Maternal diet as a modifier of environmental risk factors for child neurodevelopmental outcomes: Existing evidence and future directions

BACKGROUND AND AIM: Emerging work suggests diet may modify the effects of environmental risk factors for neurodevelopmental outcomes like autism spectrum disorder (ASD). The goal of this symposium presentation is to summarize evidence for such interactions, highlight opportunities for future work, and discuss preliminary findings for dietary factors and pesticides in association with ASD-related outcomes. METHODS: Participants (n=154) for analyses of joint effects of pesticides and diet on ASD were drawn from the Early Autism Risk Longitudinal Investigation (EARLI), a high-familial risk prospective cohort. Autism diagnosis and ASD-related traits, measured according to the Social Responsiveness Scale (SRS), were captured at 36 months. Levels of organochlorine pesticides, including hexachlorobenzene, transnonachlor, and p,p’-DDE, were measured in maternal mid-pregnancy serum samples. Associations between pesticides and SRS scores and ASD diagnosis were examined using linear and logistic regression respectively, adjusted for maternal characteristics, demographic confounders, and dietary factors like folate and vitamin D, and also stratified by key dietary factors and sources of pesticides. RESULTS:No significant associations were observed with SRS scores, though patterns differed when stratified by vegetable intake, folate, and vitamin D, with increases in SRS scores among those with higher pesticide exposure and lower intake of these factors. Increased odds of ASD was also observed for those with higher levels of transnonachlor, and this association became stronger when stratified by vegetable intake (low intake AOR for interquartile range increase =3.12, 95% CI 1.01, 9.66; high intake AOR=1.03, 95% CI 0.19, 5.55). CONCLUSIONS:Certain dietary factors like vegetable intake, or nutrients within it, may mitigate adverse effects of pesticides on ASD-related outcomes. Future work should further consider these and other joint effects, targeting nutrients and chemicals that act in key pathways like inflammation and oxidative stress, to present opportunities for mitigation and intervention. KEYWORDS: autism, pesticides, diet, interactions