Mortality associated with occupational exposure in Helsinki, Finland : a 24-year follow-up

Objectives Our objective was to study mortality related to different obstructive lung diseases, occupational exposure, and their potential joint effect in a large, randomized population-based cohort. Methods We divided the participants based on the answers to asthma and chronic obstructive pulmonary disease (COPD) diagnoses and occupational exposure and used a combined effects model and compared the results to no asthma or COPD with no occupational exposure. Results High exposure had a hazards ratio (HR) of 1.34 (1.11-1.62) and asthma and COPD coexistence of 1.58 (1.10-2.27). The combined effects of intermediate exposure and coexistence had an HR of 2.20 (1.18-4.09), high exposure with coexistence of 1.94 (1.10-3.42) for overall mortality, and sub-HR for respiratory-related mortality of 3.21 (1.87-5.50). Conclusions High occupational exposure increased overall but not respiratory-related mortality hazards, while coexisting asthma and COPD overall and respiratory-related hazards of mortality.