Changed Serum Level Of 25-hydroxy Vitamin D3 And Its Correlations With Sleep Quality And Cognition In The Patients With Chronic Insomnia Disorder

Background and objective:Chronic insomnia disorder（CID）refers to the subjective experience of frequent and persistent difficulties in initiating and maintaining sleep,resulting in poor sleep duration or quality and impaired daytime functioning（mild cognitive impairment）.However,at present,there is no effective intervention for CID itself and its related cognitive impairment in clinical practice.The main reason is that we are still not clear about the mechanism of their occurrence.Vitamin D has been shown to play an important role in sleep regulation.In addition,vitamin D deficiency is associated with cognitive impairment in a variety of neurodegenerative diseases,such as parkinson’s disease and alzheimer’s disease.However,only a few studies have found changes in serum 25-hydroxyvitamin D₃[25（OH）D₃]levels in CID patients,and the association with insomnia severity and cognitive impairment has not been explored.Therefore,this study aims to explore serum level of 25-hydroxy vitamin D₃[25（OH）D₃]and its correlations with sleep quality and cognitive function in the patients with chronic insomnia disorder（CID）.Methods:Fifty CID patients,admitted to the outpatient and inpatient department of chaohu hospital affiliated to anhui medical university from October 1,2016 to September 1,2018,and forty healthy people without sleep disorder who underwent outpatient physical examination during the same period were collected as the control group.Pittsburgh Sleep Quality Index（PSQI）was used to evaluate the sleep quality of the two groups.Some patients underwent polysomnogram（PSG）to assess their objective sleep status throughout the night.The main monitoring parameters included:Total sleep time（TST）,sleep efficiency（SE）,sleep onset latency（SOL）,wake times,wake time,non-rapid eye movement（NREM）sleep stage 1,stage 2,stage 3（N1,N2,N3）,rapid eye movement（REM）the duration of sleep and the percentage of sleep in total sleep time（N1%,N2%,N3%,REM%）.Hamilton Depression Rating Scale-17（HAMD-17）was used to evaluate the Depression of the two groups.The Montreal Cognitive Assessment（MoCA）was used to evaluate the cognitive function of the two groups."Nine box maze"test was used to evaluate the memory function of two groups of members,including object reference menory（ORM）,spatial reference menory（SRM）,object working menory（OWM）,spatial working menory（SWM）and object recognition menory（ORcM）.Serum level of 25（OH）D₃ was detected by ELISA.Results:（1）General information:There was no significant difference between the two groups in gender,age and education level（Ps>0.05）.Compared with the two groups,the HAMD-17 score of CID group was higher than that of the control group（Z=-6.424,P<0.001）.（2）Sleep quality:Compared with the control group,PSQI score（Z=-8.186,P<0.001）in CID group was significantly increased.（3）Cognitive function and memory functions:Compared to the control group,MoCA score in CID group was significantly reduced（Z=-3.876,P<0.001）.Visual space/executive function and delayed recall scores were also significantly reduced in CID group（Ps<0.001）.The error numbers of objects working（Z=-2.304,P=0.021）,spatial working（Z=-4.927,P<0.001）and object recognition memory（Z=-3.770,P<0.001）were significantly increased in CID group.（4）Change of serum level of 25（OH）D₃:The serum level of25（OH）D₃ in CID group was significantly lower than that in control group（t=-9.367,P<0.001）.（5）The relationship between serum level of 25（OH）D₃ and sleep status,duration and cognitive function:in the CID group,serum level of 25（OH）D₃ was negatively correlated with PSQI score（r=-0.320,P=0.030）,error numbers of spatial working memory（r=-0.300,P=0.043）,and course of disease（r=-0.360,P=0.014）;positively correlated with total sleep time（r=0.515,P=0.014）,MoCA score（r=0.422,P=0.003）and delayed recall（r=0.416,P=0.004）in the MoCA scale.Conclusion:The level of 25（OH）D₃ decreases in the CID patients,which is correlated with the severity and course of insomnia,and may affect the cognitive function of patients.