[1] Oregon Hlth & Sci Univ, Dept Orthopaed & Rehabil, 3181 SW Sam Jackson Pk Rd,Mailcode OP31, Portland, OR 97239 USA
[2] Calif Pacific Med Ctr, Res Inst, San Francisco, CA USA
[3] VA North Texas Hlth Care Syst, Dept Internal Med, Dallas, TX USA
[4] Univ Texas Southwestern Med Ctr Dallas, Dept Internal Med, Dallas, TX USA
[5] Univ Calif San Diego, Dept Family Med & Publ Hlth, San Diego, CA 92103 USA
[6] Univ Calif San Diego, Dept Internal Med, San Diego, CA 92103 USA
[7] Oregon Hlth & Sci Univ, Dept Family Med, 3181 SW Sam Jackson Pk Rd,Mailcode OP31, Portland, OR 97239 USA
[8] Univ Calif San Francisco, Dept Epidemiol & Biostat, San Francisco, CA 94143 USA