Prevalence and risk factors of COPD among never-smokers in two areas of Sweden - Occupational exposure to gas, dust or fumes is an important risk factor

Abstract

Background: Although active tobacco smoking is the main risk factor for COPD, it is not uncommon also among never-smokers. Different methods of defining COPD, as well as study locations, have previously yielded great variance in COPD prevalence. Aim: To study current prevalence and risk factors of COPD among never-smokers from two areas of Sweden. Methods: Data from the West Sweden Asthma Study and Obstructive Lung Disease in Northern Sweden Studies sampled in 2008-2010 was pooled. The study population consisted of 1839 subjects who performed identical spirometry and questionnaires. COPD was defined using the fixed ratio definition of post-bronchodilator FEV 1 /(F)VC, in accordance with the GOLD criteria. In addition, COPD was defined using the lower limit of normal, LLN. Results: Among the 967 never-smoking subjects, prevalence of COPD defined as FEV 1 /(F)VC 1 /FVC 2 was 2.0%, 1.4% and 1.3%. No significant difference between the two study regions was seen. Report of occupational exposure to gas, dust or fumes (GDF) was significantly associated with any COPD in never-smokers (OR 1.85, 95% CI 1.03-3.33), as well as GOLD ≥2 (OR 4.51, 1.72-11.9), after adjusting for age, educational level and exposure to passive smoking at work. Conclusion: Depending on definition, prevalence of COPD among never-smokers was 3.0-7.7%, whereas GOLD ≥2 was present in 1.3-2.0%. Exposure to GDF was a significant risk factor for any COPD as well as GOLD ≥2 among never-smokers.