Relationship between serum homocysteine level and cognitive impairment in patients with Parkinson's disease

OBJECTIVE To investigate the correlation between serum homocysteine (Hcy) and cognitive impairment (CI) in patients with Parkinson's disease (PD). METHODS Eighty-one PD patients were prospectively recruited in this study from Feb 2015 to Jan 2018 in Gansu Provincial Hospital. Of the subjects, 41 were diagnosed with cognitive impairment (PD-CI) vs. the 40 others without PD (PDN). The clinical characteristic and demographic features were recorded for the two groups. The serum Hcy, folate and vitamin B12 (VitB12) were examined by high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA). RESULTS The serum Hcy, folate, VitB12 concentration were 21.7 +/- 6.2 (mu mol/L), 9.2 +/- 3.7 (ng/mL), 354.1 +/- 123.5 (pg/mL) for PD-CI group and 14.1 +/- 5.7 (mu mol/L), 12.4 +/- 4.5 (ng/mL), 378.7 +/- 128.2 (pg/mL) for PDN group respectively. The serum level of Hcy in PD-CI group was significantly higher than that of PDN group (p<0.05), serum folate was significantly lower than PDN group (p<0.05). The diagnostic sensitivity, specificity and AUC were 77.5% (95%CI:61.6%-89.2% ), 78.1% (95%CI:62.4%-89.4%), 0.82 (95%CI:0.73-0.91) for serum Hcy and 72.5% (95%CI:56.1%-85.4%), 63.4% (95%CI:46.9%-77.9%, 0.71(95%CI:0060-0.83) for serum folate respectively as serological markers for cognitive impairment diagnosis in patients with PD. Conclusion Serum Hcy and folate were different between PD-CI and PDN patients, which may play an important role in cognitive impairment development in patients with PD and can be used as promising serological diagnostic marker.