Table 2.
Description of the sample – predictor-variables in relation to LBP.
| Status 1994. Baseline/ follow-up. | LBP at all (LBP >0 days past year) 1994 | Persistent LBP (LBP >30 days past year). 1994 | LBP at all (LBP >0 days past year) 2002 | Persistent LBP (LBP >30 days past year). 2002 | ||
| Age | 12–15 | 3,146 / 2,061 | 447 (14%) | 58 (2%) | 742 (36%) | 197 (10%) |
| 16–19 | 3,497 / 2,422 | 1,303 (37%) | 232 (7%) | 918 (38%) | 213 (9%) | |
| 20–22 | 2,820 / 2,060 | 1,343 (48%) | 298 (11%) | 883 (43%) | 226 (11%) | |
| Sex | Female | 4,873 / 3,676 | 1,761 (36)% | 366 (8%) | 1,544 (42%) | 424 (12%) |
| Male | 4,590 / 2,867 | 1,332 (29%) | 222 (5%) | 999 (35%) | 212 (7%) | |
| Smoking | 0 | 85% / 86% | 2346 (30%) | 385 (5%) | 2,080 (37%) | 490 (9%) |
| 1–10 | 7% / 7 % | 306 (46%) | 69 (10%) | 195 (44%) | 57 (13%) | |
| 11–20 | 8% / 7% | 365 (72%) | 107 (15%) | 217 (49%) | 73 (17%) | |
| >20 | 0% / 0% | 33 (72%) | 9 (30%) | 13 (48%) | 3 (11%) | |
| Alcohol consumption | <0.2 | 56% / 54% | 1084 (24%) | 185 (4%) | 1181 (38%) | 322 (10%) |
| 0.2–0.6 | 23% / 24% | 793 (43%) | 157 (9%) | 547 (40%) | 130 (9%) | |
| 0.6–1.0 | 11% / 11% | 419 (46%) | 81 (9%) | 257 (39%) | 55 (8%) | |
| >1.0 | 10% / 10% | 389 (48%) | 84 (10%) | 238 (42%) | 54 (10%) | |
| BMI | <17 | 12% / 12% | 163 (15%) | 28 (3%) | 262 (35%) | 74 (10%) |
| 18–24 | 78% / 78% | 2,459 (34%) | 455 (6%) | 1,964 (39%) | 479 (10%) | |
| 25–29 | 9% / 9% | 376 (45%) | 85 (10%) | 242 (42%) | 59 (10%) | |
| >29 | 1% / 1% | 58 (49%) | 12 (10%) | 42 (47%) | 11 (12%) | |