Work Ability Score, sick leave, respiratory symptom score and % of predicted FEV1, FVC and FEV1/FVC-ratio prebronchodilator and postbronchodilator by possible confounders: sex, smoking status, highest completed education and age category
| Outcome, summary statistics | Number | Sex | Smoking status | Highest completed education | Age category | |||||||||||
| Male | Female | P value | Never smoker | Former smoker | Daily smoker | P value | Elementary | Upper secondary | University | P value | 18–30 | 31–40 | 41–52 | P value | ||
| Work Ability Score <8, n/n total in group (%) | 261/1295 (20%) | 85/508 (17%) | 176/787 (22%) | 0.016 | 112/697 (16%) | 78/328 (24%) | 71/270 (27%) | <0.001 | 52/168 (31%) | 130/525 (25%) | 79/602 (13%) | <0.001 | 26/212 (12%) | 66/310 (21%) | 169/773 (22%) | 0.007 |
| Sick-leave in the last 12 months, n/n total in group (%) | 413/1143 (36%) | 113/453 (25%) | 300/690 (43%) | <0.001 | 182/610 (30%) | 125/297 (42%) | 106/236 (45%) | <0.001 | 44/116 (38%) | 180/464 (39%) | 189/563 (34%) | 0.203 | 47/156 (30%) | 108/237 (46%) | 258/714 (36%) | 0.148 |
| Sick leave >14 days, n/n total in group (%) | 199/1143 (17%) | 43/453 (9%) | 156/690 (23%) | <0.001 | 78/610 (13%) | 63/297 (21%) | 58/236 (25%) | <0.001 | 20/116 (17%) | 88/464 (19%) | 91/563 (16%) | 0.428 | 15/156 (10%) | 57/237 (24%) | 127/714 (18%) | 0.060 |
| Symptom score ≥3, n/n total in group (%) | 403/1317 (31%) | 120/515 (23%) | 283/802 (35%) | <0.001 | 194/706 (27%) | 107/335 (32%) | 102/276 (37%) | 0.012 | 50/171 (29%) | 177/541 (33%) | 176/605 (29%) | 0.379 | 63/216 (29%) | 96/314 (31%) | 244/787 (31%) | 0.874 |
| Symptom score, n, mean (SEM) | 1317 | 515 1.87 (0.11) | 802 2.58 (0.10) | <0.001 | 706 2.10 (0.10) | 335 2.37 (0.15) | 276 2.72 (0.18) | 0.004 | 171 2.26 (0.21) | 541 2.49 (0.12) | 605 2.14 (0.11) | 0.095 | 216 2.26 (0.18) | 314 2.26 (0.15) | 787 2.33 (0.10) | 0.911 |
| Pre-FEV1 % of predicted value, n, mean (SEM) | 1257 | 489 94.26 (0.67) | 768 96.00 (0.49) | 0.033 | 671 95.44 (0.52) | 322 96.57 (0.77) | 264 93.50 (0.99) | 0.031 | 158 93.12 (1.08) | 515 94.06 (0.63) | 584 97.02 (0.58) | <0.001 | 199 94.45 (0.83) | 296 96.11 (0.81) | 762 95.25 (0.54) | 0.428 |
| Pre-FVC % of predicted value n, mean (SEM) | 1257 | 489 98.25 (0.44) | 768 98.25 (0.56) | 0.028 | 671 98.86 (0.46) | 322 100.14 (0.68) | 264 98.93 (0.82) | 0.284 | 158 97.37 (0.99) | 515 98.34 (0.54) | 584 100.46 (0.50) | 0.002 | 199 99.25 (0.81) | 296 99.91 (0.66) | 762 98.92 (0.47) | 0.498 |
| Pre-FEV1/FVC-ratio in %, n, mean (SEM) | 1257 | 489 0.79 (0.002) | 768 0.77 (0.003) | <0.001 | 671 0.79 (0.002) | 322 0.77 (0.003) | 264 0.76 (0.005) | <0.001 | 158 0.79 (0.006) | 515 0.77 (0.003) | 584 0.78 (0.003) | 0.093 | 199 0.81 (0.005) | 296 0.79 (0.004) | 762 0.77 (0.002) | <0.001 |
| Post-FEV1 % of predicted value, n, mean (SEM) | 1091 | 425 96.79 (0.67) | 666 99.16 (0.50) | 0.004 | 588 98.22 (0.53) | 279 99.88 (0.76) | 224 96.25 (1.00) | 0.009 | 131 95.97 (1.16) | 442 97.10 (0.64) | 518 99.78 (0.57) | <0.001 | 177 97.99 (0.84) | 264 99.10 (0.78) | 650 97.95 (0.55) | 0.478 |
| Post-FVC % of predicted value, n, mean (SEM) | 1091 | 425 98.57 (0.58) | 666 99.88 (0.46) | 0.077 | 588 98.78 (0.49) | 279 100.67 (0.70) | 224 99.28 (0.80) | 0.093 | 131 97.21 (1.12) | 442 98.85 (0.56) | 518 100.36 (0.51) | 0.012 | 177 98.92 (0.85) | 264 100.03 (0.69) | 650 99.23 (0.48) | 0.559 |
| Post-FEV1/FVC ratio in %, n, mean (SEM) | 1091 | 425 0.78 (0.004) | 666 0.81 (0.002) | <0.001 | 588 0.81 (0.003) | 279 0.80 (0.003) | 224 0.78 (0.005) | <0.001 | 131 0.81 (0.006) | 442 0.80 (0.003) | 518 0.81 (0.003) | 0.029 | 177 0.85 (0.005) | 264 0.81 (0.004) | 650 0.79 (0.003) | <0.001 |
P values were calculated using Fisher’s exact, Pearson χ2 or one-way ANOVA.Statistically significant findings, p<0.05, are bolded
ANOVA, Analysis of variance; FEV, forced expiratory volume; FEV1, forced expiratory volume after 1 s; FVC, forced vital capacity.