Long-term rotating night shift,
does it really help with Increased incidence of type 2 diabetes?
research showsThe grade is C with 50 points. NHS I followed 69,269 and NHS II 107,915 women for 18 to 20 years, with 10,126 confirmed diabetes cases. Pooled HRs for 1-2, 3-9, 10-19, and at least 20 years were 1.05, 1.20, 1.40, and 1.58, trend P<.001. Updated-BMI adjustment reduced them to 1.03, 1.06, 1.10, and 1.24, trend P<.001. For at least 20 years, adjustment attenuated the excess risk by about 58.6%, which is why the effect size was lowered.
ads claimObserved duration-risk associations do not quantify how much an individual's diabetes risk falls after stopping shifts.
Useful facts when choosing a product
- Rotating night work meant at least three nights monthly plus day or evening shifts.
- The cohorts included 177,184 women and 10,126 confirmed diabetes cases.
- At least 20 years gave HR 1.58 (1.43-1.74), reduced to 1.24 (1.13-1.37) with updated BMI.
What the research actually shows
Pan et al. analyzed 69,269 NHS I and 107,915 NHS II participants free of diabetes, cardiovascular disease, and cancer at baseline. Exposure was self-reported years of at least three night shifts monthly plus day or evening shifts; NHS II updated exposure every two to four years. Pooled HRs for 1-2, 3-9, 10-19, and at least 20 years were 1.05, 1.20, 1.40, and 1.58, trend P<.001; updated-BMI-adjusted HRs were 1.03, 1.06, 1.10, and 1.24, trend P<.001. Verdict 2243 is D with 34 points for breast cancer and overlaps the NHS exposure network, so the two verdicts were not counted as independent evidence for each other.
Why this is classified as C (50)
Large hard-event dose-response evidence is offset by about 58.6% attenuation of excess risk after BMI adjustment, same-network evidence, self-report, and residual confounding, giving C with 50 points.
Counterpoint. Female nurses do not establish the same magnitude in men or other occupations.
Rejudgment record. Cross-check applied — Duration-specific pooled hazard ratios, before-and-after BMI estimates, confirmed cases, exposure updates, and covariates in the original article
| Endpoint | H | Hard endpoint - actual events such as death |
| Replication | R1 | Single confirmatory trial |
| Independence | I2 | Decisive evidence is publicly or non-profit funded |
| Effect size | E~ | Statistically positive but below the threshold |
The scoring table and the verdict agree (C).
Sub-claim grades by effect
This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.
| Effect (sub-claim) | Grade | Basis |
|---|---|---|
| Observed association between years of rotating night work and type 2 diabetes | C | A monotonic gradient persisted after BMI adjustment. |
| Stopping night shifts prevents type 2 diabetes | ? | No shift-cessation intervention tested diabetes incidence. |
Cross-check — Codex and Claude
Evidence Table
| Study | Design | Sample | Funding | Endpoint | Result | Weight |
|---|---|---|---|---|---|---|
| Study 1 | Two prospective cohorts from the same research network | 3,961 | Public NIH funding including NCI, NHLBI, and NIDDK | Confirmed incident type 2 diabetes over 18 to 20 years | Pooled HRs for 1-2, 3-9, 10-19, and at least 20 years: 1.05, 1.20, 1.40, 1.58; after BMI: 1.03, 1.06, 1.10, 1.24 | Core large observational event evidence |
Receipt — 1 References
All 1 cited sources were verified for existence at the original page (as of 2026-08-05).
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-08-05 · Corrections: none
Cite this verdict
[Chamgap] Long-term rotating night shift x incident type 2 diabetes — Evidence Grade C·50. 1 cited sources checked. Source: https://chamgap.com/en/verdicts/blood-sugar/rotating-night-shift-type-2-diabetes/ · CC BY 4.0CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.
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