title: Plasma coenzyme Q10 levels and postmenopausal breast cancer risk: the multiethnic cohort study.
abstract: BACKGROUND
  Coenzyme Q10 (CoQ10) is a component of the mitochondrial electron transport chain and is considered an important cellular antioxidant. Decreased circulating CoQ10 levels have been reported in women with breast cancer, but evidence is limited. We examined the association of plasma CoQ10 levels with postmenopausal breast cancer risk using prospectively collected blood samples.
  
  
  METHODS
  Prediagnostic plasma levels of total CoQ10 were measured among 160 incident postmenopausal breast cancer cases and 289 controls in the Multiethnic Cohort Study. Cases and controls were individually matched on age, sex, ethnicity, study location (Hawaii or California), hormone replacement therapy use, date and time of specimen collection, and hours of fasting. Logistic regression was used to compute odds ratios and 95% confidence intervals.
  
  
  RESULTS
  Plasma CoQ10 levels were positively associated with breast cancer risk, overall (P = 0.04). The association was stronger after women diagnosed within 1 year of blood draw were excluded to eliminate possible preclinical cases (odds ratio for the highest versus the lowest tertile, 2.26; 95% confidence interval, 1.22-4.19; P for trend = 0.01).
  
  
  CONCLUSIONS
  Higher CoQ10 levels in postmenopausal women may be associated with increased breast cancer risk.
  
  
  CONCLUSIONS
  A potential role for CoQ10 in the development and progression of breast cancer has been postulated, but epidemiologic evidence is lacking. Findings from this prospective cohort study add to the limited literature, indicating the potential positive association of circulating CoQ10 with postmenopausal breast cancer risk.
authors.affiliation: Epidemiology Program, Cancer Research Center of Hawaii, University of Hawaii, Honolulu, Hawaii 96813, USA. wchai@crch.hawaii.edu
authors.forename: Weiwen
authors.initials: W
authors.lastname: Chai
authors.forename: Robert V
authors.initials: RV
authors.lastname: Cooney
authors.forename: Adrian A
authors.initials: AA
authors.lastname: Franke
authors.forename: Yurii B
authors.initials: YB
authors.lastname: Shvetsov
authors.forename: Christian P
authors.initials: CP
authors.lastname: Caberto
authors.forename: Lynne R
authors.initials: LR
authors.lastname: Wilkens
authors.forename: Loïc
authors.initials: L
authors.lastname: Le Marchand
authors.forename: Brian E
authors.initials: BE
authors.lastname: Henderson
authors.forename: Laurence N
authors.initials: LN
authors.lastname: Kolonel
authors.forename: Marc T
authors.initials: MT
authors.lastname: Goodman
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000097:blood* / Q000208:ethnology*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause / Q000097:blood*; D011446:Prospective Studies; D012307:Risk Factors; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014451:Ubiquinone; C024989:coenzyme Q10