The Association Between Occupational Exposure To Vapor, Gas, Dust And Fume And Different Definitions Of COPD, Emphysema And Chronic Bronchitis: The Swedish Cardiopulmonary Bioimage Study (scapis)

Objectives: To elucidate whether different spirometric definitions of chronic obstructive pulmonary disease (COPD) affect the risk estimates of tobacco smoking or occupational exposures, to investigate the relation between occupational exposure and CT-confirmed emphysema and the risk of chronic bronchitis Methods: 1,050 subjects aged 50 to 64 years were investigated with forced expiratory volume in one second (FEV ), (forced vital capacity) FVC and 1 slow vital capacity (SVC) before and 15 minutes after inhalation 400 µg of salbutamol. COPD was defined as the ratio FEV /VC<0.7 PREDIL 1 using the maximum value of FVC or SVC before bronchodilation, and COPD as the ratio FEV /VC<0.7 using the maximum value of GOLD 1 FVC or SVC after bronchodilation. COPD was defined as the ratio FEV /VC below LLN using the maximum value of FVC or SVC. LLN 1 Emphysema was classified according to CT findings, and all subjects with at least mild emphysema in any zone of the lung were categorized as having emphysema. Occupational exposure was defined as an affirmative answer to items about occupational exposure to vapor, gas, dust and fume, with addition of items about occupational exposure to welding fumes or diesel exhausts. Odds ratios were calculated in models adjusted for age, gender and smoking habits. Results: The risks of occupational exposures were quite similar regardless of whether COPD or COPD definition was applied. COPD GOLD LLN PREDIL showed higher and statistically significant increased risks of the different classifications of occupational exposures. Occupational exposures were associated with an increased risk for chronic bronchitis, among men and women and among “never smokers” as well as among “ever-smokers”. When stratified for gender, occupational exposure among men was significantly associated with emphysema (OR 2.0, 95% CI 1.04-3.9). There was no association among women. Current smoking was strongly associated with emphysema, OR 15.3 (95% CI 6.1-38.9), but also[MR5] with former smoking OR 3.1 (95% CI 1.2-7.8). For COPD and COPD the risk related to current smoking GOLD LLN were similar regardless the definition. Conclusions The risks of COPD in relation to smoking or occupational exposures were quite similar regardless the definitions used. Occupational exposures were associated with a doubled risk for CT-verified emphysema, especially among men. Occupational exposures were associated with a doubled risk for chronic bronchitis, especially among “never-smokers”.