Non-communicable diseases: pack-years of smoking: practice question

A PSM question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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PSM · Non-communicable diseases: pack-years of smoking

Sample item

A 55-year-old man has smoked 30 cigarettes a day for 20 years. How much has he smoked in pack-years, taking a pack as 20 cigarettes?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. 30 pack-years

Pack-years equal packs smoked per day multiplied by the number of years of smoking. Thirty cigarettes a day is 1.5 packs, and 1.5 packs multiplied by 20 years gives 30 pack-years. The measure helps to quantify exposure and estimate cancer and COPD risk.

Option by option

  • A. 15 pack-years

    This results from halving the daily cigarette count before multiplying by 1 year.

  • B. 30 pack-years (correct)

    Correct. 1.5 packs per day for 20 years equals 30 pack-years.

  • C. 20 pack-years

    This results from counting 30 cigarettes as 1 pack per day for 20 years.

  • D. 40 pack-years

    This results from counting 2 packs per day for 20 years.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More PSM questions

Questions about this PSM question

What is the answer to this PSM question?

The best answer is B, 30 pack-years. Pack-years equal packs smoked per day multiplied by the number of years of smoking.

Why is "15 pack-years" not the answer?

This results from halving the daily cigarette count before multiplying by 1 year.

Why is "20 pack-years" not the answer?

This results from counting 30 cigarettes as 1 pack per day for 20 years.

Why is "40 pack-years" not the answer?

This results from counting 2 packs per day for 20 years.

What concept does this question test?

It tests Non-communicable diseases: pack-years of smoking in PSM. Thirty cigarettes a day is 1.5 packs, and 1.5 packs multiplied by 20 years gives 30 pack-years. The measure helps to quantify exposure and estimate cancer and COPD risk.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Non-communicable diseases: pack-years of smoking?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.