title: Inflammatory biomarkers as risk factors for future atrial fibrillation. An eleven-year follow-up of 6315 men and women: the Tromsø study.
abstract: BACKGROUND
  Inflammatory biomarkers are reported as risk factors for atrial fibrillation (AF), but their impact is uncertain.
  
  
  OBJECTIVE
  We investigated the associations between inflammatory biomarkers and future AF in a large general cohort.
  
  
  METHODS
  Available markers were white blood cells (WBCs) with subgroups, fibrinogen, high-sensitivity C-reactive protein (hs-CRP), and osteoprotegerin (OPG). A total of 6315 men and women from a population survey in Tromsø, Norway in 1994 to 1995 were followed for a mean of 10.9 years. Mean age at baseline was 60 years. Measurements of height, weight, blood pressure, heart rate, total cholesterol, high-density lipoprotein (HDL) cholesterol, WBC count, and information on diabetes, angina, myocardial infarction, and antihypertensive treatment, were obtained at baseline. Fibrinogen, hs-CRP, and OPG were obtained at a follow-up visit. The outcome measure was first-ever AF, documented on an electrocardiogram. The Cox proportional hazards regression model was used to estimate hazard ratios of AF.
  
  
  RESULTS
  In the multivariable analysis, adjusted for traditional cardiovascular risk factors and other inflammatory biomarkers, hs-CRP was associated with AF in men only (hazard ratio = 1.14 for a 1 SD increase; 95% CI, 1.02-1.28). There was a significant increase in AF across quartiles of WBCs in men (P = 0.007) and in the total study population (P = 0.004). OPG was associated with AF in patients free of coronary heart disease at baseline. Fibrinogen and subgroups of WBCs showed no significant association with AF.
  
  
  CONCLUSIONS
  This population-based cohort study showed that hs-CRP was independently associated with AF in men, but apparently not in women, and that patients with WBCs in the upper quartile had increased risk of AF.
authors.affiliation: Department of Community Medicine, University of Tromsø, Tromsø, Norway. audhild.nyrnes@uit.no
authors.forename: Audhild
authors.initials: A
authors.lastname: Nyrnes
authors.forename: Inger
authors.initials: I
authors.lastname: Njølstad
authors.forename: Ellisiv B
authors.initials: EB
authors.lastname: Mathiesen
authors.forename: Tom
authors.initials: T
authors.lastname: Wilsgaard
authors.forename: John-Bjarne
authors.initials: JB
authors.lastname: Hansen
authors.forename: Tove
authors.initials: T
authors.lastname: Skjelbakken
authors.forename: Lone
authors.initials: L
authors.lastname: Jørgensen
authors.forename: Maja-Lisa
authors.initials: ML
authors.lastname: Løchen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000453:epidemiology*; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein; D003327:Coronary Disease / Q000453:epidemiology; D004562:Electrocardiography; D005260:Female; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000097:blood*; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009664:Norway / Q000453:epidemiology; D053244:Osteoprotegerin / Q000097:blood; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors
chemical_list: D015415:Biomarkers; D053244:Osteoprotegerin; D005340:Fibrinogen; D002097:C-Reactive Protein