No significant difference in prevalence between the two study areas was observed. In never-smokers, occupational exposure to gas, dust or fumes (GDF) was significantly associated with both COPD (OR 1.85, 95% CI 1.03–3.33), and GOLD ≥2 (OR 4.51, 1.72–11.9) according to definition a), after adjusting for age, educational level and exposure to passive smoking at work.