Attributable risk is defined as –
**Attributable Risk**
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### Core Concept
Attributable risk, also known as the risk difference, measures the difference in the incidence of a disease or outcome between an exposed and an unexposed group. This concept is crucial in epidemiology for assessing the impact of a risk factor on the population.
### Why the Correct Answer is Right
Attributable risk is calculated by subtracting the incidence of the disease in the unexposed group from the incidence in the exposed group. This value represents the proportion of cases in the exposed group that can be attributed to the exposure. For example, if the incidence of a disease is 10% in smokers and 5% in non-smokers, the attributable risk is 5%. This indicates that 5% of the disease cases in smokers can be attributed to smoking.
### Why Each Wrong Option is Incorrect
**Option A:** Attributable risk is not the same as the relative risk, which measures the ratio of the incidence of a disease in an exposed group to an unexposed group.
**Option B:** Attributable risk is not a measure of the odds ratio, which is used in case-control studies to estimate the strength of association between a risk factor and a disease.
**Option C:** Attributable risk is not a measure of the population attributable risk, which estimates the proportion of disease cases in the entire population that can be attributed to a specific risk factor.
### Clinical Pearl / High-Yield Fact
Attributable risk is a useful tool in public health for evaluating the effectiveness of interventions aimed at reducing disease incidence. By understanding the attributable risk, policymakers can make informed decisions about resource allocation and prioritize interventions that have the greatest impact.
### Correct Answer: A. Attributable risk measures the difference in the incidence of a disease or outcome between an exposed and an unexposed group.