In our population, with a high AME contribution, we found that SNPs in the CYP2B6 and CYP2A6 genes were associated with a lower risk of suffering COPD; of these two polymorphisms, the best studied is CYP2A6, which codes for the main hepatic enzyme metabolizing nicotine and cotinine [22]. Here, CYP2A6 is linked to chronic obstructive pulmonary disease.