[1] Johns Hopkins Univ, Dept Surg, Sch Med, Baltimore, MD USA
[2] Howard Univ, Dept Surg, Coll Med, Washington, DC USA
[3] Johns Hopkins Univ, Dept Med, Sch Med, Baltimore, MD USA
[4] Johns Hopkins, Dept Epidemiol, Sch Publ Hlth, Baltimore, MD USA
[5] NYU, Dept Surg, Langone Med Ctr, New York, NY USA
[6] Univ Wisconsin, Sch Med & Publ Hlth, Dept Surg, Madison, WI USA