title: South Asian ethnicity is associated with a lower prevalence of atrial fibrillation despite greater prevalence of established risk factors: a population-based study in Bradford Metropolitan District.
abstract: OBJECTIVE
  Previous studies indicate that South Asians (SAs) may have a reduced risk of developing atrial fibrillation (AF) despite having a higher prevalence of traditional cardiovascular risk factors. This observational study was designed to explore the relative differences between SAs and Whites in a well-defined, multi-ethnic population with careful consideration of traditional cardiovascular risk factors that are thought to contribute to the development of AF.
  
  
  RESULTS
  Anonymized data from 417 575 adults were sourced from primary care records within Bradford Metropolitan District, UK. Atrial fibrillation diagnosis was indicated by the presence on the AF Quality Outcomes Framework register. Self-reported ethnicity was mapped to census ethnic codes. The age-standardized prevalence rates of AF were calculated for comparison between the White and SA populations; our study sample presented relative proportions of 2.39 and 0.4%. Multivariable logistic regression analysis was performed to estimate the odds of developing AF given SA ethnicity. Adjustment for age, sex, and established risk factors found a 71% reduction in odds of AF in SAs when compared with Whites [odds ratio (OR): 0.29, 95% confidence interval (CI): 0.26-0.32]. When stratified by ethnicity, analyses revealed significantly different odds of AF for patients with diabetes; diabetes was not associated with the development of AF in the SA population (0.81, 95% CI: 0.63-1.05).
  
  
  CONCLUSIONS
  This study, in a multi-ethnic population, presents ethnicity as a predictor of AF in which prevalence is significantly lower in SAs when compared with Whites. This is despite SAs having a higher frequency of established risk factors for the development of AF, such as ischaemic heart disease, heart failure, hypertension, and type 2 diabetes. These findings are consistent with previous literature and add weight to the need for further investigation, although this is the first study to investigate the differential associations of individual risk factors with development of AF.
authors.affiliation: Department of Cardiology, West Yorkshire Arrhythmia Service, Leeds General Infirmary, Leeds Teaching Hospitals NHS Trust, Leeds LS1 3EX, UK.
authors.forename: Richard Geoffrey
authors.initials: RG
authors.lastname: Gillott
authors.affiliation: Department of Cardiology, West Yorkshire Arrhythmia Service, Leeds General Infirmary, Leeds Teaching Hospitals NHS Trust, Leeds LS1 3EX, UK.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Willan
authors.affiliation: Cardiovascular and Diabetes Research, Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), University of Leeds, Leeds, UK.
authors.forename: Kirti
authors.initials: K
authors.lastname: Kain
authors.affiliation: Department of Cardiology, West Yorkshire Arrhythmia Service, Leeds General Infirmary, Leeds Teaching Hospitals NHS Trust, Leeds LS1 3EX, UK.
authors.forename: Uduvil Mohanaraj
authors.initials: UM
authors.lastname: Sivananthan
authors.affiliation: Department of Cardiology, West Yorkshire Arrhythmia Service, Leeds General Infirmary, Leeds Teaching Hospitals NHS Trust, Leeds LS1 3EX, UK.
authors.forename: Muzahir Hassan
authors.initials: MH
authors.lastname: Tayebjee
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000208:ethnology* / Q000517:prevention & control; D015897:Comorbidity; D004739:England / Q000453:epidemiology; D005260:Female; D054624:Health Status Disparities; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D015995:Prevalence; D065840:Protective Factors; D018570:Risk Assessment; D012307:Risk Factors; D014504:Urban Health; D044465:White People; D055815:Young Adult
keywords: Atrial fibrillation; Ethnicity; Prevalence; Risk factors; South Asian; White