[1] Univ Med & Dent New Jersey, Robert Wood Johnson Med Sch, Div Gen Internal Med, Dept Med, New Brunswick, NJ 08903 USA
[2] Univ Maryland, Sch Med, Dept Epidemiol & Prevent Med, Baltimore, MD 21201 USA
[3] St Louis Univ, Dept Med, St Louis, MO 63103 USA
[4] Hennepin Cty Med Ctr, Dept Lab Med & Pathol, Minneapolis, MN 55415 USA
[5] Univ Minnesota, Minneapolis, MN USA
[6] Baylor Hlth Care Syst, Dept Orthopaed Surg, Dallas, TX USA
[7] Univ Western Ontario, Dept Orthopaed Surg, London, ON, Canada