Serum uric acid (SUA) has been associated with cardiovascular disease in population studies, but its relation to atrial fibrillation (AF) is largely unknown. The aim of this study was to investigate the association between baseline SUA and future AF in a large population-based cohort.METHODS AND RESULTS: A total of 6308 men and women from a population survey in Tromsø, Norway in 1994-95 were followed-up for 10.8 years. The mean age at baseline was 60 years. Information on angina, myocardial infarction, diabetes, anti-hypertensive and diuretic treatment, physical activity, smoking and alcohol, and measurements of height, weight, blood pressure, SUA, total cholesterol, and high density lipoprotein-cholesterol were obtained at baseline. The outcome measure was first-ever AF, documented on an electrocardiogram. We identified 572 cases of incident AF. In multivariable Cox proportional hazards regression analysis adjusted for cardiovascular risk factors and concomitant diseases, SUA was associated with AF in both sexes. Hazard ratio per 1 SD increase in SUA (91 μmol/L) was 1.40 [95% confidence intervals (CI), 1.14-1.72] in women and 1.17 (95% CI, 1.02-1.36) in men. The upper quartile of SUA conferred a 76% increased risk for AF in women and 49% in men as compared with the lowest quartile.CONCLUSION: This prospective population-based cohort study showed that baseline SUA was associated with an increased risk for future AF in both sexes.