Introduction
In order to prevent or mitigate adverse health effects, we must identify potentially harmful exposures, identify their sources, identify persons who are exposed, and then quantify their extent of exposure and assess their risk of adverse health effects. We can then use this information to reduce harmful exposures, thereby reducing risk and reducing adverse health effects.
The goal of human exposure assessment is to estimate and quantify human contact and entry into the body of potentially harmful agents. This includes:
- Identifying sources of hazardous agents
- Determining the concentrations of agents in environmental media (air, water, food and soil)
- Identifying pathways and routes of exposure
- Estimating intensity, duration and frequency of exposure
- Estimating the dose resulting from exposure
- Estimating the number of people exposed
- Identifying subsets of the population that are particularly vulnerable (more likely to be exposed) and those who are more susceptible (more likely to experience adverse health effects from exposures). Exposures and their health effects may be unequally distributed across populations and are often driven by social inequity.
Essential Questions:
- What types of exposures affect health outcomes?
- How can we measure exposure in individuals?
- How can we measure exposure at the population level?
Learning Objectives
After completing this section, you will be able to:
- Define exposure assessment and describe its function in epidemiologic research
- Distinguish among and give examples of acute, chronic, and time-varying exposures
- Discuss the concepts of latency and critical window, using examples to highlight the relevance of each concept in the context of a particular exposure
- Identify four approaches to collecting information on exposure, noting one strength and one imitation for each approach
- Define the term "biomarker" and distinguish between biomarkers of exposure and biomarkers of effect
- Identify the role of modeling in evaluating exposures
- Define the terms susceptibility and vulnerability
- Describe the role of occupational health epidemiology in providing insight into health effects from exposures to chemical and other toxic compounds
Levin et al, 2004. Physical health status of World Trade Center Rescue and Recovery Workers and Volunteers – New York City, July 2002-August 2004. Mortality and Morbidity Weekly Report, Centers for Disease Control and Prevention