title: Genetic polymorphism of GSTM1 and antioxidant supplementation influence lung function in relation to ozone exposure in asthmatic children in Mexico City.
abstract: BACKGROUND
  We recently reported that antioxidant supplementation with vitamins C and E mitigated ozone related decline in forced expiratory flow (FEF(25-75)) 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 FEF(25-75) and the benefit of antioxidant supplementation.
  
  
  RESULTS
  GSTM1 null children receiving placebo had significant ozone related decrements in FEF(25-75) (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.
authors.affiliation: Instituto Nacional de Salud Publica de México, Cuernavaca, Mexico. iromieu@correo.insp.mx
authors.forename: I
authors.initials: I
authors.lastname: Romieu
authors.forename: J J
authors.initials: JJ
authors.lastname: Sienra-Monge
authors.forename: M
authors.initials: M
authors.lastname: Ramírez-Aguilar
authors.forename: H
authors.initials: H
authors.lastname: Moreno-Macías
authors.forename: N I
authors.initials: NI
authors.lastname: Reyes-Ruiz
authors.forename: B
authors.initials: B
authors.lastname: Estela del Río-Navarro
authors.forename: M
authors.initials: M
authors.lastname: Hernández-Avila
authors.forename: S J
authors.initials: SJ
authors.lastname: London
mesh_terms: D000975:Antioxidants / Q000008:administration & dosage*; D001249:Asthma / Q000178:diet therapy* / Q000235:genetics / Q000503:physiopathology; D002648:Child; D019587:Dietary Supplements; D004311:Double-Blind Method; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D005540:Forced Expiratory Flow Rates / Q000502:physiology; D017353:Gene Deletion; D005838:Genotype; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D008297:Male; D008800:Mexico; D018384:Oxidative Stress / Q000235:genetics; D010126:Ozone / Q000633:toxicity*; D011110:Polymorphism, Genetic / Q000235:genetics*
chemical_list: D000975:Antioxidants; D005982:Glutathione Transferase; D010126:Ozone