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Randomized trial · measured the question itself

7.4-year trial in 15,480 adults with diabetes: omega-3 did not clearly change vascular events

ASCEND Study Collaborative Group and colleagues · The New England journal of medicine · 2018

Original title: Effects of n-3 Fatty Acid Supplements in Diabetes Mellitus.

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What the study found

No difference

Serious vascular events: 689 (8.9%) with omega-3 vs 712 (9.2%) with placebo (rate ratio, 0.97; 95% CI, 0.87 to 1.08). Death from any cause: rate ratio, 0.95. Serious side effects did not differ.

The study at a glance

Type of study
Randomized trial
Who or what was studied
15,480 people · adults with diabetes but no known heart or artery disease
What was tested
1 g a day of omega-3 capsules versus olive oil placebo, mean 7.4 years
What it measured
The question itself: heart attacks, strokes and heart deaths
Daily amount
1 g a day
How long
386 weeks
Trial registration
NCT00135226
Who has a stake
No disclosure in PubMed
No disclosure in PubMed. Funded by the British Heart Foundation and others.
Journal
The New England journal of medicine, 2018
Source
PubMed record 30146932. This page is based on the abstract only.

How much this study counts

  • ✓Randomized: people were put into groups by chance, so the groups start out alike.
  • ✓Compared with a placebo, a dummy treatment.
  • ✓Large: 15,480 people.
  • ✓Long: about 7.4 years.
  • ✓Measured the question itself: heart attacks, strokes and heart deaths.
  • •The PubMed record has no conflict-of-interest statement.
  • •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: 7 benefit, 3 no difference. This one found no difference. It differs from 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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