The BAMSE cohort reported a statistically significant association between NOx and asthma at 4 years of age in children who were both minor allele carriers for GSTP1 rs1695 and homozygous major allele carriers for TNF rs1800629 (OR = 2.9; 95% CI: 1.0–8.2 for a 44-μg/m3 increase in NOx) (Melén et al. 2008). Here, GSTP1 is linked to asthma.