Environment and Autism: Understanding Causes from an Epidemiologic Perspective

By the end of the 20^th century, very little rigorous research had been conducted to uncover the causes for autism, although a few studies provided compelling clues. This evidence pointed to several conclusions: first, that both genetic and environmental factors could play a role, and second, that the non-heritable causes might include both microbiologic (rubella, influenza) and pharmacologic (thalidomide, valproic acid) agents. Even as theories and myths have multiplied, the past decade has witnessed a new wave of increasingly rigorous epidemiologic research, some of it quite robust. This presentation will summarize: current knowledge on specific exposures in early prenatal or postnatal life that are potential or likely contributing factors to ASD; parallels with the literature on neurotoxins and cognitive impairment; and promising approaches for integrating environmental epidemiology with advances in molecular genetics. To meaningfully assess the current science, key concepts will be interwoven, including the challenges to causal inference from observational studies, and some under-appreciated implications of multifactorial causation. Reflections will be offered for future directions in research on etiologies of autism.