[1] Boston Childrens Hosp, Dept Med, Div Adolescent Med, Boston, MA 02115 USA
[2] Harvard Univ, Sch Med, Boston, MA USA
[3] Brigham & Womens Hosp, Dept Med, Channing Div Network Med, Boston, MA 02115 USA
[4] Harvard Univ, Sch Publ Hlth, Dept Epidemiol, Boston, MA 02115 USA
[5] Univ Calif Berkeley, Div Community Hlth & Human Dev, Berkeley, CA 94720 USA
[6] Harvard Univ, Sch Publ Hlth, Dept Nutr, Boston, MA 02115 USA
[7] Univ Guelph, Guelph, ON N1G 2W1, Canada
[8] Massachusetts Gen Hosp, Dept Emergency Med, Boston, MA 02114 USA