title: Serum organochlorines and breast cancer risk in Japanese women: a case-control study.
abstract: OBJECTIVE
  Most epidemiological studies of the association between breast cancer risk and exposure to organochlorine pesticides or polychlorinated biphenyls (PCBs), which are suspected endocrine disrupters and potential risk factors for human breast cancer, have been conducted in western countries, and the majority of results have been null and the rest inconsistent. Here, we examined these associations in Japanese women in the largest study in Asian women to date.
  
  
  METHODS
  The study was a matched case-control study of breast cancer with 403 eligible matched pairs from May 2001 to September 2005 at four hospitals in Nagano Prefecture, Japan.
  
  
  METHODS
  Serum samples were measured for PCBs and nine pesticide-related organochlorines, including dichlorodiphenyltrichloroethane (DDT). Odds ratios of breast cancer or its hormone-receptor-defined subtypes according to serum organochlorines were calculated.
  
  
  RESULTS
  No increase in the risk of breast cancer was seen among women with higher serum concentrations of any organochlorine: o,p'-DDT, p,p'-DDT, p,p'-dichlorodiphenyldichloroethylene, hexachlorobenzene, beta-hexachlorocyclohexane, trans-nonachlor, cis-nonachlor, oxychlordane, mirex, or PCBs. Rather, higher serum levels of cis-nonachlor, mirex, or total PCBs were associated with a decreased risk of breast cancer
  
  
  CONCLUSIONS
  Overall, these results suggest that breast cancer risk in Japan, a low-incidence country, is similar to that in western countries in terms of organochlorine exposure.
authors.affiliation: Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Itoh
authors.forename: Motoki
authors.initials: M
authors.lastname: Iwasaki
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Hanaoka
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kasuga
authors.forename: Shiro
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Onuma
authors.forename: Hideki
authors.initials: H
authors.lastname: Nishimura
authors.forename: Ritsu
authors.initials: R
authors.lastname: Kusama
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Tsugane
mesh_terms: D001943:Breast Neoplasms / Q000097:blood / Q000453:epidemiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000097:blood*; D007564:Japan / Q000453:epidemiology; D008875:Middle Aged; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D006843:Hydrocarbons, Chlorinated