Genetic polymorphism of GSTM1 and antioxidant supplementation influence lung function in relation to ozone exposure in asthmatic children in Mexico City.
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.
Romieu
I
I
Instituto Nacional de Salud Publica de México, Cuernavaca, Mexico. iromieu@correo.insp.mx
Sienra-Monge
J J
JJ
Ramírez-Aguilar
M
M
Moreno-Macías
H
H
Reyes-Ruiz
N I
NI
Estela del Río-Navarro
B
B
Hernández-Avila
M
M
London
S J
SJ
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*
D000975:Antioxidants; D005982:Glutathione Transferase; D010126:Ozone