The prevalence of tobacco smoking has decreased steadily since the beginning of the twenty-first century (WHO, 2018). However, the electronic cigarette (e-cigarette), developed in China in 2003 has seen a significant increase in use and are the most common type of alternative nicotine delivery system used in several countries. In some countries where this has been an increase in the use of e-cigarettes it has been associated with a reduction in cigarette smoking. As e-cigarettes do not contain tobacco and combustion, they are less harmful than conventional cigarettes and may be an aide to tobacco smoking cessation.
The aim of this review was to assess the epidemiological profile of e-cigarette users worldwide.
Methods
A protocol was registered on the Open Science Framework and searches conducted in the Embase, Medline/PubMed and Scopus databases. Studies reporting epidemiological profiles of electronic cigarette (e-cigarette) users published in English were considered. Two reviewers independently selected studies with data being extracted by a single reviewer and cross-checked by a second reviewer. Risk of bias was assessed using Joanna Briggs Institute appraisal tools. Participants who used e-cigarettes sometime in their lives, and currently no longer use them, or use them occasionally, but have not in the past 30 days, were considered ‘ever users’. Participants who reported using e-cigarettes in the past 30 days or every day were considered ‘current users’.
Results
- 43 studies published between 2012 and 2021 were included.
- 28 countries were represented 13 studies were from the USA, 4 from New Zealand, 3 from Korea,2 each from Canada, Finland, Italy Malaysia, Mexico and Poland with single studies from Brazil, China, Croatia, France, Greece, Japan, Jordan, Nigeria, Russia, Trinidad and Tobago and Wales. One study reported data from several European countries (Bulgaria, England, France, Germany, Greece, Italy, Ireland, Latvia, Poland, Portugal, Romania and Spain).
- 26 studies were considered to be at low risk of bias, 15 at moderate risk and 2 at high risk.
- Of the 1,238,392 survey participants 10.72% (132,782) were e-cigarette users of these 68,625 (48.31%) were ‘current users’ and 68,625 (51.68%) ‘ever users’.
- The highest proportion of e-cigarette users was in the 18- to 24 age group.
- The table below summaries the prevalence rates reported in the studies. Prevalence ranges represent the highest and lowest prevalence rates for each country when more than one study was included.
| Country | No. of studies | Prevalence |
| Brazil | 1 | 0.43% |
| Bulgaria | 1 | 1.5% |
| Canada | 2 | 21.71% |
| China | 1 | 8.1% |
| Croatia | 1 | 52.88% |
| England | 1 | 7.2% |
| Finland | 2 | 14.04% to 17.4% |
| France | 1 | 4.3% to 31% |
| Germany | 1 | 1.1% |
| Greece | 2 | 4.2% to 27.2% |
| Ireland | 1 | 2.7% |
| Italy | 2 | 1.1% to 6.8% |
| Japan | 1 | 7.16% |
| Jordan | 1 | 33.1% |
| Korea | 3 | 4.796% to 23.06% |
| Latvia | 1 | 1.0% |
| Malaysia | 2 | 8.14% to 12.196% |
| Mexico | 2 | 6.86 % to 10% |
| New Zealand | 4 | 13.9% to 49.63% |
| Nigeria | 1 | 4.8% |
| Poland | 2 | 0.83% to 45% |
| Portugal | 1 | 0.6% |
| Romania | 1 | 1.396% |
| Russia | 1 | 30.86% |
| Spain | 1 | 0.6% |
| Trinidad and Tobago | 1 | 24.5% |
| USA | 13 | 1.8% to 34.8% |
| Wales | 1 | 21.2% |
Conclusions
The authors concluded: –
e-cigarette users tended to be male young adults with a higher level of education. The highest prevalence of use was found in Croatia. This systematic review provides valuable information to improve the development of appropriate intervention strategies targeting e-cigarette users for more accurate anti-smoking actions.
Comments
The authors preregistered their protocol on the Open Science Framework and undertook searches in 3 major databases. However, restricting their inclusion criteria to English language studies may have excluded some relevant studies. A simple summary of prevalence is reported by the authors. The included studies are very heterogenous in the sample size and methodology and may not be truly representative of the country prevalence. E-cigarettes are commonly used as an aid to quit smoking and a recent Cochrane review ( Hartmann-Boyce J et al. 2022) concluded:-
There is high-certainty evidence that e-cigarettes (ECs) with nicotine increase quit rates compared to nicotine replacement therapy and moderate-certainty evidence that they increase quit rates compared to ECs without nicotine.
While e-cigarettes are considered to be less harmful than conventional cigarettes, their aerosol can contain nicotine, heavy metals, and cancer-causing agents. While some adverse symptoms related to the mouth have been reported the Cochrane review did not identify evidence of serious harm from nicotine e-cigarettes however they did note that the number of studies was limited, and the longest follow-up was two years.
Links
Primary Paper
Martins BNFL, Normando AGC, Rodrigues-Fernandes CI, Wagner VP, Kowalski LP, Marques SS, Marta GN, Júnior GC, Ruiz BII, Vargas PA, Lopes MA, Santos-Silva AR. Global frequency and epidemiological profile of electronic cigarette users: a systematic review. Oral Surg Oral Med Oral Pathol Oral Radiol. 2022 Nov;134(5):548-561. doi: 10.1016/j.oooo.2022.07.019. Epub 2022 Aug 9. PMID: 36182650.
Review protocol on the Open Science Framework
Other references
World Health Organization. WHO global report on trends in prevalence of tobacco smoking 2000-2025. World Health Organization;
Hartmann-Boyce J, Lindson N, Butler AR, McRobbie H, Bullen C, Begh R, Theodoulou A, Notley C, Rigotti NA, Turner T, Fanshawe TR, Hajek P. Electronic cigarettes for smoking cessation. Cochrane Database Syst Rev. 2022 Nov 17;11(11):CD010216. doi: 10.1002/14651858.CD010216.pub7. PMID: 36384212; PMCID: PMC9668543.
Picture Credits
By Centers for Disease Control and Prevention – Public Domain, Link
