1 Division of Pulmonary and Critical Care Medicine, Pulmonary Center, Boston University School of Medicine, Boston, MA. Electronic address: alwalkey@bu.edu.
2 Data Coordinating Center, Boston University School of Public Health, Boston, MA.
3 Sections of Cardiovascular Medicine and Preventive Medicine, Boston University School of Medicine, Boston, MA; Department of Epidemiology, Boston University School of Public Health, Boston, MA.