[1] Univ Massachusetts, Sch Med, Dept Orthoped & Phys Rehabil, 55 Lake Ave North, Worcester, MA 01655 USA
[2] Univ Massachusetts, Sch Med, Dept Med, Clin Epidemiol Res & Training Unit, Worcester, MA USA
[3] Harvard Med Sch, Massachusetts Gen Hosp, Div Rheumatol, Boston, MA USA
[4] Baylor Med Sch, Dept Med, Houston, TX USA
[5] Univ Penn, Dept Med, Perelman Sch Med, Philadelphia, PA 19104 USA
[6] Univ Penn, Dept Dermatol, Perelman Sch Med, Philadelphia, PA 19104 USA
[7] Univ Penn, Dept Biostat, Perelman Sch Med, Philadelphia, PA 19104 USA
[8] Univ Penn, Dept Epidemiol, Perelman Sch Med, Philadelphia, PA 19104 USA
[9] Harvard Med Sch, Brigham & Womens Hosp, Div Rheumatol Immunol & Allergy, Dept Med, Boston, MA USA