CYP27B1 and obesity due to melanocortin 4 receptor deficiency: The genotypic model confirmed a higher risk of COPD in patients with obesity (p = 0.017), overweight (p = 0.015), smokers (p = 0.016), former smokers (p < 0.001), and carriers of the CYP2R1 rs10741657-AA genotypes (p = 0.028) and CYP27B1 rs4646536-AA (p = 0.004).