The COPDGene® Study is one of the largest studies ever to investigate the underlying genetic factors of Chronic Obstructive Pulmonary Disease or COPD. At the COPDGene® Study we are looking for answers to why some smokers will develop COPD and others will not. While it has been demonstrated that cigarette smoking can cause COPD, only a minority of smokers develop this debilitating disease thus raising the question of genetic susceptibility. Through the enrollment of over 10,000 individuals, the COPDGene® Study aims to find inherited or genetic factors that make some people more likely than others to develop COPD. With the use of CT scans, COPDGene® also seeks to better classify COPD and understand how the disease may differ from person to person.