title: Obesity is a risk factor for atrial fibrillation among fertile young women: a nationwide cohort study.
abstract: OBJECTIVE
  Obesity has been associated with increased risk of atrial fibrillation (AF), but whether this risk is also prevalent in younger individuals is unknown. We therefore investigated the risk of AF in relation to body mass index (BMI) among young fertile women.
  
  
  RESULTS
  By cross-linkage of nationwide registers of childbirth and hospitalization, we identified 271 203 women without prior AF who gave birth in Denmark between 2004 and 2009. Body mass index (kg/m(2)) was examined as a risk factor for AF using proportional hazard models. Mean age was 30.6 years (4.7 SD) and median follow-up was 4.6 years (interquartile range 2.9-5.8). During the follow-up, 110 women were hospitalized with first-time AF; very few individuals had known risk factors for AF. Overall incidence rate of AF was 9.3 [95% confidence interval (CI): 7.7-11.2] per 100 000 person-years. According to BMI, the incidence rate of AF per 100 000 person-years was 7.4 (5.6-9.7) in normal weight (BMI: 18.5-24.9), 8.5 (5.5-13.1) in overweight (BMI: 25-29.9), 15.8 (9.3-26.7) in obese (BMI: 30-35), and 27.3 (15.5-48.1) in very obese (BMI >35) individuals. Multivariable regression analyses adjusted for age, hyperthyroidism, and previous use of beta-blockers revealed a hazard ratio of 2.04 (95% CI: 1.13-3.69) in the obese and 3.50 (1.86-6.58) in the very obese individuals compared with normal weight.
  
  
  CONCLUSIONS
  Obesity is a risk factor for AF among young and essentially healthy fertile women despite the low incidence of AF. These results may have implications for prevention of AF.
authors.affiliation: Department of Cardiology - post 635, Copenhagen University Hospital Gentofte, Niels Andersens Vej 65, 2900 Hellerup, Denmark. dkarasoy@gmail.com
authors.forename: Deniz
authors.initials: D
authors.lastname: Karasoy
authors.forename: Thomas
authors.initials: T
authors.lastname: Bo Jensen
authors.forename: Morten Lock
authors.initials: ML
authors.lastname: Hansen
authors.forename: Michelle
authors.initials: M
authors.lastname: Schmiegelow
authors.forename: Morten
authors.initials: M
authors.lastname: Lamberts
authors.forename: Gunnar Hilmar
authors.initials: GH
authors.lastname: Gislason
authors.forename: Jim
authors.initials: J
authors.lastname: Hansen
authors.forename: Christian
authors.initials: C
authors.lastname: Torp-Pedersen
authors.forename: Jonas Bjerring
authors.initials: JB
authors.lastname: Olesen
mesh_terms: D000328:Adult; D017677:Age Distribution; D001281:Atrial Fibrillation / Q000401:mortality*; D015992:Body Mass Index; D015984:Causality; D015331:Cohort Studies; D015897:Comorbidity; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000401:mortality*; D015994:Incidence; D009765:Obesity / Q000401:mortality*; D012042:Registries; D012307:Risk Factors; D016387:Women's Health / Q000706:statistics & numerical data*
keywords: Atrial fibrillation; Epidemiology; Obesity; Primary prevention; Risk factors