Smoking is the cause of 85% of lung cancers that occurred within a group of smokers. This is an example of which of the following statistics?
**Core Concept**
Smoking is a significant risk factor for lung cancer, and the given statement highlights the association between smoking and lung cancer incidence. This scenario illustrates a concept in epidemiology where a specific exposure (smoking) is linked to a particular outcome (lung cancer).
**Why the Correct Answer is Right**
The statement "85% of lung cancers occurred within a group of smokers" describes an example of **Attributable Risk (AR)**. Attributable Risk is a measure that quantifies the proportion of cases (in this case, lung cancers) that can be attributed to a specific risk factor (smoking). It represents the fraction of disease incidence that is due to the exposure. In this scenario, 85% of lung cancers can be attributed to smoking.
**Why Each Wrong Option is Incorrect**
**Option A:**
This option does not relate to the scenario described in the question. Attributable Risk (AR) is the correct answer.
**Option B:**
Attributable Risk Percentage (ARP) is a related concept that represents the proportion of disease incidence that can be attributed to a specific risk factor, expressed as a percentage. However, in this question, the specific value of 85% is not required to calculate ARP.
**Option C:**
Relative Risk (RR) is a measure of the ratio of the probability of an event occurring in the exposed group versus the non-exposed group. It does not directly relate to the scenario described in the question.
**Option D:**
Odds Ratio (OR) is a measure of association between an exposure and an outcome, often used in case-control studies. It is not directly relevant to the scenario described in the question.
**Clinical Pearl / High-Yield Fact**
When interpreting epidemiological data, it's essential to understand the different measures of association, such as Attributable Risk, Attributable Risk Percentage, Relative Risk, and Odds Ratio. Each has its specific application and interpretation.
**Correct Answer:** A. Attributable Risk (AR)