GSTM1 polymorphism along with PM₁₀ exposure contributes to the risk of preterm delivery

We investigated the association between the risk of preterm delivery and each metabolic gene of glutathione S-transferases mu 1 (GSTM1), theta 1 (GSTT1) and cytochrome P450IA1 (CYP1A1) along with exposure to particulate matter <10 μm (PM₁₀). This study was assumed to identify gene-environment interaction that increases the risk of preterm delivery. A case-control study was carried out on 117 women with preterm deliveries and 118 women with term deliveries in Seoul, Korea. Logistic regression analyses were performed to explore the impact of each gene, PM₁₀ exposure and their interaction on the risk of preterm birth. The risk of preterm birth was associated with the GSTM1 null genotype only. Exposure to high levels of PM₁₀ (≥75th percentile) during the third trimester of pregnancy was associated with an increased risk of preterm birth when compared to low-level exposure to PM₁₀ (<75th percentile). We found that exposure to high levels of PM₁₀ during the third trimester in the presence of the GSTM1 null genotype is significantly associated with the risk of preterm delivery. This finding is biologically plausible and provides evidence for a gene-environment interaction that increases the risk of preterm birth.