Effects of coenzyme Q10 supplementation on inflammatory markers: A systematic review and meta-analysis of randomized controlled trials

The aims of this meta-analysis were to evaluate the effects of coenzyme Q10 (CoQ10) supplementation on inflammatory mediators including C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) by analyzing published randomized controlled trials (RCTs). A systematic search in PubMed, Cochrane Library and Clinicaltrials.gov was performed to identify eligible RCTs. Data synthesis was performed using a random- or a fixed-effects model depending on the results of heterogeneity tests, and pooled data were displayed as weighed mean difference (WMD) and 95% confidence interval (CI). Seventeen RCTs were selected for the meta-analysis. CoQ10 supplementation significantly reduced the levels of circulating CRP (WMD: -0.35 mg/L, 95% CI: -0.64 to -0.05, P = 0.022), IL-6 (WMD: -1.61 pg/mL, 95% CI: -2.64 to -0.58, P = 0.002) and TNF-alpha (WMD: -0.49 pg/mL, 95% CI: -0.93 to -0.06, P = 0.027). The results of meta-regression showed that the changes of CRP were independent of baseline CRP, treatment duration, dosage, and patients characteristics. In the meta-regression analyses, a higher baseline IL-6 level was significantly associated with greater effects of CoQ10 on IL-6 levels (P for interaction = 0.006). In conclusion, this meta-analysis of RCTs suggests significant lowering effects of CoQ10 on CRP, IL-6 and TNF-alpha. However, results should be interpreted with caution because of the evidence of heterogeneity and limited number of studies. (C) 2017 Elsevier Ltd. All rights reserved.