Exposure to hexachlorobenzene during pregnancy and children's social behavior at 4 years of age

BACKGROUND: Hexachlorobenzene (HCB) is an organochlorine chemical that has been used in agriculture and industrial processes. Behavioral impairment after HCB exposure has been described if animal models, but little information is available in humans. OBJECTIVES: Our goal was to study the association of prenatal exposure to HCB with the social behavior of preschool children. METHODS: Two birth cohorts in Ribera d'Ebre and Menorca (Spain) were set up between 1997 and 1199 (n = 475). The California Preschool Social Competence Scale and the Attention-Deficit hyperactivity Disorder (ADHD) were scored by each 4-year-old child's teacher. Organochlorine compounds were measured in cord serum. Children's diet and parental sociodemographic information were obtained through questionnaire. RESULTS: Children with concentrations of HCB > 1.5 ng/mL at birth had a statistically significant increased risk of having poor Social Competence [relative risk (RR) = 4.04; 95% confidence interval (CI), 1.76-9.58] and ADHD (RR = 2.71; 95% CI, 1.05-6.96) scores. No association was found between HCB and the cognitive and psychomotor performance of these children. CONCLUSIONS: Prenatal exposure to current concentrations of HCB in Spain is associated with a decrease in the behavioral competence at preschool ages. These results should be considered when evaluating the potential neurotoxicologic effects of HCB.