Correlation Study Of Narcolepsy Type 1 And Serum Vitamin B₁₂

BackgroundNarcolepsy type 1（NT1）can be defined as a rare chronic neurological disorder typified by irresistible excessive daytime sleepiness（EDS）and episodes of sudden collapse.Selective disruption of hypocretin neurons in the lateral hypothalamic region that control the sleep-wake cycle is thought to be the main pathophysiological mechanism underlying NT1.Previous case studies have found that vitamin B₁₂supplementation significantly improves EDS symptoms in NT1 patients.In addition,the prevalence of psychiatric comorbidity is increased in NT1 patients,and vitamin B₁₂ plays an important role in the pathogenic mechanisms of psychiatric disorders.At present,it is not clear how serum vitamin B₁₂ levels change in NT1 patients and whether they are involved in the pathophysiological mechanisms of NT1.ObjectiveThe main objective of this study was to assess the differences in serum vitamin B₁₂ levels between NT1 patients and controls and to investigate whether vitamin B₁₂ is an independent risk factor for NT1.In addition,differences in clinical characteristics of NT1 patients were determined based on vitamin B₁₂status,and serum vitamin B₁₂ levels were correlated with sleep quality,mood disturbance,and sleepiness severity in NT1.MethodsSerum vitamin B₁₂levels were retrospectively analyzed in 60 NT1 patients and age-and sex-matched 60 controls,and the Pittsburgh sleep quality index（PSQI）,the Epworth Sleepiness Scale（ESS）,the Hamilton Anxiety Scale(HAMA₁₄)and the 24-item Hamilton Depression Rating Scale(HAMD₂₄)were used to assess patients’sleep quality,sleepiness severity,anxiety and depression status.Based on the results of univariate logistic analysis,a multi-factor logistic regression model was constructed to predict the risk factors that independently affected NT1.The diagnostic validity of vitamin B₁₂ on NT1 was assessed using receiver operating characteristic（ROC）curve analysis.In addition,grouping was performed according to vitamin B₁₂levels to determine differences in clinical characteristics between NT1 patient groups,and serum vitamin B₁₂levels were further correlated with ESS,PSQI,and HAMA₁₄ and HAMD₂₄ scale scores in NT1 patients.Results:1.Serum vitamin B₁₂ levels were significantly lower in patients in the NT1 group,and multifactorial logistic regression showed that serum vitamin B₁₂ was an independent risk factor for NT1（P<0.001;OR=0.96;95%CI:0.94-0.98）.2.The area under the ROC curve predicted by serum vitamin B₁₂ was 0.938（95%CI:0.86-0.99,P<0.001）,with sensitivity of 95.0%and specificity of 88.3%.3.By gender subgroup analysis,serum vitamin B₁₂ levels were lower in men with NT1 compared with women（P<0.05）,suggesting gender differences.4.The PSQI score and HAMD₂₄ score of NT1 patients in the serum vitamin B₁₂ deficiency group were significantly higher than those in the group with normal serum vitamin B₁₂ levels（P<0.05）,and no differences were seen between ESS and HAMA₁₄ scores.5.In NT1 patients,serum vitamin B₁₂was negatively correlated with HAMD₂₄score（r=-0.376,P<0.05）,and correlation analysis after further adjustment for relevant variables revealed that serum vitamin B₁₂ levels were still negatively correlated with HAMD₂₄ score（r=-0.457,P<0.001）.Conclusion:1.serum vitamin B₁₂ levels were significantly lower in NT1 patients and vitamin B₁₂ deficiency was an independent risk factor for NT1,and these results provide in vivo evidence for a role of vitamin B₁₂in NT1 pathogenesis.2.Serum vitamin B₁₂ levels were lower in male NT1 patients,which may provide a new perspective to explain the higher prevalence in the male group of NT1 patients.3.Serum vitamin B₁₂ was negatively correlated with depressive status scores in NT1 patients,which has important implications for finding more risk factors for psychiatric co-morbidity in NT1 patients to improve prevention strategies and find new therapeutic targets.4.Vitamin B₁₂ deficiency is a preventable and treatable disease,and attention should be paid to screening for vitamin B₁₂ deficiency in NT1 individuals,and further prospective randomized controlled studies are needed to clarify the pathogenic mechanism of vitamin B₁₂ in NT1 and the effect of vitamin B₁₂supplementation on symptom treatment.