Objective: We evaluated if occupational exposures were associated with increased incidence of chronic obstructive pulmonary disease (COPD) in the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA).
Methods: Pre-bronchodilator ratio of forced expiratory volume in one second over forced vital capacity (FEV1/FVC) was measured in 4,551 non-asthmatic participants (ages 18 to 64) in SAPALDIA at baseline in 1991 and at follow-up in 2001-2003. COPD was defined as FEV1/FVC < lower limit of normal (LLN, predictions according to the Quanjer spirometric reference equation). Using a job-exposure matrix, historical exposures (ever, never as reference) to mineral dusts, biological dusts, and gases or fumes were determined from self-reported occupations at baseline and during follow-up. Incident rate ratios (IRRs) of COPD were estimated for each exposure after adjustment for potential confounders. Gender, chronic bronchitis at baseline, and smoking status were evaluated for effect modification.
Results: Positive associations were observed between COPD and all occupational exposures but were not statistically significant (p>0.05). Relative to unexposed participants without chronic bronchitis, those with chronic bronchitis who were also exposed to either mineral dusts (IRR: 1.47, 95%CI: 1.00-2.15), biological dusts (IRR: 1.61, 95%CI: 1.12-2.31), or gases/fumes (IRR: 1.53, 95%CI: 1.10-2.12) had increased incidence of COPD. No considerable differences in IRRs were observed across sex and smoking status.
Conclusion: In Swiss working adults with pre-existing chronic bronchitis, occupational exposures to mineral and biological dusts, and gases/fumes increased the risk of incident COPD.