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Trial, not randomized · measured the question itself

Reanalysis of a trial in 25,871 older US adults: omega-3 lowered heart attack risk

Hamaya and colleagues · The American journal of clinical nutrition · 2025

Original title: A Bayesian analysis of the VITAL trial: effects of ω-3 fatty acid supplementation on cardiovascular events.

Under review. A person has not yet checked this summary against the paper. It is written from the PubMed abstract. Until a person checks it, search engines are asked not to list this page.

What the study found

Points to benefit

With earlier trial results added, hazard ratios for coronary artery disease were 0.88 to 0.93 and for heart attack 0.82 to 0.90. Stroke risk was unchanged.

The study at a glance

Type of study
Trial, not randomized
Who or what was studied
25,871 people · older US adults in the VITAL trial, with no heart disease at the start
What was tested
840 mg a day of EPA and DHA versus placebo, reanalyzed using earlier trial results, median 5.3 years
What it measured
The question itself: heart attacks, strokes and heart deaths
Daily amount
840 mg a day
How long
276 weeks
Trial registration
NCT01169259
Who has a stake
No stake declared
Financial support from the National Institutes of Health.
Journal
The American journal of clinical nutrition, 2025
Source
PubMed record 40032221. This page is based on the abstract only.

How much this study counts

  • –Not randomized: the groups may differ in ways that affect the result.
  • ✓Compared with a placebo, a dummy treatment.
  • ✓Large: 25,871 people.
  • ✓Long: about 5.3 years.
  • ✓Measured the question itself: heart attacks, strokes and heart deaths.
  • ✓No competing interests declared.
  • •Summarized from the PubMed abstract only. The full paper may hold details the abstract leaves out.

✓ Strength– Limit• Note

These points come from fixed rules about the type of study, its size and length, what it measured, and who has a stake. Every study on Digestery gets the same rules.

Where this study sits

Each dot is one on-topic paper on this question. Steps near the top answer the question more directly.

↑ Stronger evidence

  1. Trials in people: heart attacks, strokes and heart deaths

    11

    7 benefit, 4 no difference

    ↑ This study is the ringed dot

  2. Trials in people: other measures

    3

    1 benefit, 2 no difference

  3. Trials in people: lab tests or safety

    0

    None among the papers we read.

  4. Population studies

    0

    None among the papers we read.

  5. Blood levels and genes

    0

    None among the papers we read.

↓ Weaker evidence

  • Points to benefit
  • Mixed
  • No difference
  • No direction
  • Points to harm

How it fits with the other research

The short answer to “Does fish oil prevent heart disease?”

Little or no effect in most trials.

Confidence: moderate. Based on 21 on-topic papers.

Read the full answer

Of the other 10 papers on the same step: 6 benefit, 4 no difference. This one found benefit. It agrees with most of them.

Other papers on the same step

See all 21 studies on this question

How this page was made

Label

First read of the abstract
Claude Sonnet
Independent second read
Claude Haiku
Differences settled
The two reads agreed on every checked field. Claude Opus 5.5.
Headline
Claude Sonnet, from the checked study record. A script checked its numbers and wording.
Numbers
Checked against the abstract by a script
“How much this study counts”
Fixed rules, the same for every study
Source check by a person
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