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Cited by 526Sleep and Work-Related FatigueCircadian rhythm and melatoninWorkplace Health and Well-being

Shift work and diabetes mellitus: a meta-analysis of observational studies

Open access
Gan, Yong, Yang, Chen, Tong, Xinyue, Sun, Huilian, Cong, Yingjie, Yin, Xiaoxu, Li, Liqing, Cao, Shiyi +6 more·2015·Occupational and Environmental Medicine
DOI 10.1136/oemed-2014-102150
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Abstract

BACKGROUND: Observational studies suggest that shift work may be associated with diabetes mellitus (DM). However, the results are inconsistent. No systematic reviews have applied quantitative techniques to compute summary risk estimates. OBJECTIVES: To conduct a meta-analysis of observational studies assessing the association between shift work and the risk of DM. METHODS: Relevant studies were identified by a search of PubMed, Embase, Web of Science and ProQuest Dissertation and Theses databases to April 2014. We also reviewed reference lists from retrieved articles. We included observational studies that reported OR with 95% CIs for the association between shift work and the risk of DM. Two authors independently extracted data and assessed the study quality. RESULTS: Twelve studies with 28 independent reports involving 226 652 participants and 14 595 patients with DM were included. A pooled adjusted OR for the association between ever exposure to shift work and DM risk was 1.09 (95% CI 1.05 to 1.12; p=0.014; I(2)=40.9%). Subgroup analyses suggested a stronger association between shift work and DM for men (OR=1.37, 95% CI 1.20 to 1.56) than for women (OR=1.09, 95% CI 1.04 to 1.14) (p for interaction=0.01). All shift work schedules with the exception of mixed shifts and evening shifts were associated with a statistically higher risk of DM than normal daytime schedules, and the difference among those shift work schedules was significant (p for interaction=0.04). CONCLUSIONS: Shift work is associated with an increased risk of DM. The increase was significantly higher among men and the rotating shift group, which warrants further studies.

AI snapshot

Written from the paper’s full text.

TL;DR

This meta-analysis of 12 observational studies (28 independent reports; 226,652 participants and 14,595 diabetes mellitus cases) found that ever exposure to shift work was associated with a 9% increased risk of diabetes mellitus. The association was stronger among men and rotating shift workers.

Key findings

  • The pooled adjusted OR for ever exposure to shift work and diabetes mellitus was 1.09 (95% CI 1.05 to 1.12; p=0.014; I²=40.9%). Cohort studies yielded OR 1.12 (95% CI 1.06 to 1.19; I²=52.9%), and cross-sectional studies yielded OR 1.06 (95% CI 1.03 to 1.09; I²=10.9%).
  • The association was stronger in men (OR=1.37, 95% CI 1.20 to 1.56) than in women (OR=1.09, 95% CI 1.04 to 1.14), with p for interaction=0.01.
  • Rotating shifts had the highest point estimate among shift schedules (OR=1.42, 95% CI 1.19 to 1.69), and the difference among shift work schedules was significant (p for interaction=0.04). Mixed shifts (OR=1.4, 95% CI 0.84 to 2.33) and evening shifts (OR=1.73, 95% CI 0.85 to 3.52) were not statistically associated with higher risk.
  • Publication bias assessment suggested asymmetry: Egger test p=0.002, Begg test p=0.072; trim-and-fill corrected OR was 1.08 (95% CI 1.05 to 1.12).

Methods

  • The authors searched PubMed, Embase, Web of Science, and ProQuest Dissertation and Theses databases to April 2014, and included observational studies reporting ORs with 95% CIs for the association between shift work and diabetes mellitus.
  • Twelve studies with 28 independent reports were included: seven prospective cohort studies, one retrospective cohort study, and four cross-sectional studies, published between 1983 and 2013.
  • Two authors independently extracted data and assessed study quality; pooled adjusted ORs were calculated using fixed-effects or random-effects models depending on heterogeneity, with subgroup, sensitivity, and publication bias analyses performed in STATA V.11.0.

Limitations

  • The paper states that shift work was not clearly defined in most original studies, that different definitions for shift work exposure and diabetes mellitus outcome were used across studies, and that limited information precluded a dose-response analysis.
  • Evident from the text: the included studies were observational, so causality cannot be established; heterogeneity was moderate (I²=40.9%), and the Egger test suggested publication bias, although correction did not materially alter the pooled OR.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1136/oemed-2014-102150

Cites

51 of 51 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 15 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Twelve studies with 28 independent reports involving 226,652 participants and 14,595 patients with diabetes mellitus were included in the meta-analysis.

    “Twelve studies with 28 independent reports involving 226 652 participants and 14 595 patients with DM were included.”
    • Also stated in: § Study selection and evaluation · plain
      “Twelve studies 13 14 21-29 with 28 independent reports were finally included in the meta-analysis.”
    Quote in the paperSubstantial claim
  • Findingown data

    Rotating shifts are associated with an increased risk of diabetes mellitus (OR=1.42, 95% CI 1.19 to 1.69).

    “The highest point estimate was noted for rotating shifts (OR=1.42,95% CI 1.19 to 1.69).”
    • Also stated in: § DISCUSSION · boosted
      “First, that the pooled OR for workers with rotating shifts (1.42, 95% CI 1.19 to 1.69) is clearly higher than that for other shift groups.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.
    • Rests on an assumption: The shift schedule classifications (rotating, irregular/unspecified, night, mixed, evening) are valid and comparable across the included studies.
  • Findingown data

    Irregular or unspecified shifts are associated with an increased risk of diabetes mellitus (OR=1.06, 95% CI 1.04 to 1.08).

    “Irregular or unspecific shifts | 6 | 1.06 | 1.04 to 1.08”
    • Also stated in: § Subgroup analyses · plain
      “rotating shifts, irregular and unspecific shifts and night shifts were associated with an increased risk of DM.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.
    • Rests on an assumption: The shift schedule classifications (rotating, irregular/unspecified, night, mixed, evening) are valid and comparable across the included studies.
  • Findingown data

    The pooled adjusted OR for the association between ever exposure to shift work and diabetes mellitus risk was 1.09 (95% CI 1.05 to 1.12; p=0.014; I2=40.9%).

    “A pooled adjusted OR for the association between ever exposure to shift work and DM risk was 1.09 (95% CI 1.05 to 1.12; p=0.014;I 2 =40.9%).”
    • Also stated in: § Association between shift work and risk of DM · plain
      “The pooled OR of DM for shift work was 1.09 (95% CI 1.05 to 1.12), and a moderate heterogeneity was seen ( p=0.014;I 2 =40.9%).”
    • Also stated in: § DISCUSSION · plain
      “Compared with individuals who had never been exposed to shift work, the risk of DM was increased by 9% for shift workers.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.
  • Findingown data

    The association between shift work and diabetes mellitus remained significant in most subgroup analyses.

    “Furthermore, the association remained significant in most subgroup analyses.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.
  • May combine two claims. 19
  • Classified as probably not a substantial claim. 7

  • May combine two claims.

    Findingown data

    For cross-sectional studies, the combined OR was 1.06 (95% CI 1.03 to 1.09), with low heterogeneity (I2=10.9%).

    “For cross-sectional studies, the combined OR was 1.06 (95% CI 1.03 to 1.09), and a low heterogeneity was detected with an I 2 =10.9% across crosssectional studies.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.

  • May combine two claims.

    Findingown data

    The association with shift work was more pronounced for participants from Europe than Asia and the USA, but the difference did not reach statistical significance (p for interaction=0.13).

    “In the subgroup analysis of study location, the association with shift work was much higher in European participants than in those from Asia and the USA, but the difference did not reach statistical significance ( p for interaction=0.13).”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.

  • May combine two claims.

    Findingown data

    Study design, occupation, and adjustment for family history of diabetes mellitus did not influence the summary ORs.

    “Study design, occupation and adjustment for family history of DM also did not influence the summary ORs (see table 1).”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.

  • May combine two claims.

    Findingown data

    Leave-one-out analyses showed that none of the individual studies significantly influenced the overall result, with pooled OR range from 1.08 (95% CI 1.05 to 1.11; p=0.057) to 1.13 (95% CI 1.07 to 1.20; p=0.008).

    “The positive association was not materially changed in the leave-one-out analyses by omitting one study in turn, with a pooled OR range from 1.08 (95% CI 1.05 to 1.11; p=0.057) to 1.13 (95% CI 1.07 to 1.20; p=0.008), which indicated that none of the individual studies significantly influenced the overall result.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.

  • May combine two claims.

    Findingown data

    The increased risk of diabetes mellitus associated with shift work was more evident in groups with a rotating shift schedule, male shift workers, and lack of statistical control for BMI or physical activity.

    “The increased risk was more evident in the groups with a rotating shift schedule, male shift workers and lack of statistical control for BMI or physical activity.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.

  • May combine two claims.

    Findingown data

    Exclusion of one study without adjusting any confounded factors yielded a pooled OR of 1.08 (95% CI 1.05 to 1.12), with I2=37.2%.

    “Exclusion of one study without adjusting any confounded factors yielded a pooled OR of 1.08 (95% CI 1.05 to 1.12).A medium heterogeneity was detected with an I 2 =37.2%.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.

  • May combine two claims.

    Findingown data

    The Egger test suggested evidence of publication bias, but the Begg test did not (Egger, p=0.002; Begg, p=0.072).

    “The Egger test suggested evidence of publication bias, but the Begg test did not (Egger, p=0.002,Begg, p=0.072).”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.

  • May combine two claims.

    Findingown data

    For cohort studies, the combined OR was 1.12 (95% CI 1.06 to 1.19), with moderate heterogeneity (I2=52.9%, p=0.007).

    “For cohort studies, the combined OR was 1.12 (95% CI 1.06 to 1.19), and there was a moderate heterogeneity (I 2 =52.9%, p=0.007).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.

  • May combine two claims.

    Findingown data

    All shift work schedules except mixed and evening shifts were associated with a statistically higher risk of diabetes mellitus than normal daytime schedules, and the difference among schedules was significant (p for interaction=0.04).

    “All shift work schedules with the exception of mixed shifts and evening shifts were associated with a statistically higher risk of DM than normal daytime schedules, and the difference among those shift work schedules was significant ( p for interaction=0.04).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.
    • Rests on an assumption: The shift schedule classifications (rotating, irregular/unspecified, night, mixed, evening) are valid and comparable across the included studies.

  • May combine two claims.

    Findingown data

    When the large sample study was excluded, the associations with shift work were still stronger in men than in women (p for interaction=0.004) and higher in the rotating shift group than in other groups (p for interaction=0.019).

    “Moreover, when this large sample study was excluded, the associations with shift work were still stronger in men than in women for DM ( p for interaction=0.004), and higher in the rotating shift group than in other groups ( p for interaction=0.019).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.

  • May combine two claims.

    Findingown data

    Using the trim-and-fill method, eight potentially missing studies would be needed to obtain funnel plot symmetry, and the corrected OR was 1.08 (95% CI 1.05 to 1.12; random-effects model, p=0.006).

    “Using the trim-and-fill method to assess the impact of any potential publication bias, we found that eight potentially missing studies would be needed to obtain funnel plot symmetry for DM (see figure 4).The corrected OR using the trim-and-fill method was 1.08 (95% CI 1.05 to 1.12; random-effects model, p=0.006).”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.

  • May combine two claims.

    Findingown data

    The sample in the meta-analysis was large, but the heterogeneity of included studies is moderate.

    “It is worth mentioning that the sample in our meta-analysis was large-larger than that of the other studies combined-but the heterogeneity of our included studies is moderate.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.
    • Rests on an assumption: The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.
    • Rests on an assumption: The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.
    • Rests on an assumption: The association between shift work and diabetes mellitus is not substantially explained by residual confounding.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    Repeated disruption of the circadian system owing to shift work may influence androgen secretion through regulation of the hypothalamic-pituitary-gonadal axis, which could contribute to the greater diabetes mellitus risk in men than in women.

    “The possible adverse effect of repeated disruption of the circadian system owing to shift work may influence androgen secretion through regulation of the hypothalamic-pituitary-gonadal axis, which could contribute to the greater DM risk in men than in women.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The human body was exposed to continuous stress from attempts to adjust as quickly as possible to varying working hours, but was frustrated by continuous shift rotation.

    “In most cases, the human body was exposed to continuous stress from attempts to adjust as quickly as possible to the varying working hours, but at the same time was frustrated by the continuous shift rotation.31”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [31] Costa, 2003, Shift work and occupational medicine: an overview, Occup Med (Lond) source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Hypoandrogenism is associated with insulin resistance and type 2 diabetes mellitus in men.

    “Some studies [32][33][34][35][36][37][38] have suggested that hypoandrogenism is associated with insulin resistance and T2DM in men.”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [32] Andersson, 1994, Testosterone concentrations in women and men with NIDDM, Diabetes Care source

      Not checked in the free run.

    • cites [33] Simon, 2001, Androgen therapy improves insulin sensitivity and decreases leptin level in healthy adult men with low plasma total testosterone: a 3-month randomized placebo-controlled trial, Diabetes Care source

      Not checked in the free run.

    • cites [34] Muller, 2005, Endogenous sex hormones and metabolic syndrome in aging men, J Clin Endocrinol Metab source

      Not checked in the free run.

  • May combine two claims.

    Interpretationnone given

    Shift work may interfere with the normal synchrony of the light-dark cycle, sleeping and eating patterns, which might cause a mismatch of circadian rhythms.

    “First, shift work may interfere with the normal synchrony of the light-dark cycle, sleeping and eating patterns, which might cause a mismatch of circadian rhythms;”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Insufficient sleep and poor sleep quality may develop and exacerbate insulin resistance.

    “Some studies have shown that insufficient sleep and poor sleep quality may develop and exacerbate insulin resistance. [44][45]][46]”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [44] Van Cauter, 2011, Sleep disturbances and insulin resistance, Diabet Med source

      Not checked in the free run.

    • cites [45] Najafian, 2013, Association between sleep duration and diabetes mellitus: Isfahan Healthy Heart Program, Niger J Clin Pract source

      Not checked in the free run.

    • cites [46] Cappuccio, 2010, Quantity and quality of sleep and incidence of type 2 diabetes: a systematic review and meta-analysis, Diabetes Care source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Circadian disruption may accelerate the development of type 2 diabetes mellitus in diabetes-prone individuals.

    “it is already known that circadian disruption may accelerate the development of T2DM in diabetes-prone individuals.40”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [40] Gale, 2011, Disruption of circadian rhythms accelerates development of diabetes through pancreatic beta-cell loss and dysfunction, J Biol Rhythms source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    Shift work might increase the risk of diabetes mellitus by disturbing socio-temporal patterns as a result of working irregular hours, which might contribute to family problems, reduce social support and induce stress.

    “First, by disturbing socio-temporal patterns as a result of working irregular hours, which might contribute to family problems, reduce social support and induce stress.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Shift work makes workers change their bed time frequently, which leads to sleeping problems like poor sleep quality, followed by disturbance of chronobiological rhythms.

    “Second, shift work makes the workers change their bed time frequently, 41 which leads to sleeping problems like poor sleep quality, followed by the disturbance of the chronobiological rhythms.42 43”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [41] Chen, 2006, A prospective study of night shift work, sleep duration, and risk of Parkinson's disease, Am J Epidemiol source

      Not checked in the free run.

    • cites [42] Mansukhani, 2012, Sleep deprivation in resident physicians, work hour limitations, and related outcomes: a systematic review of the literature, Postgrad Med source

      Not checked in the free run.

    • cites [43] Sallinen, 2010, Shift work, sleep, and sleepiness—differences between shift schedules and systems, Scand J Work Environ Health source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    This is the first meta-analysis to systematically quantify the strength of association between shift work and diabetes mellitus.

    “This is the first meta-analysis to systematically quantify the strength of association between shift work and DM.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The limited information provided in the included studies precluded the possibility of a dose-response analysis.

    “Finally, the limited information provided in the included studies precluded the possibility of a dose-response analysis.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Shift work was not clearly defined in most original studies, which might have affected judgement of the results.

    “Although the shift work is relatively objective and specific, it was not clearly defined in most original studies, which might have affected judgement of the results.”
    Quote in the paperNot a substantial claim
23 of 23

  • The paper relies on this without support.

    The different definitions of shift work exposure and diabetes mellitus outcome across included studies are sufficiently comparable to be pooled in a meta-analysis.

    “Second, different definitions for shift work exposure and DM outcome were used across studies, which might have introduced heterogeneity into the studies' results.”

  • The paper relies on this without support.

    The adjusted risk estimates from included studies are comparable enough to combine, despite differences in covariates adjusted.

    “We preferentially pooled multivariable adjusted risk estimates where such estimates were reported.”

  • The paper relies on this without support.

    The included study populations are representative of shift workers generally, allowing generalisation of the pooled estimate.

    “The meta-analysis of 12 observational studies with 28 independent reports including 226 652 participants (14 595 patients with DM) confirmed a positive association between shift work and DM.”

  • The paper relies on this without support.

    The association between shift work and diabetes mellitus is not substantially explained by residual confounding.

    “The increased risk was more evident in the groups with a rotating shift schedule, male shift workers and lack of statistical control for BMI or physical activity.”

  • The paper relies on this without support.

    The shift schedule classifications (rotating, irregular/unspecified, night, mixed, evening) are valid and comparable across the included studies.

    “We classified shift work schedules according to the original study methodological description as rotating, irregular and unspecified, night, mixed and evening.”
5 of 5

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Many human health effects are linked to misalignment of chronotype, including cancer, obesity, and diabetes.

    “Many human health effects are linked to the misalignment of chronotype (Knutson and von Schantz 2018), including cancer, obesity (Gyarmati et al. 2016; Papantoniou et al. 2016, 2017; Gan et al. 2018; Shi et al. 2020; Yousef et al. 2020), and diabetes (Gan et al. 2015; Larcher et al. 2015, 2016).”

    From Archaic Introgression Shaped Human Circadian Traits (2023) · cites this paper as Gan et al. 2015

    Gan et al. is cited for diabetes, not for cancer or obesity. The paper’s Discussion links shift work to possible circadian-rhythm mismatch, and its conclusions report an association between shift work and diabetes. It does not assess misalignment of an individual’s chronotype specifically, so the diabetes link is supported at a different level of specificity. (LLM, conf=0.82)

    Experimental — accuracy not yet measured

  • A recent meta-analysis of 12 observational studies found that rotating shift work is associated with increased risk of type 2 diabetes.

    “A recent meta-analysis of 12 observational studies found that among different types of shift work, rotating shift work is associated with increased risk of type 2 diabetes (123).”

    From Chronotype: Implications for Epidemiologic Studies on Chrono-Nutrition and Cardiometabolic Health (2019) · cites this paper as [123]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Rotating shifts are not the highest-risk schedule by point estimate

    Minor

    The paper says rotating shifts have a higher pooled OR than the other shift groups, but the table gives evening shifts a higher point estimate (1.73 versus 1.42). The evening-shift estimate is imprecise, but it still contradicts the comparison of point estimates.

  • Combined-sex heterogeneity statistics are incompatible

    Minor

    For four reports, an I2 of 0% means the heterogeneity statistic does not exceed its degrees of freedom. Its heterogeneity p value therefore cannot be 0.014; the two values in this row are incompatible.

2 of 2

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Authors
Gan, Y., Yang, C., Tong, X., Sun, H., Cong, Y., Yin, X., Li, L., Cao, S., Dong, X., Gong, Y., Shi, O., Deng, J., Bi, H., & Lu, Z.
Affiliations
  • Huazhong University of Science and Technology (CN)
  • Jiangxi Science and Technology Normal University (CN)
Corresponding author
Lu, Zuxun
ORCID
Venue
Occupational and Environmental Medicine
Publisher
BMJ
Published
2014-07-16
Volume
72
Issue
1
Pages
72-78
ISSN
  • 0007-1072 (ISSN-L)
  • 1351-0711
  • 1470-7926
DOI
10.1136/oemed-2014-102150
OpenAlex
W2100675645
Semantic Scholar
57a723be3083384ce9699e5d10a64996e6df9637
Cited by
526
References
51
Citations by year
2026: 33 · 2025: 34 · 2024: 29 · 2023: 51 · 2022: 57 · 2021: 45 · 2020: 78 · 2019: 58 · 2018: 42 · 2017: 34 · 2016: 30 · 2015: 24 · 2014: 10
FWCI
4.39
Type
journal article
Language
en
Open access
Locations
  • Occupational and Environmental Medicine (publishedVersion)
  • PubMed (publishedVersion)
  • HighWire Press Open Archive (submittedVersion)
Topics
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and Work-Related Fatigue
  • Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
  • Health Sciences › Health Professions › General Health Professions › Workplace Health and Well-being
Keywords
shift work, diabetes mellitus, diabetes risk, rotating shifts, evening shift, sex differences, occupational health
MeSH terms
Diabetes Mellitus, Female, Humans, Male, Risk Factors, Sex Factors, Work Schedule Tolerance, Workplace, Observational Studies as Topic

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-10.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-10.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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