SCGB1A1 and chronic obstructive pulmonary disease: Significantly decreased serum levels of SCGB1A1 in BMS-COPD subjects (total: n = 50; male: n = 11; female: n = 39) were detected with the severity of COPD as classified by GOLD stages (Figure 3a), mMRC grades (Figure 3b), CAT scores (Figure 3c), BODE index (Figure 3d), and SGRQ-C (%) (Figure 3e).