Background: Early life exposure to lead, mercury, polychlorinated biphenyls (PCBs), polybromide diphenyl ethers (PBDEs), organophosphate pesticides (OPPs), and phthalates have been associated with lowered IQ in children. In some studies, these neurotoxicants impact males and females differently. We aimed to examine the sex-specific effects of exposure to developmental neurotoxicants on intelligence (IQ) in a systematic review and meta-analysis.
Method: We screened abstracts published in PsychINFO and PubMed before December 31st, 2021, for empirical studies of six neurotoxicants (lead, mercury, PCBs, PBDEs, OPPs, and phthalates) that (1) used an individualized biomarker; (2) measured exposure during the prenatal period or before age six; and (3) provided effect estimates on general, nonverbal, and/or verbal IQ by sex. We assessed each study for risk of bias and evaluated the certainty of the evidence using Navigation Guide. We performed separate random effect meta-analyses by sex and timing of exposure with subgroup analyses by neurotoxicant.
Results: Fifty-one studies were included in the systematic review and 20 in the meta-analysis. Prenatal exposure to developmental neurotoxicants was associated with decreased general and nonverbal IQ in males, especially for lead. No significant effects were found for verbal IQ, or postnatal lead exposure and general IQ. Due to the limited number of studies, we were unable to analyze postnatal effects of any of the other neurotoxicants.
Conclusion: During fetal development, males may be more vulnerable than females to general and nonverbal intellectual deficits from neurotoxic exposures, especially from lead. More research is needed to examine the nuanced sex-specific effects found for postnatal exposure to toxic chemicals.
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http://dx.doi.org/10.1186/s12940-023-01029-z | DOI Listing |
Epigenetics
December 2025
Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA, USA.
The effects of chronically stressing male mice can be transmitted across generations by stress-specific changes in their sperm miRNA content, which induce stress-specific phenotypes in their offspring. However, how each stress paradigm alters the levels of distinct sets of sperm miRNAs is not known. We showed previously that exposure of male mice to chronic social instability (CSI) stress results in elevated anxiety and reduced sociability specifically in their female offspring across multiple generations because it reduces miR-34c levels in sperm of stressed males and their unstressed male offspring.
View Article and Find Full Text PDFImportance: Childhood maltreatment (CM) is associated with the early onset of psychiatric and medical disorders and accelerated biological aging.
Objective: To identify types of maltreatment and developmental sensitive periods that are associated with accelerated adult brain aging.
Design: Participants were mothers of infants recruited from the community into a study assessing the effects of CM on maternal behavior, infant attachment, and maternal and infant neurobiology.
Few of the many chemicals that regulatory agencies are charged with assessing for risk have been carefully tested for developmental neurotoxicity (DNT). To speed up testing efforts, as well as to reduce the use of vertebrate animals, great effort is being devoted to alternate laboratory models for testing DNT. A major mechanism of DNT is altered neuronal architecture resulting from chemical exposure during neurodevelopment.
View Article and Find Full Text PDFFront Toxicol
January 2025
Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, United States.
Primary cell cultures from rodent brain are widely used to investigate molecular and cellular mechanisms of neurotoxicity. To date, however, it has been challenging to reliably culture endogenous microglia in dissociated mixed cultures. This is a significant limitation of most neural cell models given the growing awareness of the importance of interactions between neurons, astrocytes and microglia in defining responses to neurotoxic exposures.
View Article and Find Full Text PDFEndocrinology
January 2025
Cardiopulmonary Immunotoxicology Branch, Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC.
Maternal exposure to ozone during implantation results in reduced fetal weight gain in rats. Offspring from ozone-exposed dams demonstrate sexually dimorphic risks to high-fat diet feeding in adolescence. To better understand the adolescent hepatic metabolic landscape following fetal growth restriction, RNA sequencing was performed to characterize the effects of ozone-induced fetal growth restriction on male and female offspring.
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