"The sharp increase in the use of e-cigarettes has not led more British children to take up cigarettes or regard smoking as normal," The Guardian reports.
There's been some concern about the popularity of e-cigarettes among young people, and whether it could increase the number of teen smokers by making smoking seem more socially acceptable.
A new study provides survey data taken from more than 200,000 teenagers (aged 13 to 15 years) between 1998 and 2015. It looked at the impact of the recent surge in e-cigarette use.
The number of teens who'd ever tried smoking fell dramatically from 60% to 19% in that time, while regular smoking decreased from 19% to 5%.
Only a quarter (25%) now think it's acceptable to even try smoking, compared with nearly three-quarters in 1998.
This suggests that the popularity of vaping has not "normalised" smoking among teens.
But the study also leaves important unanswered questions, notably that the use of e-cigarettes or their perceived acceptability has not even been questioned.
What remains of concern is that there could have been a rise in the number of non-smoking teens who are now instead trying e-cigarettes for the first time.
While e-cigarettes are far less harmful than tobacco, the nicotine they contain is very addictive, so some young people may end up with an expensive habit that can be hard to break.
This study was conducted by researchers from the universities of Cardiff, Bristol, Glasgow, Edinburgh and Stirling, and funded by the National Institute for Health Research.
The UK media's reporting of the study was accurate, but may have benefited from mentioning that use of vaping or views on e-cigarettes were not assessed by this study.
This was a repeated cross-sectional study, where teens were questioned over time to see whether the rapid rise in the popularity and use of e-cigarettes has influenced smoking habits and views.
The surge in the use of e-cigarettes is said to have started in the UK in around 2011.
While many consider that vaping has had "small but important" effects on adult stop smoking rates, public health organisations are still said to be divided on whether there should be greater regulation of e-cigarette use.
Among adults, e-cigarettes are mostly used by smokers or ex-smokers. But there's concern that some young people are experimenting with e-cigarettes when they have never smoked previously, and may then go on to smoke cigarettes.
The study made use of several cross-sectional surveys carried out among secondary school students in England, Scotland and Wales:
These surveys were carried out annually or every few years, with variable time periods.
For example, the Welsh HSBC survey was carried out between 1998 and 2013, while the SHRN survey was conducted in 2015 only.
The researchers looked at responses to questions on whether people had ever smoked or smoked regularly.
The surveys differed slightly in the questions asked and response options given.
For example, the SDDU and SALSUS asked people to agree with different statements, such as:
The HSBC and SHRN asked at what age they "smoked a cigarette (more than just a puff)", with the response options ranging from "never" to a range of ages.
SALSUS and SDDU also questioned attitudes, asking: "Do you think it is OK for someone your age to try a cigarette to see what it is like?"
Similar questions were asked about alcohol and cannabis.
The researchers looked at changes over time from 1998, when smoking was thought to peak, and considered 2010 as the date when e-cigarettes were first introduced to the UK.
There were 248,324 survey respondents across the years in total.
Smoking rates among 13- to 15-year-olds declined from 1998 to 2015, with the percentage of "ever smokers" decreasing from a massive 60% in 1998 to 19%, while regular smoking decreased from 19% to 5%.
Perceptions of smoking also changed from 70% of teens thinking it was OK to try smoking in 1999, to 27% in 2015.
Despite the decrease, when accounting for age, gender and other potential confounders like socioeconomic status, the decline in the rate of "ever smoking" (odds ratio [OR] 1.01, 95% confidence interval [CI] 0.99 to 1.03) or "regular smoking" (OR 1.04, CI 1.00 to 1.08) fell short of statistical significance.
But there was a significant decrease in the acceptability of smoking (OR 0.88, 95% CI 0.86 to 0.90).
The researchers said their study is "the first to test whether proliferation of e-cigarettes during a period of limited regulation led to changes in smoking trajectories as well as smoking attitudes among young people.
"Our results provide little evidence that re-normalisation of smoking occurred during this period."
This is a useful study that makes use of regular secondary school surveys conducted across the UK over the past 20 years.
Despite the lack of significance for smoking rates, it gives encouragement that the popularity of smoking among teenagers has clearly declined and is viewed as less acceptable.
The use of e-cigarettes is known to have increased nationally among the general population in recent years.
So this study may provide support for the view that increased vaping has not "re-normalised" smoking among young people.
But we need to be cautious before attributing smoking patterns and attitudes within this study directly to vaping.
This study has not even assessed teens' views on vaping, or whether they have tried or regularly used e-cigarettes.
The dramatic decline in the popularity of smoking since the turn of the millennium could largely be the result of increased education and awareness of the harms of smoking, and that it's now less socially acceptable, particularly since the smoking ban in public places.
But what will be of concern to some is that while teens may be less likely to try smoking or think it acceptable, there may have been a massive increase in the perceived acceptability of vaping and the number of teens who have tried e-cigarettes if they'd been asked about it in the surveys.
As the researchers say, e-cigarettes are mostly used as way to quit smoking among adults.
But there's concern that some young people might take up vaping having never smoked previously.
Nicotine is an addictive substance, so teens could potentially make this a regular habit in the way teens of past decades may have started smoking.
The potential long-term harms of the chemicals in e-cigarettes are still largely unknown.
Although this study is positive on the one hand, it still leaves some unanswered questions and doubts about the effect of e-cigarettes among young people on the other.
E-cigarettes should ideally be viewed as a temporary stop smoking aid, like other stop smoking therapies.