Table 4 Effect of C‐reactive protein (CRP, mg/l) on change in lung function using linear regression between 1991 and 2000.
| 1991 Serum CRP (n = 1241) | Average serum CRP (mean of 1991 and 2000) (n = 1219) | |
|---|---|---|
| Decline in FEV1 (ml) | 0 (–3 to +4) | –2 (–7 to +3) |
| Stratified by smoking status | ||
| Never | +1 (–2 to +4) | 0 (–6 to +4) |
| Ex | –2 (–15 to +10) | –5 (–18 to +8) |
| Current | +2 (–16 to +21) | –3 (–20 to +14) |
| pinteraction = 0.969 | pinteraction = 0.978 | |
| Stratified by gender | ||
| Male | + 3 (–3 to +9) | 0 (–8 to +9) |
| Female | –2 (–5 to +2) | –5 (–10 to 0) |
| pinteraction = 0.082 | pinteraction = 0.116 | |
| Stratified by BMI (kg/m2) | ||
| >20 | +27 (–30 to +84) | +53 (+8 to +99) |
| 20–24.9 | +3 (–5 to +11) | –4 (–14 to +6) |
| 25–29.9 | +3 (–3 to +9) | +1 (–7 to +9) |
| >30 | –2 (–7 to +3) | –4 (–12 to +5) |
| pinteraction = 0.563 | pinteraction = 0.685 | |
| FVC (ml) | +3 (–1 to +7)* | +1 (–6 to +7)† |
| Stratified by smoking status | ||
| Never | +4 (–1 to +8) | +4 (–3 to +10) |
| Ex | –3 (–20 to +13) | –10 (–26 to +7) |
| Current | +16 (–7 to +39) | +9 (–12 to +30) |
| pinteraction = 0.489 | pinteraction = 0.471 | |
| Stratified by gender | ||
| Male | +8 (0 to +16) | +7 (–4 to +18) |
| Female | –1 (–5 to +3) | –5 (–12 to +2) |
| pinteraction = 0.016 | pinteraction = 0.027 | |
| Stratified by BMI (kg/m2) | ||
| >20 | –22 (–104 to +60) | +41 (–29 to +111) |
| 20–24.9 | +5 (–5 to +15) | +1 (–11 to +14) |
| 25–29.9 | +9 (+1 to +16) | +5 (–5 to +16) |
| >30 | –1 (–7 to +5) | –4 (–14 to +6) |
| pinteraction = 0.0148 | pinteraction = 0.0618 |
FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; BMI, body mass index.
Residuals calculated for men and women individually and adjusted for gender, age, age2, height and age‐height interaction and the model was adjusted for smoking status (categorical), smoking pack‐years, and BMI (continuous).
*n = 1240.
†n = 1218.