[1] Univ Rochester, Dept Pediat, Rochester, NY 14642 USA
[2] Univ Minnesota, Sch Publ Hlth, Div Epidemiol, Minneapolis, MN 55455 USA
[3] Univ Oslo, Dept Nutr, Oslo, Norway
[4] Univ Minnesota, Dept Pediat, Minneapolis, MN 55455 USA
[5] Wake Forest Univ, Dept Epidemiol & Prevent, Div Publ Hlth Sci, Winston Salem, NC 27109 USA