Question

If X percent of stroke in a population is attributable to hypertension, and removing hypertension from the population would prevent this proportion of strokes, this scenario is an example of:

• A. Relative risk
• B. Attributable risk
• C. Population attributable risk
• D. Odds ratio

Hint:

Burden in the whole population removable by eliminating the exposure to think population-level attributable measure.

Answer 1

The Correct Option is C

Step 1: Identify the measure of association in question.
The question asks about the proportion (percent) of disease (stroke) in the whole population that is due to an exposure (hypertension) and could be removed if the exposure were eliminated. This is the definition of Population Attributable Risk (PAR) / Population Attributable Fraction.

Step 2: Define the terms.
• Relative risk (RR) = incidence in exposed / incidence in unexposed. It measures the strength of association, not a population burden.
• Attributable risk (AR) = incidence in exposed − incidence in unexposed. It is the excess risk in the exposed group only.
• Population attributable risk (PAR) = incidence in total population − incidence in unexposed. The Population Attributable Fraction is the proportion of disease in the whole population attributable to the exposure, i.e. the percent that would be prevented by removing the exposure.

Step 3: Map to the scenario.
\(X\%\) of all strokes in the population being preventable by removing hypertension is precisely the population attributable fraction, derived from PAR. Hence the answer is Population attributable risk.

Step 4: Why the others are wrong.
RR and odds ratio are ratios that quantify association strength, not a removable population burden. AR applies only to the exposed subgroup, not the entire population.

Key fact: PAR (and the population attributable fraction) is used by public-health planners to estimate the impact of removing a risk factor from the entire population.