Randomised controlled trialcited by the Tayebat archiveabstract only checked A-SUP-22 standard review
VITAL: vitamin D for prevention
Vitamin D Supplements and Prevention of Cancer and Cardiovascular Disease.
Overview
Manson JE et al.. N Engl J Med 2019 · PMID 30415629 · DOI 10.1056/NEJMoa1809944
No prevention of cancer or heart disease; no safety problems.
Does the study support the specific claim? Yes · Methodological quality: high
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Prevention.
- How was the study done?
RCT.
- How many people, animals or samples were studied?
25,871.
- What was actually found?
Null.
- How large was the observed effect?
HR 0.96/0.97.
- What do the results mean in everyday life?
No need in replete adults.
- What are the study's limitations?
Replete population.
- What does it say about Elawady's specific claim?
Supports C-SUP-01.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
Effect in deficiency.
Scientific in-depth review
1. Full reference
- Authors
- Manson JE, Cook NR, Lee IM, Christen W, Bassuk SS, Mora S, Gibson H, Gordon D, Copeland T, D'Agostino D, Friedenberg G, Ridge C, Bubes V, Giovannucci EL, Willett WC, Buring JE, VITAL Research Group
- Journal
- N Engl J Med
- Year
- 2019
- Identifier
- PMID 30415629 DOI 10.1056/NEJMoa1809944 · PMC6425757
- Verification
- verified – PubMed E-utilities efetch, 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
not stated in abstract; grants: NCI NIH HHS, NHLBI NIH HHS, NIAMS NIH HHS, NIMH NIH HHS
2. Research question
Does vitamin D3 2,000 IU/d prevent cancer and CVD?
3. Study design and population
- Study design
- Randomised controlled trial – Randomised placebo-controlled 2×2 factorial trial (VITAL, vitamin D arm)
- Population
Men ≥50, women ≥55
- Country
USA
- Period
median 5.3 years
- Sample size
25,871
- Inclusion and exclusion criteria
see abstract
4. Methods and endpoints
- Exposure / intervention
Vitamin D3 2,000 IU/d
- Comparator
Placebo
- Endpoints
Invasive cancer; major CV events
- Statistical methods
Cox
5. Actual results
- Results
Cancer HR 0.96 (0.88–1.06); CV events HR 0.97 (0.85–1.12); cancer death HR 0.83 (0.67–1.02); no excess hypercalcaemia or adverse events.
- Absolute risks
not reported in abstract
- Authors' conclusion
Vitamin D did not lower cancer or CV events.
6. Strengths
- Large RCT
7. Weaknesses
- Mostly vitamin-D-replete population
8. Risk of bias
- Orienting tool
- RoB 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- low
- Rationale
Simplified RoB 2.
9. Assessment of the statistical interpretation
See results.
10. Relevance to the specific claim
C-SUP-01; C-SUP-07 (limits harm claim).
11. Independent contrary findings
12. Transferability to Germany and Europe
High: biology and trial populations comparable to European adults.
13. Overall methodological judgement
High-quality null.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | high |
| Risk of bias | low |
| Precision of results | high |
| Directness | direct |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | correctly reported |
14. Open questions
15. Linked fact checks
- When popular oral supplements (calcium, beta-carotene, vitamin E, omega-3, multivitamins, glucosamine, selenium, vitamin A) were tested in large long-term placebo-controlled trials, most failed to deliver the promised prevention of disease. – Studies supporting the claim
- Certain supplements caused specific harms: more hip fractures (vitamin A), kidney stones (vitamin C), falls and fractures (high-dose vitamin D), type 2 diabetes (selenium), and no benefit for knee pain (glucosamine). – Studies contradicting or limiting the claim
Use by the Tayebat archive
Note: according to the archive, the studies were compiled by the archive operators. Whether Dr. Elawady himself cited this study is not established.
- What the archive says about the study
Listed in the archive bibliography of the oral-supplements rule without its own interpretation; used implicitly to support the rule summary that supplements 'failed or caused harm' in large trials.
- A. What was actually studied?
Does vitamin D3 2,000 IU/d prevent cancer and CVD?
- B. What did the authors find?
Cancer HR 0.96 (0.88–1.06); CV events HR 0.97 (0.85–1.12); cancer death HR 0.83 (0.67–1.02); no excess hypercalcaemia or adverse events.
- C. What conclusions do the authors themselves draw?
Vitamin D did not lower cancer or CV events.
- D. What does the archive derive from it?
Supports 'failed'.
- E. Is this derivation scientifically justified?
Yes for prevention in replete adults; shows no harm at daily dose.
- Adequacy of the interpretation (by the archive)
- correctly reported