Hypovitaminosis D is A Biological Vulnerability for Depressive Symptoms in Major Depression at the Era of the Coronavirus Disease Outbreak

Background: Major depressive disorder (MDD) is a prevalent mental health condition causing substantial global issues. Emerging evidence indicates that depression rates have risen during the coronavirus disease (COVID-19) pandemic. Insufficient vitamin D levels have been linked to increased psychological problems and heightened responses to stress. Objectives: This study aims to investigate the connection between serum vitamin D levels and depressive symptoms in individuals with MDD compared to healthy controls during the COVID-19 pandemic. Materials and Methods: This cross-sectional study included 90 MDD patients diagnosed according to Diagnostic and Statistical Manual of Mental Illnesses (DSM)-5 criteria version 7.0.2, assessed using the Mini International Neuropsychiatric Interview. During COVID-19 lockdown measures, participants completed the Patient Health Questionnaire depression module (PHQ-9) to assess depressive severity. Blood samples were collected for vitamin D assays. Statistical analyses were conducted using Statistical Package for the Social Sciences (SPSS), including receiver operating characteristic (ROC) curve analysis to predict depressive symptom severity. Results: Patient and control groups had similar mean age and body mass index (BMI), with most participants classified as obese (BMI > 30 kg/m 2 ). Female patients were predominant in the study. MDD patients exhibited significantly lower mean serum vitamin D levels compared to controls (10.3 ± 6.2 vs. 18.1 ± 9.6 ng/mL). Female patients had higher vitamin D levels than males. Correlations among serum vitamin D levels, BMI, MDD duration, and age were insignificant. ROC curve analysis indicated that lower vitamin D levels moderately predict MDD presence (area under curve [AUC] = 0.750) and, to a lesser extent, severe MDD (AUC = 0.739). Conclusion: The study suggests an inverse association between serum vitamin D levels and clinical depression during the COVID-19 era. However, the evidence is not entirely conclusive, prompting the need for further randomized trials to determine whether this relationship is causal.