Question
100 individuals are diagnosed with lung cancer in a population of 100000. Out of 100 patients, 80 were smokers and 20000 were smokers in total population. What is PAR‑
Show Answer
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Correct Answer » B
Explanation
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Formula for Population Attributable Risk Percentage (PAR%)
PAR% = (Ip − Iu) / Ip × 100
Where:
- Ip = Incidence in total population
- Iu = Incidence in unexposed population
Step 1: Calculate Incidence in Total Population (Ip)
Ip = Total cases / Total population
Ip = 100 / 100000
Ip = 0.001
Step 2: Calculate Incidence in Unexposed Population (Non-smokers)
Total smokers = 20,000
Total non-smokers = 100000 − 20000
= 80,000
Cases among smokers = 80
Cases among non-smokers = 100 − 80
= 20
Iu = Cases among non-smokers / Total non-smokers
Iu = 20 / 80000
Iu = 0.00025
Step 3: Apply PAR% Formula
PAR% = (0.001 − 0.00025) / 0.001 × 100
PAR% = (0.00075 / 0.001) × 100
PAR% = 0.75 × 100
PAR% = 75%
