Vitamin D: An Overlooked Parameter in Studies of Depression Using Optic Coherence Tomography

The relationship between depression and inflammation and the resulting vascular/neuronal damage have been demonstrated in recent studies. In this study we aimed to investigate inflammation and the possible degeneration that can be caused by depression and accompanying vitamin D deficiency using a non-invasive imaging method of optical coherence tomography (OCT).

Twenty-four healthy controls and 42 drug free major depressive patients matched for age, sex and eye measurements were compared in terms of vitamin D, C Reactive Protein (CRP) and OCT parameters. The Hamilton Depression Rating Scale (HAM-D), The Clinical Global Impressions Scale (CGI) and Global Assessment of Functioning Scale (GAF) were used to assess disease severity.

CRP level and choroidal thickness in the major depression group were significantly higher than the healthy controls. Vitamin D level and the ganglion cell layer (GCL) volume was significantly lower in the major depression group compared to healthy controls. Positive correlation was found between HAM-D and CRP in major depressive patients; a negative correlation was found between current attack duration and GCL volume. CGI was positively correlated with CRP and HAM-D. GAS was negatively correlated with CRP and HAM-D.

It has been shown that major depression might be an inflammatory disorder with possible degenerative processes observed with OCT and CRP measurements. But longitudinal follow up studies are needed to demonstrate a cause and effect relationship.