Passive smoking exposure is associated with increased risk of COPD in never smokers

Passive smoking, or environmental tobacco smoke (ETS), is a risk factor for lung cancer, cardiovascular disease, and childhood asthma, but a relationship with COPD has not been fully established. Our aim was to study ETS as a risk factor for COPD in never smokers.

Data from three cross-sectional studies within the Obstructive Lung Disease in Northern Sweden (OLIN) database were pooled. Of the 2,182 lifelong never smokers, 2,118 completed structured interviews and spirometry of acceptable quality. COPD was defined according to the GOLD (Global Initiative for Chronic Obstructive Lung Disease) criteria using postbronchodilator spirometry. The association of COPD with ETS in single and multiple settings was calculated by multivariate logistic regression adjusting for known risk factors for COPD.

COPD prevalence was associated with increased ETS exposure: 4.2% (no ETS), 8.0% (ETS ever at home), 8.3% (ETS at previous work), and 14.7% (ETS ever at home and at both previous and current work), test for trend P = .003. Exclusion of subjects aged ≥ 65 years and subjects reporting asthma yielded similar results. ETS in multiple settings, such as ever at home and at both previous and current work, was strongly associated to COPD (OR, 3.80; 95% CI, 1.29-11.2).

In this population-based sample of never smokers, ETS was independently associated with COPD. The association was stronger for ETS in multiple settings. ETS in multiple settings was, after age, the strongest risk factor for COPD and comparable to personal smoking of up to 14 cigarettes/d in comparable materials. The findings strongly advocate measures against smoking in public places.