title: Coffee consumption is not associated with increased risk of atrial fibrillation: results from two prospective cohorts and a meta-analysis.
abstract: BACKGROUND
  Whether coffee consumption affects the risk of developing atrial fibrillation (AF) remains unclear. We sought to investigate the association between coffee consumption and incidence of AF in two prospective cohorts, and to summarize available evidence using a meta-analysis.
  
  
  METHODS
  Our study population comprised 41,881 men in the Cohort of Swedish Men and 34,594 women in the Swedish Mammography Cohort who had provided information on coffee consumption in 1997 and were followed up for 12 years. Incident cases of AF were ascertained by linkage with the Swedish Hospital Discharge Register. For the meta-analysis, prospective studies were identified by searching PubMed and Embase through 22 July 2015, and by reviewing the reference lists of retrieved articles. Study-specific relative risks were combined using a random effects model.
  
  
  RESULTS
  We ascertained 4,311 and 2,730 incident AF cases in men and women, respectively, in the two cohorts. Coffee consumption was not associated with AF incidence in these cohort studies. The lack of association was confirmed in a meta-analysis, including six cohort studies with a total of 10,406 cases of AF diagnosed among 248,910 individuals. The overall relative risk (95% confidence interval) of AF was 0.96 (0.84-1.08) for the highest versus lowest category of coffee consumption, and 0.99 (0.94-1.03) per 2 cups/day increment of coffee consumption.
  
  
  CONCLUSIONS
  We found no evidence that coffee consumption is associated with increased risk of AF.
authors.affiliation: Unit of Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. susanna.larsson@ki.se.
authors.forename: Susanna C
authors.initials: SC
authors.lastname: Larsson
authors.affiliation: Department of Cardiology, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Nikola
authors.initials: N
authors.lastname: Drca
authors.affiliation: Department of Cardiology, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Jensen-Urstad
authors.affiliation: Unit of Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Alicja
authors.initials: A
authors.lastname: Wolk
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000209:etiology*; D002318:Cardiovascular Diseases / Q000209:etiology*; D003069:Coffee / Q000009:adverse effects*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors
chemical_list: D003069:Coffee