Low serum uric acid levels are associated with the nonmotor symptoms and brain gray matter volume in Parkinson's disease.

Background Uric acid (UA) plays a protective role in Parkinson's disease (PD). To date, studies on the relationship between serum UA levels and nonmotor symptoms and brain gray matter volume in PD patients have been rare. Methods Automated enzymatic analysis was used to determine serum UA levels in 68 healthy controls and 88 PD patients, including those at the early (n = 56) and middle-late (n = 32) stages of the disease. Evaluation of motor symptoms and nonmotor symptoms in PD patients was assessed by the associated scales. Image acquisition was performed using a Siemens MAGNETOM Prisma 3 T MRI scanner. Results Serum UA levels in early stage PD patients were lower than those in healthy controls, and serum UA levels in the middle-late stage PD patients were lower than those in the early stage PD patients. Serum UA levels were significantly negatively correlated with the disease course, dysphagia, anxiety, depression, apathy, and cognitive dysfunction. ROC assessment confirmed that serum UA levels had good predictive accuracy for PD with dysphagia, anxiety, depression, apathy, and cognitive dysfunction. Furthermore, UA levels were significantly positively correlated with gray matter volume in whole brain. Conclusions This study shows that serum UA levels were correlated with the nonmotor symptoms of dysphagia, anxiety, depression, apathy, and cognitive dysfunction and the whole-brain gray matter volume. That is the first report examining the relationships between serum UA and clinical manifestations and imaging features in PD patients.