| Age | CRP category | Women | Men | ||||
| No (% FEV1) | 95% CI | p Value | No (% FEV1) | 95% CI | p Value | ||
| 26 | Low (⩽1 mg/l) | 104 (107.3) | 105.0 to 109.6 | 190 (101.6) | 99.7 to 103.5 | ||
| Medium (1–3 mg/l) | 108 (102.8) | 100.4 to 105.2 | 154 (99.2) | 97.0 to 101.4 | |||
| High (>3 mg/l) | 167 (100.0) | 97.9 to 102.0 | <0.001 | 94 (100.1) | 97.3 to 102.9 | 0.093 | |
| 32 | Low (⩽1 mg/l) | 166 (106.6) | 104.8 to 108.4 | 224 (99.8) | 98.2 to 101.5 | ||
| Medium (1–3 mg/l) | 126 (105.7) | 103.6 to 107.9 | 161 (96.7) | 94.9 to 98.6 | |||
| High (>3 mg/l) | 110 (101.7) | 99.2 to 104.1 | 0.004 | 63 (95.0) | 91.9 to 98.2 | 0.001 | |
Pregnant women are excluded. CRP, C-reactive protein; FEV1, forced expiratory volume in one second; 95% CI = 95% confidence intervals for mean. p values for trend across CRP categories.