title: Smoking habits and coenzyme Q10 status in healthy European adults.
abstract: BACKGROUND
  Coenzyme Q10 (CoQ10) is a lipophilic endogenously synthesised antioxidant that is present in nearly all human tissues and plays an important role in mitochondrial energy production. It has been postulated that smoking has a consumptive effect on CoQ10.
  
  
  METHODS
  To further define the relation between smoking and the serum CoQ10 status, 276 healthy volunteers aged 19 to 62 years were grouped into non-smokers (n = 113; 77 male, 36 female) and smokers (n = 163; 102 male, 61 female). Serum lipid profile was analysed by standard clinical chemistry. Coenzyme Q10 concentration and redox status were analysed by high-pressure liquid chromatography with electrochemical detection.
  
  
  RESULTS
  Male smokers showed higher serum CoQ10 levels than female smokers. This sex-related difference was accounted for when CoQ10 was related to low-density lipoprotein (LDL) cholesterol as the main carrier of CoQ10 in the circulation. Neither LDL-adjusted CoQ10 concentration nor redox status significantly differed when smokers and non-smokers were compared. Regarding the smoking history, the number of cigarettes consumed per day did not significantly affect the CoQ10 status. Interestingly, with increasing time of smoking habit we observed increasing levels of LDL-adjusted serum CoQ10 concentration (Spearman's p < 0.002) and of the reduced form of CoQ10 (Spearman's p < 0.0001).
  
  
  CONCLUSIONS
  As an adaptive response to oxidative stress in long-term smokers an increased demand for antioxidant capacity may be covered by increasing levels of LDL-adjusted CoQ10 serum concentrations and by a concomitantly increased availability of the reduced, active form of CoQ10, possibly by induction of enzymes that are involved in converting CoQ10ox to CoQ10red.
authors.affiliation: Children's Hospital of Datteln, Witten-Herdecke University, Datteln, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Niklowitz
authors.affiliation: Institute of Human Nutrition and Food Science, Division of Molecular Prevention, Christian Albrechts University of Kiel, Kiel, Germany.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Fischer
authors.affiliation: Institute of Human Nutrition and Food Science, Division of Molecular Prevention, Christian Albrechts University of Kiel, Kiel, Germany.
authors.forename: Simone
authors.initials: S
authors.lastname: Onur
authors.affiliation: Children's Hospital of Datteln, Witten-Herdecke University, Datteln, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Paulussen
authors.affiliation: Children's Hospital of Datteln, Witten-Herdecke University, Datteln, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Menke
authors.affiliation: Institute of Human Nutrition and Food Science, Division of Molecular Prevention, Christian Albrechts University of Kiel, Kiel, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Döring
keywords: cigarette smoking; coenzyme Q10; oxidative stress; ubiquinol