1. Harvard Medical School, Boston, Massachusetts
2. Division of Pulmonary, Critical Care, and Sleep Medicine, and
3. Tufts University School of Medicine, Boston, Massachusetts
4. Division of Social and Community Medicine, Cambridge Health Alliance, Cambridge, Massachusetts
5. City University of New York at Hunter College, New York, New York; and
6. Harvard T. H. Chan School of Public Health and Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, Massachusetts