Abstract
Background Long-term exposure to ambient air pollution has been linked to childhood-onset asthma, although evidence is still insufficient. Within the multicentre project Effects of Low-Level Air Pollution: A Study in Europe (ELAPSE), we examined the associations of long-term exposures to particulate matter with a diameter <2.5 µm (PM2.5), nitrogen dioxide (NO2) and black carbon (BC) with asthma incidence in adults.
Methods We pooled data from three cohorts in Denmark and Sweden with information on asthma hospital diagnoses. The average concentrations of air pollutants in 2010 were modelled by hybrid land-use regression models at participants’ baseline residential addresses. Associations of air pollution exposures with asthma incidence were explored with Cox proportional hazard models, adjusting for potential confounders.
Results Of 98 326 participants, 1965 developed asthma during a mean follow-up of 16.6 years. We observed associations in fully adjusted models with hazard ratios of 1.22 (95% CI 1.04–1.43) per 5 μg·m−3 for PM2.5, 1.17 (95% CI 1.10–1.25) per 10 µg·m−3 for NO2 and 1.15 (95% CI 1.08–1.23) per 0.5×10−5 m−1 for BC. Hazard ratios were larger in cohort subsets with exposure levels below the European Union and US limit values and possibly World Health Organization guidelines for PM2.5 and NO2. NO2 and BC estimates remained unchanged in two-pollutant models with PM2.5, whereas PM2.5 estimates were attenuated to unity. The concentration–response curves showed no evidence of a threshold.
Conclusions Long-term exposure to air pollution, especially from fossil fuel combustion sources such as motorised traffic, was associated with adult-onset asthma, even at levels below the current limit values.
Abstract
Long-term exposure to air pollution, especially from fossil fuel combustion sources such as motorised traffic, is associated with the development of asthma in adults, even at levels below the current EU and US limit values and possibly WHO guidelines https://bit.ly/2QW5yA7
Footnotes
This article has an editorial commentary: https://doi.org/10.1183/13993003.00064-2021
This article has supplementary material available from erj.ersjournals.com
Data sharing: This is an observational cohort study and requests for data can be made by contacting the corresponding author.
Author contributions: The study was conceptualised and designed by Z.J. Andersen, G. Hoek, B. Brunekreef, P. Ljungman and S. Liu. G. Hoek and B. Brunekreef are Principal Investigators of the ELAPSE project. Statistical analysis and drafting of the manuscript was conducted by S. Liu. Z.J. Andersen helped in drafting the manuscript. J.T. Jørgensen and U.A. Hvidtfeldt prepared the individual cohort data for the analyses. G. Hoek, B. Brunekreef, J. Chen and M. Strak coordinated the ELAPSE project, helped in preparing pooled data for analyses and provided support with the access to pooled cohort data. S.P. Rodopoulou, E. Samoli and K. Katsouyanni contributed with the statistical analysis strategy and scripts for the statistical analyses. K. de Hoogh worked for the exposure assessment. All authors have read and revised the manuscript for important intellectual content, and contributed to the interpretation of the results. All authors have approved the final draft of the manuscript.
Conflict of interest: S. Liu has nothing to disclose.
Conflict of interest: J.T. Jørgensen has nothing to disclose.
Conflict of interest: P. Ljungman has nothing to disclose.
Conflict of interest: G. Pershagen has nothing to disclose.
Conflict of interest: T. Bellander has nothing to disclose.
Conflict of interest: K. Leander has nothing to disclose.
Conflict of interest: P.K.E. Magnusson has nothing to disclose.
Conflict of interest: D. Rizzuto has nothing to disclose.
Conflict of interest: U.A. Hvidtfeldt has nothing to disclose.
Conflict of interest: O. Raaschou-Nielsen has nothing to disclose.
Conflict of interest: K. Wolf has nothing to disclose.
Conflict of interest: B. Hoffmann has nothing to disclose.
Conflict of interest: B. Brunekreef has nothing to disclose.
Conflict of interest: M. Strak has nothing to disclose.
Conflict of interest: J. Chen has nothing to disclose.
Conflict of interest: A. Mehta has nothing to disclose.
Conflict of interest: R.W. Atkinson has nothing to disclose.
Conflict of interest: M. Bauwelinck has nothing to disclose.
Conflict of interest: R. Varraso has nothing to disclose.
Conflict of interest: M-C. Boutron-Ruault has nothing to disclose.
Conflict of interest: J. Brandt has nothing to disclose.
Conflict of interest: G. Cesaroni has nothing to disclose.
Conflict of interest: F. Forastiere has nothing to disclose.
Conflict of interest: D. Fecht has nothing to disclose.
Conflict of interest: J. Gulliver has nothing to disclose.
Conflict of interest: O. Hertel has nothing to disclose.
Conflict of interest: K. de Hoogh has nothing to disclose.
Conflict of interest: N.A.H. Janssen has nothing to disclose.
Conflict of interest: K. Katsouyanni has nothing to disclose.
Conflict of interest: M. Ketzel has nothing to disclose.
Conflict of interest: J.O. Klompmaker has nothing to disclose.
Conflict of interest: G. Nagel has nothing to disclose.
Conflict of interest: B. Oftedal has nothing to disclose.
Conflict of interest: A. Peters has nothing to disclose.
Conflict of interest: A. Tjønneland has nothing to disclose.
Conflict of interest: S.P. Rodopoulou has nothing to disclose.
Conflict of interest: E Samoli has nothing to disclose.
Conflict of interest: D.T. Kristoffersen has nothing to disclose.
Conflict of interest: T. Sigsgaard has nothing to disclose.
Conflict of interest: M. Stafoggia has nothing to disclose.
Conflict of interest: D. Vienneau has nothing to disclose.
Conflict of interest: G. Weinmayr has nothing to disclose.
Conflict of interest: G. Hoek has nothing to disclose.
Conflict of interest: Z.J. Andersen has nothing to disclose.
Support statement: This work is supported by the Health Effects Institute (4954-RFA14-3/16-5-3) and a grant from the China Scholarship Council (201806010406). SALT and TwinGene are substudies of The Swedish Twin Registry (STR) which is managed by Karolinska Institutet and receives additional funding through the Swedish Research Council under grant 2017-00641. Funding information for this article has been deposited with the Crossref Funder Registry.
- Received August 11, 2020.
- Accepted November 17, 2020.
- Copyright ©ERS 2021