1. Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
2. Endocrine Research Unit, San Francisco Veterans Affairs Health Care System, San Francisco, CA 94121, USA
3. Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA 94143, USA
4. Program of Advanced Musculoskeletal Imaging, Cleveland Clinic, Cleveland, OH 44195, USA
5. Icelandic Heart Association Research Institute, 201 Kópavogur, Iceland
6. Faculty of Medicine, University of Iceland, Reykjavik, Iceland
7. Department of Medicine, Stanford University, Stanford, CA 94305, USA
8. Geriatric Research Education and Clinical Center, Veterans Affairs Health Care System, Palo Alto, CA 94304, USA
9. Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
10. Veterans Affairs San Diego Healthcare System, San Diego, CA 92161, USA
11. Center for Clinical and Translational Research, Maine Medical Center Research Institute, Scarborough, ME 04074, USA
12. Center for Bone Quality, Department of Endocrinology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
13. The Mount Sinai Bone Program and Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
14. Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA 94143, USA