1Department of Medicine, University of California, Davis, School of Medicine, Sacramento, CA, USA
2Medical Service, Department of Veterans Affairs Northern California Health Care System, Martinez and Sacramento, CA, USA
3Department of Medicine, Washington Hospital Center, Washington, DC, USA
4Division of Endocrinology, Diabetes and Nutrition, University of Maryland Medical Center, Baltimore, MD, USA
5Department of Biostatistics, University of Michigan, School of Public Health, USA