Background: Passive smoking is widespread, and environmental tobacco smoke contains many potent respiratory irritants. This analysis aimed to estimate the effect of passive smoking on respiratory symptoms, bronchial responsiveness, lung function, and total serum IgE in the European Community Respiratory Health Survey.
Methods: This analysis included data from 7882 adults (age 20-48 years) who had never smoked, from 36 centres in 16 countries. Information on passive smoking, respiratory symptoms, asthma, and allergic rhinitis was gathered through a structured interview. Spirometry and methacholine challenge were carried out, and total and specific IgE were measured. The effect of passive smoking was estimated by means of logistic and multiple linear regression for each country and combined across countries by random-effects meta-analysis.
Findings: In 12 of the 36 centres, more than half the participants were regularly involuntarily exposed to tobacco smoke. The prevalence of passive smoking in the workplace varied from 2.5% in Uppsala, Sweden, to 53.8% in Galdakao, Spain. Passive smoking was significantly associated with nocturnal chest tightness (odds ratio 1.28 [95% CI 1.02 to 1.60]), nocturnal breathlessness (1.30 [1.01 to 1.67]), breathlessness after activity (1.25 [1.07 to 1.47]), and increased bronchial responsiveness (effect -0.18 [-0.30 to -.05]). Passive smoking in the workplace was significantly associated with all types of respiratory symptoms and current asthma (odds ratio 1.90 [95% CI 0.90 to 2.88]). No significant association was found between passive smoking and total serum IgE.
Interpretation: Passive smoking is common but the prevalence varies widely between different countries. Passive smoking increased the likelihood of experiencing respiratory symptoms and was associated with increased bronchial responsiveness. Decreasing involuntary exposure to tobacco smoke in the community, especially in workplaces, is likely to improve respiratory health.