TY - JOUR T1 - Genetic polymorphism of <em>GSTM1</em> and antioxidant supplementation influence lung function in relation to ozone exposure in asthmatic children in Mexico City JF - Thorax JO - Thorax SP - 8 LP - 10 VL - 59 IS - 1 AU - I Romieu AU - J J Sienra-Monge AU - M Ramírez-Aguilar AU - H Moreno-Macías AU - N I Reyes-Ruiz AU - B Estela del Río-Navarro AU - M Hernández-Avila AU - S J London Y1 - 2004/01/01 UR - http://thorax.bmj.com/content/59/1/8.abstract N2 - Background: We recently reported that antioxidant supplementation with vitamins C and E mitigated ozone related decline in forced expiratory flow (FEF25–75) in 158 asthmatic children in an area with high ozone exposure in Mexico City. Methods: A study was undertaken to determine whether deletion of glutathione S-transferase M1 (GSTM1 null genotype), a gene involved in response to oxidative stress, influences ozone related decline in FEF25–75 and the benefit of antioxidant supplementation. Results:GSTM1 null children receiving placebo had significant ozone related decrements in FEF25–75 (percentage change per 50 ppb of ozone 2.9 (95% CI −5.2 to −0.6), p = 0.01); GSTM1 positive children did not. Conversely, the effect of antioxidants was stronger in children with the GSTM1 null genotype. Conclusions: Asthmatic children with a genetic deficiency of GSTM1 may be more susceptible to the deleterious effects of ozone on the small airways and might derive greater benefit from antioxidant supplementation. ER -