Prenatal Environmental Tobacco Smoke and Null Genotypes of Glutathione S-Transferase T1 were Associated with Fetal Cord Blood IgE

Abstract

P-120 Introduction: Elevated cord blood IgE (cbIgE) is a predictor for atopic diseases. Environmental tobacco smoke (ETS) exposure are known associated with cbIgE levels. However, interactive effects on cbIgE is unclear between ETS and genotypes of glutathione s-transferase (GST) T1. A birth-cohort study was conducted to assess the association between gene-environmental interaction and cbIgE. Methods: Between July 2001 and July 2005, 1080 mother-infant pairs are recruited from 8 maternity hospitals in Taiwan. Questionnaires were completed by mothers prior to and immediately following birth. CAP system were used to measure maternal IgE, specific IgE to common allergens, and cbIgE levels. GSTT1/M1 (null/non-null) was determined by polymerase chain reaction (PCR). Results: A total of 745 mother-infant pairs had all measurements satisfactorily completed. The prevalence of elevated cbIgE (≥ 0.35 IU/ml) and maternal prenatal ETS exposure was 23.7% and 39.3%, respectably. The frequency of null GSTT1, M1 genotype was 48.0% and 57.0%, respectively. Male infants (p=0.0002), birth season in Spring (p=0.019), maternal history of atopy (p=0.0008), elevated maternal total IgE (p<0.0001) were associated with elevated cbIgE. Birth weight, gestational age, birth order, parental socioeconomical status, paternal atopy history, and GSTM1 genotype was not associated with cbIgE. Both maternal prenatal ETS exposure (OR=0.48, 95% CI =0.28∼0.80) and GSTT1 null genotype (OR=0.54, 95% CI=0.33∼0.86) were negatively associated with high cbIgE, while OR for those with both GSTT1 null genotype and ETS exposure were 0.30 (95% CI=0.16∼0.54) after adjusting for the above variables. Discussion and Conclusions: Our study found maternal prenatal ETS exposure and GSTT1 null genotype associated with lower cbIgE, adjusting for confounding factors. When both ETS and GSTT1 null genotypes were present, the OR for high IgE were even lower. This finding is somewhat different from previous studies about ETS effects on asthma occurrence. Further follow-up of these children on their development of asthma, allergic rhinitis, or atopic dermatitis will provide valuable information about the prenatal and early childhood risk factors for atopic diseases.