The most comprehensive study to date investigating whether e-cigarettes are a gateway into or out of smoking finds that, at the population level, there is no sign that e-cigarettes and other alternative nicotine delivery products promote smoking.
The study, led by Queen Mary University of London and funded by the National Institute of Health and Care Research (NIHR), also found some evidence that these products compete against cigarettes and so may be speeding up the demise of smoking, but this finding is only tentative and more data are needed to determine the size of this effect.
The study compared the time course of use and sales of electronic cigarettes with that of smoking rates and cigarette sales in countries with historically similar smoking trajectories, but differing current e-cigarette regulations. It compared the United Kingdom and United States with Australia, where sales of nicotine containing e-cigarettes are banned. It also looked at interactions between smoking and nicotine alternatives that are popular in other countries, including the use of oral nicotine pouches in Sweden and products that heat rather than burn tobacco in Japan and South Korea where they are widely used.
The decline in smokers in Australia has been slower than in the UK, and slower than in both the UK and the USA among young people and in lower socioeconomic groups. The decline in cigarette sales has also accelerated faster in the UK than in Australia. The increase in heated tobacco product sales in Japan was accompanied by a significant decrease in cigarette sales.
Researchers note that because people may use both cigarettes and alternative products, prevalence figures for these products overlap, and so longer time periods are needed to determine any effects of exclusive use of the new products on smoking prevalence. They also say that the indications that alternative nicotine products are replacing smoking – especially the size of this effect – need to be confirmed when more data become available. As further prevalence and sales data emerge, the analyses will become more informative.
Professor Peter Hajek, Director of Health and Lifestyle Research Unit, Wolfson Institute of Population Health, Queen Mary University of London, said: "The results of this study alleviate the concern that access to e-cigarettes and other low-risk nicotine products promote smoking. There is no sign of that, and there are some signs that they in fact compete against cigarettes, but more data over a longer time period are needed to determine the size of this effect."
Co-author, Professor Lion Shahab, Co-Director of the UCL Tobacco and Alcohol Research Group, said: "This comprehensive analysis provides reassurance that countries which have adopted a more progressive stance towards e-cigarettes have not seen a detrimental impact on smoking rates. If anything, the results suggest that - more likely than not - e-cigarettes have displaced harmful cigarettes in those countries so far. However, as this is fast moving field, with new technologies entering the market every year, it remains important to continue monitoring national data."
Professor Brian Ferguson, Director of the Public Health Research Programme (NIHR) commented: "The initial findings from this study are valuable but no firm conclusions can be drawn yet. More research is needed in this area to understand further the impact that alternative nicotine delivery products, such as e-cigarettes, might have on smoking rates.”
This research, published in the journal Public Health Research, was funded by the National Institute for Health and Care Research.
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