[1] Buddhist Tzu Chi Gen Hosp, Dept Pediat, Taichung Branch, Taichung 42743, Taiwan
[2] Changhua Christian Hosp, Dept Pediat, Div Pediat Emergency Med, Changhua, Taiwan
[3] Changhua Christian Hosp, Epidemiol & Biostat Lab, Changhua, Taiwan
[4] Natl Yang Ming Univ, Inst Clin Med, Taipei 112, Taiwan