[1] Amer Univ Beirut, Dept Pediat & Adolescent Med, Fac Med, Beirut, Lebanon
[2] Amer Univ Beirut, Fac Hlth Sci, Beirut, Lebanon
[3] Univ Damascus, Fac Med, Damascus, Syria
[4] Univ St Joseph, Fac Med, Beirut, Lebanon
[5] Amer Univ Beirut, Dept Internal Med, Beirut, Lebanon
[6] McMaster Univ, Dept Clin Epidemiol & Biostat, Hamilton, ON, Canada
[7] SUNY Buffalo, Dept Med, Buffalo, NY 14260 USA