Table 1 Baseline characteristics of study population.
| Cross‐sectional population 1991 | Cross‐sectional population 2000 | ||||
|---|---|---|---|---|---|
| Total | Provided blood for CRP | Total | Provided blood for CRP | ||
| Number of participants | 2633 | 2442 | 1346 | 1301 | |
| Men, N (%) | 1312 (50) | 1224 (50) | 668 (50) | 647 (50) | |
| Mean (SD) age (years) | 44.4 (13.6) | 44.7 (13.5) | 56.1 (12.4) | 56.1 (12.3) | |
| Mean (SD) height (m) | 1.68 (0.1) | 1.68 (0.1) | 1.68 (0.1) | 1.68 (0.1) | |
| Mean (SD) BMI (kg/m2) | 25.5 (4.0) | 25.5 (4.0) | 26.8 (4.4) | 26.8 (4.4) | |
| n = 2614 | n = 2425 | ||||
| Smoking status, N (%) | |||||
| Never | 1306 (50) | 1201 (49) | 680 (51) | 654 (50) | |
| Ex | 730 (28) | 681 (28) | 510 (38) | 494 (38) | |
| Current | 597 (23) | 560 (23) | 156 (12) | 153 (12) | |
| Mean (SD) FEV1 (l) | 3.19 (0.92) | 3.18 (0.93) | 2.84 (0.85) | 2.84 (0.85) | |
| N = 1343 | N = 1298 | ||||
| Mean (SD) FEV1 in 1991 (l) | – | – | 3.2 (0.84) | 3.18 (0.85) | |
| Mean (SD) FVC (l) | 3.94 (1.08) | 3.94 (1.08) | 3.67 (1.01) | 3.67 (1.01) | |
| N = 1342 | N = 1297 | ||||
| Mean (SD) FVC in 1991 (l) | – | – | 3.94 (1.00) | 3.94 (1.01) | |
| Wheeze in past 12 months, n (%) | 632 (24) | 596 (24) | 343 (25) | 271 (21) | |
| Median (IQR) CRP (mg/l) | – | 1.14 (0.55–2.42) | – | 1.69 (0.80–3.79) | |
| Response in 2000 by deciles of CRP in 1991 (% total) | |||||
| 1 | 116 (9.4) | ||||
| 2 | 129 (10.4) | ||||
| 3 | 123 (10.0) | ||||
| 4 | 132 (10.7) | ||||
| 5 | 125 (10.1) | ||||
| 6 | 133 (10.8) | ||||
| 7 | 129 (10.4) | ||||
| 8 | 125 (10.1) | ||||
| 9 | 115 (9.3) | ||||
| 10 | 107 (8.7) | ||||
BMI, body mass index; CRP, C‐reactive protein; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; IQR, interquartile range.