The effects of smoking on asthmatic children - how can we study this in indoor air quality

Introduction : The Respira study involved standard respiratory questionnaires, environmental monitoring of homes and clinical exam of cases and controls aged between 11 and 14 years. Aims and Objectives : To compare the different effects of smoking in asthmatic children (n=65) and controls (n=59) in various phases of their life, and to attempt to identify the presence of smoking related elements in particulate matter (PM2.5) sampled in 45 homes. Materials and Methods : Parents were given questionnaires and a subgroup of homes were chosen to have indoor air sampling of PM2.5 and this was analysed for various elements. Results : Children with asthmatic symptoms had greater exposure to daily smoking (n=15/65) than controls (n=5/59) (p=0.0271) and in the first year of life (p=0.00596). There was no statistical significance for smoking during pregnancy (p=0.961), exposure to second hand smoke during pregnancy (p=0.138) or breastfeeding. The relationship of Cadmium and Thallium levels in PM2.5 was compared to symptoms and the smoking habits. There were marginal differences in cadmium and thallium levels between the asthma (mean 0.439 ng/m 3 ) and control (mean 0.268ng/m 3 ) groups (p=0.254). There was no significant difference in cadmium and thallium levels in homes where there was smoking on a daily basis when compared to smoke-free houses (p=0.254). Conclusion : Children with asthma had a greater exposure to smoking both in their early years of life and presently. There is no correlation between cadmium and thallium levels in PM2.5 and smoking habits, and therefore there must be other sources for these two elements in PM2.5 in this study.