Long-Term Exposure to Road Traffic Noise and Air Pollution, and Incident Atrial Fibrillation in the Danish Nurse Cohort

BACKGROUND: Associations between long-term exposure to air pollution and road traffic noise have been established for ischemic heart disease, but findings have been mixed for atrial fibrillation (AF). OBJECTIVES: The goal of the study was to examine associations of long-term exposure to road traffic noise and air pollution with AF. METHODS: Time-varying Cox regression models were used to estimate associations of 1-, 3-, and 23-y mean road traffic noise and air pollution exposures with AF incidence in 23,528 women enrolled in the Danish Nurse Cohort (age [Formula: see text] at baseline in 1993 or 1999). AF diagnoses were ascertained via the Danish National Patient Register. Annual mean weighted 24-h average road traffic noise levels ([Formula: see text]) at the nurses’ residences, since 1970, were estimated using the Nord2000 model, and annual mean levels of particulate matter with a diameter [Formula: see text] ([Formula: see text]) and nitrogen dioxide ([Formula: see text]) were estimated using the DEHM/UBM/AirGIS model. RESULTS: Of 23,528 nurses with no prior AF diagnosis at the cohort baseline, 1,522 developed AF during follow-up. In a fully adjusted model (including [Formula: see text]), the estimated risk of AF was 18% higher [hazard ratio (HR); 95% confidence interval (CI): 1.18; 1.02, 1.36] in nurses with residential 3-y mean [Formula: see text] levels [Formula: see text] vs. [Formula: see text] , with similar findings for 1-y mean exposures. A [Formula: see text] increase in 3-y mean [Formula: see text] was associated with incident AF before and after adjustment for concurrent exposure to road traffic noise (HR 1.09; 95% CI: 1.00, 1.20 and 1.08; 95% CI: 0.97, 1.19, respectively). Associations with 1-y mean [Formula: see text] exposures were positive but closer to the null and not significant. Associations with [Formula: see text] were null for all time periods before and after adjustment for road traffic noise and inverse when adjusted for concurrent [Formula: see text]. CONCLUSION: Our analysis of prospective data from a cohort of Danish female nurses followed for up to 14 y provided suggestive evidence of independent associations between incident AF and 1- and 3-y exposures to road traffic noise and [Formula: see text]. https://doi.org/10.1289/EHP8090