[1] Khon Kaen Univ, Fac Publ Hlth, Dept Epidemiol, Khon Kaen 40002, Thailand
[2] Khon Kaen Univ, Fac Publ Hlth, Dept Biostat & Demog, Khon Kaen 40002, Thailand
[3] Khon Kaen Univ, Fac Med, Canc Unit, Khon Kaen 40002, Thailand
[4] Khon Kaen Univ, Fac Med, Dept Pediat, Khon Kaen 40002, Thailand