title: Stillbirth and slow metabolizers of caffeine: comparison by genotypes.
abstract: BACKGROUND
  Cytochrome P4501A2 (CYP1A2) and N-acetyltransferase 2 (NAT2) are key enzymes in the metabolism of caffeine. The polymorphism of these genes facilitates the detection of fast and slow metabolizers, and if caffeine is causally related to stillbirth, we expect slow metabolizers to have a higher risk of stillbirth at any given intake of caffeine. Gluthatione S-transferase alpha1 (GSTA1) may also be active in the metabolism of caffeine as it conjugates glutathione to aromatic amines. Our study, therefore, included analyses of the association between GSTA1 and stillbirth.
  
  
  METHODS
  A nested case non-case study among women who participated in the Danish National Birth Cohort: 142 cases of singleton stillbirths and 157 controls of singleton live births.
  
  
  RESULTS
  Slow oxidizer status (CYP1A2), slow acetylator status (NAT2), and low activity of GSTA1 were not individually associated with the risk of stillbirth [odds ratio (OR) = 1.06, 95% confidence interval (95% CI) 0.67-1.67, OR = 0.95, 95% CI 0.60-1.51, and OR = 1.42, 95% CI 0.88-2.28, respectively]. We did, however, observe that subjects with a combination of slow CYP1A2, slow NAT2, and low GSTA1 genes had almost a 2-fold risk of stillbirth compared with subjects with other combinations of genotypes.
  
  
  CONCLUSIONS
  We found no link between any single genotype and the risk of stillbirth. An association between a combination of genotypes and stillbirth was discovered. Caffeine may be causally related to stillbirth, but larger studies using Mendelian randomization are needed to verify this.
authors.affiliation: The Danish Epidemiology Science Centre, Department of Epidemiology, Institute of Public Health, University of Aarhus, 8000 Aarhus, Denmark. bhb@soci.au.dk
authors.forename: Bodil Hammer
authors.initials: BH
authors.lastname: Bech
authors.forename: Herman
authors.initials: H
authors.lastname: Autrup
authors.forename: Ellen Aagaard
authors.initials: EA
authors.lastname: Nohr
authors.forename: Tine Brink
authors.initials: TB
authors.lastname: Henriksen
authors.forename: Jørn
authors.initials: J
authors.lastname: Olsen
mesh_terms: D000123:Acetyltransferases / Q000235:genetics; D002110:Caffeine / Q000378:metabolism*; D016022:Case-Control Studies; D019388:Cytochrome P-450 CYP1A2 / Q000235:genetics; D005260:Female; D005838:Genotype; D005982:Glutathione Transferase / Q000235:genetics; D006801:Humans; D016015:Logistic Models; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D011247:Pregnancy; D018570:Risk Assessment / Q000379:methods; D050497:Stillbirth
chemical_list: D002110:Caffeine; D019388:Cytochrome P-450 CYP1A2; D000123:Acetyltransferases; D005982:Glutathione Transferase