Strengthening Inferences in Environmental Epidemiology

Background:  Environmental chemical exposures are increasingly recognized as contributors to the development of neurological diseases. However, exposure measurement is frequently challenged by uncertainty in the relevant etiological window, and the retrospective nature of study designs for rare developmental outcomes, like Autism. 

Objectives:  This talk will describe the principals of causal inference in molecular environmental epidemiology, opportunities for exposure assessment that take advantage of new developments in environmental biomarkers, and will consider other conventional approaches to exposure assessment that may be implemented in case-control and prospective study designs.

Conclusions:  Attention to causal inference methods will strengthen the impact of the literature linking environmental exposures to developmental outcomes. Replication and consistency, temporality, and dose-response will be discussed in connection with standard criteria for evaluating biomarker validity, using a series of conventional and novel biomarkers of environmental toxicants as case studies. Examples of persistent and non-persistent contaminants measured in conventionally collected matrices, such as urine and blood, will be examined. In addition, biomarkers that make use of novel matrices, including blood spots, hair, and exfoliated deciduous teeth, will be discussed. Exposure assessment methods that strengthen the evidence linking environmental exposure to health outcomes will contribute to a better understanding of the relevant etiological pathways.