We estimate that there are approximately 68 million nicotine vaping product users worldwide.

This estimate should be treated with caution, as there is great uncertainty about some of the individual country estimates, and for 152 countries and territories data were missing. There is also variation in survey definitions of vaping. It is obvious from the data collected and assessed in our database that the available information is often of poor quality – survey samples are not numerous enough to provide sufficient precision to measure such small parts of the population. The sampling method of many studies is not probabilistic, which makes it impossible to generalise the measured values correctly per population. It is well known that monitoring risk behaviours in hidden populations is not straightforward.