Individuals diagnosed with asthma, in either the COPD or smoking control groups, are included in COPDGene. COPD subjects are often diagnosed with asthma, and therefore excluding asthmatics would not provide an accurate distribution of COPD subjects. In order to include the full spectrum of COPD subjects, potential participants will not be excluded based on spirometric bronchodilator responsiveness. Both case and control groups will be monitored throughout the study for numbers of asthmatics (as defined by report of physician diagnosis of asthma) in each group and data analysis both with and without asthmatics will assess the impact of the asthma phenotype on inferences from our genetic analyses.
