1. Exposure, Epidemiology, and Risk Program, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA
2. Center of Molecular and Genetic Epidemiology, Department of Environmental and Occupational Health, Ca’ Granda Ospedale Maggiore Policlinico IRCCS Foundation, Università degli Studi di Milano, Milan, Italy
3. Channing Laboratory, and
4. Division of Pulmonary and Critical Care Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
5. VA Normative Aging Study, Veterans Affairs Boston Healthcare System and the Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA