In consistency with these results, in the recessive model, obesity (p = 0.016), overweight (p = 0.013), smokers (p = 0.014), former smokers (p < 0.001), and CYP27B1 rs4646536-A allele carriers (p = 0.013) were associated with a higher COPD risk. This evidence concerns the gene CYP27B1 and obesity due to melanocortin 4 receptor deficiency.