POSTNATAL MATERNAL SMOKING INCREASES THE PREVALENCE OF ASTHMA BUT NOTOF BRONCHIAL HYPERRESPONSIVENESS OR ATOPY IN THEIR CHILDREN

We have compared the prevalence of asthma, bronchial hyperresponsivene ss (BHR), and atopy in relation to parental smoking in children aged 7 to 13 years. Information on the presence of asthma was obtained from a questionnaire, BHR was assessed by a methacholine challenge test, an d atopy was defined as a positive response to a skin prick test. A com plete history of the parents' smoking habits during their children's l ife, including prenatal smoking habits, was recorded. The prevalence o f maternal smoking increased from 37.9% during pregnancy to 45.3% at t he cross-sectional survey. None of the outcomes was significantly rela ted to paternal smoking, whereas postnatal maternal smoking was positi vely associated with asthma (odds ratio [OR] = 2.8; 95% confidence int erval [CI], 1.3 to 6.1), A negative association between prenatal mater nal smoking and atopy was found (OR = 0.6; 95% CI, 0.3 to 0.9), We fou nd no significant association between BHR and parental smoking. Our re sults indicate that postnatal maternal smoking increases the prevalenc e of asthma in the offspring without inducing BHR.