title: Low uric acid levels in patients with Parkinson's disease: evidence from meta-analysis.
abstract: OBJECTIVE
  The association between Parkinson's disease (PD) and uric acid levels has gained intensive interest in recent years. We applied meta-analysis to investigate serum uric acid levels in patients with PD in comparison with healthy controls.
  
  
  METHODS
  We searched three electronic databases and reference lists up to January 2013. Two collaborators reviewed all the articles and data disagreement was resolved through discussion. Six studies met the eligibility criteria and were included in the meta-analysis of uric acid levels in patients with PD in comparison with controls.
  
  
  METHODS
  1217 patients with PD and 1276 matched healthy controls.
  
  
  RESULTS
  The meta-analysis results showed that patients with PD had lower levels of uric acid than healthy controls (summary standardised mean difference (SMD)=-0.52, 95% CI (-0.72 to -0.31)). Further gender subgroup analysis (summary SMD=-0.56, 95% CI (-0.72 to -0.41) for women; summary SMD=-0.62, 95% CI (-0.94 to -0.31) for men) indicated lower uric acid levels in patients with PD than healthy controls in women and men.
  
  
  CONCLUSIONS
  It was found that patients with PD had lower serum levels of uric acid than healthy controls and this association was more significant in men than in women. More efforts are encouraged to explore the prognostic and therapeutic implications for PD of the present findings.
authors.affiliation: Shandong Provincial Research Center for Bioinformatic Engineering and Technique, Shandong University of Technology, Zibo, People's Republic of China.
authors.forename: Liang
authors.initials: L
authors.lastname: Shen
authors.forename: Hong-Fang
authors.initials: HF
authors.lastname: Ji