title: Dependence of radiation dose on the behavioral patterns among school children: a retrospective analysis 18 to 20 months following the 2011 Fukushima nuclear incident in Japan.
abstract: After radioactive incidents, the exposure risk in daily activities among children is a major public concern. However, there are limited methods available for evaluation of this risk, which is essential to future health risk management. To this end, this study assessed the relationship between behavioral patterns of school children and radiation exposure for a period of 18-20 months following the 2011 Fukushima nuclear incident. The assessed population comprised 520 school children from Minamisoma city, located 20 km north of the nuclear plant. Data for the doses were obtained using individual dosimeters and from results of a behavior survey administered by the City Office. The mean value of the doses in the study period was 0.34 mSv, with a standard deviation of 0.14 mSv, indicating an annual dose of ∼1.36 mSv, which includes doses from natural sources. Our results showed that behavior with respect to outdoor activities had no statistically significant relationship to the dose. A 0.1 μSv/h increase in the air dose rate at home was associated with a 10% increase in the dose; however, a 0.01 μSv/h increase in the air dose rate on the school grounds was associated with a 2% increase in the dose. This study indicates that the air contamination levels at the places where children spend most of their day are the significant predictors of the dose, as opposed to the levels at those outdoor locations in which short periods of time spent.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, Norfolk Place, London W2 1PG, UK.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Nomura
authors.affiliation: Department of Radiation Protection, Minamisoma Municipal General Hospital, 2-54-6 Takami-cho, Haramachi-ku, Minamisoma, Fukushima 975-0033, Japan Division of Social Communication System for Advanced Clinical Research, the Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Tsubokura
authors.affiliation: Faculty of Policy Management, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-8520, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Furutani
authors.affiliation: Department of Physics, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Ryugo S
authors.initials: RS
authors.lastname: Hayano
authors.affiliation: Division of Social Communication System for Advanced Clinical Research, the Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kami
authors.affiliation: Department of Radiation Protection, Minamisoma Municipal General Hospital, 2-54-6 Takami-cho, Haramachi-ku, Minamisoma, Fukushima 975-0033, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kanazawa
authors.affiliation: Department of Radiation Protection, Minamisoma Municipal General Hospital, 2-54-6 Takami-cho, Haramachi-ku, Minamisoma, Fukushima 975-0033, Japan minamisoma-kyukyu@bz04.plala.or.jp.
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Oikawa
mesh_terms: D000293:Adolescent; D002648:Child; D002652:Child Behavior; D002675:Child, Preschool; D004307:Dose-Response Relationship, Radiation; D062406:Fukushima Nuclear Accident; D006801:Humans; D007564:Japan; D011834:Radiation Monitoring; D012044:Regression Analysis; D012189:Retrospective Studies; D012574:Schools; D011795:Surveys and Questionnaires
keywords: Fukushima nuclear incident; behavior pattern; external radiation dose; school children