Chronic Obstructive Pulmonary Disease (COPD) is the fourth leading cause of death in the United States and an important public health problem 1. An estimated 24 million individuals in the U.S. may be affected by COPD 2. Both the number of affected individuals and the number of deaths from COPD are expected to increase as the population ages 3. COPD is a heterogeneous condition, with a variety of disease-related phenotypes 4,5. Better understanding of the disease mechanisms is needed to develop effective treatments and prevention strategies. To accomplish this, we need improved understanding of the etiology of COPD, clinical classifications of the disease that are biologically and medically coherent, and knowledge of genetic factors that influence risk of COPD.
