[Correlation analysis of serum calcium level and cognition in the patients with Parkinson's disease]

Objective: To investigate the relation between cognition and serum calcium in the patients with Parkinson's disease (PD), analyze the related factors of cognition, and evaluate the correlation of serum calcium with specific cognitive domains. Methods: A total of 77 patients with Parkinson's disease who was hospitalized in the Second Affiliated Hospital of Soochow University, from Dce 2013 to May 2015 were subjected to the cognitive, motor and depression function assessment, and the fasting blood calcium samples were collected from the PD patients and 75 normal control subjects. According to cognitive function, PD patients were divided into dementia group and without dementia group. Then the serum calcium levels of three groups and the related factors of the cognitive were analyzed by multiple linear regression. Results: (1) The level of serum calcium in PD group with dementia (2.21±0.09) mmol/L was significantly lower than the normal control group (2.30±0.09)mmol/L (P<0.001), and there was no difference between the level of serum calcium in PD group without dementia (2.27±0.13 mmol/L) and normal control group (P=0.144). The level of serum calcium in PD group with dementia was lower than PD group without dementia, and there was marked statistical significance (P=0.023). (2) In PD patients, the cognitive scores correlated with serum calcium levels, education, H-Y stages and Unified Parkinson's Disease Rating Scale (UPDRS) Ⅲ scores (P<0.05), but didn't with gender, age, disease duration, depression levels, Body Mass Index (BMI) and total equivalent levodopa doses (P>0.05). (3) In PD patients, serum calcium level correlated with the visuospatial and executive capability, calculation ability, language ability (P1=0.004; P2=0.027; P3=0.021). Conclusions: (1) There is correlation between the serum calcium and the cognitive impairment. Lower serum calcium level predicts worse cognitive scores. (2) In PD patients, the change of the cognitive function is affected by their education, H-Y stages and UPDRSⅢ scores. (3) The serum calcium level of PD patients closely relates to the cognitive domain of the visuospatial and executive capability, calculation ability, and language ability.