Coenzyme Q10 for Parkinson's disease

 

Abstract

Background

A number of preclinical studies in both in vitro and in vivo models of Parkinson's disease have demonstrated that coenzyme Q10 can protect the nigrostriatal dopaminergic system. Some clinical trials have looked at the neuroprotective effects of coenzyme Q10 in patients with early and midstage Parkinson's disease.

Objectives

To assess the evidence from randomized controlled trials on the efficacy and safety of treatment with coenzyme Q10 compared to placebo in patients with early and midstage Parkinson's disease.

Search methods

We searched the Cochrane Movment Disorders Group Trials Register, CENTRAL (The Cochrane Library 2009, Issue 4), MEDLINE (January 1966 to March 2011), and EMBASE (January 1985 to March 2011). We handsearched the references quoted in the identified trials, congress reports from the most important neurological association and movement disorder societies in Europe and America (March 2011), checked reference lists of relevant studies and contacted other researchers.

Selection criteria

We included randomized controlled trials (RCTs) that compared coenzyme Q10 to placebo for patients who suffered early and midstage primary Parkinson's disease. Studies in which the method of randomization or concealment were unknown were included. Cross-over studies were excluded.

Data collection and analysis

Two review authors independently assessed trial quality and extracted data. All disagreements were resolved by consensus between authors and were explained. We attempted to contact the authors of studies for further details if any data were missing and to establish the characteristics of unpublished trials through correspondence with the trial coordinator or principal investigator. Adverse effects information was collected from the trials.

Main results

Four randomized, double-blind, placebo-controlled trials with a total of 452 patients met the inclusion criteria and were included in the review. In overall, there were improvements in activities of daily living (ADL) UPDRS (WMD -3.12, 95% CI -5.88 to -0.36) and Schwab and England (WMD 4.43, 95% CI 0.05 to 8.81) for coenzyme Q10 at 1200 mg/d for 16 months versus placebo.

In safety outcomes, only the risk ratios (RR) of pharyngitis (RR 1.04, 95% CI 0.18 to 5.89) and diarrhea (RR 1.39, 95% CI 0.62 to 3.16) are mild elevated between coenzyme Q10 therapy and placebo and there were no differences in the number of withdrawals due to adverse effects (RR 0.61, 95% CI 0.23 to 1.62).

Authors' conclusions

Coenzyme Q10 therapy with 1200 mg/d for 16 months was well tolerated by patients with Parkinson's disease. The improvements in ADL UPDRS and Schwab and England were positive, but it need to be further confirmed by larger sample. For total and other subscores of UPDRS, the effects of coenzyme Q10 seemed to be less clear.

 

Plain language summary

[Coenzyme Q10 for Parkinson's Disease.]

[Mitochondrial dysfunction has been well established to occur in Parkinson's disease and appears to play a role in the pathogenesis of the disorder. A deficit in brain coenzyme Q10 status may be involved in the pathophysiology of Parkinson's disease. Mitochondria play a central role in apoptotic cell death through a number of mechanisms. Coenzyme Q10 as an antioxidant, can affect certain of these processes. Theoretically, coenzyme Q10 can interfere with Parkinson's disease progression. There are four randomized, double-blind, placebo-controlled trials that tested coenzyme Q10 for Parkinson's disease. The results show coenzyme Q10 at dose of 1200mg/d for 16 months is well-tolerated and might disability as measured improve ADL UPDRS and Schwab and England. However this data is uncertain and precludes that this treatment be recommended for clinical use without further confirmatory trials are done.]