Adjusted quantile regression (50th) analysis of surfactant composition (phospholipids and proteins) by the background characteristics, asthma and smoking (n=200)
| Explanatory variables | DPPC (wt%) coefficient (95% CI) | POPC (wt%) coefficient (95% CI) | PC14:0/16:0 (%) coefficient (95% CI) | PC16:0/18:2 (%) coefficient (95% CI) | SP-A (wt%) coefficient (95% CI) | Albumin (wt%) coefficient (95% CI) |
| Age (years) | −0.07 (−0.14 to −0.01)* | −0.03 (−0.04 to −0.01)* | 0.14 (0.01 to 0.26)* | 0.07 (0.01 to 0.12)* | −0.01 (−0.04 to 0.02) | 0.07 (0.02 to 0.11)* |
| Sex, male (ref) | 0.60 (−0.10 to 1.30) | 0.06 (−0.20 to 0.32) | −0.88 (−2.87 to 1.12) | −0.46 (−1.44 to 0.52) | −0.15 (−0.57 to 0.27) | −0.40 (−1.34 to 0.54) |
| Weight (kg) | 0.01 (−0.03 to 0.04) | −0.01 (−0.10 to 0.10) | 0.12 (0.01 to 0.25)* | 0.01 (−0.03 to 0.05) | −0.02 (−0.03 to 0.01) | −0.02 (−0.04 to 0.01) |
| Height (cm) | 0.01 (−0.05 to 0.07) | 0.01 (−0.01 to 0.03) | 0.14 (0.01 to 0.26)* | 0.02 (−0.04 to 0.08) | −0.01 (−0.03 to 0.03) | −0.03 (−0.08 to 0.01) |
| BMI (kg/m2) | 0.55 (−0.05 to 1.15) | 0.19 (−0.10 to 0.39) | −0.77 (−2.02 to 0.47) | −0.08 (−0.78 to 0.62) | −0.22 (−0.51 to 0.08) | 0.10 (−0.42 to 0.62) |
| Asthma | −1.11 (−2.81 to 0.57) | −0.19 (−0.75 to 0.37) | 3.43 (0.05 to 6.93)* | 1.75 (0.09 to 3.41)* | 0.71 (0.03 to 1.39)* | −1.21 (−2.33 to −0.10)* |
| Smokers | 1.82 (0.50 to 3.14)* | 0.41 (0.04 to 0.80)* | 1.50 (−1.33 to 4.33) | 0.18 (−1.25 to 1.60) | 0.80 (0.11 to 1.49)* | −0.42 (−1.56 to 0.71) |
Significant associations (*) are also marked in bold.
BMI, body mass index; DPPC, di-palmitoyl-di-phosphatidyl-choline; ECRHS-III, European Community Respiratory Health Survey III; PC, phosphatidylcholine; SP-A, surfactant protein A.