GSTP1 and asthma: The main findings of the pooled analyses were that NO2 (OR = 1.23; 95%-CI: 1.03, 1.46, for a 10-μg/m3 increase in NO2) and GSTP1 rs1138272 (TT/TC vs. CC; OR = 1.49; 95%-CI: 1.20, 1.84) were marginally associated with asthma and a significant interaction between GSTP1 rs1138272 and NO2 on asthma was detected (Bonferroni-corrected p = 0.012) [23].