Efficacy of vitamin D supplementation in depression in adults: a systematic review.
What this study found
Vitamin D supplementation did not show a significant overall benefit for depression symptoms. The pooled postintervention effect was small and nonsignificant in the classic meta-analysis (SMD = −0.14, 95% CI −0.41 to 0.13; P = .32), and the dichotomous outcome was also null (OR = 0.93, 95% CI 0.54 to 1.59; P = .79). Subgroup analyses by dose, sex, location, sampling, and population did not identify a clear effect. Adverse events were generally absent or similar to placebo, but overall evidence quality was low.
- Study & population
- Systematic review and meta-analysis of 6 randomized controlled trials in adults 18 years and older who were at risk of depression, had depressive symptoms, or had a primary diagnosis of depression.
- Intervention
- Oral vitamin D supplementation was evaluated across 6 randomized trials, mainly as cholecalciferol, with regimens ranging from 1,500 IU/day to 20,000 IU twice weekly, 50,000 IU weekly, or 500,000 IU once yearly; one trial used calcitriol 0.25 g twice daily.
- Key limitation
- Evidence quality was low because of heterogeneity and risk of bias.
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Open PDFOriginal abstract
CONTEXT Randomized controlled trials (RCTs) investigating the efficacy of vitamin D (Vit D) in depression provided inconsistent results. OBJECTIVE We aim to summarize the evidence of RCTs to assess the efficacy of oral Vit D supplementation in depression compared to placebo. DATA SOURCES We searched electronic databases, two conference proceedings, and gray literature by contacting authors of included studies. STUDY SELECTION We selected parallel RCTs investigating the effect of oral Vit D supplementation compared with placebo on depression in adults at risk of depression, with depression symptoms or a primary diagnosis of depression. DATA EXTRACTION Two reviewers independently extracted data from relevant literature. DATA SYNTHESIS Classical and Bayesian random-effects meta-analyses were used to pool relative risk, odds ratio, and standardized mean difference. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation tool. RESULTS Six RCTs were identified with 1203 participants (72% females) including 71 depressed patients; five of the studies involved adults at risk of depression, and one trial used depressed patients. Results of the classical meta-analysis showed no significant effect of Vit D supplementation on postintervention depression scores (standardized mean difference = -0.14, 95% confidence interval = -0.41 to 0.13, P = .32; odds ratio = 0.93, 95% confidence interval = 0.54 to 1.59, P = .79). The quality of evidence was low. No significant differences were demonstrated in subgroup or sensitivity analyses. Similar results were found when Bayesian meta-analyses were applied. CONCLUSIONS There is insufficient evidence to support the efficacy of Vit D supplementation in depression symptoms, and more RCTs using depressed patients are warranted.