[1] Childrens Hosp, Neuroepidemiol Unit, Boston, MA 02115 USA
[2] Harvard Univ, Sch Med, Boston, MA 02115 USA
[3] Harvard Univ, Sch Publ Hlth, Boston, MA 02115 USA
[4] William Beaumont Hosp, Royal Oak, MI 48073 USA
[5] DeVos Childrens Hosp, Grand Rapids, MI 49503 USA
[6] Univ Massachusetts, Sch Med, Worcester, MA 01655 USA
[7] Univ N Carolina, Chapel Hill, NC 27599 USA
[8] New England Med Ctr, Boston, MA 02111 USA
[9] George Washington Univ, Med Ctr, Washington, DC 20037 USA
[10] E Carolina Univ, Sch Med, Greenville, NC 27858 USA
[11] Yale Univ, Sch Med, New Haven, CT 06520 USA
[12] Massachusetts Gen Hosp, Boston, MA 02114 USA
[13] Beth Israel Deaconess Med Ctr, Boston, MA 02215 USA
[14] Michigan State Univ, Sparrow Hosp, E Lansing, MI 48823 USA
[15] Wake Forest Univ, Bowman Gray Sch Med, Winston Salem, NC 27157 USA
[16] NIH, DBEPS, ORS, Bethesda, MD 20892 USA
[17] Univ Chicago, Chicago, IL 60637 USA
[18] Childrens Hosp, Baystate Med Ctr, Springfield, MA 01199 USA
[19] Brigham & Womens Hosp, Boston, MA 02115 USA