title: Low level maternal smoking and infant birthweight reduction: genetic contributions of GSTT1 and GSTM1 polymorphisms.
abstract: BACKGROUND
  Genetic susceptibility to tobacco smoke might modify the effect of smoking on pregnancy outcomes.
  
  
  METHODS
  We conducted a case-control study of 543 women who delivered singleton live births in Kaunas (Lithuania), examining the association between low-level tobacco smoke exposure (mean: 4.8 cigarettes/day) during pregnancy, GSTT1 and GSTM1 polymorphisms and birthweight of the infant. Multiple linear-regression analysis was performed adjusting for gestational age, maternal education, family status, body mass index, blood pressure, and parity. Subsequently, we tested for the interaction effect of maternal smoking, GSTT1 and GSTM1 genes polymorphisms with birthweight by adding all the product terms in the regression models.
  
  
  RESULTS
  The findings suggested a birthweight reduction among light-smoking with the GSTT1-null genotype (-162.9 g, P = 0.041) and those with the GSTM1-null genotype (-118.7 g, P = 0.069). When a combination of these genotypes was considered, birthweight was significantly lower for infants of smoking women the carriers of the double-null genotypes (-311.2 g, P = 0.008). The interaction effect of maternal smoking, GSTM1 and GSTT1 genotypes was marginally significant on birthweight (-234.5 g, P = 0.078). Among non-smokers, genotype did not independently confer an adverse effect on infant birthweight.
  
  
  CONCLUSIONS
  The study shows the GSTT1-null genotype, either presents only one or both with GSTM1-null genotype in a single subject, have a modifying effect on birthweight among smoking women even though their smoking is low level. Our data also indicate that identification of the group of susceptible subjects should be based on both environmental exposure and gene polymorphism. Findings of this study add additional evidence on the interplay among two key GST genes and maternal smoking on birth weight of newborns.
authors.affiliation: Department of Environmental Sciences, Vytautas Magnus University, Donelaicio st, 58, 44248, Kaunas, Lithuania.
authors.forename: Asta
authors.initials: A
authors.lastname: Danileviciute
authors.forename: Regina
authors.initials: R
authors.lastname: Grazuleviciene
authors.forename: Algimantas
authors.initials: A
authors.lastname: Paulauskas
authors.forename: Ruta
authors.initials: R
authors.lastname: Nadisauskiene
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Nieuwenhuijsen
mesh_terms: D000328:Adult; D001724:Birth Weight / Q000235:genetics*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D059647:Gene-Environment Interaction; D020022:Genetic Predisposition to Disease; D005838:Genotype; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D016014:Linear Models; D008097:Lithuania; D008297:Male; D011110:Polymorphism, Genetic; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000235:genetics*; D011446:Prospective Studies; D012907:Smoking / Q000009:adverse effects* / Q000235:genetics; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D005982:Glutathione Transferase; D014028:Tobacco Smoke Pollution; C413545:glutathione S-transferase T1