Effect of Occupational Exposures on Decline of Lung Function in Early Chronic Obstructive Pulmonary Disease

Rationale: Several occupational exposures adversely affect lung function. Objectives: This study reports the influence of continued occupa-tional dust and fume exposures on the rate of decline of lung function in participants with early chronic obstructive pulmonary disease (COPD) studied in a population-based study. Methods: Subjects consisted of 5,724 participants in the LungHealth Study, a multicenter study of smoking cessation and anticholinergic bronchodilator administration in smokers with early COPD (3,592 men; 2,132women). Averagepost-bronchodilator FEV1 at entrywas 78.4 % predicted for men and 78.2 % predicted for women; all participants had an FEV1/FVC ratio less than 0.70. Measurements and Main Results: Participants underwent a baseline evaluation and five annual follow-up assessments, including ques-tionnaires and spirometry. The effect of ongoing dust or fume exposure on FEV1 in each follow-up year was statistically evaluated with a mixed-effects regression model, which was adjusted for FEV1 at entry, age, airway responsiveness to methacholine, baseline smoking intensity, and time-varying (yearly) smoking status during each follow-up year. Inmenwith early COPD, each year of continued fume exposure was associated with a 0.25 % predicted reduction in post-bronchodilator FEV1 % predicted. Continued smoking and airway hyperresponsiveness were also associated with reduction in FEV1 during each year of follow-up in both men and women. Statistically significant effects of dust exposureon the rate of decline were not found, norwere effects of fume exposure noted inwomen. Conclusions: These results suggest a need for secondary prevention by controlling occupational fume exposures