG indices such as P wave duration, area, and amplitude did not appear to explain the race–ethnic differences in AF prevalence [33].…”

“…Current understanding of the pathophysiology and epidemiology of AF is based primarily on studies in non-Hispanic whites (NHWs) populations with limited data on the nonwhite populations. The few previous studies that addressed the risk of AF across different races/ethnicities focused on non-Hispanic black (NHB) versus NHW populations [2–8]. These few studies have consistently reported that NHB individuals have lower AF burden compared with their NHW counterparts.…”

Diabetes mellitus and atrial fibrillation: Pathophysiological mechanisms and potential upstream therapies

“…Even though the relationship between non-alcoholic fatty liver disease and AF in type 2 DM is currently unknown, the putative role of non-alcoholic fatty liver disease in AF development may have significant implications in terms of screening the increasing population of patients with liver abnormality [16]. Apart from the aforementioned risk factors, several additional parameters (aging [17], ethnicity [18][19][20][21][22], hyperuricemia [23], pulse pressure [24], heart rate recovery [25], and heart failure [26]) seem to be associated with increased AF risk in the setting of DM. The clinical and demographic parameters that influence the relationship between DM and AF are presented in Table 1.…”

Smoking, sex, risk factors and abdominal aortic aneurysms: a prospective study of 18 782 persons aged above 65 years in the Southern Community Cohort Study

“…19 Cases of incident AAA were defined as Medicare beneficiaries aged ≥65 years with at least one new medical claim with an International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9 CM) diagnosis code of 441.3 (ruptured AAA) or 441.4 (AAA without rupture) within the Medicare institutional (Medicare Provider Analysis and Review, MEDPAR), Part-B carrier or outpatient base claims files during this period. Thus, in this study incident, AAA is defined as a new diagnosis made in the clinical setting through physician-initiated screening.…”