Hammitt noted that his list of exposure pathways was “not very well researched” and that his intention was for the list to be “provocative.” Another public health effect to consider that he said does not really fit into any one of these five pathways is antibiotic resistance. He suggested that one way to analyze antibiotic resistance is by examining the distribution of resistant microbial strains and the ways that people can come into contact with those strains (i.e., the chance of infection from all possible pathways).

Calculate Exposure-Response Function

After identifying exposure, the next step is to calculate what is known as the exposure-response function, that is, the probability of an adverse health effect given exposure to a certain quantity of stressor.

Attach Value

The third and final step is valuation. Because multiple health effects can arise, with the same food sometimes having both “good” and “bad” effects (e.g., eating fish can be cardio-protective because of its omega-3 fatty acid content, while at the same time serving as a major exposure pathway to methyl mercury, which has negative health effects), valuation involves aggregating those effects not just for individuals, but also across a population (the “social aggregation problem”). Economists attach value in one of two ways: via either monetary value (i.e., willingness to pay [WTP]); or health utility (i.e., quality-adjusted life years [QALYs], value per statistical life, or a related concept).

Analyzing Health Effects

Hammitt offered some thoughts on how one might use risk assessment to analyze health outcomes associated with four major sources of exposure: (1) diet; (2) nutrients, contaminants, and pesticides; (3) energy; and (4) waste streams.

Diet clearly affects the risk of many diseases and health effects, from cardiovascular disease to obesity, not just for the person actually consuming any given diet, but also for his or her offspring. The major source of information for analyzing those effects is epidemiological data. Hammitt commented on how diet itself is affected by many factors, including prices and convenience (i.e., as determined by availability, distribution, and preparation), consumer information about the consequences of eating different types of foods, and traditions and customs. To examine how these many factors impact diet, Hammitt speculated that the major data sources would



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