[1] Chiang Mai Univ, Fac Med, Dept Pediat, Div Pediat Hematol & Oncol, 110 Intawaroros Rd, Chiang Mai 50200, Thailand
[2] Chiang Mai Univ, Fac Med, Dept Surg, Div Pediat Surg, Chiang Mai, Thailand
[3] Chiang Mai Univ, Fac Med, Ctr Clin Epidemiol & Clin Stat, Chiang Mai, Thailand
[4] Chiang Mai Univ, Fac Med, Clin Surg Res Ctr, Dept Surg, Chiang Mai, Thailand
[5] Chiang Mai Univ, Fac Med, Thalassemia & Hematol Ctr, Chiang Mai, Thailand