Long-Term Exposure to Traffic-Related Air Pollution and Risk of Incident Atrial Fibrillation: A Cohort Study

BACKGROUND: Atrial fibrillation is the most common sustained arrhythmia and associated with cardiovascular morbidity and mortality. The few studies conducted on short-term effects of air pollution on episodes of atrial fibrillation indicates a positive association, though not consistently.

OBJECTIVES: The aim of this study was to evaluate the long-term impact of traffic-related air pollution on incidence of atrial fibrillation in the general population.

METHODS: In the Danish Diet, Cancer, and Health cohort of 57,053 people aged 50-64 years at enrolment in 1993-1997, we identified 2,700 cases of first-ever hospital admission for atrial fibrillation from enrolment to end of follow-up in 2011. For all cohort members, exposure to traffic-related air pollution assessed as nitrogen dioxide (NO2) and nitrogen oxides (NOx) was estimated at all present and historical residential addresses from 1984 to 2011 using a validated dispersion model. We used Cox proportional hazard model to estimate associations between long-term residential exposure to NO2 and NOx and risk of atrial fibrillation, after adjustment for lifestyle and socioeconomic position.

RESULTS: A 10 µg/m(3) higher 10-years' time-weighted mean exposure to NO2 preceding diagnosis was associated with an 8% higher risk of atrial fibrillation (incidence rate ratio: 1.08; 95% confidence interval: 1.01-1.14) in adjusted analysis. Though weaker, similar results were obtained for long-term residential exposure to NOx. We found no clear tendencies regarding effect modification of the association between NO2 and atrial fibrillation by sex, smoking, hypertension or myocardial infarction.

CONCLUSION: We found long-term residential traffic-related air pollution to be associated with higher risk of atrial fibrillation. Accordingly, the present findings lend further support to the demand for abatement of air pollution.