DDT and Neurodevelopment of School-Age Mexican Children Born in the US and in Mexico

ISEE-674 Objective: Dichlorodiphenyltrichloroethane (DDT) was banned in the United States (US) by 1972; however, DDT continued to be used in Mexico for domestic food production and for malaria control until the 1990s and 2000 respectively. Both animal and epidemiologic studies indicate that DDT is a neurodevelopmental toxicant. Maternal levels of DDT are valid measures of in utero exposure and future dietary exposures to children. The objective of the study is to compare neurodevelopment of Mexican-American children and children in Mexico whose mothers have been exposed to varying levels of DDT. Materials and Methods: We measured DDT in blood collected from 426 Mexican immigrant pregnant women and conducted 285 neurodevelopmental assessments of their children aged 5 years in the keystone project of the Center for Children's Environmental Health Research at UC Berkeley. We also collected neurodevelopmental and exposure data from 160 5-year-old children currently residing in areas of Mexico where the Mexican immigrant mothers originated. We will compare findings of the neurodevelopmental assessments of the Mexican-American children with those of the Mexican children. Results: Women born in coastal Mexico had 225% and 150% higher levels of p,p′-DDT and o,p′-DDT respectively. We will present results of the neurodevelopmental assessments from subscales of the McCarthy Scales of Children's Abilities, the Wechsler Preschool and Primary Scale of Intelligence, and the Neuropsychological Test Battery for Children for the 285 5-year-old Mexican-American children and the 160 5-year-old Mexican children. We will examine the relationship of residing in areas of Mexico recently sprayed with DDT and neurodevelopment. Conclusions: Time spent living outside the US and being born in areas of Mexico with intensive and recent use of DDT were significant predictors of higher levels of DDT in maternal serum. We will discuss results of neurodevelopmental assessments in relation to the mother's exposure to DDT.