Effect of the Antiandrogen DDE on Anthropometric Measures at Birth

Overview

Experimental studies have documented the p'p-DDT, p'p-DDE (a metabolite of DDT) and other organochlorine (OC) compounds have estrogenic and/or antiandrogenic activities capable of altering normal endocrine functions. It has been postulated that exposure to these toxins during embriogenesis may cause urogenital malformations. However, this hypothesis has not yet been evaluated in humans populations with relatively high levels of exposure. The primary goal of this project is to study in utero exposure to DDE in relation to anogenital distance in humans. Anogenital distance is measured from a gender and species specific landmark on the genitalia, such as the junction of the penis and the scrotum in male humans, to the center of the anus. Altered anogenital distance is a sensitive manifestation of prenatal endocrine disruption in animal models; whether it is a sensitive endpoint in humans has not been studied. We will test the hypothesis that DDE, an androgen-receptor blocker, decreases anogenital distance in male humans who have been chronically but not occupationally exposed to DDT in Mexico. Study participants will be newborns and their mothers who live in the state of Chiapas, Mexico and who have been exposed to DDT through house spraying programs to control malaria in this area. Anogenital distance will be measured at birth and in utero exposure to DDE will be determined by measuring DDE in maternal blood. Demonstration that p'p-DDT or p'p-DDE may interfere with normal endocrine functions during embriogenesis will provide a model to increase our understanding of how other- more prevalent-environmental estrogens may act and will open new possibilities for research and potential control of etiologic factors related with this important public health problem....

We propose to follow the women and children enrolled in our original study (n= approximately 850 of each). In the original study, women were enrolled and interviewed while in the hospital for delivery, their blood was drawn, and anthropometric measurements were performed on their newborn male infants. The follow-up will be done primarily to determine the number of months that the mother breast feeds her child. Secondary endpoints will be infant infection as reported by the mother, and child growth as determined by measurement of height and weight and related measures (none in the genital region, as in the original study). Breast feeding duration, infections, and growth may be related to exposure to the DDT metabolite, DDE. The follow-up visits will be every three months from 6 to 18 months after birth, and study nurses will visit subjects in their home. For some subjects, there would be fewer follow-up visits, due to study scheduling or breastfeeding cessation. Mothers would be interviewed and mothers and children will undergo standard anthropometric assessments. This protocol does not call for collection of biologic specimens and poses minimal risk to subjects.