Lead exposure is associated with behavioral problems in children, but the age(s) of greatest susceptibility to low-level lead exposure is unknown.
We evaluated the association of repeated blood lead concentrations with parent-reported behaviors to identify periods of heightened susceptibility during infancy and childhood (HOME Study; Cincinnati, OH; 2003–2006; n = 244).
We quantified lead in whole blood samples (ages 1, 2, 3, 4, 5, and 8 years) and assessed behavior using the Behavioral Assessment System for Children-2 (BASC-2; ages 2, 3, 4, 5, and 8 years). We used multiple informant models and modified Poisson regression to estimate covariate-adjusted associations of ln-transformed blood lead concentrations with continuous BASC-2 T-scores and the relative risk of behavior scores classified as at-risk or clinically significant, respectively.
We observed trends indicating that higher blood lead concentrations at all ages were adversely associated with scores on behavioral scales. On the Externalizing Problems and Adaptive Skills scales, these associations were strongest for blood lead concentrations at age 8 years (β = 3.1-point; 95% CI = 0.7, 5.4 and β = −2.2-point; 95% CI = −4.9, 0.5, respectively) compared with other ages. Overall, higher blood lead concentrations were associated with elevated risk of behavior scores classified as at-risk or clinically significant on the Adaptive Skills, Behavioral Symptom Index, and Externalizing Problems scales.
Contemporary levels of lead exposure during the first 8 years of life were associated with ADHD-related behaviors, specifically aggression, hyperactivity, and conduct problems.
Our results highlight the importance of primary lead prevention across childhood.
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Data are available upon reasonable request. The HOME Study Principal Investigators welcome new collaborations with other investigators and have actively engaged in collaborative data sharing projects. Interested investigators should contact Drs. JMB (joseph_ braun_ 1@brown. edu) and KY (kimberly. yolton@ cchmc. org) to obtain additional information about The HOME Study, discuss collaborative opportunities, and request a project proposal form. The HOME Study Protocol Review Committee reviews proposed research projects to ensure that they do not overlap with extant projects and are an efficient use of scarce resources (e.g., biospecimens).
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The authors would like to acknowledge David E. Jacobs, Sherry Dixon, Jonathan Wilson, and Kofi Berko for their contribution to this research. The authors and publisher are solely responsible for the accuracy of the statements and interpretations contained in this publication. Such interpretations do not necessarily reflect the views of the US Government. The HOME Study and this research was supported by the National Institutes of Environmental Health Sciences grants P01ES011261, R01ES014575, and R01ES020349. Additional support for this research was received through a grant (MDLTS0008-18) from the United States Department of Housing and Urban Development.
JMB’s institution was financially compensated for his services as an expert witness for plaintiffs in litigation related to PFAS-contaminated drinking water; these funds were not paid to JMB directly. BPL has served as an expert witness for plaintiffs in litigation related to lead poisoning prevention cases, but he received no personal payments for his services. His institution was financially compensated for some of those cases. The other authors declare they have no actual or potential competing financial interests.
The institutional review boards (IRB) of Cincinnati Children’s Hospital Medical Center (CCHMC) and the participating prenatal clinics and delivery hospitals approved the HOME Study. Brown University deferred to the CCHMC IRB as the IRB of record. Women provided written informed consent for themselves and their children after research assistants explained study protocols during face-to-face visits.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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Sears, C.G., Lanphear, B.P., Xu, Y. et al. Identifying periods of heightened susceptibility to lead exposure in relation to behavioral problems. J Expo Sci Environ Epidemiol 32, 1–9 (2022). https://doi.org/10.1038/s41370-021-00389-3