title: Distribution of glutathione S-transferase M1, P1 and T1 genotypes in different age-groups of Finns without diagnosed cancer.
abstract: BACKGROUND
  Xenobiotic metabolizing enzymes (XMEs) are important detoxifiers of hazardous environmental agents, and their polymorphisms may therefore modify the risk of environmentally induced cancers. Consequently, the XME polymorphisms have been extensively studied in this context during recent years. Particular attention has been given to the polymorphisms of glutathione S-transferase (GST) M1, P1 and T1 genes. Previous studies have provided abundant data indicating these polymorphisms as important modifiers of individual susceptibility to cancers of environmental origin. It can be postulated that if the at-risk genotypes of these genes were real risk factors for the environmental cancers, their prevalence would presumably decrease with age in cancer-free part of the population.
  
  
  METHODS
  We tested the hypothesis in a population based group of 2105 Finns (1,051 men, 1,054 women) in five age strata (27, 37, 47, 57 and 67 years of age), all without clinically diagnosed cancer.
  
  
  RESULTS
  For GSTM1 genotype, a significant interaction was seen between gender and age among never smokers (p=0.003). Currently smoking men tended to be less likely (OR 0.57, 95% CI 0.31-1.03), and currently smoking women more likely (OR 1.70, 95% CI 0.97-2.97) homozygotes for the GSTP1*B allele compared with never smokers. Moreover, the likelihood of being a concurrent carrier of the putatively protective genotypes of all of the three studied GSTs was almost three-fold (OR 2.80, 95% CI 1.10-7.12) in heavy smokers in the two oldest age-groups compared with the other genotypes.
  
  
  CONCLUSIONS
  Our findings based on a novel study design provide support to the previous case-control studies suggesting that GST genotypes modify individual risk of environmentally-induced cancers.
authors.affiliation: Finnish Institute of Occupational Health, Topeliuksenkatu 41 a A, 41 a A, FI-00250, Helsinki, Finland.
authors.forename: Anu
authors.initials: A
authors.lastname: Voho
authors.forename: Olli
authors.initials: O
authors.lastname: Impivaara
authors.forename: Jorma
authors.initials: J
authors.lastname: Järvisalo
authors.forename: Katja
authors.initials: K
authors.lastname: Metsola
authors.forename: Harri
authors.initials: H
authors.lastname: Vainio
authors.forename: Ari
authors.initials: A
authors.lastname: Hirvonen
mesh_terms: D000328:Adult; D000368:Aged; D002274:Carcinogens, Environmental; D005260:Female; D005387:Finland; D005838:Genotype; D051549:Glutathione S-Transferase pi / Q000097:blood / Q000235:genetics; D005982:Glutathione Transferase / Q000097:blood / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology* / Q000235:genetics; D012306:Risk; D012907:Smoking; D044465:White People / Q000235:genetics
chemical_list: D002274:Carcinogens, Environmental; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase; C413545:glutathione S-transferase T1; C496556:GSTP1 protein, human