Pack Year - Definition

Definition

A way to measure the amount a person has smoked over a long period of time. It is calculated by multiplying the number of packs of cigarettes smoked per day by the number of years the person has smoked. For example, 1 pack year is equal to smoking 20 cigarettes (1 pack) per day for 1 year, or 40 cigarettes per day for half a year, and so on.

One pack year is the equivalent of 365.24 packs of cigarettes or of 7,305 cigarettes.

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