Long-term exposure to road traffic noise and incident heart failure ina Danish Nurse Cohort

Abstract

Objectives: Evidence of the non-auditory effects of road traffic noise exposure on health is growing. We examined the association between long-term exposure to road traffic noise and incident heart failure (HF) using various exposure windows and thresholds of the road traffic noise. Methods: We used the Danish Nurse Cohort with 22,304 female nurses who at recruitment in 1993 and 1999 reported information on HF risk factors, and linked them to the Danish National Patient and Cause of Death Registries for the first hospital contact or out-of hospital death due to HF until 2014. Road traffic noise levels in 1970-2013 were estimated by Nord2000 model as the annual mean of a weighted 24h average (Lden). We examined the associations between multi-year (up to 23 years) exposures to Lden and HF incidence using time-varying Cox regression models and estimated the effects at or above the thresholds using piece-wise linear regression models after controlling for individual covariates and air pollution levels. Results: We observed a non-linear relationship between incident HF incidence (n=438) and road traffic noise. Notably, in models adjusting for individual covariates, the hazard ratio (HR) (95% confidence intervals [CI]) of incident HF was 1.22 (95% CI: 1.05, 1.42) per 10 dB of 23-year exposures at or above 37 dB. After controlling for PM2.5, the association was attenuated (HR:1.13 [95% CI: 0.96, 1.33]), but it remained robust to adjustment for NO2 (HR:1.21 [95% CI: 1.01, 1.46]). Associations were weaker with shorter exposure windows (1- and 3-year running mean of Lden). Conclusion: Long-term exposure to road traffic noise may increase the risk of HF.