CYP2R1 and chronic obstructive pulmonary disease: The SNPs of the genes CYP2R1 rs10741657, CYP27B1 rs4646536, and CYP27B1 rs703842 showed a significant association with the risk of developing COPD and the VDR-Fokl rs2228570 a tendency toward the statistical association (Supplementary Table S6).