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Pooled review (meta-analysis)

Pooled review: sleeping under 7 or over 8 hours linked to higher diabetes risk

Liu and colleagues · Annals of medicine · 2025

Original title: Sleep features and the risk of type 2 diabetes mellitus: a systematic review and meta-analysis.

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

Mixed

Sleep under 7 h (OR = 1.18; 95% CI = 1.13, 1.23) or over 8 h (OR = 1.13; 95% CI = 1.09, 1.18) raised diabetes risk. Lowest risk was at 7 to 8 h, a U-shape.

The study at a glance

Type of study
Pooled review (meta-analysis)
Who or what was studied
adults in observational studies of type 2 diabetes
What was tested
Night sleep under 7 h or over 8 h compared with 7 to 8 h; also sleep quality, evening type and naps
What it measured
The question itself: death, heart disease and other health outcomes
Who has a stake
No stake declared
No competing interests declared.
Journal
Annals of medicine, 2025
Source
PubMed record 39748566. This page is based on the abstract only.

How much this study counts

  • ✓Pools the results of many studies.
  • •A pooled review is only as strong as the studies it pools.
  • ✓Measured the question itself: death, heart disease and other health outcomes.
  • ✓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

This paper is not on the ladder. It is a pooled review (meta-analysis), and reviews and opinion pieces discuss studies that are already counted on the steps below.

↑ 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

↓ 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
  • Part of the finding “Diabetes and weight follow similar patterns”.
  • Summed up in “What reviews found”: Pooled observational studies (number not given). Under 7 hours (OR 1.18) and over 8 hours (OR 1.13) were both linked to type 2 diabetes, a U-shape with lowest risk at 7 to 8 hours.

Other reviews on this question

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 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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