title: Effect of Coenzyme Q10 Supplementation on Diabetes Biomarkers: a Systematic Review and Meta-analysis of Randomized Controlled Clinical Trials.
abstract: BACKGROUND
  Several studies have investigated the effect of Co-Q10 on diabetes biomarkers, but findings are inconsistent. This systematic review and meta-analysis of clinical trials was conducted to summarize the effect of Co-Q10 supplementation on diabetes biomarkers.
  
  
  METHODS
  We searched Pubmed, EMBASE, Science direct, ISI web of science, and Google Scholar for randomized controlled trials from 1989 until March 2016. We included randomized controlled trials reporting fasting blood glucose (FBG), fasting insulin and HbA1c. In total, we found 16 articles that examined the effect of Co-Q10 on fasting blood glucose, fasting insulin and HbA1c. Mean ± standard deviations (SD) of defined outcomes were used for calculating standardized mean differences (SMD) and its 95% confidence interval (95%CI) between intervention and control treatments based on Hedges' estimator.
  
  
  RESULTS
  Our preliminary meta-analysis on 14 eligible studies regarding the effect of Co-Q10 supplementation on FBG indicated a slightly significant decrement (SMD:-0.28 mg/d; 95% CI: -0.12, 0.04), with a substantial between-study heterogeneity (Cochrane Q test, I2 = 93.9%, P < 0.0001). After removal of three studies, heterogeneity was eliminated and a slightly significant decrease was found in FBG (SMD: -0.20 mg/dL, 95% CI: -0.38, -0.02). The effect of Co-Q10 on HbA1c and fasting insulin was not significant. SMDs for the effect of Co-Q10 on HbA1c and fasting insulin were -0.05% (95% CI: -0.22, 0.12) and 0.12 pmol/L (95% CI: -0.21, 0.44), respectively.
  
  
  CONCLUSIONS
  Co-Q10 supplementation slightly but significantly reduced fasting blood glucose, but not fasting insulin and HbA1c. More long-term studies are necessary to examine the association between Co-Q10 supplementation and diabetes biomarkers. This study was funded by the School of Nutrition and Food Science, Isfahan University of Medical Sciences.
authors.affiliation: 1)Food Security Research Center, Isfahan University of Medical Sciences, Isfahan, Iran. 2)Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Maedeh
authors.initials: M
authors.lastname: Moradi
authors.affiliation: 1)Food Security Research Center, Isfahan University of Medical Sciences, Isfahan, Iran. 2)Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Fahimeh
authors.initials: F
authors.lastname: Haghighatdoost
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Awat
authors.initials: A
authors.lastname: Feizi
authors.affiliation: Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Bagher
authors.initials: B
authors.lastname: Larijani
authors.affiliation: 1)Food Security Research Center, Isfahan University of Medical Sciences, Isfahan, Iran. 2)Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran. 5)Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran. 6)Diabetes Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Leila
authors.initials: L
authors.lastname: Azadbakht
mesh_terms: D000975:Antioxidants / Q000627:therapeutic use*; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000737:chemistry*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D006442:Glycated Hemoglobin / Q000737:chemistry; D006801:Humans; D007328:Insulin / Q000097:blood; D016032:Randomized Controlled Trials as Topic; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007328:Insulin; D014451:Ubiquinone; C024989:coenzyme Q10