PARENTAL SMOKING AND ALLERGIC SENSITIZATION IN CHILDREN

Background - A systematic review was conducted of the effects of paren tal smoking on immunoglobulin (IgE) levels, skin prick positivity, and allergic rhinitis or eczema in children. Asthma was excluded in order to distinguish more clearly the effect of passive smoke exposure on a llergic sensitisation. Methods - Thirty six relevant publications were identified after consideration of 692 articles selected by electronic search of the Embase and Medline databases using keywords relevant to passive smoking in children. The search was completed in April 1997 a nd identified nine studies of IgE in neonates, eight of IgE in older c hildren, 12 which included skin prick tests, and 10 describing symptom s of allergic disease other than asthma or wheezing. A quantitative me ta-analysis was possible only for the studies reporting skin prick tes ts. Results - Several large studies failed to confirm early reports of a substantial or statistically significant association of maternal sm oking with concentrations of total serum IgE in neonates or in older c hildren. No consistent association emerged between parental smoking an d allergic rhinitis or eczema. Few of these studies adjusted for poten tial confounding variables. The quantity and quality of evidence was g reatest for skin prick tests, and studies of parental smoking during p regnancy or infancy were broadly consistent in showing no adverse effe ct on prick positivity (pooled odds ratio 0.87, 95% confidence interva l 0.62 to 1.24). There was much greater and statistically significant (p = 0.002) heterogeneity of odds ratios relating current parental smo king to skin prick positivity. Conclusions - Parental smoking, either before or immediately after birth, is unlikely to increase the risk of allergic sensitisation in children.