Vitamin D deficiency and depressive symptoms: Meta-analysis of studies

Aim. The aim of this study was the identification and summarization of studies examining the relationship between vitamin D levels and the risk of depression and depressive symptoms severity, published between January 2008 and January 2019.Methods. A systematic review of literature published within the last 10 years and acces-sible in PubMed database was conducted by each author separately based on predetermined inclusion criteria.Results. Out of the 823 studies qualified to the initial abstract analysis, 24 were included into the full-text review and 18 into the meta-analysis. Statistically significant odds ratio was obtained for risk of depression in the course of vitamin D deficiency (OR = 1.51; 95% CI: 1.4-1.62; p < 0.01).Conclusions. The analysis of available literature seems to indicate that there is an as-sociation between risk of depression and vitamin D deficiency. However, current literature does not give the possibility to state explicitly what is the exact mechanism and direction of this dependency.