BTN1A1 and chronic obstructive pulmonary disease: Besides, there was negative association of Septin-8, Corticosteroid-binding globulin (CBG), Butyrophilin subfamily 1 member A1 (BTN1A1) and Dystroglycan (DAG1) with overall COPD risk (Septin-8: OR, 0.68; 95% CI, 0.57–0.79; PFDR = 8.00 × 10−4; CBG: OR, 0.81; 95% CI, 0.74–0.89; PFDR = .005; BTN1A1: OR, 0.82; 95% CI, 0.75–0.90; PFDR = .010 and DAG1: OR, 0.51; 95% CI, 0.35–0.73; PFDR = .024).