Prenatal exposure to pyrethroids and chlorpyrifos and IQ in 7-year-old children from the Odense Child Cohort

Stine Søgaard Normann; Iben Have Beck; Flemming Nielsen; Marianne Skovsager Andersen; Niels Bilenberg; Tina Kold Jensen; Helle Raun Andersen

doi:10.1016/j.ntt.2024.107352

Prenatal exposure to pyrethroids and chlorpyrifos and IQ in 7-year-old children from the Odense Child Cohort

Neurotoxicol Teratol. 2024 Apr 16:103:107352. doi: 10.1016/j.ntt.2024.107352. Online ahead of print.

Authors

Stine Søgaard Normann¹, Iben Have Beck², Flemming Nielsen², Marianne Skovsager Andersen³, Niels Bilenberg⁴, Tina Kold Jensen⁵, Helle Raun Andersen²

Affiliations

¹ Department of Clinical Pharmacology, Pharmacy and Environmental Medicine, Institute of Public Health, University of Southern Denmark, Odense, Denmark. Electronic address: snormann@health.sdu.dk.
² Department of Clinical Pharmacology, Pharmacy and Environmental Medicine, Institute of Public Health, University of Southern Denmark, Odense, Denmark.
³ Department of Endocrinology, Odense University Hospital, Odense, Denmark.
⁴ Department of Child and Adolescent Psychiatry, Mental Health Services in Region of Southern Denmark, University of Southern Denmark, Odense, Denmark.
⁵ Department of Clinical Pharmacology, Pharmacy and Environmental Medicine, Institute of Public Health, University of Southern Denmark, Odense, Denmark; Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark; OPEN Patient data Explorative Network, Odense, Denmark.

PMID: 38636567
DOI: 10.1016/j.ntt.2024.107352

Abstract

Background: Organophosphates and pyrethroids are two major groups of insecticides used for crop protection worldwide. They are neurotoxicants and exposure during vulnerable windows of brain development may have long-term impact on human neurodevelopment. Only few longitudinal studies have investigated associations between prenatal exposure to these substances and intelligence quotient (IQ) at school age in populations with low, mainly dietary, exposure.

Objective: To investigate associations between maternal urinary concentrations of insecticide metabolites at gestational week 28 and IQ in offspring at 7-years of age.

Materials and methods: Data was derived from the Odense Child Cohort (OCC). Metabolites of chlorpyrifos (TCPy) and pyrethroids (3-PBA, cis- and trans-DCCA, 4-F-3PBA, cis-DBCA) were measured in maternal urine collected at gestational week (GW) 28. An abbreviated version of the Danish Wechsler Intelligence Scale for Children fifth edition (WISC-V) consisting of four subtests to estimate full scale IQ (FSIQ) was administered by trained psychologists. Data were analyzed by use of multiple linear regression and adjusted for confounders.

Results: 812 mother/child-pairs were included. Median concentrations were 0.21 μg/L for 3-PBA, 1.67 μg/L for TCPy and the mean IQ for children were 99.4. Null association between maternal 3-PBA and child IQ at 7 years was seen, but with trends suggesting an inverse association. There was a significant association for maternal TCPy and child IQ at mid-level exposure. Trans-DCCA above the level of detection (LOD) was also associated with slightly lower child IQ, but the association was also not statistically significant.

Conclusions: We found no significant associations between maternal 3-PBA metabolites and child IQ at 7 years, but with trends suggesting an inverse association. A non-significant trend between maternal TCPy exposure and child IQ in 7-year-children was seen even in this low exposed population. Given the widespread exposure and increasing use of insecticides, this should be elaborated in future studies.

Keywords: Chlorpyrifos; Cognitive development; Cohort study; IQ; Neurotoxicology; Pyrethroids.