Vitamin D and Reduced Mortality Risk

Research synthesisVery low evidenceMixed effect size3 studies · 1 beneficial · 2 neutral · 0 harmful

Across 3 studies, 1 reported beneficial moderate-sized effects on reduced mortality risk, while 2 found neutral effects. The predominant effect size was mixed, with the single beneficial study showing a moderate effect and the neutral studies showing small effects. The most-studied population was preterm infants (one large meta-analysis with 4,357 participants), and the only specified dose was ≥800 IU/day of vitamin D, which showed no significant benefit.

Effective dose range: ≥800 IU/d
Studied populations: preterm infants

Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. Many of the included studies did not reach statistical significance — effect may be smaller than the predominant direction suggests. The only beneficial study was an observational review, while the highest-quality evidence (meta-analysis of RCTs) found no significant effect.

Generated Jul 11, 2026

Doses used in studies

IU/day: 800 (median 800, IQR 800–800) — 1 study

Safety in these studies

Overall tolerabilityReported
Vitamin D might demonstrate the greatest therapeutic potential, particularly in patients with severe sepsis and respiratory failure, with benefits associated with achieving appropriate therapeutic concentrations.
from: The Role of Vitamins in Sepsis: A Narrative Review.

3 of 3 papersPopulation:

Clinical efficacy of different supplemental doses of vitamins A and D in preventing bronchopulmonary dysplasia in preterm infants: A network meta-analysis based on randomized controlled trials.
- 2026-05-22
- Meta-Analysis · n = 4,357
- Medicine 105(21)
- - Qingfeng Yu
  - Xiao Chen
  - Jing Chen
  - Lan Peng
  - Kui Luo
- PubMed: 42175407
- DOI: 10.1097/md.0000000000048956
3 Insights on
- Reduced Mortality Risk
- High evidence
- Infants
No statistically significant differences in mortality were observed among any of the supplementation strategies or placebo
Effect
Neutral
Effect size
Small
Significant
No
Dose
≥3330 IU/d
The Role of Vitamins in Sepsis: A Narrative Review.
- 2025-10-23
- Review
- Nutrients 17(21)
- - Paweł Radkowski
  - Anna Gogojewicz
  - Joanna Charasna
  - Łucja Pilaczyńska-Szcześniak
  - Łukasz Grabarczyk
- PubMed: 41228403
- DOI: 10.3390/nu17213330
1 Insight on
- Reduced Mortality Risk
- Moderate evidence
- Rigorous Journal
Vitamin C, despite its well-documented antioxidant and microcirculatory effects, has not yet shown consistent evidence of mortality reduction.
Effect
Neutral
Effect size
Small
Significant
No
The Role and Clinical Significance of Vitamin D in Chronic Obstructive Pulmonary Disease.
- 2025-06-23
- Review
- International journal of chronic obstructive pulmonary disease 20
- - Mengqing Sun
  - Yang Qian
  - Chenting Cai
  - Jiaqian Zhang
  - Ruonan Qi
  - Hongying Ma
  - Qunli Ding
  - Shanshan Wang
  - Dan Lv
- PubMed: 40585424
- DOI: 10.2147/copd.s520795
3 Insights on
- Reduced Mortality Risk
- Low evidence
Clinical observational studies have demonstrated significant associations between vitamin D deficiency and increased exacerbation frequency, accelerated lung function decline, and elevated mortality risk.
Effect
Beneficial
Effect size
Moderate
Significant
Yes

Vitamin D and Reduced Mortality Risk

Clinical efficacy of different supplemental doses of vitamins A and D in preventing bronchopulmonary dysplasia in preterm infants: A network meta-analysis based on randomized controlled trials.

The Role of Vitamins in Sepsis: A Narrative Review.

The Role and Clinical Significance of Vitamin D in Chronic Obstructive Pulmonary Disease.