[1] Univ Washington, Dept Pediat, OC 7-820 POB 5371, Seattle, WA 98195 USA
[2] Univ N Carolina, Dept Pediat, 101 Manning Dr,CB 7039, Chapel Hill, NC 27515 USA
[3] Wake Forest Sch Med, Dept Biostat & Data Sci, Med Ctr Blvd, Winston Salem, NC 27157 USA
[4] Kaiser Permanente Southern Calif, Dept Res & Evaluat, 100 S Robles Ave,2nd Floor, Pasadena, CA 91101 USA
[5] Univ N Carolina, Dept Nutr, 101 Manning Dr, Chapel Hill, NC 27599 USA
[6] Univ N Carolina, Dept Med, 101 Manning Dr, Chapel Hill, NC 27599 USA