Association of low-dose exposure to persistent organic pollutants with global DNA hypomethylation in healthy Koreans.
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.
Kim
Keon-Yeop
KY
Department of Preventative Medicine, School of Medicine, Kyungpook National University, Daegu, Korea.
Kim
Dong-Sun
DS
Lee
Sung-Kook
SK
Lee
In-Kyu
IK
Kang
Jung-Ho
JH
Chang
Yoon-Seok
YS
Jacobs
David R
DR
Steffes
Michael
M
Lee
Duk-Hee
DH
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
D004785:Environmental Pollutants; D055768:Halogenated Diphenyl Ethers; D006843:Hydrocarbons, Chlorinated; D009930:Organic Chemicals; D010575:Pesticides; D011078:Polychlorinated Biphenyls