Vitamin D supplementation and total cancer incidence and mortality: a meta-analysis of randomized controlled trials
Keum N, et al • Annals of Oncology
Key Finding
Cancer mortality: 13% reduction (RR 0.87, 95% CI 0.79-0.96, p=0.005); Cancer incidence: no effect (RR 0.98, 95% CI 0.93-1.03, p=0.42)
Key Findings
- 1Cancer mortality: 13% reduction (RR 0.87, p=0.005)
- 2Cancer incidence: no effect (RR 0.98, p=0.42)
- 3Daily dosing more effective than bolus
- 4Target 25(OH)D: 54-135 nmol/L
Original title: “Vitamin D supplementation and total cancer incidence and mortality: a meta-analysis of randomized controlled trials”
Plain English Summary
Meta-analysis of 10 RCTs found that vitamin D supplementation significantly reduced cancer mortality by 13% (RR 0.87, 95% CI 0.79-0.96, p=0.005) but had no effect on cancer incidence. Daily dosing appeared more effective than bolus administration.
In-Depth Analysis
Abstract
The researchers examined whether vitamin D supplementation affects cancer incidence and mortality. They found supplementation significantly lowered cancer mortality but not cancer incidence.
Methods
- •Design: Meta-analysis of randomized controlled trials
- •Search: PubMed and Embase through November 2018
- •Cancer incidence: 10 trials, 6,537 cases
- •Cancer mortality: 5 trials, 1,591 deaths
- •Follow-up: 3–10 years
Key Results
Cancer Incidence
"The summary RR was 0.98 (95% CI 0.93–1.03; P = 0.42; I² = 0%)" — no significant protective effect
Cancer Mortality
"The summary RR was 0.87 (95% CI 0.79–0.96; P = 0.005; I² = 0%)" — 13% reduction in cancer deaths
Total Mortality
- •7% reduction (RR 0.93) across eight trials
Dosing
- •Daily dosing more effective than infrequent bolus administration
- •Target 25(OH)D: 54–135 nmol/L may help reduce cancer mortality
Paradigm Relevance
How this study applies to different clinical perspectives:
Standard Medical
RelevantConventional clinical guidelines used by most doctors
Why it matters:
Evidence for supplementation benefit in cancer patients; does not support supplementation for cancer prevention
Research Consensus
RelevantCurrent scientific understanding, often ahead of guidelines
Why it matters:
Key evidence distinguishing incidence vs mortality effects; supports 40+ ng/mL levels for those with or at high risk for cancer
Metabolic Optimization
RelevantProactive targets for optimal health, not just disease absence
Why it matters:
Important nuance: vitamin D may improve cancer survival even if it doesn't prevent cancer; supports daily dosing over bolus
Study Details
- Type
- Meta-Analysis
- Methodology
- Meta-analysis of RCTs; cancer incidence: 10 trials with 6,537 cases; cancer mortality: 5 trials with 1,591 deaths; follow-up 3-10 years
Evidence Quality
Grade A - Meta-analysis of RCTs. Source: PMC6821324
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Original Source
DOI (Digital Object Identifier) is a permanent link to this publication. Unlike website URLs that can change, a DOI always resolves to the correct source.
Related Studies
Health Effects of Vitamin D supplementation: Lessons Learned from Randomized Controlled Trials and Mendelian Randomization Studies
Bouillon R, et al • J Bone Miner Res • 2023
Cancer mortality: daily dosing RR 0.88 (95% CI 0.78-0.98, 10 trials); bolus RR 1.07 (ineffective); VITAL: normal BMI cancer OR 0.76; shift focus to deficient individuals
International Vitamin D Supplementation Guidelines
Pludowski P, et al • Journal of Steroid Biochemistry and Molecular Biology • 2018
Target 25(OH)D levels of 30-50 ng/mL (75-125 nmol/L) recommended for general health; higher targets (40-60 ng/mL) for specific conditions.
Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data
Martineau AR, et al • BMJ • 2017
Overall ARTI reduction OR 0.88 (95% CI 0.81-0.96); daily/weekly dosing OR 0.81; profound deficiency (<25 nmol/L) + daily dosing OR 0.30 (NNT 4)