[1] Univ Alabama Birmingham, Dept Pediat, Div Pediat Hematol Oncol, Birmingham, AL USA
[2] Texas Childrens Hosp, Baylor Coll Med, Dept Pediat, Div Pediat Hematol Oncol, Birmingham, AL USA
[3] Univ Alabama Birmingham, Dept Biostat, Birmingham, AL USA
[4] Univ Alabama Birmingham, Sch Publ Hlth, Birmingham, AL USA
[5] Univ Alabama Birmingham, Dept Pediat, 1600 7 th Ave South, Birmingham, AL 35233 USA