Objective: To investigate the interaction of smoking and history of long-term occupational exposure to organic solvents on the prevalence of chronic bronchitis (CB) among middle aged and elderly men.
Methods: A questionnaire on health, lifestyle, and working conditions, and a clinical examination including measurements of height, weight, and peak-flow. Self-reported occupational solvent exposure for 5 years or more was compared to never exposed. Three thousand two hundred eight men aged 63 +/- 10 years were included.
Results: Four hundred sixty one men had CB (14.4%). Current smoking and the interaction of smoking and long-term occupational exposure to organic solvents (> 5 years) were the factors most strongly associated with prevalence of CB. In the solvent exposed group odds ratio for CB was 7.0 (95% confidence interval [CI]: 3.4 to 14.5) comparing current smokers with non-smokers against only 3.7 (95% CI: 2.8 to 4.8) in the nonexposed group, also after control for potential confounders. Among nonsmokers only, long-term exposure to organic solvents was not associated with an increased prevalence of CB.
Conclusion: Current or previous occupational exposure to organic solvents doubles the smoking related risk of CB, probably due to an additional irritative effect in the alveolar and bronchial mucosa.