title: Association of low-dose exposure to persistent organic pollutants with global DNA hypomethylation in healthy Koreans.
abstract: BACKGROUND
  Global DNA methylation levels have been reported to be inversely associated with blood levels of persistent organic pollutants (POPs), xenobiotics that accumulate in adipose tissue. Whether these associations extend to a population with much lower concentrations of POPs is not known.
  
  
  OBJECTIVE
  This study was performed to examine whether low-dose exposure to POPs was associated with global DNA hypomethylation in Koreans.
  
  
  METHODS
  The amount of global DNA hypomethylation was estimated by the percent 5-methyl-cytosine (%5-mC) in Alu and LINE-1 assays in 86 apparently healthy Koreans. Among various POPs, organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenylethers (PBDEs) were measured.
  
  
  RESULTS
  Most OC pesticides were inversely and significantly associated with %5-mC in the Alu assay, with correlation coefficients in the range 0.2 to 0.3 after adjusting for age, sex, body mass index, smoking, and alcohol. The strongest OC pesticide associations with %5-mC in the Alu assay were observed with oxychlordane, trans-nonachlor, and p,p -dichlorodiphenyldichloroethylene. The correlation coefficient of age with %5-mC in the Alu assay was 0.24, similar to correlations of OC pesticides with %5-mC in the Alu assay. Most PCBs and PBDEs showed nonsignificant inverse trends with %5-mC in the Alu assay, but for some PCBs the U-shaped association was significant. On the other hand, POPs were not associated with %5-mC in the LINE-1 assay.
  
  
  CONCLUSIONS
  We found that low-dose exposure to POPs, in particular OC pesticides, was associated with global DNA hypomethylation in apparently healthy Koreans.
authors.affiliation: Department of Preventative Medicine, School of Medicine, Kyungpook National University, Daegu, Korea.
authors.forename: Keon-Yeop
authors.initials: KY
authors.lastname: Kim
authors.forename: Dong-Sun
authors.initials: DS
authors.lastname: Kim
authors.forename: Sung-Kook
authors.initials: SK
authors.lastname: Lee
authors.forename: In-Kyu
authors.initials: IK
authors.lastname: Lee
authors.forename: Jung-Ho
authors.initials: JH
authors.lastname: Kang
authors.forename: Yoon-Seok
authors.initials: YS
authors.lastname: Chang
authors.forename: David R
authors.initials: DR
authors.lastname: Jacobs
authors.forename: Michael
authors.initials: M
authors.lastname: Steffes
authors.forename: Duk-Hee
authors.initials: DH
authors.lastname: Lee
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D044466:Asian People; D019175:DNA Methylation / Q000187:drug effects*; D003710:Demography; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis*; D004785:Environmental Pollutants / Q000097:blood / Q000633:toxicity*; D005260:Female; D055768:Halogenated Diphenyl Ethers; D006262:Health; D006801:Humans; D006843:Hydrocarbons, Chlorinated; D007723:Korea / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D009930:Organic Chemicals / Q000097:blood / Q000633:toxicity*; D010575:Pesticides; D011078:Polychlorinated Biphenyls; D012016:Reference Values; D013997:Time Factors
chemical_list: D004785:Environmental Pollutants; D055768:Halogenated Diphenyl Ethers; D006843:Hydrocarbons, Chlorinated; D009930:Organic Chemicals; D010575:Pesticides; D011078:Polychlorinated Biphenyls