Maternal smoking: in utero exposure promote allergic sensitization

Exposure to tobacco smoke in utero appears to promote allergic sensitization in children, suggests a French study whose results were presented on the first day of post Respiratory Research, organized by the Reims Respiratory Society of French language (SPLF).

Chantal Raherison, University Hospital of Bordeaux, and colleagues analyzed data from 7798 children aged 9 to 11 years randomly recruited in 108 schools in six French cities (Bordeaux, Clermont-Ferrand, Créteil, Marseille, Reims, Strasbourg ) between 1999 and 2001, to pass the assessment of asthma and allergic disease tests.

After reviewing the results of these tests, the authors identified an eczema-quarter of participants, rhinitis in 12.9% of them asthma in 9.9% of them and atopy in a quarter of young participants. The existence of a maternal atopy was reported for 21.7% of children and 21.6% of mothers of young participants reported smoking during pregnancy.

According to the analysis, in utero exposure to cigarette smoke appeared associated with positive results to prick tests for house dust mites (22.2% against 15.4% in non-exposed children) . In contrast, paternal smoking does not seem to have any significant impact on allergic sensitization.

Children for whom maternal atopy was reported, awareness of house dust mites also was significantly more common in cases of maternal smoking during pregnancy (30% against 19% in non-exposed children).

The results of this study also show an awareness of cat allergens in children with a maternal history of atopy and who were exposed to cigarette smoke during their first year of life (7.5% against 3 4% for children without maternal atopy).

This study suggests that passive smoking plays a role in the development of allergic sensitization in children but with different effects depending on maternal atopy and exposure window, the authors conclude.

The days of respiratory research are held annually in the fall to promote exchanges between researchers and clinicians. Created by SPLF, they also involve French companies physiology, pharmacology and immunology and Inserm.