NAD(P)H: Quinone oxidoreductase 1, glutathione S-transferase M1, environmental tobacco smoke exposure, and childhood asthma.

Environmental tobacco smoke (ETS) exposure might increase the risk for childhood asthma, and we hypothesized the effect may be modified by the phase II genes NAD(P)H: quinone oxidoreductase 1 (NQO1) and glutathione S-transferase (GST) M1. To investigate the genetic and environmental associations with asthma, GSTM1 and NQO1 functional polymorphisms and ETS were analyzed in a two-staged cross-sectional study among elementary schoolchildren in Taiwan. Multiple logistic regression analysis revealed a significant association between the Ser allele of the NQO1 Pro187Ser polymorphism and asthma (OR=1.6, 95% CI 1.3-1.8). Although GSTM1 genotype itself was not significantly associated with asthma (OR=1.0, 95% CI 0.8-1.1), the GSTM1 genotype modified the association between the NQO1 polymorphism and asthma in children exposed to ETS (p=0.0002). The NQO1 gene might be involved in the development of asthma, especially in children carrying the GSTM1 null genotype who are exposed to ETS.