Table 4
Comparison of the nested logistic models for the relation between physical workloads (lifting and carrying loads over 10 kg) and low back pain (method by Witte and Greenland13)
| Model | −2 log likelihood | Likelihood ratio* | Degrees of freedom | p value |
|---|---|---|---|---|
| *Likelihood ratio statistic (χ2) comparing the nested models. | ||||
| †Compared to the intercept only model. | ||||
| ‡Compared to the linear model. | ||||
| §Compared to the quadratic model. | ||||
| ¶Compared to the quadratic spline restricted both tails. | ||||
| Lifting and carrying loads over 10 kg (work hours per week) | ||||
| Intercept only | 721.5 | |||
| Linear | 711.1 | 10.4† | 1 | 0.02 |
| Quadratic | 707.0 | 4.1‡ | 1 | 0.04 |
| Quadratic spline restricted both tails | 703.3 | 3.7§ | 1 | 0.05 |
| Quadratic spline | 700.5 | 2.8¶ | 2 | 0.25 |
