[1] Univ Western Ontario, Biol, London, ON, Canada
[2] Shalamar Inst Hlth Sci, Internal Med, Lahore, Pakistan
[3] Ziauddin Univ, Med, Karachi, Pakistan
[4] Harvard Med Sch, Clin Res, Boston, MA 02115 USA
[5] Univ Norte, Med, Barranquilla, Colombia
[6] Rafik Hariri Univ Hosp, Surg, Beirut, Lebanon
[7] Cent Pk Med Coll, Internal Med, Lahore, Pakistan
[8] Indus Hosp & Hlth Network, Epidemiol & Publ Hlth, Karachi, Pakistan