No association between coffee consumption and risk of atrial fibrillation: A Mendelian randomization study

Some observational studies have found that habitual coffee and caffeine consumption might reduce the risk of atrial fibrillation (AF). We conducted a two-sample Mendelian randomization study to explore the potential association between coffee consumption and AF.This study was based on summary-level data from the Atrial Fibrillation Consortium, including 588 190 individuals (65 446 cases and 522 744 non-cases). Nine single-nucleotide polymorphisms associated with coffee consumption at significance level of P < 5 × 10-8 were used as instrumental variables and were obtained from a genome-wide association study that included up to 375 833 individuals. The odds ratio of AF per genetically-predicted 50% increase of coffee consumption was 0.98 (95% confidence interval, 0.88, 1.10; P = 0.80) in the standard inverse-variance weighted analysis. Results were consistent in sensitivity analyses using the weighted median and MR-Egger methods, and no directional pleiotropy (P = 0.37) was observed. Moreover, complementary analyses that separated the coffee-related single-nucleotide polymorphisms based on their association with blood levels of caffeine metabolites (lower, higher, unrelated or unknown association) revealed no association with AF.This study does not support a causal association between habitual coffee consumption and risk of AF.