In summary we identified two candidate loci associated with age at smoking initiation in COPD patients. We show that variation in the CHRNA3/CHRNA5 locus on chromosome 15q25 locus and the CYP2A6 locus on chromosome 19q13 were associated with lifetime average CPD among COPD patients. The latter gene may play a significant role in the current smoking intensity among COPD patients. Future studies in larger populations of COPD subjects will be required to determine the overlap between genetic determinants of smoking behavior in the general population and in COPD subjects.
