A Roadmap for Efficient Systematic Reviews of Human Exposure Studies
A key step of a systematic review is the evaluation of individual studies. This evaluation informs how much weight each study will receive during the synthesis and summary of the evidence. Several tools and approaches exist for the evaluation of studies containing human exposure data. Despite the robustness of these frameworks, there is difficulty in applying them toward individual chemicals, because they are chemical-agnostic. A reviewer must have chemical-specific knowledge to effectively use these tools. In this presentation we introduce a roadmap for developing chemical-specific evaluation criteria that can supplement existing study evaluation tools.
To develop this roadmap, we identified multidisciplinary factors that are essential to evaluating the exposure domain. Principles of analytical chemistry, toxicokinetics, industrial hygiene, exposure sciences, and epidemiology informed the roadmap along with case examples from U.S. Environmental Protection Agency Integrated Risk Information System (IRIS) assessments and from the published literature.
We will first present the roadmap, which gives an overview of the multidisciplinary types of information that must be collected for a specific chemical(s) of interest. We then present case examples from systematic reviews conducted by EPA’s IRIS program for three chemicals: hexavalent chromium, methylmercury, and ethylbenzene. For each example, we show how chemical-specific information outlined in the roadmap was integrated with the general IRIS study evaluation approach. These examples illustrate how the roadmap can be used to enhance the utility IRIS’S or other existing study evaluation tools and approaches to support a more efficient and robust systematic review process.