[1] Baylor Coll Med, Dept Pediat, Childrens Nutr Res Ctr, Houston, TX 77030 USA
[2] Univ Memphis, Memphis, TN 38152 USA
[3] HealthPartners Res Fdn, Minneapolis, MN 55454 USA
[4] NHLBI, Div Epidemiol & Clin Applicat, Bethesda, MD 20892 USA
[5] George Washington Univ, Ctr Biostat, Rockville, MD 20852 USA
[6] Duke Clin Res Inst, Durham, NC 27715 USA