One of the big innovations Juul pioneered was adding acid to the liquid in e-cigarettes to make the nicotine aerosol less alkaline and easier to inhale. This so-called protonated nicotine allows the e-cigarettes to deliver higher doses of the addictive drug nicotine. Therefore, we would expect to see increasing measures of addiction among e-cigarette using youth.
And since Juul pioneered protonated nicotine, it has been widely adopted by other e-cigarette companies
Abra Jeffers, Jonathan Winickoff and I just published “Nicotine addiction and intensity of e-cigarette use by adolescents in the US, 2014-2021” in JAMA Network Open that shows that is exactly what happened.
This increasing addiction is reflected in two measures: (1) how many days per month youth use e-cigarettes, and (2) how soon after waking e-cigarette users use their first tobacco product.
We examined these two measures in the National Youth Tobacco Survey (NYTS) that CDC and FDA collect among middle and high school students between 2014 and 2021.
As shown in the graph above, the number of days per month that kids used e-cigarettes steadily increased over time. From 2014 to 2018, youth only used e-cigarettes a median of 3-5 days/month and only 9% were using them every day. Indeed, the relatively infrequent use of e-cigarettes was often cited by e-cig advocates that e-cig use by kids wasn’t that much of a problem.
But, as Juul and Juul copycats penetrated the market, the number of days shifted up over time: By 2021 young e-cig users were using them a median of 10-19 days per month and 25% were using them every day.
In addition, e-cigarette nicotine addiction, measured as the odds of use within 5 minutes of waking, increased over time. By 2019 more youth e-cigarette users were using their first tobacco product within 5 minutes of waking than for cigarettes and all other products combined. The percent of sole e-cigarette users who used e-cigarettes within 5 minutes of waking was around 1% through 2017, but then it increased every year, reaching 10.3% youth using their first e-cigarette within 5 minutes of waking by 2021.
By 2019 more e-cigarette users were using their first tobacco product within 5 minutes of waking—an indicator of addiction—than for cigarettes and all other tobacco products combined.
In addition, the age at which youth first use e-cigarettes dropped each year. Age at first use of e-cigarettes fell by 1.9 months per year, while age at first use of cigarettes, cigars, and smokeless tobacco did not change significantly. By 2017, e-cigarettes became the most common first tobacco product used.
These patterns are continuing. In October 2022, FDA and CDC released 2022 NYTS data showing that 2.55 million adolescents use e-cigarettes and 27.6% of adolescents use e-cigarettes daily. The comparable numbers we found for 2021 were 2.1 million and 24.7%.
One would expect the FDA to see the higher addictiveness of protonated nicotine as a problem, but they actually see it as a good thing, arguing that it makes e-cigarettes more attractive to adult smokers. (FDA has still not told anyone how many kids they are willing to trade for an adult smoker who “switches.”)
FDA did not discuss any issues related to kids or the addictiveness of protonated nicotine when it decided not to authorize the sale of Juul. Juul appealed and FDA is allowing it to keep selling its e-cigs while they discuss how to proceed. FDA must consider the increasing addictive effects of modern e-cigarettes when making a final decision about Juul as well as other protonated nicotine e-cigarettes and other tobacco products.
There is another immediate implication of our findings. On election day, November 8, California voters will decide whether to support Proposition 31, which would ratify the Legislature’s decision to end the sale of flavored tobacco products, including flavored e-cigarettes. Our paper provides another good reason to vote “yes” on Prop 31.
Here is the abstract:
Importance: As e-cigarettes have become more effective at delivering the addictive drug nicotine, they have become the dominant form of tobacco use by US adolescents.
Objective: To measure intensity of youth use and dependence level of e-cigarettes, cigarettes and other tobacco products among US adolescents and their dependence level over time.
Design, Setting, and Participants: This survey study analyzed the cross-sectional National Youth Tobacco Surveys from 2014-2021. Confirmatory analysis was conducted using Youth Behavioral Risk Factor Surveillance System from 2015-2019. The surveys were administered to national probability samples of US students in grades 6 to 12.
Exposures: Use of e-cigarette and other tobacco product use before and after the introduction of e-cigarettes delivering high levels of nicotine.
Main Outcomes and Measures: First tobacco product used, age of initiation and intensity of use (days/month), and nicotine addiction (measured as time after waking to first use of any tobacco product use).
Results: A total of 151,573 respondents were included in the analysis (51.1% male and 48.9% female; mean [SEM] age, 14.57 [0.03] years). Prevalence of e-cigarette use peaked in 2019 and then declined. Between 2014 and 2021, the age of e-cigarette initiation of e-cigarette use decreased, and intensity of use and addiction increased. By 2017, e-cigarettes became the most common first product used (77.0%). Age at initiation of use did not change for cigarettes or other tobacco products, and changes in intensity of use were minimal. By 2019 more e-cigarette users were using their first tobacco product within 5 minutes of waking than for cigarettes and all other products combined. Median e-cigarette use also increased from 3 to 5 d/mo in 2014-2018 to 6 to 9 d/mo in 2019-2020 and 10 to 19 d/mo in 2021.
Conclusions and Relevance: The changes detected in this survey study may reflect the higher levels of nicotine delivery and addiction liability of modern e-cigarettes that use protonated nicotine to make nicotine easier to inhale. The increasing intensity of use of modern e-cigarettes highlights the clinical need to address youth addiction to these new high-nicotine products over the course of many clinical encounters. In addition, stronger regulation including comprehensive bans on the sale of flavored tobacco products, should be implemented.
The full citation is: Glantz S, Jeffers A, Winickoff J. Nicotine addiction and intensity of e-cigarette use by adolescents in the US, 2014-2021.” JAMA Network Open 2022; 5(11): e2240671. doi:10.1001/jamanetworkopen.2022.40671. It is available for free here.