High-nicotine vape use surged by 80% among US 18-24 year olds between 2017 and 2022, and was associated with large increases in daily vaping and nicotine dependence, finds a data analysis published online in the journal Tobacco Control.
The findings prompt the researchers to call on the Food and Drug Administration (FDA) to review marketing approvals for these products to reflect their addictive potential as a matter of urgency.
E-cigarette sales in the US were relatively steady at 6–7 million units/month between 2014 and late 2017. But advances in technology, coupled with the introduction of flavours, heralded the arrival of palatable high-nicotine (5%) e-cigarettes, note the researchers.
And between 2017 and 2021, e-cigarette sales tripled to over 20 million units/month in the US, boosted by the popularity of these products with young people, many of whom didn't smoke conventional cigarettes.
The researchers therefore wanted to find out whether vaping high-nicotine e-cigarettes might be associated with increased nicotine dependence, particularly among young adults.
They drew on the US Population Assessment of Tobacco and Health (PATH ) Study (45,971 12+year-olds in 2013), which re-interviewed a large nationally representative sample in 2017 (32,822 respondents), 2019 (34, 309 respondents), 2021 (30,516 respondents) and 2022 (30,801 respondents).
Those who vaped (3000–4000 at each time point) were asked about the frequency of use and nicotine strength of their usual e-cigarette. Dependence symptoms were assessed using a separate 16-point questionnaire.
In 2017, 4%+ nicotine strength was the highest option for respondents, with 1% reporting this. This increased to just over 15% in 2019, to just over 24% in 2021, and to nearly 25% in 2022.
Among those who vaped in 2022, the odds of vaping high-nicotine e-cigarettes were strongly associated with age: the odds for 18–24-year olds were 15 times higher than among those aged 55+, and more than 70% higher among those who vaped daily than among those who didn't.
The odds for males were 55% higher than for females, and the odds of high-nicorine vaping among those who also smoked cigarettes daily were much lower than for those who had never smoked.
Between 2017 and 2022, the proportion of US 18–24-year olds who vaped rose by 80%, from just over 10% to nearly 19%, while the proportion of those who vaped daily doubled from just over 26% to 55.5%.
In 2017, less than 4% of those who vaped, regardless of age or frequency of use, vaped high-nicotine e-cigarettes.
But among 18–24-year olds who vaped daily, the use of high-nicotine e-cigarettes rose rapidly from just over 3% in 2017, to just over 40% in 2019, and to just over 49% in 2022.
Among those who vaped daily in 2022, the proportion of those vaping high-nicotine e-cigarettes fell significantly with age: 33% among 25-34 year olds; 18% among 35-54 year olds; and 4.5% among those aged 55+. A similar pattern emerged for those who didn't vape daily.
In 2017, nicotine dependence among 18–24-year olds who vaped exclusively was much lower than among those who smoked exclusively. But this difference had disappeared by 2022.
Vaping high- rather than low-nicotine e-cigarettes in 2019 was associated with an increase in nicotine dependence within each age group by 2022 and significantly (31%) lower odds of vaping abstinence in 2022.
Among those who used the same e-cigarette brands, particularly Vuse and JUUL, 18–24-year olds chose a high-nicotine option more than twice as often as those aged 25+, suggesting a potential marketing effect, say the researchers.
This is an observational study, so cannot establish cause and effect. And further long term research, drawing on subsequent waves of the PATH study, will be needed to find out if the increased nicotine dependence in young adults identified in this study is associated with lifelong nicotine dependency and significant health consequences, say the researchers.
But they suggest: "These findings support the concerns expressed in the 2016 Surgeon General's report that the US may be at the start of another epidemic of long-term nicotine dependence with associated adverse health consequences."
And they conclude: "Although the health consequences of vaping are expected to be less than cigarette smoking, they will likely still be substantial. These results suggest that there is an urgent need to reassess whether high-nicotine e-cigarettes meet the public health standard required by US Congress for the US FDA to authorise their marketing."
