1. Pulmonary, Allergy, Sleep, and Critical Care Medicine Section, Medical Service, VA Boston Healthcare System, Boston, Massachusetts, USA
2. Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
3. Research and Development Service, VA Boston Healthcare System, Boston, Massachusetts, USA
4. Divison of Primary Care and Rheumatology Section, VA Boston Healthcare System, Boston, Massachusetts, USA
5. Boston University School of Medicine, Boston, Massachusetts, USA
6. Department of Physical Medicine and Rehabilitation, VA Boston Healthcare System, Boston, Massachusetts, USA
7. Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA