Individual characteristics of the different cohorts at baseline
| Variable | Classification | 91–92 (n=630) n (%) | 92–99 (n=729) n (%) | 91–92–99 (n=269) n (%) |
|---|---|---|---|---|
| *Mean (SD). | ||||
| †Mean of answers to both questions on duration of LBP within the preceding 12 months as indicated in the illustrated and the non-illustrated part of the questionnaire. | ||||
| Sex | Female | 578 (92) | 664 (91) | 253 (94) |
| Age (y)* | 36 (10) | 34 (10) | 37 (9) | |
| Nationality | Swiss | 368 (67) | 440 (69) | 162 (68) |
| Employment in current job (y)* | 14 (9) | 13 (9) | 14 (8) | |
| Employment | 100% | 321 (51) | 361 (50) | 114 (42) |
| Frequent lifting | 306 (49) | 353 (49) | 135 (50) | |
| Awkward working posture | 256 (41) | 362 (51) | 107 (40) | |
| Lifetime duration of LBP (y)* | 9 (7) | 10 (7) | 10 (7) | |
| LBP† | ||||
| No pain | 0 days | 193 (31) | 195 (27) | 86 (32) |
| Mild | 1–7 days | 205 (33) | 260 (36) | 94 (35) |
| Moderate to severe | ⩾ 8 days | 232 (37) | 274 (38) | 89 (33) |
| Within preceding 12 months | ||||