[1] Oregon Hlth & Sci Univ, Portland, OR 97239 USA
[2] Univ Washington, Seattle, WA 98195 USA
[3] Rush Univ, Med Ctr, Chicago, IL 60612 USA
[4] George Washington Univ, Washington, DC USA
[5] Stanford Univ, Stanford, CA 94305 USA
[6] Johns Hopkins Univ, Baltimore, MD USA
[7] Northwestern Univ, Evanston, IL USA
[8] VA Pittsburgh Healthcare Syst, Pittsburgh, PA USA
[9] Univ Pittsburgh, Pittsburgh, PA USA
[10] Palmer Coll Chiropract, Davenport, IA USA
[11] Natl Ctr Complementary & Alternat Med, Bethesda, MD USA
[12] Natl Inst Arthritis Musculoskeletal & Skin Dis, Bethesda, MD USA
[13] New England Baptist Hosp, Roxbury Crossing, MA USA
[14] Dartmouth Coll, Hanover, NH USA
[15] Grp Hlth Res Inst, Seattle, WA USA