Effects of coenzyme Q10 supplementation on plasma C-reactive protein concentrations: A systematic review and meta-analysis of randomized controlled trials

The aim of this systematic review and meta-analysis of prospective interventional studies was to investigate the effects of coenzyme Q10 (CQ10) on plasma C-reactive protein (CRP) levels. PubMed/Medline, Web of Science (WoS), Cochrane Database and Google Scholar databases were searched (up to December 2016) to identify prospective studies evaluating the impact of CQ10 supplementation on CRP. Random effects models meta-analysis was used for quantitative data synthesis. Sensitivity analysis used the leave-one-out method, and heterogeneity was quantitatively assessed using the I² index. Systematic review PROSPERO database registration: CRD42016038155. From a total of 119 entries identified via searches, 7 studies were finally included to the analysis. The results of the meta-analysis indicated a non-significant reduction in CRP concentrations following supplementation with CQ10 with a weighted mean difference [WMD] of -0.25mg/l (95% confidence intervals [CI] -0.56 to 0.06, I²=42.0%). The WMD for the effects on interleukin 6 (IL6) was -0.72pg/dl, (95% CI -1.24 to -0.24, I²=51.8%). These findings were robust in sensitivity analyses. Random-effects meta-regression revealed that changes in plasma CRP levels were independent of the dosage of CQ10 (slope: -0.0005; 95% CI: -0.005, 0.004; p=0.832) while duration of supplementation was the dependent mediator (slope: slope: -0.111; 95% CI: -0.21, -0.004; p=0.042). In conclusion, CQ10 supplementation has a borderline favourable effect on CRP levels, and a significant effect on IL-6 level. This suggests that CQ10 supplementation likely attenuates subclinical inflammation.