[1] Emory Univ & Childrens Healthcare Atlanta, Dept Pediat, Atlanta, GA USA
[2] RTI Int, Statist Epidemiol Unit, Res Triangle Pk, NC USA
[3] Case Western Reserve Univ, Dept Pediat, Rainbow Babies & Childrens Hosp, Cleveland, OH 44106 USA
[4] Univ Texas Dallas, Dept Pediat, SW Med Ctr, Dallas, TX 75230 USA
[5] RTI Int, Statist & Epidemiol Unit, Rockville, MD USA
[6] Wayne State Univ, Dept Pediat, Detroit, MI 48202 USA
[7] Eunice Kennedy Shriver Natl Inst Child Hlth & Hum, Bethesda, MD USA
[8] Human Dev & Natl Canc Inst, Natl Inst Hlth, Bethesda, MD USA
[9] Brown Univ, Dept Pediat, Women & Infants Hosp, Providence, RI 02912 USA
[10] Univ Alabama Birmingham, Dept Pediat, Birmingham, AL USA
[11] Univ Texas Houston, Sch Med, Dept Pediat, Houston, TX USA
[12] Univ Calif San Diego, Dept Pediat, San Diego, CA 92103 USA
[13] Univ Miami, Miller Sch Med, Miami, FL 33136 USA
[14] Cincinnati Childrens Hosp, Med Ctr, Dept Pediat, Cincinnati, OH USA
[15] Yale Univ, Sch Med, Dept Pediat, New Haven, CT 06510 USA
[16] Stanford Univ, Sch Med, Dept Pediat, Palo Alto, CA 94304 USA
[17] Tufts Med Ctr, Boston, MA USA
[18] Univ Rochester, Sch Med & Dent, Rochester, NY USA
[19] Indiana Univ, Sch Med, Dept Pediat, Indianapolis, IN 46202 USA
[20] Univ Iowa, Iowa City, IA USA
[21] Wake Forest Univ, Winston Salem, NC 27109 USA
[22] Univ New Mexico, Hlth Sci Ctr, Albuquerque, NM 87131 USA
[23] Duke Univ, Dept Pediat, Durham, NC 27706 USA