[1] Louisiana State Univ, Dept Epidemiol, Sch Publ Hlth, Hlth Sci Ctr, New Orleans, LA USA
[2] Harvard Univ, Sch Publ Hlth, Dept Nutr, Boston, MA 02115 USA
[3] Brigham & Womens Hosp, Dept Med, Channing Lab, Boston, MA USA
[4] Harvard Univ, Sch Med, Boston, MA USA
[5] Harvard Univ, Sch Publ Hlth, Dept Epidemiol, Boston, MA 02115 USA
[6] Eunice Kennedy Shriver Natl Inst Child Hlth & Hum, Div Epidemiol Stat & Prevent Res, NIH, Bethesda, MD USA