Associations of Maternal Exposure to Dichlorodiphenyltrichloroethane and Pyrethroids With Birth Outcomes Among Participants in the Venda Health Examination of Mothers, Babies and Their Environment Residing in an Area Sprayed for Malaria Control

Abstract

Although effective in controlling malaria, Indoor Residual Spraying results in elevated exposure to insecticides such as dichlorodiphenyltrichloroethane (DDT) and pyrethroids. These chemicals cross the placenta but no studies have examined their associations with birth outcomes in populations residing in indoor residual spraying areas. We investigated this question in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), a birth cohort study of 751 South African children born between 2012 and 2013. We measured maternal peripartum serum DDT and urine pyrethroid metabolite concentrations and collected data on birth weight, length, head circumference and gestational duration. We analyzed data using marginal structural models with inverse probability of treatment weights, generalized propensity scores and standard conditional linear regression. p,p'-DDT, o,p'-DDT and, to a lesser extent, p,p'-dichlorodiphenyldichloroethylene were related to elevated birth weight, length and head circumference among girls only, using all three analytical methods. Changes in gestational duration did not mediate this relation, suggesting exposures accelerate fetal growth, which is consistent with the known estrogenic properties of o,p'-DDT and p,p'-DDT. No associations were found with pyrethroid metabolites. Results suggest prenatal exposure to DDT is related to elevated birth size. Further studies are needed to elucidate the implications of these findings.

Maternal peripartum urinary pyrethroid metabolites are associated with thinner children at 3.5 years in the VHEMBE birth cohort (Limpopo, South Africa)

“…Overall, despite the ubiquity of their use, few epidemiologic investigations have been conducted on the relation between fetal exposure to pyrethroids and growth in early childhood besides work conducted in this cohort 14 , 18 . Moreover, conflicting evidence for the influence of pyrethroids on birth characteristics 12 , 13 , 15 – 18 and child size 14 , 19 predominate. Studies in our cohort have several notable differences and advantages over past work including larger sample size, use of biomarkers of exposure (i.e., pyrethroid metabolite concentrations), and longer follow-up.…”

“…Our previous work in a rural South African birth cohort with high exposure to pyrethroids and DDT suggests associations between prenatal exposure to insecticides and early child size. We found that prenatal exposure to DDT and dichlorodiphenyl dichloroethylene (DDE, a DDT breakdown product) was associated with greater birth size (birth weight, length, and head circumference) 18 and larger weight-for-age at 1 and 2 years among girls 14 . In contrast, maternal urine concentrations of several pyrethroid metabolites were associated with lower weight-forage at 1 and 2 years, especially among boys.…”

“…One study by Zhang et al 15 found associations between concentrations of the metabolite 3-phenoxybenzoic acid (3-PBA) and higher birth weight and head circumference. Others have found no associations with birth weight or other child anthropometrics at birth 15 – 18 or at 1 year 19 . Prior studies have been limited by small sample sizes, self-reported usage rather than the use of biomarkers, low detection frequencies, or limited durations of follow-up.…”

Integrating environmental health and genomics research in Africa: challenges and opportunities identified during a Human Heredity and Health in Africa (H3Africa) Consortium workshop

“…He reported that IRS was associated with elevated serum DDT/DDE and urinary pyrethroid metabolite concentrations in peripartum samples collected from 751 VHEMBE women 24,25 . Associations between maternal exposure to DDT and hypertensive disorders of pregnancy 26 , larger birth size 27 , and higher body composition measures, and marginally altered motor development were found among VHEMBE girls at age 1 and/or 2 years 28 . Prenatal exposure to pyrethroids was also associated with lower body composition measures among boys 28 and altered motor development among girls aged 1 to 3.5 years 29,30 .…”

Early-life exposure to p,p′-DDT and p,p′-DDE in South African children participating in the VHEMBE study: An assessment using repeated serum measurements and pharmacokinetic modeling

“…In many countries, including South Africa, DDT has been used for decades (Mabaso et al, 2004), resulting in elevated body burdens of DDT and its breakdown product dichlorodiphenyldichloroethylene (DDE) in individuals living in sprayed homes (Gaspar et al, 2017). Concerns have been raised regarding the potential health effects related to exposure to these chemicals, especially in developing children (Bouwman and Kylin, 2009; Chevrier et al, in press; Coker et al, 2018; Eskenazi et al, 2009; Huang et al, in press). …”