Trends in Youth Smoking and E-Cigarette Use

The use of electronic nicotine delivery systems (ENDS, including e-cigarettes) among young smokers is not related to an increase or decrease in smoking.

Among young adults (YAs) aged 18 to 24 in the United States, the widespread use of ENDS has raised questions about how these products will affect future tobacco and nicotine users.

The National Academies of Sciences, Engineering, and Medicine (NASEM) recently published a literature review on the public health impacts of ENDS, concluding that the harm to adult smokers may be reduced, but if more non-smokers, especially young people, are induced to start smoking as a result, this approach could actually cause harm. The authors of the NASEM report found "moderate evidence" supporting the assertion that "the use of e-cigarettes increases the frequency and intensity of future smoking." Recently, a new study published in JAMA Network Open explored this issue: Is there a connection between the use of ENDS among young smokers and changes in smoking frequency or intensity?
 
This cohort study used three waves of data from the Population Assessment of Tobacco and Health (PATH) study (2013-2014, 2014-2015, and 2015-2016), an ongoing longitudinal cohort study of adults and youth. A total of 1,096 YAs (ages 18-24) were included in the analysis from August 2018 to October 2019.

Among the 1,096 YA sample, 609 (55.6%) were young women, 698 (63.7%) were white, and 276 (25.2%) were Hispanic. The average (SD) age was 21.4 (1.9) years, with 584 (53.3%) having completed at least a college education. Among them, 214 (19.5%) were marijuana users in the past 30 days, and 161 (14.75%) smoked daily in the past 30 days. In the first wave, the average smoking frequency and intensity increased with the increase in smoking frequency over the past 30 days until the end of the second wave. In the third wave, the average change in smoking frequency was close to zero across all groups (0.4 - 0.7 days). From the second to the third wave, the average change in smoking intensity varied more, from 5.0 cigarettes (at the end of the initial phase) to 22.6 cigarettes or more (at the end of the past 30 days of using 6 days).
 
Description of the sample size and exposure status of the youth analysis in waves 1-3 of the Tobacco Health Population Assessment study

Connection between ENDS use at the end of wave 2 and changes in smoking at wave 3:

In the PSM dataset, the number of smoking days in the past 30 days increased by 0.33 to 1.64 days, depending on the definition of ENDS use at the end of wave 2; these changes were unrelated to the final use in wave 2. Between waves 2 and 3, there was also an increase in smoking intensity in the past 30 days, especially among YAs who used ENDS for 6 days or more in the past 30 days; however, these estimates were not associated with smokers in wave 2. Those who used ENDS for 6 days or more in the past 30 days reported an increase of 44.4 cigarettes compared to those who had never used ENDS, but this increase was not statistically significant.
 
Unweighted associations between different levels of ENDS exposure at wave 2 and changes in smoking frequency and intensity at wave 3

In this study, the use of electronic nicotine delivery systems among young adult smokers was not related to an increase or decrease in smoking over the year from 2014 to 2015. However, with the rapid development of the e-cigarette market, the future use of e-cigarettes may take different directions.

References:

Pearson JL, Sharma E, Rui N, et al. Association of Electronic Nicotine Delivery System Use With Cigarette Smoking Progression or Reduction Among Young Adults. JAMA Netw Open. 2020;3(11):e2015893. doi:10.1001/jamanetworkopen.2020.15893