Objectives: To determine the influence of pre- and postnatal tobacco exposure in the development of bronchiolitis.
Patients and methods: A questionnaire was given to the parents of children hospitalized between August 2001 and August 2002. It included items on parental smoking habits and maternal smoking during pregnancy. Clinical, analytical and radiological criteria were used to diagnose bronchiolitis.
Results: Of 450 children, 123 (27.3 %) were diagnosed with bronchiolitis. The control group was composed of 327 children. A total of 61.6 % of the children had at least one parent who smoked and 32.9 % of these children developed bronchiolitis; 39.1 % had non-smoking parents and 18.2 % were hospitalized with bronchiolitis (OR 2.20 [1.39-3.47]). Of the entire group of children studied, 35.3 % had mothers who smoked and 37.7 % of these children had bronchiolitis compared with 21.4 % of children whose mothers were non-smokers (OR 2.22 [1.45-3.39]). A total of 49.6 % had fathers who smoked, and 32.3 % of these children were diagnosed with bronchiolitis compared with 22 % of children whose fathers were non-smokers (OR 1.65 [1.10-2.57]). Forty-four percent of children whose mothers smoked during pregnancy were hospitalized with bronchiolitis compared with only 20.9 % of non-exposed children (OR 2.96 [1.90-4.62]). The large number of mothers who smoked during pregnancy (27.8 %) was notable. Multivariant analysis with logistic regression was performed and the only variable that remained statistically significant was smoking during pregnancy (p < 0.00001; OR 3.27 [1.39-7.71]).
Conclusions: Maternal smoking during pregnancy seems to be the main risk factor for the subsequent development of bronchiolitis