Maternal Exposures Associated with Autism Spectrum Disorder in Jamaica

Background: Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder with poorly defined etiology. Many genetic and environmental factors may be involved in the manifestation of ASD, and most cases are thought to result from gene-environment interactions. Since neurodevelopment begins during the first few weeks of pregnancy and continues after birth, exposures experienced by the mother during pregnancy or breastfeeding have the potential to interrupt fetal and infant neurodevelopmental mechanisms and possibly contribute to disorders such as ASD. Maternal exposures that are believed to have adverse effects on neurodevelopment include bacterial and viral infections, physical trauma, and pesticides and other products containing volatile organic compounds.

Objectives: To investigate the associations of ASD in Jamaican children with maternal exposures, including fever over 101^oF or infection requiring antibiotics, physical trauma such as a car accident or fall, degreasers, oil-based paints, paint solvents, and pesticides or herbicides.

Methods: We used data from 298 pairs of Jamaican children 2-8 years of age enrolled in the Epidemiological Research on Autism in Jamaica (ERAJ) or ERAJ- Phase II matched case-control studies to assess the associations of maternal exposures with ASD in Jamaican children. Conditional logistic regression models were used for all crude and adjusted analyses. Potential confounders were included in the model if the magnitude of the adjusted matched odds ratio (MOR) differed from the crude MOR by ≥10% or if they are considered important potential confounders according to published literature. We also used conditional logistic regression models to investigate interactions between maternal exposures in relation to ASD in Jamaican children.

Results: After adjusting for potential confounders, maternal exposures to fever or infection (adjusted MOR = 3.12, 95% CI: 1.74 – 5.60), physical trauma (adjusted MOR = 2.02, 95% CI: 1.01 – 4.05), and oil-based paints (adjusted MOR = 1.99, 95% CI: 1.14 – 3.46) were significantly associated with ASD in the children. Further investigation revealed that maternal exposure to oil-based paints may be an effect modifier for the relationship between maternal exposure to pesticides or herbicides and ASD. Specifically, the association between maternal exposure to pesticides or herbicides and ASD in Jamaican children was stronger among those with maternal exposure to oil-based paints (MOR = 2.45, 95% CI: 1.41 – 4.26) compared to those without maternal exposure to oil-based paints (MOR = 1.74, 95% CI: 1.29 – 2.35).

Conclusions: Our findings suggest that maternal exposures to fever or infection, physical trauma, and oil-based paints occurring from 3 months before conception until the end of breastfeeding may be associated with ASD in Jamaican children. Additionally, maternal exposure to oil-based paints may modify the association between maternal exposure to pesticides or herbicides and ASD in Jamaican children. These findings require replication in other populations.