United States: Study of nicotine use among adolescents from 1999 to 2020

A cross-sectional study used data from the National Youth Tobacco Survey to report on the evolution of nicotine product consumption among middle and high school students in the United States since 1999[1] as well as the risks associated with these consumptions. The study reveals that exposure to and consumption of nicotine products was decreasing until the arrival and development of electronic cigarettes.

This study includes 16 years of cross-sectional survey data. Each survey was conducted on a sample of 15,000 to 36,000 students in grades 6 to 12. To estimate nicotine exposure, the study assessed use of various tobacco and nicotine products (cigarettes, cigars, chewing tobacco/snuff, e-cigarettes, bidis, hookah, and kreteks) in the 30 days preceding the survey, measuring frequency of use in number of days for each product.

The frequency of cigarette, cigar, and chewing tobacco use was included in all surveys, the frequency of bidis and kreteks use was taken into account in studies from 1999 to 2011, the frequency of e-cigarette use was added from 2014 and the frequency of hookah use since 2016.

Decline in smoking prevalence, rise in vaping

Over the past two decades, tobacco use among American adolescents has steadily declined. In 2020, 1.6% of middle school students and 4.6% of high school students reported smoking cigarettes in the past 30 days, compared to 12.8% of middle school students and 34.8% of high school students, respectively, in 1999.

On the other hand, e-cigarette use has increased significantly in recent years. Since 2014, e-cigarettes have become the most widely used nicotine product among middle and high school students. From 2017 to 2019, use of these products increased from 11.7 to 27.5 per cent among high school students and from 3.3 to 10.5 per cent among middle school students. In 2020, however, use decreased substantially, reaching 19.6 per cent among high school students and 4.7 per cent among middle school students. The study authors believe the precise reasons for the decrease in use in 2020 are unknown, but may be attributed to the cases of vaping-associated pneumonia (VAIP) that occurred in the United States in 2019.

A resurgence of overall nicotine exposure with the development of electronic cigarettes

For high school and middle school students, the average number of days of exposure to and use of nicotine products declined steadily until 2013, before the popularity of e-cigarettes.

On average, across all high school students surveyed, the average number of days of nicotine exposure and consumption was 5.6 days per month in 1999, and it decreased to 2.2 days per month in 2017, before rising again to 3.6 days per month in 2020. For middle school students, the average number of days of exposure and consumption of nicotine products fluctuated from 1.3 days per month in 1999, to 0.4 days per month in 2017, and 0.7 days per month in 2020.

If we consider young people who reported using tobacco and nicotine products, the number of days of exposure and consumption decreased fairly steadily, from 16.8 days per month in 2000 to 12.1 days/month in 2015, then increased again to 15.3 days/month in 2020. Among middle school students who used tobacco, the number of days of exposure/consumption was generally stable at around 11.5 days per month from 2000 to 2009, then decreased to 8 days per month in 2015 and increased to 11 days per month in 2020.

Uncertainties about the risks associated with electronic cigarettes

This study suggests that the increased health risks associated with nicotine product use among US adolescents depend on the assessment of risks associated with vaping.

To account for the differential long-term health risks of the products, the study treated all combustible tobacco products (cigarettes, cigars, hookahs, bidis, and kreteks) as having a risk weight of 1. Because there is no agreed-upon risk weight for e-cigarette use, the authors varied the risk weight from 0.1 to 1 to demonstrate the full range of possibilities.

With an e-cigarette risk weighting adjusted to 0.1, the average number of days of exposure/consumption among high school students has continued to decrease since 2013, from 2.5 days per month to 2 days per month in 2019 and 1.4 days per month in 2020. With a risk weighting of 1, identical to that of combustible products, the average number of days of exposure/consumption has increased steadily since 2013 to reach 5.3 days per month in 2019 and 3.9 days per month in 2020. Similar trends were observed among middle school students.

The authors note that while e-cigarette use is likely far less harmful to health than smoking, teen vaping raises serious concerns. Most e-cigarettes contain nicotine, exposing young people to the main chemical responsible for smoking addiction. Nicotine can be particularly harmful to adolescents and their developing brains. Studies have reported that e-cigarette use by youth who have never smoked increases the likelihood that they will try smoking within 6–18 months of initiating e-cigarettes.

Keywords: Nicotine, United States, adolescents, e-cigarettes, vaping

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