In a defined population, approximately 67% of all stroke cases are attributable to uncontrolled hypertension. If hypertension were adequately managed, 2/3rd of stroke burden could be eliminated. This is an example of:

1. A

   Relative risk

2. B

   Attributable risk

3. C

   Population attributable risk

4. D

   Odds Ratio

Appeared in: AIIMS Delhi NO - 2017

Explanation

• Population Attributable Risk (PAR) is the proportion of disease incidence in a population that is due to a specific exposure.
• The question explicitly states that 67% of all stroke cases in the defined population are attributable to hypertension.
• This figure represents the amount by which the disease could be reduced in that population if the risk factor were eliminated, which is the definition of PAR.

Why Other Options Were Wrong

• Option A: Relative Risk (RR) compares the incidence of disease in an exposed group to an unexposed group. The question provides a proportion of disease in the total population, not a comparison of incidence rates between two groups.
• Option B: Attributable Risk (AR) calculates the excess risk in the exposed group only. The question is concerned with the risk attributable to hypertension in the entire population.
• Option D: The Odds Ratio (OR) is a measure of association, typically calculated in case-control studies. It estimates the odds of exposure in cases versus controls, which is different from the population-level impact described.

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Epidemiological measures of risk and impact as background academic context rather than a clinical decision trigger.
• Understanding Population Attributable Risk is crucial for public health nurses and policymakers to prioritize interventions. A high PAR, like for hypertension and stroke, indicates that a large number of cases can be prevented through population-wide strategies.
• This concept justifies large-scale public health campaigns for blood pressure screening, promoting healthy diets, exercise, and ensuring access to antihypertensive medications.
• What if? If a risk factor had a very high Relative Risk (e.g., RR=20) but was very rare in the population, its Population Attributable Risk would be low. In that case, public health efforts might focus on targeted screening for the rare exposure rather than a broad population-wide campaign.

How to Approach the Question

• First, identify the core information provided: a percentage (67%) of a disease (stroke) in a 'defined population' is linked to a specific risk factor (hypertension).
• Next, analyze the keywords 'in a defined population' and 'attributable to'. This points towards a measure that considers the entire population, not just an exposed subgroup.
• Evaluate the options based on their definitions. Relative Risk and Attributable Risk focus on comparing exposed vs. unexposed groups.
• Recognize that 'Population Attributable Risk' is the only measure that directly quantifies the proportion of disease in the total population that is due to a specific exposure.
• Confirm this by noting the statement that eliminating the risk would eliminate that proportion of the disease burden, which is the practical meaning of PAR.

Concept Tested & Keywords

• Concept Tested: Epidemiological measures of risk and impact
• Stem keywords: defined population, stroke cases, uncontrolled hypertension, attributable, burden eliminated
• Lead-in keywords: This is an example of

Question ID

QuqGuW_TEgeA7N6YNo-a6A

Copy ID

Reference Book

E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart A (pp 26-201 of 604) pp. 71-73, 72-74