To investigated the involvement of pulmonary function impairment in ulcerative colitis (UC), to explore a scientific basis for the Chinese medicine (CM) theory of exterior-interior correlation between Lung (Fei) and Large intestine (Dachang). Totally 120 patients with a diagnosis of UC were recruited and the demographics, clinical data, and blood samples were collected. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) concentrations were measured. Every patient accepted pulmonary function test and took chest radiograph (CXR).> Pulmonary function abnormalities were present in 72 of 120 patients. The median (interquartile range) vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), carbon monoxide diffusion capacity (DLCO) of lung, total lung capacity (TLC) and functional residual volume (FRV) were decreased in distal UC and pancolitis compared with ulcerative prochitis (P < 0.0005). Male patients had increased VC, FEV1/FVC, and residual volume (RV)/TLC compared with female (P < 0.0005), but decreased DLCO and carbon monoxide iffusion capacity (K-CO) of lung/alveolar ventilation (P < 0.0005). Age was strongly correlated with RV (Spearman rank correlation coefficient (rs)=-0.57,P < 0.0001), and RV/TLC (rs=0.48,P < 0.0001). Age was also correlated with FEV1/FVC (rs=-0.29, P=0.001), forced expiratory flow in 75% vital capacity (FEF75%, rs=-0.20, P=0.03), DLCO (rs=-0.21, P=0.02), TLC (rs=-0.25, P=0.006), and FRV (rs=-0.28, P=0.002). The course of disease was correlated with FEF75% (rs=-0.18, P=0.049) and K-CO (rs=-0.19, P=0.036). Chest radiograph abnormalities were presented in 38 of 120. Pulmonary symptoms were presented in 10 of 120. Other extraintestinal complications were presented in 21 of 120. Pulmonary function impairment was more frequently than other extraintestinal complications in UC patients, which may be affected by sex, age, extent and course of disease. These results may be a scientific basis for the theory of exterior-interior correlation between Lung and Large intestine.
