Recalling a smoking history decade by decade

Why go decade by decade?

FAQ 8 says the pack year calculation “relies on the patient giving an accurate history which can be determined by asking patients to recall what they smoked in each decade of their life.” The questions below can be used to recall your own history or, for clinicians, to take a patient’s.

What do you note for each decade?

1. Start at the age smoking began. FAQ 2 says starting and stopping dates are important to show the time of exposure.
2. For each decade (teens, twenties, thirties and so on), list every type of tobacco smoked regularly: cigarettes, cigars, spliffs, cigarillos, bidis, a pipe, loose tobacco for roll-ups, or a waterpipe (shisha).
3. For each type, note the amount: the number a day for most types, pipe bowls a day, grams or ounces a week of loose tobacco, or 20-minute sessions a week of a waterpipe.
4. Note how many years in that decade were smoked at that amount. Part years can be entered as decimals, for example 2.5 years.
5. Note any years with no smoking at all, and the year smoking stopped, if it has.

How do the decades become periods?

In the calculator, a period is an amount and a number of years. Each type of tobacco has its own step, and each step can hold as many periods as needed: choose “Add another period” when the amount changed.

A period does not have to match a decade. The calculator multiplies each amount by its years and adds the results, so 20 a day across two decades can go in as one period or two, with the same total. The order of the periods makes no difference either.

Leave out the years with no smoking. If two types were smoked in the same years, enter both, each with its own periods. There is more on this in entering a smoking history that changed.

What does a worked example look like?

Here is one history, recalled decade by decade:

The 20-a-day years run on from the twenties into the thirties, so they go in as one period of 14 years. The 3 years with no smoking are left out.

The calculator shows 19 pack years, with 19.4 before rounding. On the history step, this person would say they have stopped, give the year, and enter 26 as the total years smoked (4 + 14 + 3 + 5). With two types entered, the calculator suggests 21 to 26 years and asks for overlapping years to be counted once; here none overlapped.

How often should the history be updated?

FAQ 8 says people who continue to smoke should have their pack years recalculated every five years. “Save or share a link” keeps the answers in the link itself, so the periods can be opened again later and a new one added.

If you are worried about your health, speak to your GP practice or use NHS 111.