The long-term exposure to 3 components of air pollution and road traffic noise was linked to an increased risk for heart failure (HF), according to study results published in the Journal of the American Heart Association.

In the current study, researchers used data from the Danish Nurse Cohort (DNC), which launched in 1993 as a questionnaire for members of the Danish Nurse Organization. Researchers collected data on clinical characteristics of participants by linking the cohort to the Danish National Patient Register. The researchers also estimated the risk for HF and the impact of exposure to air pollution and road traffic noise based on participants’ residential addresses, using the Danish air pollution modeling system and noise surveillance from within 3 km of their home.

A total of 22,189 women nurses were eligible for study inclusion. The mean age for participants was 52.6±7.7 years; body mass index (BMI) was 23.7±3.5; 34.8% had never smoked; 61.9% were moderate drinkers; 12.4% had hypertension; and 1.2% had diabetes. A total of 484 nurses developed HF during the study.

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The 3-year average of fine particulate matter (PM2.5) was 21.0 μg/m3, nitrogen dioxide (NO2) was 13.5 μg/m3, and weighted 24-hour noise level (Lden) was 52.6 dB. Nitrogen dioxide was correlated with PM2.5 (r=0.58) and Lden (r=0.62).

For every 5.1 μg/m3 addition of PM2.5, the risk for HF was increased (hazard ratio [HR], 1.36; 95% CI, 1.20-1.55; P <.05). Similarly, with an additional 8.6 μg/m3 in NO2, HF risk increased (HR, 1.18; 95% CI, 1.08-1.29; P <.05), and for every 9.3 dB louder traffic noise, HF risk increased as well (HR, 1.18; 95% CI, 1.06-1.32; P <.05).

Models that were fully adjusted and considered all pollutants attenuated the relationship between HF risk and PM2.5 (HR, 1.14; 95% CI, 0.94-1.38), NO2 (HR, 1.00; 95% CI, 0.85-1.17), and Lden (HR, 1.09; 95% CI, 0.94-1.26).

Researchers observed a modification effect between PM2.5 exposure among former smokers (HR, 1.72; 95% CI, 1.25-2.36) and individuals with hypertension (HR, 1.41; 95% CI, 1.02-1.93).

This study was limited by not having access to indoor air quality or noise pollution data or information about socioeconomic status.

“In conclusion, our study suggests that long-term exposures to air pollution and road traffic noise were independently associated with HF incidence. Associations with HF were strongest and most robust with PM2.5, whereas associations with NO2 attenuated to unity after adjustment for copollutants,” the researchers noted. “We found a positive association between road traffic noise and HF, which attenuated slightly after adjustment for air pollutants. Former smokers and patients who are hypertensive seemed most susceptible to the adverse effects of PM2.5 on HF.”


Lim Y-H, Jørgensen JT, So R, et al. Long-term exposure to air pollution, road traffic noise, and heart failure incidence: the Danish Nurse Cohort. J Am Heart Assoc. 2021;e021436. doi:10.1161/JAHA.121.021436