title: Effects of prenatal exposure to polychlorinated biphenyls and dioxins on mental and motor development in Japanese children at 6 months of age.
abstract: Several studies have shown that prenatal and/or postnatal background-level exposure to environmental chemicals, such as polychlorinated biphenyls (PCBs) and dioxins, induces adverse effects on the neurodevelopment of children. However, other studies have not detected any harmful influences on neurodevelopment. Furthermore, except in western countries, no developmental tests have been carried out in relation to detailed assessment of exposure to PCBs and dioxins. In this study (the Hokkaido Study on Environment and Children's Health), the effect of prenatal exposure to background levels of PCBs and dioxins on infant neurodevelopment in Japan/Sapporo was elucidated. The associations between the total or individual isomer level of PCBs and dioxins in 134 Japanese pregnant women's peripheral blood and the mental or motor development of their 6-month-old infants were evaluated using the second edition of the Bayley Scales of Infant Development. The mean level of total toxicity equivalency quantity (TEQ) was 18.8 (4.0-51.2) pg/g lipid in blood of 134 mothers. After adjustment for potential confounding variables, the total TEQ value was shown not to be significantly associated with mental developmental index (MDI) or psychomotor developmental index (PDI). However, the levels of one polychlorinated dibenzo-p-dioxin (PCDD) isomer, total PCDDs, and total PCDDs/polychlorinated dibenzofurans (PCDFs) were significantly negatively associated with MDI, and the levels of two PCDD isomers and three PCDF isomers were significantly negatively associated with the PDI. In conclusion, the background-level exposure of several isomers of dioxins during the prenatal period probably affects the motor development of 6-month-old infants more than it does their mental development.
authors: Department of Public Health, Hokkaido University Graduate School of Medicine, and Sapporo Toho Hospital, Japan. sonomi@sapmed.ac.jp
authors: Sonomi
authors: S
authors: Nakajima
authors: Yasuaki
authors: Y
authors: Saijo
authors: Shizue
authors: S
authors: Kato
authors: Seiko
authors: S
authors: Sasaki
authors: Akiko
authors: A
authors: Uno
authors: Nobuo
authors: N
authors: Kanagami
authors: Hironori
authors: H
authors: Hirakawa
authors: Tsuguhide
authors: T
authors: Hori
authors: Kazuhiro
authors: K
authors: Tobiishi
authors: Takashi
authors: T
authors: Todaka
authors: Yuji
authors: Y
authors: Nakamura
authors: Satoko
authors: S
authors: Yanagiya
authors: Yasuhito
authors: Y
authors: Sengoku
authors: Takao
authors: T
authors: Iida
authors: Fumihiro
authors: F
authors: Sata
authors: Reiko
authors: R
authors: Kishi