Clinical characteristics of the general population from the Swedish CArdioPulmonary bioImage Study (SCAPIS) grouped according to transfer coefficient of the lung for carbon monoxide (KCO) in relation to Global Lung Function Initiative (GLI) lower limit of normal (LLN) and SCAPIS LLN (n=15 040)
| Characteristic | KCO | p-value | ||||
| >GLI LLN and >SCAPIS LLN (G1) | >GLI LLN but <SCAPIS LLN (G2) | <GLI LLN and <SCAPIS LLN (G3) | G1 versus G2 | G1 versus G3 | G2 versus G3 | |
| Subjects | 13 573 (90.2) | 818 (5.4) | 649 (4.3) | |||
| Age years | 57.5±4.3 | 56.8±4.3 | 59.0±4.2 | |||
| Female % | 51.5 | 52.9 | 56.9 | |||
| Smoking habits % | ||||||
| Never smokers | 47.9 | 31.1 | 14.0 | |||
| Former smokers | 37.1 | 36.7 | 35.3 | |||
| Current smokers | 11.6 | 30.2 | 48.8 | |||
| Missing information | 3.4 | 2.1 | 1.8 | |||
| Cough % | 17.5 | 27.3 | 34.0 | <0.001 | <0.001 | 0.009 |
| Chronic bronchitis % | 4.4 | 8.3 | 13.2 | <0.001 | <0.001 | 0.006 |
| Sputum production % | 10.4 | 16.7 | 24.9 | <0.001 | <0.001 | <0.001 |
| Wheeze % | 6.8 | 11.5 | 18.2 | <0.001 | <0.001 | 0.001 |
| Dyspnoea# % | 9.5 | 13.6 | 27.4 | <0.001 | <0.001 | <0.001 |
| Sick leave due to respiratory problems % | 4.6 | 6.8 | 8.3 | 0.006 | <0.001 | 0.359 |
| Having reported asthma % | 7.8 | 7.9 | 9.5 | 0.955 | 0.016 | 0.359 |
| Having reported COPD % | 1.0 | 2.0 | 10.3 | 0.024 | <0.001 | <0.001 |
| Emphysema¶ % | 4.3 | 13.9 | 35.9 | <0.001 | <0.001 | <0.001 |
| FEV1/FVC <SCAPIS LLN % | 8.1 | 22.1 | 44.4 | <0.001 | <0.001 | <0.001 |
| FEV1/FVC <GLI LLN % | 3.6 | 10.4 | 29.6 | <0.001 | <0.001 | <0.001 |
Data are presented as n, n (%) or mean±sd. COPD: chronic obstructive pulmonary disease; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity. #: modified Medical Research Council (mMRC) score ≥2; ¶: based on high-resolution computed tomography (HRCT) findings.