Smoking and incidence of atrial fibrillation: Results from the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND Cigarette smoking increases the risk of coronary heart disease, but whether smoking increases atrial fibrillation (AF) is uncertain. OBJECTIVE The purpose of this study was to determine the association of cigarette smoking with incident AF in a population-based cohort of blacks and whites. METHODS We determined the risk of incident AF through December 2002 in relation to baseline (1987-1989) smoking status and cigarette-years of smoking in over 15,000 participants of the prospective Atherosclerosis Risk in Communities (ARIC) study. RESULTS Over a mean follow-up of 13.1 years, 876 incident AF events were identified. Compared to never smokers, the multivariable-adjusted hazard ratios (HRs) for AF were 1.32 (95% confidence interval [CI] 1.10-1.57) in former smokers, 2.05 (95% CI 1.71-2.47) in current smokers, and 1.58 (95% CI 1.35-1.85) in ever smokers. In the highest tertile of accumulated smoking amount (> 675 cigarette-years), the incidence of AF was 2.10 times greater (95% CI 1.74-2.53) than in those who never smoked. Associations were similar by gender, race, type of event (AF and atrial flutter), and when only AF events identified by study exam ECGs were included. Finally, individuals who quit smoking exhibited a trend indicating a slightly lower risk of developing AF (HR 0.88, 95% CI 0.65-1.17) compared to those who continued to smoke. CONCLUSION Smoking was associated with the incidence of AF, with more than a two-fold increased risk of AF attributed to current smoking. In addition, a trend toward a lower incidence of AF appeared among smokers who quit compared to continued smokers.