A priori versus practical approach: multivariable estimates of risk describing the association between shift length and occupational injury or illness depend on the definition of exposure
| A priori approach N=961 827 | Practical approach N=926 763 | |||
|---|---|---|---|---|
| Relative risk (95% CI) | p Value | Relative risk (95% CI) | p Value | |
| ≤8 h | Referent | – | Referent | – |
| >8 and ≤12 h | 1.43 (1.04 to 1.97) | 0.03 | 1.16 (0.88 to 1.53) | 0.30 |
| >12 and ≤16 h | 1.82 (1.17 to 2.82) | 0.008 | 1.43 (1.05 to 1.95) | 0.025 |
| >16 and ≤24 h | 2.29 (1.52 to 3.46) | <0.001 | 1.93 (1.33 to 2.81) | 0.001 |
| >24 h | 1.68 (0.23 to 12.42) | 0.61 | 2.88 (1.74 to 4.77) | <0.001 |
| Continuous (hours) | 1.04 (1.02 to 1.07) | <0.001 | 1.03 (1.02 to 1.04) | <0.001 |
| ≥10 h | 1.37 (1.05 to 1.77) | 0.018 | 1.24 (0.99 to 1.56) | 0.06 |
| ≥12 h | 1.49 (1.18 to 1.88) | 0.001 | 1.38 (1.12 to 1.70) | 0.002 |
| 8 h category | Referent | – | Referent | – |
| 12 h category | 1.33 (1.05 to 1.70) | 0.018 | 1.22 (0.96 to 1.54) | 0.10 |
| 16 h category | 2.08 (1.12 to 3.86) | 0.021 | 1.42 (0.99 to 2.05) | 0.06 |
| 24 h category | 2.05 (1.44 to 2.90) | <0.001 | 2.13 (1.54 to 2.96) | <0.001 |
Each estimate in the table represents a separate multivariable model adjusted for the previously described covariates.
Estimates between the lines are from different models.