Cigarette smoking is the most important environmental risk factor for COPD, and smoking cessation is the most important therapeutic intervention to prevent its progression. Our current study identified two loci on chromosomes 2q21 and 6p21 as candidates for containing genes influencing age at smoking initiation in COPD patients, both showing suggestive levels of genome-wide significance. Furthermore, this study confirmed that certain SNPs in the nicotinic acetylcholine receptor locus on chromosome 15q25 and SNPs in the CYP2A6 locus on chromosome 19q13 were associated with CPD in COPD patients. Of importance, we additionally confirmed in COPD subjects the previously reported association of a marker (rs3025343) in the DBH locus with smoking cessation.
