Causal relationship between air pollution and chronic obstructive pulmonary disease in European and East Asian populations: a Mendelian randomization study

ABSTRACT

Epidemiologic studies have suggested a possible association between air pollution and chronic obstructive pulmonary disease (COPD), but it is controversial and difficult to draw causal inferences. Five methods were adopted to evaluate the causal relationship between air pollution and COPD in European and East Asian populations by using MR Analysis. A statistically significant causal relationship between PM2.5 and COPD was observed in the European population (OR: 2.34; 95% CI: 1.06–5.05; p = 0.033). Statistical significance remained after adjustment for confounding factors (adjusted OR: 2.28; 95% CI: 1.01–5.20; p = 0.048). In East Asian populations, PM2.5 absorbance, a proxy for black carbon, was statistically associated with COPD (OR: 1.41; 95% CI: 1.09–1.81; p = 0.007). We did not adjust for confounders in East Asian populations, as the association was independent of known confounders (e.g. smoking, respiratory tract infections, etc.). In conclusion, increased concentrations of PM2.5 and PM2.5 absorbance were associated with an increased risk of COPD.

KEYWORDS:

• Air pollution
• chronic obstructive pulmonary disease
• particulate matter
• absorbance
• nitrogen oxides

Abbreviations

PM	=	Particulate matter;
NO2	=	Nitrogen dioxide;
NOx	=	Nitrogen oxides;
IVs	=	Instrumental variables;
MR	=	Mendelian randomization;
GWAS	=	Genome-wide association studies;
IVW	=	Inverse variance weighted;
SNPs	=	Single nucleotide polymorphisms;
COPD	=	chronic obstructive pulmonary disease;
CI	=	Confidence Interval;
HR	=	Hazard ratio;
OR	=	Odds ratio.

Acknowledgements

We thank the IEU Open GWAS project (https://gwas.mrcieu.ac.uk/datasets/) for providing summary results data for the analyses.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Availability of data and materials

Publicly available datasets were analyzed in this study. This data can be found here: https://gwas.mrcieu.ac.uk/datasets/.

Authors’ contributions

MTS and MG: designing, carrying out the study, analyzing the data, and writing the article. The manuscript was reviewed for intellectual and clinical content by MJL, TTW, QC and XRR. JBQ: designing, revising, and financial support. All authors read and approved the final manuscript.

Ethics approval and consent to participate

There were no patients directly involved in the overall process of our study. Our study was based on publicly available data only. All human studies included in this analysis were conducted according to the Declaration of Helsinki.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/09603123.2024.2334781.

Additional information

Funding

This work was supported by the National Natural Science Foundation Program of China (82073653 and 81803313), Hunan Outstanding Youth Fund Project (2022JJ10087), National Key Research and Development Project (2018YFE0114500), China Postdoctoral Science Foundation (2020M682644), Hunan Provincial Science and Technology Talent Support Project (2020TJ-N07), Hunan Provincial Key Research and Development Program (2018SK2063), Open Project from NHC Key Laboratory of Birth Defect for Research and Prevention (KF2020006) and Natural Science Foundation of Hunan Province (2018JJ2551).