First paragraph: Electronic cigarette (e-cigarette) use is now common in many countries, particularly in the developed world. Even in countries that don't permit the sale of nicotine containing e-cigarettes, use has risen in recent years. Along with this has come a rise in concern about uptake amongst young people, particularly in jurisdictions where youth tobacco smoking rates have fallen to low levels. The reasons for this concern are many and varied, but some of this relates to a perception that e-cigarettes may result in a new generation of adults who are dependent on nicotine. To date we have identified at least 24 published, peer reviewed journal articles on e-cigarette use in youth, with at least as many again published survey reports. The majority of these only describe recent or ever use of these products and don't differentiate experimentation from regular use. An exception is in studies from the countries of the United Kingdom, where four recent surveys conducted in a 12-month period from 2013 to 2014 shed some light on ever and regular use amongst smoking and nonsmoking young people. Figure 1 summarizes results from these four surveys, each of which has yielded very similar findings.