title: Plasma coenzyme Q10 reference intervals, but not redox status, are affected by gender and race in self-reported healthy adults.
abstract: BACKGROUND
  Abnormal concentrations of coenzyme Q(10) have been reported in many patient groups, including certain cardiovascular, neurological, hematological, neoplastic, renal, and metabolic diseases. However, controls in these studies are often limited in number, poorly screened, and inadequately evaluated statistically. The purpose of this study is to determine the reference intervals of plasma concentrations of ubiquinone-10, ubiquinol-10, and total coenzyme Q(10) for self-reported healthy adults.
  
  
  METHODS
  Adults (n=148), who were participants in the Princeton Prevalence Follow-up Study, were identified as healthy by questionnaire. Lipid profiles, ubiquinone-10, ubiquinol-10, and total coenzyme Q(10) concentrations were measured in plasma. The method used to determine the reference intervals is a procedure incorporating outlier detection followed by robust point estimates of the appropriate quantiles.
  
  
  RESULTS
  Significant differences between males and females were present for ubiquinol-10 and total coenzyme Q(10). Blacks had significantly higher Q(10) measures than whites in all cases except for the ubiquinol-10/total Q(10) fraction.
  
  
  CONCLUSIONS
  The fraction of ubiquinol-10/total coenzyme Q(10) is a tightly regulated measure in self-reported healthy adults, and is independent of sex and racial differences. Different reference intervals for certain coenzyme Q(10) measures may need to be established based upon sex and racial characteristics.
authors.affiliation: Division of Pathology and Laboratory Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229-3030, USA. m.miles@cchmc.org
authors.forename: Michael V
authors.initials: MV
authors.lastname: Miles
authors.forename: Paul S
authors.initials: PS
authors.lastname: Horn
authors.forename: John A
authors.initials: JA
authors.lastname: Morrison
authors.forename: Peter H
authors.initials: PH
authors.lastname: Tang
authors.forename: Ton
authors.initials: T
authors.lastname: DeGrauw
authors.forename: Amadeo J
authors.initials: AJ
authors.lastname: Pesce
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D003067:Coenzymes; D005006:Ethnicity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D012016:Reference Values; D012737:Sex Factors; D012907:Smoking; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000097:blood*
chemical_list: D015415:Biomarkers; D003067:Coenzymes; D014451:Ubiquinone; C026663:ubiquinol-10; C024989:coenzyme Q10; C025204:Ubiquinone Q2