AUTHOR=Zhu Dao-min , Zhao Wenming , Zhang Biao , Zhang Yu , Yang Ying , Zhang Cun , Wang Yajun , Zhu Jiajia , Yu Yongqiang 

TITLE=The Relationship Between Serum Concentration of Vitamin D, Total Intracranial Volume, and Severity of Depressive Symptoms in Patients With Major Depressive Disorder

JOURNAL=Frontiers in Psychiatry

VOLUME=Volume 10 - 2019

YEAR=2019

URL=https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2019.00322

DOI=10.3389/fpsyt.2019.00322

ISSN=1664-0640

ABSTRACT=Background: Depression has been linked to vitamin D deficiency. However, little attention was paid to the neural substrate underlying this association. 
Methods: 50 patients with major depressive disorder (MDD) were enrolled in this study. High-resolution structural magnetic resonance imaging was performed to calculate total intracranial volume (TIV). Peripheral venous blood samples were collected to measure serum vitamin D concentration. Hamilton Rating Scale for Depression (HAMD) was used to assess severity of depression symptoms. The relationship among TIV, serum vitamin D concentration and HAMD score was examined using correlation, linear regression and mediation analyses.
Results: In patients with MDD, HAMD score was negatively correlated with TIV and serum vitamin D concentration, and TIV was positively correlated with serum vitamin D concentration. Linear regression analyses showed TIV and serum vitamin D concentration were significant predictors of HAMD score. Importantly, mediation analysis revealed that TIV significantly mediated the relationship between serum vitamin D concentration and HAMD score.
Conclusion: Our findings suggest that TIV may serve as a potential neural biomarker for monitoring responses to adjuvant therapy of vitamin D in patients with MDD.