title: Low-dose persistent organic pollutants increased telomere length in peripheral leukocytes of healthy Koreans.
abstract: Although shortened telomeres have been found in many cancers, elongated telomere length has been observed as an early response after low-dose treatment with various chemical carcinogens in vitro and animal experiments, suggesting low-dose exposure to carcinogenic chemicals may function as a tumour promoter at the very early stage of carcinogenesis in humans. This cross-sectional study was performed to examine whether low-dose exposure to persistent organic pollutants (POPs), lipophilic xenobiotics that mainly bioaccumulate in adipose tissue, is associated with telomere length of peripheral blood leukocytes in apparently healthy persons. Telomere length was measured using quantitative polymerase chain reaction method in 84 apparently healthy Koreans. Among various POPs, serum concentrations of organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs) and polybrominated diphenylethers were measured. Most OC pesticides and PCBs were positively and significantly associated with telomere length with correlation coefficients from about +0.25 to +0.35. The strongest associations were observed with p,p'-dichlorodiphenyldichloroethylene, PCB99, PCB153, PCB180, PCB183 and PCB187. When we examined adjusted means of telomere length by quintiles of POPs, the steeper increases of telomere length tended to be observed within relatively lower ranges of POPs. Besides serum concentrations of POPs, none of the other variables studied, including age, were associated with telomere length in this study. We found that telomere length was increasing across low doses of exposure to POPs in which the majority of study subjects were found, suggesting that low-dose POPs may act as a tumour promoter in carcinogenesis in humans.
authors.affiliation: Department of Preventive Medicine, School of Medicine, Kyungpook National University, 101 Dongin-dong, Jung-gu, Daegu, 700-422 Korea.
authors.forename: Ji-Yeon
authors.initials: JY
authors.lastname: Shin
authors.forename: Yi Young
authors.initials: YY
authors.lastname: Choi
authors.forename: Hyo-Sung
authors.initials: HS
authors.lastname: Jeon
authors.forename: Jun-Hyun
authors.initials: JH
authors.lastname: Hwang
authors.forename: Sung-Ae
authors.initials: SA
authors.lastname: Kim
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: Jae Yong
authors.initials: JY
authors.lastname: Park
authors.forename: Duk-Hee
authors.initials: DH
authors.lastname: Lee
mesh_terms: D044466:Asian People; D003633:Dichlorodiphenyl Dichloroethylene / Q000097:blood; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000097:blood*; D005260:Female; D006262:Health; D006801:Humans; D007962:Leukocytes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009930:Organic Chemicals / Q000097:blood*; D011078:Polychlorinated Biphenyls / Q000097:blood; D056910:Republic of Korea; D018709:Statistics, Nonparametric; D016615:Telomere / Q000378:metabolism*
chemical_list: D004785:Environmental Pollutants; D009930:Organic Chemicals; D003633:Dichlorodiphenyl Dichloroethylene; D011078:Polychlorinated Biphenyls; C014024:2,4,5,2',4',5'-hexachlorobiphenyl