1. Department of Medicine, Division of Endocrinology and Metabolism, School of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana 70112
2. Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
3. Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115
4. National Heart and Lung Institute, Imperial College London, Royal Brompton Hospital, London SW3 6NP, United Kingdom