Assessing the Relation between Plasma PCB Concentrations and Elevated Autistic Behaviours using Bayesian Predictive Odds Ratios
- DOI
- Language of the publication
- English
- Date
- 2019-02-05
- Type
- Article
- Author(s)
- Bernardo, Brendan A.
- Lanphear, Bruce P.
- Venners, Scott A.
- Arbuckle, Tye E.
- Braun, Joseph M.
- Muckle, Gina
- Fraser, William D.
- McCandless, Lawrence C.
- Publisher
- MDPI
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by impaired social communication and repetitive or stereotypic behaviours. In utero exposure to environmental chemicals, such as polychlorinated biphenyls (PCBs), may play a role in the etiology of ASD. We examined the relation between plasma PCB concentrations measured during pregnancy and autistic behaviours in a subset of children aged 3⁻4 years old in the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a pregnancy and birth cohort of 546 mother-infant pairs from Canada (enrolled: 2008⁻2011). We quantified the concentrations of 6 PCB congeners that were detected in >40% of plasma samples collected during the 1st trimester. At age 3⁻4 years, caregivers completed the Social Responsiveness Scale-2 (SRS), a valid and reliable measure of children's reciprocal social and repetitive behaviours and restricted interests. We examined SRS scores as both a continuous and binary outcome, and we calculated Bayesian predictive odds ratios for more autistic behaviours based on a latent variable model for SRS scores >60. We found no evidence of an association between plasma PCB concentrations and autistic behaviour. However, we found small and imprecise increases in the mean SRS score and odds of more autistic behaviour for the highest category of plasma PCB concentrations compared with the lowest category; for instance, an average increase of 1.4 (95%PCI: -0.4, 3.2) in the mean SRS (exposure contrast highest versus lowest PCB category) for PCB138 translated to an odds ratio of 1.8 (95%PCI: 1.0, 2.9). Our findings illustrate the importance of measuring associations between PCBs and autistic behaviour on both continuous and binary scales.
Plain language summary
Health Canada helps to protect the health of Canadians by assessing and managing the risks associated with exposure to environmental chemicals. Polychlorinated Biphenyls (PCBs) were used widely as ingredients in many industrial materials, such as sealing and caulking compounds, cutting oils, inks and paint additives and to make coolants and lubricants for certain kinds of electrical equipment, such as transformers and capacitors. PCBs are extremely persistent, lasting for many years because they do not break down easily on their own and they are difficult to destroy. Prenatal exposure to PCBs has been associated with cognitive deficits and behavioral problems in children. Autism spectrum disorder (ASD) is a condition characterized by impaired social communication and repetitive or stereotypic behaviours. In utero exposure to environmental chemicals, such as polychlorinated biphenyls (PCBs), may play a role in the etiology of ASD. This study examined the relation between PCB concentrations measured during the 1st trimester of pregnancy and autistic behaviours in children aged 3-4 years old in the Maternal-Infant Research on Environmental Chemicals (MIREC) Study. This analysis was on 546 mother-infant pairs from this national-level study. Six different PCBs congeners were measured in maternal blood. At age 3-4 years, the parents completed the Social Responsiveness Scale-2 (SRS), a valid and reliable measure of children’s reciprocal social and repetitive behaviors. The study found small but imprecise increases in the mean SRS score for the highest PCB concentrations compared with the lowest. Higher SRS scores suggest more symptoms of behavior associated with ASD. In conclusion, this study found no significant association between blood PCB concentrations during pregnancy and small increases in autistic behaviours. Further research is needed to determine whether new studies will find similar results in other populations.
Subject
- Health,
- Health and safety