Age-related changes in plasma coenzyme Q10 concentrations and redox state in apparently healthy children and adults

Background: Coenzyme Q(10) (CoQ) is an endogenous enzyme cofactor, which may provide protective benefits as an antioxidant. Because age-related CoQ changes and deficiency states have been described, there is a need to establish normal ranges in healthy children. The objectives of this study are to determine if age-related differences in reduced CoQ (ubiquinol), oxidized CoQ (ubiquinone), and CoQ redox state exist in childhood, and to establish reference intervals for these analytes in healthy children. Methods: Apparently healthy children (n = 68) were selected from individuals with no history of current acute illness, medically diagnosed disease, or current medication treatment. Self-reported healthy adults (n = 106) were selected from the ongoing Princeton Follow-up Study in greater Cincinnati. Participants were assessed for lipid profiles, ubiquinol concentration, ubiquinone concentration, total CoQ concentration, and CoQ redox ratio. Results: Mean total CoQ and ubiquinol concentrations are similar in younger children (0.2-7.6 years) and adults (29-78 years); however, lipid-adjusted total CoQ concentrations are significantly increased in younger children. Also CoQ redox ratio is significantly increased in younger and older children compared with adults. Conclusions: Elevated CoQ and redox ratios in children may be an indication of oxidative stress effects, which are associated with early development of coronary heart disease. (C) 2004 Elsevier B.V. All rights reserved.