Table 2. GRADE assessment summary of findings.
| Outcome | Number of SR/MA | Risk estimate from review with highest quality scorea | Quality of EVIDENCE | Comments |
|---|---|---|---|---|
| A) Shift work | ||||
| Breast Cancer | 12 | Every exposed: RR 1.1 (1.03 to 1.18, I2 = 62)[31] | ⊕⊕⊕ Moderate | Upgraded due to dose response |
| Dose response (every 5 years): RR 1.05 (1.01 to 1.10, I2 = 55)[27]b | ||||
| Ischemic heart disease | 1 | RR 1.13 (1.08 to 1.20, I2 = 52.7) [33] | ⊕⊕ Low | |
| Ischemic stroke | 2 | Risk Ratio 1.05 (1.01 to 1.09, I2 = 0)[40] | ⊕⊕ Low | |
| Gestational Hypertension | 1 | OR 1.19 (0.97 to 1.45, I2 = 2)[54]c | ⊕⊕ Low | |
| Myocardial infarction | 2 | RR 1.27 (1.17 to 1.39, I2 = 0)[33] | ⊕⊕ Low | |
| Preterm delivery | 5 | RR 1.2 (1.01 to 1.42, phet = 0.002)[53] | ⊕⊕ Low | Significant heterogeneity but robust conclusions in subgroup analysis |
| Small for gestational age | 4 | RR 1.07 (0.96 to 1.96, phet = 0.51)[53] | ⊕⊕ Low | |
| All-cause mortality | 2 | Risk Ratio 1.04 (0.97 to 1.11)[40] | ⊕ Very low | Downgrade for heterogeneity and imprecision |
| CVD: any event (CHD, IHD, MI, stroke) | 2 | ES 1.17 (1.09 to 1.25, I2 = 67)[38] | ⊕ Very low | Downgrade for heterogeneity No upgrade for dose response due to low quality of review |
| Depression | 2 | Risk Estimate 1.42 (0.92 to 2.19, I2 = 74.4)[59] | ⊕ Very low | Downgrade for high risk of bias, heterogeneity, and imprecision |
| Diabetes mellitus | 2 | RR 1.4 (1.18 to 1.66, I2 = 95)[42] | ⊕ Very Low | Downgrade for heterogeneity |
| Hypertension | 1 | OR 1.10 (1.00 to 1.20, I2 = 85)[60] | ⊕ Very Low | Downgrade for heterogeneity |
| Low birth weight | 2 | OR 1.27 (0.93 to 1.74, phet = 0.39)[52] | ⊕ Very Low | Downgrade for high risk of bias and imprecision |
| Metabolic Syndrome | 2 | RR 1.59 (1.00 to 2.54, phet = 0.049)[50] | ⊕ Very low | Downgrade for high risk of bias and publication bias |
| Miscarriage | 3 | OR 1.12 (0.96 to 1.3, phet = 0.53)[51] | ⊕ Very low | Downgrade for high risk of bias |
| Obesity | 4 | OR 1.25 (1.11 to 1.41, I2 = 95.9)[48] | ⊕ Very low | Downgrade for high risk of bias and heterogeneity |
| Occupational Injuries | 1 | RR 1.33 (0.98 to 1.8, I2 = 98.4)[61]b | ⊕ Very low | Downgrade for high risk of bias, heterogeneity, and imprecision |
| Preeclampsia | 1 | OR 1.05 (0.63 to 1.75, I2 = 0%)[54]d | ⊕ Very low | Downgrade for imprecision |
| Colorectal cancer | 2 | OR 1.15 (1.01 to 1.32, I2 = 40.2)[32] | ⊕ Very low | Downgrade for high risk of bias and publication bias |
| Hematologic cancers | 1 | OR 1.08 (0.99 to 1.17, I2 = 54.7)[32] | ⊕ Very low | Downgrade for high risk of bias |
| Lung cancer | 1 | OR 1.08 (0.87 to 1.35, I2 = 53.4)[32] | ⊕ Very low | Downgrade for high risk of bias |
| Prostate cancer | 5 | 1.05 (1.00 to 1.11, I2 = 24)[17] | ⊕ Very low | Downgrade for publication bias No upgrade for dose-response due to low quality of SR |
| Reproductive system cancers | 1 | OR 1.06 (0.85 to 1.32, I2 = 49.5)[32] | ⊕ Very low | Downgrade for high risk of bias |
| Skin cancer | 1 | OR 0.93 (0.5 to 1.74, I2 = 74.9)[32] | ⊕ Very low | Downgrade for high risk of bias and publication bias |
| B) Long work hours | ||||
| Stroke | 1 | RR 1.33 (1.11 to 1.61, I2 = 0)[35] | ⊕ Moderate | Upgrade due to dose response |
| Coronary disease | 2 | RR 1.13 (1.02 to 1.26 I2 = 0)[35] | ⊕⊕ Low | |
| Depression | 2 | OR 1.14 (1.03 to 1.25, I2 = 45.1)[63] | ⊕⊕ Low | |
| Low birthweight | 1 | OR 1.43 (1.11 to 1.84, I2 = 0)[54] | ⊕⊕ Low | |
| Preterm delivery | 2 | OR 1.12 (1.11 to 1.33, I2 = 30)[54] | ⊕⊕ Low | |
| Any CVD (CHD, IHD, MI) | 1 | OR 1.37 (1.11 to 1.70, phet = 0.037)[34] | ⊕ Very low | Downgrade evidence for high risk of bias and heterogeneity |
| Diabetes Mellitus | 2 | RR 1.14 (0.35 to 3.72, I2 = 67)[43] | ⊕ Very low | Downgrade for high risk of bias, heterogeneity, imprecision, and publication bias |
| Gestational Hypertension | 1 | OR 0.99 (0.72 to 1.37, I2 = 62)[54] | ⊕ Very low | Downgrade for heterogeneity |
| Miscarriage | 2 | OR 1.36 (1.25 to 1.49, phet = 0.02)[51] | ⊕ Very low | Downgrade for heterogeneity and publication bias |
| Small for Gestational Age | 1 | OR 1.16 (1.0 to 1.36, I2 = 57)[54] | ⊕ Very Low | Downgrade for heterogeneity |
a–exposure is any type of shift work or >8 hours work per day unless specified otherwise
b–increase in risk every 5 year increase in exposure to shift work
c—exposure is rotating shift work
d–exposure is fixed shift work, GRADE assessment: ⊕ - very low, ⊕⊕ - low, ⊕⊕⊕ - moderate, phet−p-value for heterogeneity test