Among subjects free of respiratory symptoms at baseline, the effect of BHR on the risk of physician-diagnosed asthma at follow-up was restricted to GSTP1 105 Ile/Ile carriers (OR 4.57, 95% CI 2.43 to 8.57 vs 1.40, 95% CI 0.58 to 3.39; p for interaction = 0.023).
We describe an association study designed to examine whether allelic variation at the glutathione-S-transferase GSTP1 locus influences expression of the BHR and atopy phenotypes in asthma.