Shift work and health outcomes: an umbrella review of systematic reviews and meta-analyses of epidemiological studies.
Level 3 - non-randomized controlled study
Umbrella review of systematic reviews and meta-analyses of observational epidemiological studies
PubMed 34473048 · doi:10.5664/jcsm.9642
What was done
Authors conducted an umbrella review searching MEDLINE, Web of Science, and Embase through April 25, 2020 (PROSPERO CRD42020188537). They identified systematic reviews and meta-analyses of epidemiological studies evaluating associations between shift work and health outcomes. For each included review, they evaluated summary effect sizes, 95% confidence intervals, 95% prediction intervals, between-study heterogeneity, small-study effects, and excess-significance bias to classify evidence validity.
What was found
Eight systematic reviews and meta-analyses covering 16 associations were included. Highly suggestive evidence was reported for associations between shift work and myocardial infarction (ever vs. never) and incident diabetes mellitus (per 5-year increment). Suggestive evidence was found for shift work (ever vs. never) and incident diabetes mellitus. Evidence was weak for prostate cancer incidence (ever vs. never; rotating night shift vs. daytime) and colorectal cancer incidence (longest vs. shortest duration). The abstract reports no numerical effect sizes or confidence intervals.
Why it matters
This review distinguishes between well-supported cardiometabolic risks (myocardial infarction and diabetes) and less substantiated oncologic associations in shift work epidemiology, helping prioritize clinical and occupational health interventions.
Limits
The underlying evidence comes entirely from observational epidemiological studies prone to confounding. Numerical risk estimates, participant sample sizes, and detailed definitions of shift schedules or exposure durations are omitted in the abstract.
Cited by
- partial Shift work is a known carcinogen and increases the risk of developing diabetes and dementia.