Tobacco smoking, exposure to second-hand smoke, and asthma and wheezing in schoolchildren: a cross-sectional study

Aim To analyse the association between tobacco smoking, exposure to second-hand smoke (SHS) and reports of wheezing and asthma in a sample of schoolchildren. Methods A structured questionnaire was administered to 1766 students (7th grade, aged 12-13years) at 25 schools in Terrassa, Spain (2006). We determined the prevalence of active smoking, exposure to SHS and reports of wheezing and asthma, and their association by means of prevalence odds ratios (OR) and 95% confidence intervals (CI). Results 97.5% of children were nonsmokers, 1.5% were experimental smokers and 1% were regular smokers. 41.1% of children reported exposure to SHS at home, 40.0% at school, 53.9% in their leisure time and 33.2% while using private or public transportation. Wheezing was reported by 9.2% of children, and 9.2% reported asthma. A significant association was found between smoking tobacco and wheezing: OR in experimental smokers=3.0 (95% CI 1.2-7.7), and OR in active smokers=4.2 (95% CI 1.4-12.5). Exposure to SHS while using transportation was associated with wheezing (OR=1.4; 95% CI 1.0-2.0). Tobacco smoking and exposure to SHS were not associated with asthma. Conclusion Active and experimental smokers, and those who reported exposure to SHS while using public or private transportation, had higher likelihood of reporting wheezing. No association between active or passive smoking and asthma was observed.