Table 3 Univariate and multivariate risk ratios (95% confidence intervals) of the association between sex specific tertiles of physical capacity and low back pain, SMASH, 1994–97 (n = 1328).
| Physical capacity | Total events/total number at risk* | Crude RR (95% CI)† | Adjusted RR (95% CI) |
|---|---|---|---|
| Isokinetic lifting strength back muscles | High (86/1060) | 1.00 | 1.00‡ |
| Moderate (98/1056) | 0.99 (0.83 to 1.19) | 1.01 (0.84 to 1.21) | |
| Low (96/1055) | 1.06 (0.89 to 1.27) | 1.09 (0.91 to 1.31) | |
| Static endurance back extensors | High (87/1003) | 1.00 | 1.00‡ |
| Moderate (85/991) | 1.14 (0.93 to 1.39) | 1.13 (0.93 to 1.38) | |
| Low (94/1010) | 1.43 (1.19 to 1.71) | 1.42 (1.19 to 1.71) | |
| Flexion of the spine | High (94/1160) | 1.00 | 1.00‡ |
| Moderate (99/1015) | 1.08 (0.91 to 1.29) | 1.09 (0.91 to 1.30) | |
| Low (129/1469) | 1.10 (0.94 to 1.30) | 1.12 (0.95 to 1.31) | |
| Rotation of the spine | High (92/1179) | 1.00 | 1.00§ |
| Moderate (119/1194) | 1.09 (0.92 to 1.30) | 0.99 (0.82 to 1.19) | |
| Low (111/1268) | 1.18 (1.00 to 1.39) | 1.10 (0.92 to 1.32) |
*Summarisation of occurrence annually during follow up divided by a summarisation of all workers at risk annually during follow up.
†RR, risk ratio; CI, confidence interval. Including the covariate duration of follow up.
‡Adjusted for duration of follow up, and age.
§Adjusted for duration of follow up, age, and isokinetic lifting strength.