Benefits and Barriers to Using Epidemiology Data in Environmental Risk Assessment

Over the past three decades, a formal risk assessment process has been developed to provide consistent and transparent methods for the assessment of potential human health risks from exposure to environmental chemicals. Given a focus on risk to human health, epidemiological studies that identify associations between exposure to environmental chemicals and adverse health effects in humans have the potential to provide critically important information to this process. For many chemicals, however, available epidemiology studies have been found to have limited utility in informing human health risk assessments. In order to investigate this paradox, we have used several case examples to explore the utility of various types of epidemiological data in informing key elements of the risk assessment process (hazard identification, exposure-response assessment, and exposure assessment). Examples from the epidemiologic literature on environmental chemicals are used to illustrate the issues that arise in using available studies for various types of chemical risk assessments. The case examples illustrate several advantages in using epidemiology data, but also identify a number of barriers to its use, frequently related to limitations in exposure assessment. The examples also highlight ways in which the utility of both toxicology and epidemiology data can be enhanced by considering the data in combination, and integrating the results across study categories. Recent scientific developments offer hope for improving the utility of both types of data, and thus enhancing the reliability of future risk assessment efforts.