Trajectories of Early Life PBDE Exposure in Relation to Neurocognitive Development in Children

摘要

Polybrominated diphenyl ethers (PBDEs) are persistent environmental chemicals that were used extensively as flame retardants in furniture and furnishings. Prenatal and childhood exposure to PBDEs is associated with reduced neurocognitive performance, however, longitudinal patterns of early life exposure have not been previously examined in relation to neurodevelopment. We measured PBDEs in umbilical cord and/or venous blood collected from 334 African American and Dominican children enrolled in a New York City-based birth cohort between 1998 and 2006. At follow-up visits, research workers administered the Wechsler Intelligence Scales for Children (WISC-IV) (mean±sd age: 8±1 years) and the Children's Memory Scales (CMS) (11 ±1 years); scores are standardized to a meantsd of 100±15. We conducted latent class growth curve analysis to estimate trajectories of BDE-47 (ng/g lipid) exposure overtime. We then used multiple regression to examine exposure trajectories, as a categorical variable, in relation to continuous scores on the WISC-IV and CMS. All children had at least one measure of PBDEs at birth, $2$35, 7 or 9 years. We identified 4 trajectories of BDE-47 exposure: persistent low (33%), prenatal high (21%), toddler peak (36%) and sustained childhood high (11%). Compared to girls in the persistent low trajectory, girls in the sustained childhood high group performed significantly worse on the WISC-IV Working Memory Index (B [95% Cl] = -6.48 [-11.65, -1.30]) and girls and boys in this group performed significantly worse on the CMS Immediate Recall Visual Memory Index (Girls: B [95% Cl] = -6.83 [-13.02-0.64]; Boys: B [95% Cl] = -8.35 [-16.6$4-0.07]). We did not observe significant effects on WISC-IV or CMS verbal memory domains. Children with sustained high exposure to BDE-47 throughout childhood (2-9 years) may be at risk for auditory working memory (girls) and visual memory (girls and boys) deficits compared to children with low exposure throughout childhood.