Correlation Between Plasma Melatonin Levels And Non-motor Symptoms In Patients With Parkinson's Disease

ObjectiveTo assess plasma melatonin levels in patients with Parkinson's disease(PD)and to analysis the relationship between plasma melatonin levels and non-motor symptoms.Methods1.Sixty-one patients with idiopathic PD treated in the People's Hospital of Zhengzhou University were selected,and general clinical data such as patient name,gender,age,course of disease,medical history,and medication status were collected.At the same time,58 healthy volunteers with matching gender and age were recruited.2.The severity of disease in PD patients was scored by the Unified Parkinson's Disease Rating Scale and the Hoehn and Yahr Staging scale.The quality of life in PD patients was assessed by the 39-item Parkinson's Disease Questionnaire.The non-motor symptoms were assessed by the 14-item Hamilton Anxiety Rating Scale,the 24-item Hamilton Depression Rating Scale,the Parkinson Disease Sleep Scale,the Epworth Sleepiness Scale and the Non-Motor Symptoms Scale for PD.3.Plasma melatonin levels were measured using an enzyme-linked immunosorbent assay.4.SPSS version 22.0 and GraphPad Prism 8 software were used to analyze plasma melatonin levels between two groups and the relationship between plasma melatonin levels and non-motor symptoms in PD patients.Results1.Compared with the healthy controls,the plasma melatonin levels were significantly higher in PD patients(12,82±4.85 vs.19.40±4.23,P<0.001).2.Significant negative correlations were found between plasma melatonin concentrations and levodopa equivalent daily dose(r=-0.262,P<0.05,n=61).3.There were no significant differences in the distribution of plasma melatonin concentrations by Hoehn and Yahr stage in PD patients(r=-0.069,P>0.05,n=61).4.This study found that the non-motor symptoms that were inversely related to plasma melatonin levels were cardiovascular symptoms(r=-0.255,P<0.05),sleep disorders(r=-0.328,P<0.05),and gastrointestinal dysfunction(r=-0.265,P<0.05).The closest relationship was with sleep disorders.The remaining non-motor symptoms were not associated with plasma melatonin levels(P>0.05).5.Higher plasma melatonin concentrations were detected in the negative cardiovascular symptom group than in the cardiovascular symptom group(20.13±3.74 vs.16.93±3.74,P<0.05).Higher plasma melatonin concentrations were detected in the non-sleep-disorders group than in the sleep disorders group(22.12±5.93 vs.18.86±3.66,P<0.05).In addition,the plasma melatonin concentration was higher in the group without gastrointestinal dysfunction than in the gastrointestinal dysfunction group(21.71±4.44 vs.18.35±3.74,P<0.05).6.Plasma melatonin levels in PD patients were further subdivided according to sleep-related scales,and the results showed that the plasma melatonin level and the total score of the PSQI scale(r=-0.2 55,P<0.05),the-daytime dysfunction of the PSQI scale sub-item(r=-0.308,P<0.05)were negatively correlated and sub-item 12 of the PDSS scale were positively correlated(r=0.336,P<0.05).Conclusion1.Compared with the healthy controls,the plasma melatonin levels were significantly higher in PD patients.2.Non-motor symptoms that are significantly negatively correlated with plasma melatonin levels are cardiovascular symptoms,sleep disorders and gastrointestinal dysfunction.Among these non-motor symptoms,sleep disorders have the closest correlation with plasma melatonin levels.The remaining non-motor symptoms were not related to plasma melatonin levels.