Randomised controlled trialcited by the Tayebat archiveabstract only checked A-SUP-08 standard review
VITAL: fish oil in healthy adults
Marine n-3 Fatty Acids and Prevention of Cardiovascular Disease and Cancer.
Overview
Manson JE et al.. N Engl J Med 2019 · PMID 30415637 · DOI 10.1056/NEJMoa1811403
No reduction in major cardiovascular events or cancer.
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?
Primary prevention.
- How was the study done?
RCT.
- How many people, animals or samples were studied?
25,871.
- What was actually found?
Null primary end points.
- How large was the observed effect?
HR 0.92.
- What do the results mean in everyday life?
Not needed for prevention.
- What are the study's limitations?
Fewer MIs secondary.
- What does it say about Elawady's specific claim?
Supports.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
Effect in high-risk.
Scientific in-depth review
1. Full reference
- Authors
- Manson JE, Cook NR, Lee IM, Christen W, Bassuk SS, Mora S, Gibson H, Albert CM, 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 30415637 DOI 10.1056/NEJMoa1811403 · PMC6392053
- 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
Do marine n-3 fatty acids (1 g/d) prevent CVD and cancer?
3. Study design and population
- Study design
- Randomised controlled trial – Randomised placebo-controlled 2×2 factorial trial (VITAL, omega-3 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
1 g/d marine n-3
- Comparator
Placebo
- Endpoints
Major CV events; invasive cancer
- Statistical methods
Cox
5. Actual results
- Results
Major CV event HR 0.92 (0.80–1.06); cancer HR 1.03 (0.93–1.13); total MI HR 0.72 (0.59–0.90) (secondary); death HR 1.02.
- Absolute risks
not reported in abstract
- Authors' conclusion
Supplementation did not lower major CV events or cancer.
6. Strengths
- Large RCT
7. Weaknesses
- Secondary MI benefit
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
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 result.
| 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
- Omega-3 capsules do not prevent cardiovascular disease and increase the risk of atrial fibrillation; Elawady rejects omega-3 capsules. – Studies supporting 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?
Do marine n-3 fatty acids (1 g/d) prevent CVD and cancer?
- B. What did the authors find?
Major CV event HR 0.92 (0.80–1.06); cancer HR 1.03 (0.93–1.13); total MI HR 0.72 (0.59–0.90) (secondary); death HR 1.02.
- C. What conclusions do the authors themselves draw?
Supplementation did not lower major CV events or cancer.
- D. What does the archive derive from it?
Supports 'omega-3 failed'.
- E. Is this derivation scientifically justified?
Yes for primary end points; secondary MI reduction omitted.
- Adequacy of the interpretation (by the archive)
- correctly reported