Vapors, gases, dusts and fumes at work and chronic obstructive pulmonary disease/bronchitis: a systematic review and meta-analyses

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is the third leading cause of death after cardiovascular disease and stroke. A 2019 American Thoracic Society (ATS) statement estimated that 13-15% of all COPD is attributable to occupational exposures. RESEARCH QUESTION: This study reports on a systematic review with meta-analysis (PROSPERO 2022 CRD42022302451) that was undertaken to characterize jobs and work exposures associated with an increased risk of developing COPD. METHODS: Five databases were searched (MEDLINE, Embase, CINAHL, Cochrane Systematic reviews, Register of Controlled Trials) from inception until February 26, 2025. Studies published in English or Chinese that studied workers (or workplace exposures) in relation to COPD, chronic bronchitis (CB) or emphysema and reported on a minimum of 15 exposed cases, with a comparison group, were included. The National Heart, Blood, and Lung Institute (NHLBI) Study Quality Assessment Tool was used. All reported estimates (e.g., RR, OR, HR) were extracted. Random effects models were used to estimate meta effect estimates (mEE) with 95% confidence intervals. Stratified models were constructed by study design, smoking, and sex, where possible. RESULTS: After de-duplication, 9115 citations were screened. Following full-text review 257 studies met the inclusion criteria. Most were cross-sectional (71%) and conducted in Europe or North America (68%). Most were fair quality (72%) with only 5.8% assessed as good quality. Results showed a consistent relationship between workplace exposure to vapours, gases, dusts or fumes (VGDF) for spirometry-defined COPD (mEE 1.51; 95% CI 1.31-1.73; n = 20 studies), self-reported COPD (mEE 1.48; 95% CI 1.23-1.77; n = 14) and chronic bronchitis (mEE 1.83; 95% CI 1.51-2.21; n = 29). This relationship was slightly stronger in non-smokers and was weaker among women. INTERPRETATION: There was a consistent relationship of workplace exposures with both CB and COPD. The effect of occupational exposures on COPD outcomes appears to be at least additive with smoking. CLINICAL TRIAL REGISTRATION: The project was registered with PROSPERO, the International Prospective Register of Systematic Reviews (PROSPERO 2022 CRD42022302451). Date of registration: 5th April 2022.