Abstract:Objective: To systematically review the association between diabetes mellitus (DM) and the risk of Parkinson’s disease (PD). Methods: PubMed, CNKI, Wanfang Data, and VIP were searched for related articles published up to March 2016. Case-control studies on PD and DM were retrieved, related data were extracted, and Review Manager 5.3 was used for data analysis. Results: Seven articles which met the inclusion criteria were included in the meta-analysis, with a total of 5143 PD patients and 5713 controls. Data processing showed that in spite of significant heterogeneity (I2 = 76%, P <0.010), the incidence rate of diabetes was negatively correlated with the incidence rate of PD [odds ratio (OR)=0.62, 95% confidence interval(CI)=0.41 to 0.94]. Due to significant heterogeneity in data, subgroup analysis was performed based on the mean age at the time of PD diagnosis and smoking history, and the results showed that for PD in patients aged ≤67.2 years（OR=0.35，95% CI=0.21 to 0.59）, in patients aged >67.2 years(OR=0.69，95%CI=0.38 to 1.24), and in patients with a history of smoking（OR=0.56，95%CI=0.33 to 0.94） and in patients without a history of smoking（OR=0.74，95%CI=0.27 to 1.99）. In addition, the sensitivity analysis confirmed the reliability of the above results. Conclusion: The results of the case-control studies suggest that DM may reduce the incidence rate of PD despite of significant heterogeneity. Further studies focusing on the common pathogenesis of DM and PD and the pathogenic factors interacting with one another are needed to investigate the association between DM and PD.
