[1] Chiang Mai Univ Hosp, Div Pediat Surg, Div Surg, 110 Intavaroros Rd, Chiang Mai 50200, Thailand
[2] Thammasat Univ Hosp, Ctr Excellence Appl Epidemiol, Bangkok, Thailand
[3] Chiang Mai Univ Hosp, Div Gastroenterol, Dept Pediat, Chiang Mai, Thailand
[4] Mahidol Univ, Siriraj Hosp, Div Pediat Surg, Dept Surg, Bangkok, Thailand
[5] Chiang Mai Univ Hosp, Dept Radiol, Chiang Mai, Thailand