89. Association Between Gestational Exposure to Toxicants and Autistic Behaviors Using Bayesian Quantile Regression (lay summary)

Alampi JD, Lanphear BP, Braun JM, Chen A, Takaro TK, Muckle G, Arbuckle TE, McCandless LC. American Journal of Epidemiology 2021 Mar 29:kwab065. doi: 10.1093/aje/kwab065

A number of studies have reported associations between prenatal exposure to some chemicals and adverse effects on child behaviour.  Autism Spectrum Disorder (ASD) impacts how a person perceives and socializes with others, causing problems in social interaction and communication.  1 in 66 Canadian children and youth (ages 5-17) are diagnosed with ASD, making ASD one of the most common developmental disabilities.

In this analysis of data from the Maternal-Infant Research on Environmental Chemicals (MIREC) study, researchers from Simon Fraser University used a complex statistical method known as “Bayesian quantile regression” to assess associations between various chemicals and autistic behaviors.  Phthalates are a group of chemicals used to make plastics more flexible and harder to break or as solvents (dissolving agents) for other materials. Lead, cadmium and manganese are metals. These chemicals were measured in 1st trimester urine or blood of women in the MIREC Study.  Autistic behaviors were assessed in their 3-4-year-old children (n=478) using the Social Responsiveness Scale (SRS).  Higher scores meant more autistic-like behaviors.

This study observed that among children with the highest SRS scores, lead, cadmium, and several phthalates were associated with small to moderate increases in SRS scores. Manganese and some pesticides were associated with small to moderate decreases in SRS scores.

As this study was the first to use this complex statistical method to investigate the associations between prenatal chemical exposure and autistic behaviours, additional research is necessary to confirm these results.