Risk Assessment and Risk Communication
All health care professionals confront questions involving risk on a daily basis. In the area of toxicology, these questions may take many forms. An anxious parent with questions about a child’s potentially toxic exposure, an urgent consultation for a critically ill patient in the emergency department or intensive care unit, a request to interpret a laboratory test, media requests for information about environmental public health issues, a response to a hazard-materials situation, and biopreparedness education all involve directed communication of information and recommendations. Toxicologists and Certified Specialists in Poison Information (CSPIs) must establish rapport and provide information, instructions, and when appropriate, reassurance, typically by telephone or in short face-to-face interactions. For CSPIs, attribution of the patient’s complaints to one or more potential exposures and ascertaining the true reason or concern behind a call are also difficult given the limited information and time and lack of visual clues that are usually available during a clinical evaluation. All of these situations require a knowledgeable, compassionate, and well-reasoned response.
This chapter focuses on two particular components of this response: risk assessment and risk communication. These principles apply equally to individual calls to poison control centers, interactions with the public and medical professionals in educational outreaches, occupational and environmental exposure evaluations, and supportive roles with other public health agencies in bioterrorism preparedness, environmental public health tracking programs, and research.
In the context of this text, risk assessment is the process of determining the likelihood of toxicity for an individual or group after a perceived exposure to some substance, generally referred to as a xenobiotic. It involves determining the nature and extent of the exposure (ie, xenobiotic, dose, duration, route) and its specific clinical effects, defining an exposure pathway, and assessing the likelihood of effects from a given situation. A published body of knowledge can be applied to some components of risk characterization or assessment. An overview and a number of tools can be accessed through the Web sites of the US Environmental Protection Agency (EPA) and the Agency for Toxic Substance and Disease Registry (ATSDR) of the Centers for Disease Control and Prevention (CDC).1,9 However, any given risk assessment is often based on incomplete information. This may include such features as uncertainty regarding the exposure xenobiotic or mixture, whether there has been an actual exposure or just proximity to the xenobiotic (completion of an exposure pathway), lack of the exact dose, or unpredictable features such as host factors (underlying medical conditions or genetic polymorphisms) that could modify the response to a potential exposure. Unfortunately, those conducting a risk assessment are affected by their own biases and assumptions in the interpretation of their results, as are the people to whom a risk assessment is communicated. The emotional response to being “poisoned” makes evaluation and attribution even more difficult.