Young people who are non-smokers but have tried e-cigarettes are over four times more likely to try smoking in the future, a new study has found.
Researchers from the University of Bristol's Tobacco and Alcohol Research Group (TARG), with support from Bristol's MRC Integrative Epidemiology Unit and the National Institute for Health Research Bristol Biomedical Research Centre, combined the results of 17 studies to investigate whether e-cigarette use compared with non-use in young non-smokers is associated with subsequent cigarette smoking.
The study found that young people who had never smoked before but had used e-cigarettes were four and a half times more likely to go on to use cigarettes (OR, 4.59; 95% CI, 3.60-5.85) when the data were meta-analysed in a random effects model. However, heterogeneity was high (I2=88%).
The authors point out a number of limitations in the included studies, such as the use of self-reported measures of smoking history, the absence of negative controls and the omission of considerations of the nicotine content of e-cigarette liquids.
Lead author, Jasmine Khouja from TARG, said: “Policymakers have used the findings of studies, including the studies we reviewed in this research, to support the heavy regulation of e-cigarettes, including restrictions on flavours and even total bans, but the evidence that e-cigarette use might cause young people to take up smoking is not as strong as it might appear.”
The research is published in Tobacco Control.