We showed that existing alleles in CYP2B6 and CYP2A6 were associated with a minor risk of COPD; in the Mexican population with a high contribution of CEU and the presence of the haplotype in CHRNA5-CHRNA3, there was a predisposition to an increased risk of disease (Figure 3). This evidence concerns the gene CHRNA5 and chronic obstructive pulmonary disease.