[1] Ctr Dis Control & Prevent, Natl Ctr Birth Defects & Dev Disabil, 4770 Buford Highway NE,MS S106-4, Atlanta, GA 30341 USA
[2] Emory Univ, Emory Autism Resource Ctr, Atlanta, GA 30322 USA
[3] Georgia State Univ, Sch Publ Hlth, Atlanta, GA 30303 USA
[4] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Epidemiol, Baltimore, MD USA
[5] Univ Colorado, JFK Partners, Anschutz Med Campus, Aurora, CO USA
[6] Univ N Carolina, Carolina Inst Dev Disabil, Chapel Hill, NC 27515 USA
[7] Childrens Hosp Philadelphia, Ctr Autism Res, Philadelphia, PA 19104 USA