Frequency of Youth E-Cigarette, Tobacco, and Poly-Use in the United States, 2015: Update to Villanti et al., “Frequency of Youth E-Cigarette and Tobacco Use Patterns in the United States: Measurement Precision Is Critical to Inform Public Health”

Our recently published study in Nicotine and Tobacco Research¹ using data from the 2014 National Youth Tobacco Survey (NYTS) showed that the majority of US middle and high school students had not used tobacco or e-cigarettes in the past 30 days. Among youth who reported any past 30-day tobacco or e-cigarette use, poly-use was the dominant pattern of use. Tobacco-naïve youth rarely reported using e-cigarettes, and most e-cigarette users were ever users of other tobacco products.¹ With the release of the 2015 NYTS data, we sought to update estimates of past 30-day frequency of cigarette, cigar, smokeless, and e-cigarette use in context of past 30-day and ever tobacco product use in US middle and high school students (N = 17 711).

Overall, e-cigarette and tobacco use patterns remained largely consistent between 2014 and 2015. The majority of youth (eg, 81.1% in 2015 vs. 83.0% in 2014) continued to report no tobacco or e-cigarette use in the past 30 days. The proportion of youth in 2015 who reported any past 30-day e-cigarette use was 11.3%. Similar to 2014, most of the youth who reported any past 30-day e-cigarette use in 2015 had also used a tobacco product in the past month (65.2%) or had ever used tobacco products (86.1%). The 2015 survey reported that among the 4.0% of past 30-day exclusive e-cigarette users, 61% (2.4% of youth) had ever used a tobacco product and 39% (1.6% of youth) were tobacco naïve. It remained rare in 2015 for tobacco naïve youth to have reported using e-cigarettes on 10 or more days in the past month (less than 0.1%). As stated in our 2014 report,¹ any inferences about causality (ie, role of e-cigarettes in the pathway out of or into tobacco use) cannot be inferred and must be interpreted cautiously in light of the shared liability model of uptake of products that “travel together.”^2,3

Frequency of past 30-day cigarette, cigar, and smokeless tobacco use among youth also remained largely consistent from 2014 to 2015. Across all products, the largest frequency category remained “1–2 days”; this accounted for 35.5% of any past 30-day cigarette users, 53.6% of any past 30-day cigar users, 36.8% of any past 30-day smokeless tobacco users, and 45.1% of any past 30-day e-cigarette users. We continued to see a bi-modal distribution among any past 30-day cigarette and smokeless use, with the next largest frequency category remaining daily use (1.2% cigarette; 1.1% smokeless). Among daily users of tobacco products, cigarette use remained the most prevalent in 2015. Prevalence decreased with increasing frequency of use among past 30-day e-cigarette and cigar use, with the smallest frequency category being “20–29 days” (0.6% e-cigarette; 0.2% cigar). Poly-use ranged from 64.6% of past 30-day e-cigarette users to 83.9% of past 30-day cigarette users.

Consistent with the 2016 MMWR⁴ showing few changes in prevalence of product-specific use between 2014 and 2015, our findings highlight that the underlying patterns of youth tobacco and e-cigarette use were relatively similar during this timeframe. Although the majority of research on youth e-cigarette use does not assess the temporal regularity of use,^5,6 several surveys in the United Kingdom have examined frequency of e-cigarette use beyond past 30-day use.⁵ Consistent with our analyses, findings from these surveys found that although ever e-cigarette use ranged from 8% to 12%, only a very small proportion reported use more than monthly (0.4%–2%) or weekly (0.7%–1%); more frequent use of e-cigarettes was isolated to youth who had used tobacco products.⁵ Our findings, in concert with international evidence on youth e-cigarette use, demonstrate how prevalence estimates for a single product mask the complex patterns of use in youth. Together, our 2014 and 2015 analyses reinforce the critical need for precision in measures and metrics for interpreting prevalence estimates. This 2015 update of our 2014 results further reinforces the utility of a common approach to complex data on youth emerging product use patterns. Given the rapidly evolving tobacco product and alternative nicotine delivery device marketplace, a complete picture of the potential public health impact of products that differ along the continuum of toxicity, dependence liability, and appeal must continue to incorporate the substantial differences in prevalence by frequency of use and by exclusive and poly-product use.^3,7 However, regardless of frequency of use or distribution of co-use, underage youth should not use any tobacco or nicotine containing products.

Funding

All authors were supported by Truth Initiative. ACV was also supported by the Centers of Biomedical Research Excellence P20GM103644 award from the National Institute on General Medical Sciences and the Tobacco Centers of Regulatory Science (TCORS) award P50DA036114 from the National Institute on Drug Abuse and Food and Drug Administration (FDA). JLP was also supported by the Office of the Director of the NIH, NIDA/NIH, and the FDA Center for Tobacco Products (K01DA037950). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH or the Food and Drug Administration. Lauren Collins had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. The funders had no role in the design and conduct of the study; analysis and interpretation of the data; or preparation, review, or approval of the manuscript.

Declaration of Interests

None declared.