Efficacy and Acceptability of Vitamin D Supplements for Depressed Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Abstract: Objective: This systematic review and meta-analysis synthesized the evidence from randomized controlled trials (RCTs) to compare depressive symptom reduction and all-cause dropout rates between depressed patients receiving vitamin D supplements and placebo. Methods: The inclusion criteria for meta-analysis were RCTs comparing depressive symptom reduction or all-cause dropout rates between depressed patients receiving vitamin D supplements and those receiving placebo. We searched PubMed, Embase, Web of Science, and the Cochrane Library on January 3, 2022. The frequentist pairwise meta-analysis was performed using a random-effects model. In addition, subgroup analyses for categorical variables and meta-regressions for continuous variables were performed on potential mediating factors for vitamin D efficacy. Results: Twenty trials were systematically reviewed. The meta-analysis included 18 RCTs of 1,980 participants with a median age of 39.2 years. Seventeen trials gave vitamin D supplements orally. Four trials had a high risk of bias. The pooled data revealed that vitamin D supplements were significantly superior to placebo in reducing depressive symptoms (18 trials, standardized mean difference = -0.49, 95%CI = -0.75 to -0.23, I2 = 81%). Depressed adults might respond better than children and adolescents with depression. Patients with more severe depression tended to respond to vitamin D better than those with less severe depression ( = -2.55, p = 0.053). The pooled dropout rates were not significantly different between groups (risk ratio = 0.84, 95%CI = 0.61 to 1.16, I2 = 0%). Conclusion: Limited evidence suggests that vitamin D supplements are well accepted and have medium efficacy in reducing depressive symptoms.Short Description: “Is vitamin D supplement effective and safe for depressed patients?”Name of Sponsoring Organization(s): N/A