Dose-Reponse
The dose-response relationship is an essential concept in toxicology. It correlates exposures with changes in body functions or health.
What is Dose Response?
In general, the higher the dose, the more severe the response. The dose-response relationship is based on observed data from experimental animal, human clinical, or cell studies.
Knowledge of the dose-response relationship establishes:
- causality: that the chemical has induced the observed effects
- the threshold effect: the lowest dose where an induced effect occurs
- the slope of the dose response: the rate at which injury builds up
The variables which must be considered in making a full determination of the consequences of dose include:
- Dose Amount: measure of the magnitude of the dose
- Dose Frequency: how often exposure occurs, e.g., daily, weekly, five days out of seven, etc.
- Dose Duration: how long a total period dose exposure occurs, e.g., a week, a month, a year, a lifetime.
- Subject Variability (Natural): individual characteristics such as age, sex, body weight, ethnic background, and genetics
- Subject Variability (Health Status): whether any pre-existing health conditions, such as asthma, diabetes, or hypertension, may affect susceptibility to an agent
- Route of Exposure: how the person is exposed. (three most common routes of exposure are ingestion, inhalation and skin contact)
- Lethal Doses/Concentrations
- Lethal Dose 0% (LD0): represents the dose at which no individuals are expected to die. This is just below the threshold for lethality
- Lethal Dose 10% (LD10): refers to the dose at which 10% of the individuals will die
- Lethal Concentration 50% (LC50): used for inhalation toxicity, air concentrations are used for exposure values. The LC50 refers to the calculated concentration of a gas lethal to 50% of a group. Occasionally LC0 and LC10 are also used.
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4-7. What is the dose-response relationship?
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