Prenatal p,p´-DDE exposure and neurodevelopment among children 3.5-5 years of age

Abstract

Background: The results of previous studies suggest that prenatal exposure to bis[p-chlorophenyl]-1,1,1-trichloroethane (DDT) and to its main metabolite, 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (DDE), impairs psychomotor development during the first year of life. However, information about the persistence of this association at later ages is limited.

Objectives: We assessed the association of prenatal DDE exposure with child neurodevelopment at 42-60 months of age.

Methods: Since 2001 we have been monitoring the neurodevelopment in children who were recruited at birth into a perinatal cohort exposed to DDT, in the state of Morelos, Mexico. We report McCarthy Scales of Children's Abilities for 203 children at 42, 48, 54, and 60 months of age. Maternal DDE serum levels were available for at least one trimester of pregnancy. The Home Observation for Measurement of the Environment scale and other covariables of interest were also available.

Results: After adjustment, a doubling of DDE during the third trimester of pregnancy was associated with statistically significant reductions of -1.37, -0.88, -0.84, and -0.80 points in the general cognitive index, quantitative, verbal, and memory components respectively. The association between prenatal DDE and the quantitative component was weaker at 42 months than at older ages. No significant statistical interactions with sex or breastfeeding were observed.

Conclusions: These findings support the hypothesis that prenatal DDE impairs early child neurodevelopment; the potential for adverse effects on development should be considered when using DDT for malaria control.

Conflict of interest statement

The content is solely the responsibility of the authors and does not necessarily represent the official views of the Fogarty International Center or the National Institutes of Health.

The authors declare they have no actual or potential competing financial interests.

Figures

Figure 1

Morelos Perinatal Cohort Study 2001–2009.

Figure 2

Maternal serum DDE during the third trimester and McCarthy Scales of Children’s Ability components according to age at evaluation. Interactions between serum DDE (continuous) and age at examination for each McCarthy component estimated through mixed-effects multivariate models. All models were adjusted for child’s age at examination, mother’s education and marital status when child was 4 years old, and HOME score. Additionally, the GCI model was adjusted by sex of child and attendance at a child care center; the quantitative model also was adjusted by maternal IQ and child’s birth weight; the verbal model also was adjusted by maternal age and IQ, birth weight, infant height at the time of the evaluation, and attendance at a child care center; the memory model also included maternal age and IQ, birth weight, and attendance at a child care center.