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Gene study (Mendelian randomization)

Gene study of 404,044 adults: short-sleep genes linked to higher heart disease risk

Ai and colleagues · European heart journal · 2021

Original title: Causal associations of short and long sleep durations with 12 cardiovascular diseases: linear and nonlinear Mendelian randomization analyses in UK Biobank.

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

Genes for short sleep raised risk of high blood pressure, blood clots in lung, coronary artery disease, heart attack and chronic heart disease (P < 0.001). Genes for long sleep were not linked to any of the 12.

The study at a glance

Type of study
Gene study (Mendelian randomization)
Who or what was studied
404,044 people · white British adults in UK Biobank
What was tested
Genes linked to sleep length, short sleep (6 h or less) and long sleep (9 h or more), used to test effects on 12 heart diseases
What it measured
The question itself: death, heart disease and other health outcomes
Who has a stake
No disclosure in PubMed
No disclosure in PubMed.
Journal
European heart journal, 2021
Source
PubMed record 33822910. This page is based on the abstract only.

How much this study counts

  • •A gene study: it uses natural gene differences as a kind of experiment. It is less affected by lifestyle than surveys, but it rests on assumptions that can fail.
  • ✓Large: 404,044 people.
  • ✓Measured the question itself: death, heart disease and other health outcomes.
  • •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: death and chronic disease

    0

    Not done yet. This is the step that would answer the question.

  2. Trials in people: other measures

    1

    1 benefit

  3. Trials in people: lab tests or safety

    0

    None among the papers we read.

  4. Population studies

    11

    5 benefit, 4 mixed, 2 no difference

  5. Blood levels and genes

    1

    1 benefit

    ↑ This study is the ringed dot

↓ Weaker evidence

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

How it fits with the other research

The short answer to “How much sleep do adults need for good health?”

Lowest risk at about 7 hours.

Confidence: low. Based on 22 on-topic papers.

Read the full answer

Few other papers sit on the same step, so there is little to compare it with.

Other papers on the same step

None among the papers we read.

See all 22 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 differed. The reviewer checked the abstract and kept the first read. 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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