Logistic regression analysis for nodding off at the wheel in the last 3 years
| Variable | B | Wald test | p value | Odds ratio | Lower 95% CI | Upper 95% CI |
| Epworth score | 0.19 | 22.6 | <0.00001 | 1.21 | 1.12 | 1.31 |
| RDI | 0.001 | 0.012 | >0.05 | 1.001 | 0.98 | 1.02 |
| Tracking error | 0.13 | 0.43 | >0.05 | 1.14 | 0.77 | 1.69 |
| Reaction time | 0.04 | 0.11 | >0.05 | 1.05 | 0.80 | 1.38 |
| Off-road events/h | 0.0008 | 0.04 | >0.05 | 1.0008 | 0.99 | 1.001 |
RDI = respiratory disturbance index.
5-150 OR for every 1 unit increase in variable (i.e. estimated risk of nodding off at the wheel increases by 1.21 for every increase in Epworth score by 1)