Calculate the prevalence of a disease when the incidence is 5 per 1000 population per year and the mean duration of the disease is 10 years.

1. A

   20 per 1000 population

2. B

   50000 per 1000 population

3. C

   50 per 1000 population

4. D

   100 per 1000 population

Appeared in: UPUMS Nsg officer-2023

Explanation

• The relationship between prevalence (P), incidence (I), and mean duration (D) of a disease is given by the formula P = I × D, assuming stable conditions.
• Incidence is the rate of new cases, given as 5 per 1000 population per year.
• The mean duration of the disease is 10 years.
• Multiplying the incidence by the duration (5 cases/1000 population/year × 10 years) yields a prevalence of 50 per 1000 population.

Why Other Options Were Wrong

• Option A: This value (20) would result from an incorrect calculation, possibly assuming a duration of 4 years (5 x 4 = 20) instead of 10.
• Option B: This value (50,000) is a significant miscalculation, likely from incorrectly multiplying the result by the population base (50 × 1000) instead of expressing it as a rate per 1000.
• Option D: This value (100) would result from an incorrect calculation, possibly assuming a duration of 20 years (5 x 20 = 100) or an incidence of 10 (10 x 10 = 100).

Related Visual

Clinical Relevance

• Nursing practice connection: Knowing Relationship between disease prevalence, incidence, and duration helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
• Understanding prevalence is crucial for public health nurses to assess the burden of a disease in a community and plan for necessary healthcare services, resources, and staffing.
• Incidence data helps in identifying disease outbreaks and evaluating the effectiveness of preventive measures like vaccination campaigns or health education.
• What if? If a new treatment shortens the disease duration to 2 years without changing the incidence, the new prevalence would be 5 x 2 = 10 per 1000 population, significantly reducing the disease burden on the healthcare system.

How to Approach the Question

• Identify the goal of the question, which is to 'calculate the prevalence'.
• Scan the question for the given data points: 'incidence' (5 per 1000 population per year) and 'mean duration' (10 years).
• Recall the fundamental formula that connects these three epidemiological measures: Prevalence = Incidence × Duration (P = I × D).
• Substitute the given values into the formula: P = 5 × 10.
• Calculate the result: 50. The unit remains 'per 1000 population'.
• Match the calculated result (50 per 1000 population) with the provided options.

Concept Tested & Keywords

• Concept Tested: Relationship between disease prevalence, incidence, and duration.
• Stem keywords: prevalence, incidence, mean duration, calculate
• Lead-in keywords: Calculate

Question ID

Qk1ye_JNNB_8rPhX0R0FfY

Copy ID

Reference Book

E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart A (pp 26-201 of 604) pp. 55-57, 53-55