The effects of uric Acid, serum vitamin d3, and their interaction on Parkinson's disease severity.

Objectives. In current study, the relationships between serum vitamin D3 levels and serum UA concentrations as well as their interaction with severity of PD were evaluated in a sample of Iranian PD patients. Method. In a cross sectional study at the one of the main referral hospitals in central region of Iran, during September to November 2011, 112 patients were recruited. Severity of PD was evaluated sing H&R stages and UPDRS. Results. The Spearman rank correlation coefficient suggests the negative significant association between serum vitamin D3 and UPDRS in patients aged >62 (r = -0.34, P < 0.05). No statistically significant association was observed between the UA levels and severity of PD (represented by H&Y categories) in different levels of serum vitamin D3 not only in total sample but also in separate age and sex groups. The linear regression coefficients suggested positive association between UA and serum vitamin D3 with UPDRSIII scores while negative relationship between UA and serum vitamin D3 interaction with UPDRSIII; however it was only statistically significant in age group ≤62 (P < 0.05). Conclusion. Our study revealed a negative correlation between interaction of serum vitamin D3 and UA with severity of PD; other studies are required to confirm our findings.