Environmental background in relation to cognitive and emotional development in children.

Abstract

Background In bird cohort studies have been observed that low levels of polychlorinated biphenyls (PCBs) have a negative effects on early cognitive development in children. More recent studies support the hypothesis of negative effects of social background and family problems as strong confounders, which affect cognitive development strongly, as environmental PCBs. Aims To examine the association of cord blood and actual PCB exposures with neurodevelopment, at 6-years of age in a cohort of children residing in polluted area of Slovakia. Methods In each period the PCB congenerswere measured by HR-GC, and grouped as dioxin-like (DL-PCBs) and non-dioxin-like (NDL-PCBs). In children at 6-years of age (n=483) also the Wechsler Intelligence Scales were administered. Mothers were interviewed to introduce socio-demographic characteristics and home environment, and to complete the questionnaires (PSAI-Preschool emotional behavior of child, and CBCL-Check List of Preschool child behavior). Multiple linear regression was used to estimate associations between PCBs concentrations (of cord blood and at 6-years of age and scores on the Wechsler Scales and the scores on questionnaires and other evaluated psychosocial factors). Results The levels of NDL-PCBs in 4.quarter were associate with significantly lower scores in cognitive task-Blocks (spatial decision - cognitive function finishing maturation in postnatal age) as in 1.quarter of NDL-PCBs (higher performance in Blocks), p=0.002. Also PCB-153 6r_lip significantly correlated with Blocks-score (p=0.061). In multiple linear regression the lower neurodevelopment was significantly influenced by intelligence of mother, lower emotional background at home and ethnic, which were consider as confounders. Conclusions This study provides evidence of an association between NDL-PCBs and decreased performance on cognitive function and emotional disruptions of mother-child contacts in children with lower social background.