TY - JOUR
T1 - Prenatal and postnatal lead exposures and intellectual development among 12-year-old Japanese children
AU - Tatsuta, Nozomi
AU - Nakai, Kunihiko
AU - Kasanuma, Yuichi
AU - Iwai-Shimada, Miyuki
AU - Sakamoto, Mineshi
AU - Murata, Katsuyuki
AU - Satoh, Hiroshi
N1 - Funding Information:
We thank all the families and members for their participation in the cohort study. We would like to acknowledge Drs. Keita Suzuki, Yukiko Nishihama, Naoyuki Kurokawa, Takashi Ohba, Satomi Kameo, Kozue Yaginuma-Sakurai and Tomoyuki Nakamura, who were the members of TSCD. This study was supported partly by the Japan Ministry of the Environment . The findings and conclusions of this article are solely the responsibility of the authors and do not represent the official views of the above agency.
Funding Information:
Financial supports were provided by the Japan Ministry of the Environment and the Japan Ministry of Health, Labor and Welfare. The funding sources had no role in the study protocol, in the collection, analysis, and interpretation of data, the writing of the report, or in the decision to submit the paper for publication. For this reason, the findings and conclusions of this article are solely the responsibility of the authors and do not represent the official views of the above government agencies.We thank all the families and members for their participation in the cohort study. We would like to acknowledge Drs. Keita Suzuki, Yukiko Nishihama, Naoyuki Kurokawa, Takashi Ohba, Satomi Kameo, Kozue Yaginuma-Sakurai and Tomoyuki Nakamura, who were the members of TSCD. This study was supported partly by the Japan Ministry of the Environment. The findings and conclusions of this article are solely the responsibility of the authors and do not represent the official views of the above agency.
Publisher Copyright:
© 2020 The Author(s)
PY - 2020/10
Y1 - 2020/10
N2 - Background: Low-level lead exposure during childhood is associated with deficit in child IQ. However, the association between prenatal lead exposure and child IQ remains inconsistent. The objective of our study was to examine the association between prenatal/postnatal lead exposure and child IQ at the age of 12. Methods: We obtained data pertaining to cord-blood and child-blood lead levels and IQ for 286 children from a prospective birth cohort study (Tohoku Study of Child Development). IQ was assessed using the Wechsler Intelligence Scale for Children-Fourth Edition. Simultaneously, the Boston Naming Test (BNT) was used to assess the children's language ability. Results: The median lead level in the cord blood was 0.8 μg/dL (5th-95th percentiles, 0.4–1.4 μg/dL), and that in the blood of 12-year-old children was 0.7 μg/dL (0.4–1.1 μg/dL). IQ and BNT scores were significantly lower in boys than in girls; therefore, multiple regression analysis was conducted separately for boys and girls. Among boys, IQ was associated with child-blood lead (B = −16.362, p = 0.033) but not cord-blood lead (B = −6.844, p = 0.309). When boys were divided into four groups according to the child-blood lead levels, there was a significant decreasing trend for IQ. The score with cues of the BNT was associated with both cord-blood (B = −5.893, p = 0.025) and child-blood (B = −7.108, p = 0.022) lead concentrations in boys. Among girls, there was no significant association of the outcomes with cord-blood or child-blood lead level. Conclusions: These findings suggest that postnatal lead exposure adversely affects the intellectual ability in boys. Furthermore, the language ability is sensitive to prenatal/postnatal lead exposure in boys.
AB - Background: Low-level lead exposure during childhood is associated with deficit in child IQ. However, the association between prenatal lead exposure and child IQ remains inconsistent. The objective of our study was to examine the association between prenatal/postnatal lead exposure and child IQ at the age of 12. Methods: We obtained data pertaining to cord-blood and child-blood lead levels and IQ for 286 children from a prospective birth cohort study (Tohoku Study of Child Development). IQ was assessed using the Wechsler Intelligence Scale for Children-Fourth Edition. Simultaneously, the Boston Naming Test (BNT) was used to assess the children's language ability. Results: The median lead level in the cord blood was 0.8 μg/dL (5th-95th percentiles, 0.4–1.4 μg/dL), and that in the blood of 12-year-old children was 0.7 μg/dL (0.4–1.1 μg/dL). IQ and BNT scores were significantly lower in boys than in girls; therefore, multiple regression analysis was conducted separately for boys and girls. Among boys, IQ was associated with child-blood lead (B = −16.362, p = 0.033) but not cord-blood lead (B = −6.844, p = 0.309). When boys were divided into four groups according to the child-blood lead levels, there was a significant decreasing trend for IQ. The score with cues of the BNT was associated with both cord-blood (B = −5.893, p = 0.025) and child-blood (B = −7.108, p = 0.022) lead concentrations in boys. Among girls, there was no significant association of the outcomes with cord-blood or child-blood lead level. Conclusions: These findings suggest that postnatal lead exposure adversely affects the intellectual ability in boys. Furthermore, the language ability is sensitive to prenatal/postnatal lead exposure in boys.
KW - Child neurodevelopment
KW - Intelligence quotient
KW - Lead exposure
KW - Methylmercury exposure
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U2 - 10.1016/j.envres.2020.109844
DO - 10.1016/j.envres.2020.109844
M3 - Article
C2 - 32678746
AN - SCOPUS:85087765041
SN - 0013-9351
VL - 189
JO - Environmental Research
JF - Environmental Research
M1 - 109844
ER -