| Background and Objective:Parkinson's disease (PD) is a common neurodegenerative disease, which impacts on human health and quality of life of the elderly seriously. With the aging of our population, the incidence of Parkinson's disease is rising rapidly. Recent studies showed that a variety of factors were associated with the onset of PD, and statins might have a role in reducing the risk. In response to the ongoing debate over the relationship between the use of statins and the risk of Parkinson's disease, we performed a systematic review and meta-analysis of observational studies to examine their association.Methods:We conducted a review of the literature using MEDLINE, Pubmed, EMbase, Scopus, the Cochrane Library, CNKI, VIP, and Wanfang database, supplemented by a manual search to identify potentially relevant case-control or cohort studies though 30th June 2015. After selecting the studies according to the inclusion and exclusion criteria, the related data were extracted independently. The quality of each included study was assessed independently using the Newcastle-Ottawa Scale (NOS). All analyses were carried out using STATA 14.0 software. When homogeneity or low heterogeneity was detected, the fixed-effects model was used to calculate summary RRs. In cases of moderate heterogeneity, summary RRs were calculated using the random-effects model. For high heterogeneity, descriptive analysis was conducted instead of meta-analysis. Publication bias was assessed by the Begg's rank correlation test, the Egger's linear regression test and the funnel plot. Sensitivity analysis was conducted to test the stability of outcomes and subgroup analysis was conducted to explore the source of heterogeneity. To examine the association between individual statin use (or long-term statin use) and the risk of PD, we calculated the pooled RRs from studies providing these particular data.Results:Eleven studies (five case-control and six cohort studies) with 21,011 PD cases were included. Quality scores of NOS Scale ranged from 6 to 9 stars and seven studies were classified as high quality while four studies classified as moderate quality. Moderate homogeneity was detected among studies (Cochrane Q value= 28.18, P=0.002;/=64.5%) and random-effects model was used to obtain summary RR. Meta-analysis showed that there was a reduction in the risk of developing PD for statin users as compared with non-users (RR=0.81,95%CI:0.71-0.92, P=0.02). Sensitivity analysis demonstrated the robustness of results. Subgroup analyses showed that neither study design nor adjusted confounders and study qualities significantly influenced the effect estimates. When grouped by region, an inverse association was found in the European group (RR=0.86,95%CI:0.80-0.93, P=0.000) and the Asian group (RR=0.73,95%CI:0.60-0.88, P=0.001), while the association was non-significant in the North American group (RR=0.76,95%CI:0.54-1.08, P=0.128). Among the individual statins, atorvastatin, lovastatin, simvastatin, and rosuvastatin showed a non-significant inverse association with the risk of PD (RR=0.83,95%CI: 0.66-1.05; RR=0.61,95%C1:0.16-2.35; RR=0.68,95%C1:0.45-1.01; and RR=0.88, 95%CI:0.52-1.48, respectively), while pravastatin non-significantly increased the risk of PD (RR=1.35,95%CI:0.58-3.10). And meta-analysis showed that long-term statin use decreased the risk of PD almost significantly (RR=0.77,95%CI:0.56-1.07, P=0.120).Conclusions:Results of this systematic review suggest that statin use is associated with a reduced PD risk. The association between individual statin use (or long-term statin use) and the risk of PD was uncertain. However, randomized controlled trials and more observational studies should be performed before strong conclusions are drawn. |
PDF Full Text Request