Exposure-response function
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<section begin=glossary />
- (exposure-response function, ERF): Relationship between the exposure of a given organism, system, or (sub)population to an agent in a specific pattern during a given time and the magnitude of a continuously graded effect to that organism, system, or (sub)population.
- This term has several related terms that may have slightly different meaning. Effect and response are interchangeable words. Also the word function is used instead of relationship.
- Concentration-effect relationship
- Relationship between the exposure, expressed in concentration, of a given organism, system, or (sub)population to an agent in a specific pattern during a given time and the magnitude of a continuously graded effect to that organism, system, or (sub)population. The concentration is measured at a defined site. [1]
- Dose-response relationship
- Relationship between the amount of an agent administered to, taken up by, or absorbed by an organism, system, or (sub)population and the change developed in that organism, system,or (sub)population in reaction to the agent. [1]<section end=glossary />
Scope
What is such a representation for ERF that it fulfills the following criteria?
- It is widely applicable to all kinds of agents, exposures, and responses.
- A single ERF is widely applicable, within its domain, to different situations and populations.
- It is mathematically clear so that impact calculations can be operationalised based on it.
Definition
By nature, a response to an agent occurs at individual level (with some exceptions such as agents affecting herd immunity). Thus, the individual response should be the basic unit for ERF. If individual variation is of no interest, a population ERF can simply be expressed as the average of individual ERFs.
Result
An ERF is a mathematical construct describing the relationship between a response and an exposure. In the general form, it is described as a probability
ERF = P(response|exposure, individual, time of observation)
Technical issues
- In Opasnet, the use of term Exposure-response function (ERF) is recommended. The pages about ERFs should be named: "ERF of <agent> on <endpoint> in <population>."
- ERFs are typically variables, and they should be categorised to Category:Exposure-response functions
- In the definition of a variable, an ERF is used as data, not as a variable under the causality attribute. This is because the causality goes from the exposure to the response, and the true physiological and biochemical variables affecting the response are typically unknown or undescribed. The ERF is merely a mathematical representation of the relationship between the exposure and the response. But it describes a real-world phenomenon and thus is a variable.
See also
- A set of exposure-response functions from NEEDS project.