Do mercury and lead exposure effect development of psychological and frontal lobe function?: longitudinal study from early to middle childhood

2020 Fiscal Year Final Research Report

• Project/Area Number: 17H02197
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Childhood science (childhood environment science)
• Research Institution: Kokugakuin University Hokkaido Junior College
• Principal Investigator: Kusanagi Emiko 國學院大學北海道短期大学部, その他部局等, 教授 (90341718)
• Co-Investigator(Kenkyū-buntansha): 星 信子 札幌大谷大学短期大学部, その他部局等, 教授 (20320575) ; 高橋 義信 札幌医科大学, 医療人育成センター, 准教授 (30226906) ; 高村 仁知 奈良女子大学, 生活環境科学系, 教授 (70202158) ; 森口 佑介 京都大学, 教育学研究科, 准教授 (80546581) ; 八若 保孝 北海道大学, 歯学研究院, 教授 (60230603)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: 学童期 / 気質 / 金属暴露 / 乳歯エナメル質 / 実行機能 / 前頭葉機能 / 運動発達 / 家庭環境

Outline of Final Research Achievements

We investigated the development of psychological, motor, and brain activities as well as food intake in elementary school children whose hair metal concentrations were measured in early childhood. In addition, the levels of metal exposure during the fetal and infancy periods were determined by measuring the concentration of metals in the deciduous teeth enamel of children using ICP-MS. Early childhood exposure to mercury had an adverse effect on the development of children's temperament in school age. Aluminum and lead had an adverse effect on the development of boys’ fine motor behavior in school age. However, there was no effect of metal exposure on brain function development in school age. We found that the nutritional intake of children was associated with the development of throwing ability and cognitive flexibility. Regarding the factors affecting the amount of metal in hair in early childhood, it was revealed that yogurt intake reduced the exposure levels of lead and aluminum.

Free Research Field

発達心理学

Academic Significance and Societal Importance of the Research Achievements

金属暴露への敏感期は主に胎児期とされ、幼児期の金属暴露に関する研究が乏しい中で、幼児期金属暴露がその後の子どもの気質及び微細運動の発達に影響を与えるという結果から、発達における幼児期の重要性があらためて示された。また、殆どの研究が試験管内或いは動物実験により乳酸菌の金属暴露に対する効果を検証している中で、実際にヒトを対象にヨーグルト摂取による有害金属暴露量低減効果を見出した意義は大きく、効果を得るための摂取頻度は週４～6回以上という知見により幼児の有害金属暴露を防ぐための具体的方略を提示した。さらに乳歯エナメル質中の複数の金属濃度測定値は日本の乳幼児の金属暴露量を示す貴重な資料である。