The effect of parental smoking on presence of wheeze or airway hyper-responsiveness in New South Wales school children

Background and Aims: To assess accurately the effect of parental smoking on the respiratory health of New South Wales (NSW) school children, we obtain ed a large data set by pooling data from seven cross-sectional studies cond ucted in NSW between 1991 and 1993. Methods: A random sample of 6394 children age eight to 11 years was studied . Respiratory symptoms, family history of asthma and parental smoking histo ry were measured by questionnaire, atopy by skin prick test and airway hype r-responsiveness (AHR) by histamine inhalation test. Results: In total, 58.3% of children had at least one parent who smoked; 38 .5% were exposed to maternal smoking. After adjusting for potential confoun ders, such as atopy, parental history of asthma and bronchitis in the first two years, children who were exposed to maternal smoking had a significant ly increased risk of recent wheeze but not of AHR (odds ratios 1.33; 95% CI : 1.2-1.5 and 1.00; 95% CI: 0.9-1.2). Conclusions: The positive association with wheeze and the lack of an associ ation with AHR suggests that exposure to parental smoking leads to wheezing , but does not increase airway responsiveness.