title: Differential Impact of Risk Factors in Blacks and Whites in the Development of Atrial Fibrillation: the Reasons for Geographic And Racial Differences in Stroke (REGARDS) Study.
abstract: Despite a higher prevalence of risk factors, atrial fibrillation (AF) is less prevalent in blacks than whites. To address this paradox, we examined racial differences in the magnitude of AF risk associated with common risk factors.
  
  
  
  Participants (13,688; mean age = 63 ± 8.4 years; 56 % female; 37 % black) from the Reasons for Geographic And Racial Differences in Stroke study who were free of baseline AF were included. Incident AF was identified at a follow-up examination by electrocardiogram and self-reported medical history. Poisson regression was used to compute relative risk (RR) and 95 % confidence intervals (CI) for the association between risk factors and incident AF in blacks and whites, separately. Age- and sex-adjusted population attributable fractions (PAFs) of modifiable AF risk factors were computed.
  
  
  
  After median follow-up of 9.4 years, 997 (7.3 %) incident AF cases were detected. Black race was associated with a lower risk of AF (RR = 0.46, 95 % CI = 0.39, 0.53). Significant risk factors for AF were age, male sex, hypertension, obesity, and cardiovascular disease. A differential association was detected for smoking by race, with the association being stronger in blacks (RR = 1.41, 95 % CI = 1.07, 1.85) compared with whites (RR = 1.01, 95 % CI = 0.88, 1.16; P interaction = 0.030). The PAFs for hypertension (blacks = 27.4 %, whites = 19.4 %), obesity (blacks = 16.9 %, whites = 11.8 %), and smoking (blacks = 17.9 %, whites = 2.5 %) were higher for blacks than whites.
  
  
  
  Modifiable risk factors are important in AF development among blacks despite a lower risk of the arrhythmia. Racial differences in the magnitude of the association of individual AF risk factors do not explain the AF paradox.
authors.affiliation: Department of Medicine, Division of Cardiology, Emory University School of Medicine, 101 Woodruff Circle, Woodruff Memorial Building, Atlanta, GA, 30322, USA. wesley.oneal@emory.edu.
authors.forename: Wesley T
authors.initials: WT
authors.lastname: O'Neal
authors.affiliation: Department of Biostatistics, School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Suzanne E
authors.initials: SE
authors.lastname: Judd
authors.affiliation: Department of Neurology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA.
authors.forename: Nita A
authors.initials: NA
authors.lastname: Limdi
authors.affiliation: Section of Cardiology, Department of Internal Medicine, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: William F
authors.initials: WF
authors.lastname: McIntyre
authors.affiliation: Department of Neurology, University of Cincinnati, Cincinnati, OH, USA.
authors.forename: Dawn O
authors.initials: DO
authors.lastname: Kleindorfer
authors.affiliation: Department of Medicine, University of Vermont, Burlington, VT, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Cushman
authors.affiliation: Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Virginia J
authors.initials: VJ
authors.lastname: Howard
authors.affiliation: Department of Biostatistics, School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: George
authors.initials: G
authors.lastname: Howard
authors.affiliation: Department of Medicine, Section on Cardiology, Wake Forest School of Medicine, Winston-Salem, NC, USA.|Epidemiological Cardiology Research Center (EPICARE), Department of Epidemiology and Prevention, Wake Forest School of Medicine, Winston-Salem, NC, USA.
authors.forename: Elsayed Z
authors.initials: EZ
authors.lastname: Soliman
mesh_terms: D001741:Black or African American / Q000706:statistics & numerical data*; D000368:Aged; D001281:Atrial Fibrillation / Q000208:ethnology*; D005260:Female; D054624:Health Status Disparities; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D020521:Stroke / Q000208:ethnology / Q000401:mortality; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data*
keywords: Atrial fibrillation; Epidemiology; Race; Risk factors