title: Prenatal smoke exposure and genomic DNA methylation in a multiethnic birth cohort.
abstract: BACKGROUND
  Exposure to prenatal tobacco smoke (PTS) has been associated with a number of health outcomes in the offspring, including some childhood cancers. Lower levels of genomic DNA methylation have also been associated with several types of cancers. We investigated whether PTS was associated with global DNA methylation levels in the offspring.
  
  
  METHODS
  Our sample was drawn from a birth cohort of women born between 1959 and 1963 in New York City (n = 90). We measured methylation of repetitive elements (Sat2, Alu, LINE-1) from peripheral blood granulocytes. We combined prospectively collected data on PTS with adult epidemiologic data and blood samples collected in 2001 to 2007 (mean age, 43 years). We used linear regression to assess the association between PTS and repetitive element methylation.
  
  
  RESULTS
  Thirty-six percent of mothers smoked during pregnancy. We observed an inverse association between PTS and Sat2 methylation. This inverse association remained even after adjustment for potential mediators including child environmental tobacco smoke exposure, birth size, postnatal weight and height changes, and adult smoking status and alcohol intake (β = -0.22, 95% confidence interval = -0.40 to -0.03 for ever exposed to PTS vs. never exposed using models of log-transformed methylation levels). PTS exposure was not statistically significantly associated with LINE-1 or Alu methylation.
  
  
  CONCLUSIONS
  PTS exposure, measured at the time of pregnancy and not retrospectively reported, was associated with a decrease in Sat2 methylation but not LINE-1 or Alu methylation.
  
  
  CONCLUSIONS
  If replicated in larger studies, this study supports a persistent effect of PTS on DNA methylation levels, as measured by Sat2, in adulthood.
authors: Department of Epidemiology, Columbia University Medical Center, New York, NY, USA.
authors: Julie D
authors: JD
authors: Flom
authors: Jennifer S
authors: JS
authors: Ferris
authors: Yuyan
authors: Y
authors: Liao
authors: Parisa
authors: P
authors: Tehranifar
authors: Clara Belessiotis
authors: CB
authors: Richards
authors: Yoon Hee
authors: YH
authors: Cho
authors: Karina
authors: K
authors: Gonzalez
authors: Regina M
authors: RM
authors: Santella
authors: Mary Beth
authors: MB
authors: Terry
mesh_terms: D000328:Adult; D015331:Cohort Studies; D019175:DNA Methylation; D005006:Ethnicity; D005260:Female; D023281:Genomics; D006801:Humans; D018811:Maternal Exposure / Q000009:adverse effects*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011446:Prospective Studies; D012907:Smoking / Q000009:adverse effects* / Q000208:ethnology / Q000235:genetics; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
chemical_list: D014028:Tobacco Smoke Pollution