Effect of Coenzyme Q10 Supplementation on Diabetes Biomarkers: a Systematic Review and Meta-analysis of Randomized Controlled Clinical Trials.

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. CONCLUSION 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.