Occupational exposure to dusts, gases, and fumes and incidence of chronic obstructive pulmonary disease in the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults

Abstract

Rationale: There is limited evidence from population-based studies demonstrating incidence of spirometric-defined chronic obstructive pulmonary disease (COPD) in association with occupational exposures.

Objectives: We evaluated the association between occupational exposures and incidence of COPD in the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA).

Measurements and main results: Prebronchodilator ratio of forced expiratory volume in 1 second over forced vital capacity (FEV(1)/FVC) was measured in 4,267 nonasthmatic SAPALDIA participants ages 18-62 at baseline in 1991 and at follow-up in 2001-2003. COPD was defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criterion (FEV(1)/FVC < 0.70) and Quanjer reference equation (FEV(1)/FVC < lower limit of normal [LLN]), and categorized by severity (≥ 80% and <80% predicted FEV(1) for stage I and stage II+, respectively). Using a job-exposure matrix, self-reported occupations at baseline were assigned exposures to biological dusts, mineral dusts, gases/fumes, and vapors, gases, dusts, or fumes (VGDF) (high, low, or unexposed as reference). Adjusted incident rate ratios (IRRs) of stage I and stage II+ COPD were estimated in mixed Poisson regression models. Statistically significant (P < 0.05) IRRs of stage II+ GOLD and LLN-COPD, indicating risks between two- and fivefold, were observed for all occupational exposures at high levels. Occupational exposure-associated risk of stage II+ COPD was observed mainly in males and ages ≥ 40 years, and remained elevated when restricted to nonsmokers.

Conclusions: In a Swiss working adult population, occupational exposures to biological dusts, mineral dusts, gases/fumes, and VGDF were associated with incidence of COPD of at least moderate severity.