How waterpipe (shisha) smoking is counted

What is a waterpipe?

A waterpipe generally has a head, a body, a water bowl and a hose. The tobacco sits in the head with lit charcoal on top, and the smoke bubbles through the water before it reaches the smoker through the hose. The World Health Organization (WHO) advisory note lists other names for it, including narghile, shisha, goza and hookah.

How does the calculator count it?

• One 20-minute session counts as 25 cigarettes.
• Sessions are entered per week. The help line says: “Count each 20 minutes as one session, so an hour is 3 sessions.”
• Because the amount is weekly, the calculator divides it by 7 to give cigarettes a day, then multiplies by years and divides by 20.

Where does 25 cigarettes come from?

The References page cites the WHO Study Group on Tobacco Product Regulation (TobReg), “Advisory Note: Waterpipe tobacco smoking: Health effects, research needs and recommended actions by regulators” (2005). The WHO note says a waterpipe session typically lasts 20 to 80 minutes, and that in one session a smoker may inhale as much smoke as a cigarette smoker would from 100 or more cigarettes. Taking an 80-minute session as 100 cigarettes, the calculator counts each 20 minutes as 25 cigarettes.

How do I enter waterpipe smoking?

1. In the calculator, on “What have you smoked?”, tick Waterpipe (shisha), and anything else you smoked regularly.
2. The step asks: “How many 20-minute waterpipe sessions a week, and for how many years?”
3. Work out the time spent smoking a waterpipe in a typical week, and count each 20 minutes as one session. If you shared the waterpipe with other people, count the whole session, not just your share.
4. Enter the sessions a week and the number of years. Use a decimal point for part years, for example 2.5.
5. If the amount changed, choose Add another period and enter each amount with its own years.

For a history with several periods or gaps, see entering a smoking history that changed.

What does an hour a week for 10 years come to?

• An hour is 3 sessions: 3 × 25 = 75 cigarettes a week.
• 75 ÷ 7 = 10.71 cigarettes a day, to two decimal places.
• Over 10 years: 75 × 10 ÷ 7 = 107.14.
• 107.14 ÷ 20 = 5.36, so the calculator shows 5 pack years.

What happens after the result?

The result screen shows the total and a breakdown by type of tobacco. You can download or email a PDF, print the result, or save a link to it. Clinicians can also copy a line for the patient record.

What are the limits?

The calculator counts time spent smoking, in 20-minute sessions; it does not ask how much tobacco was used. The References page says: “This is not an exact science and approximations have been made.”

Pack years are a record of past smoking, not a diagnosis. If you are worried about your health, speak to your GP practice or use NHS 111. See how the calculation works for every conversion figure.