Gender-Dependent Effect of GSTM1 Genotype on Childhood Asthma Associated with Prenatal Tobacco Smoke Exposure

It remains unclear whether the GSTM1 genotype interacts with tobacco smoke exposure (TSE) in asthma development. This study aimed to investigate the interactions among GSTM1 genotype, gender, and prenatal TSE with regard to childhood asthma development. In a longitudinal birth cohort in Taiwan, 756 newborns completed a 6-year follow-up, and 591 children with DNA samples available for GSTM1 genotyping were included in the study,and the interactive influences of gender-GSTM1 genotyping-prenatal TSE on childhood asthma development were analyzed. Among these 591 children, 138 (23.4%) hadphysician-diagnosed asthmaat 6 years of age, and 347 (58.7%) werenull-GSTM1. Prenatal TSE significantly increased the prevalence of childhood asthma innull-GSTM1children relative to those withpositiveGSTM1. Further analysis showed that prenatal TSE significantly increased the risk of childhood asthma in girls withnull-GSTM1. Furthermore, among the children without prenatal TSE, girls withnull-GSTM1had a significantly lower risk of developing childhood asthma and a lower total IgE level at 6 years of age than those withpositiveGSTM1. This study demonstrates that the GSTM1 null genotype presents a protective effect against asthma development in girls, but the risk of asthma development increases significantly under prenatal TSE.