Study of developmental disorders among newborns in Fukushima City after the Great East Japan Earthquake and nuclear power plant accident; an adjunct study of the Fukushima Regional Center of the Japan Environmental and Children's Study (JECS).

The present adjunct study of the Japan Environment and Children's Study (JECS) aimed to determine the occurrence of developmental disorders in Fukushima Prefecture, which was exposed to low-dose radiation. At two medical institutions in Fukushima City, we enrolled 339 pregnant women from September 2013 through May 31, 2014, who delivered 335 neonates (174 male, including one set of twins) between November 4, 2013 and November 11, 2014. The parents of four neonates declined to participate in the present study and one neonate died. Therefore, 334 families agreed to participate in additional surveys until March 2017. Child Behavior Checklists (CBCL) were mailed to all 334 families during the month of their infant's second birthday and we received 236 responses (response rate, 70%). All responses were below the 69 percentile in the CBCL, and no responses indicated significant problem behaviors. Boys tended to have higher values for items associated with developmental problems, but symptoms of autism were not evident. The mental health of the mothers indicated in the previous study might not have influenced the children. Autism spectrum disorder (ASD) is not obvious by the age of three years and thus it might become apparent as the children grow older.