Long-term air pollution and road traffic noise exposure and COPD: the Danish Nurse Cohort.

Background: While air pollution has been linked to the development of chronic obstructive pulmonary disease (COPD), evidence on the role of environmental noise is just emerging. We examined the associations of long-term exposure to air pollution and road traffic noise with COPD incidence.
Methods: We defined COPD incidence for 24 538 female nurses from the Danish Nurse Cohort (age >44 years) as the first hospital contact between baseline (1993 or 1999) and 2015. We estimated residential annual mean concentrations of particulate matter with an aerodynamic diameter <2.5 µm (PM _2.5 ) since 1990 and nitrogen dioxide (NO ₂ ) since 1970 using the Danish Eulerian Hemispheric Model/Urban Background Model/Air Geographic Information System modelling system, and road traffic noise (L _den ) since 1970 using the Nord2000 model. Time-varying Cox regression models were applied to assess the associations of air pollution and road traffic noise with COPD incidence.
Results: 977 nurses developed COPD during a mean of 18.6 years' follow-up. We observed associations with COPD for all three exposures with HRs and 95% CIs of 1.19 (1.01-1.41) per 6.26 µg·m ^-3 for PM _2.5 , 1.13 (1.05-1.20) per 8.19 µg·m ^-3 for NO ₂ and 1.15 (1.06-1.25) per 10 dB for L _den . Associations with NO ₂ and L _den attenuated slightly after mutual adjustment, but were robust to adjustment for PM _2.5 . Associations with PM _2.5 were attenuated to null after adjustment for either NO ₂ or L _den . No potential interaction effect was observed between air pollutants and noise.
Conclusion: Long-term exposure to air pollution, especially traffic-related NO ₂ , and to road traffic noise were independently associated with COPD.
Competing Interests: Conflict of interest: S. Liu has nothing to disclose. Conflict of interest: Y-H. Lim has nothing to disclose. Conflict of interest: M. Pedersen has nothing to disclose. Conflict of interest: J.T. Jørgensen has nothing to disclose. Conflict of interest: H. Amini has nothing to disclose. Conflict of interest: T. Cole-Hunter has nothing to disclose. Conflict of interest: A.J. Mehta has nothing to disclose. Conflict of interest: R. So has nothing to disclose. Conflict of interest: L.H. Mortensen has nothing to disclose. Conflict of interest: R.G.J. Westendorp has nothing to disclose. Conflict of interest: S. Loft has nothing to disclose. Conflict of interest: E.V. Bräuner has nothing to disclose. Conflict of interest: M. Ketzel has nothing to disclose. Conflict of interest: O. Hertel has nothing to disclose. Conflict of interest: J. Brandt has nothing to disclose. Conflict of interest: S.S. Jensen has nothing to disclose. Conflict of interest: J.H. Christensen has nothing to disclose. Conflict of interest: T. Sigsgaard has nothing to disclose. Conflict of interest: C. Geels has nothing to disclose. Conflict of interest: L.M. Frohn has nothing to disclose. Conflict of interest: M. Brborić has nothing to disclose. Conflict of interest: J. Radonić has nothing to disclose. Conflict of interest: M. Turk Sekulic has nothing to disclose. Conflict of interest: K. Bønnelykke has nothing to disclose. Conflict of interest: C. Backalarz has nothing to disclose. Conflict of interest: M.K. Simonsen has nothing to disclose. Conflict of interest: Z.J. Andersen has nothing to disclose.
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