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E-cigarette and cigarette purchasing among young adults before and after implementation of California’s tobacco 21 policy
  1. Sara Schiff1,
  2. Fei Liu1,
  3. Tess Boley Cruz1,2,3,
  4. Jennifer B Unger1,2,3,
  5. Sam Cwalina1,
  6. Adam Leventhal1,2,3,
  7. Rob McConnell1,2,3,
  8. Jessica Barrington-Trimis1,2,3
  1. 1 Department of Preventive Medicine, University of Southern California, Los Angeles, California, USA
  2. 2 University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California, USA
  3. 3 Institute for Addiction Science, University of Southern California, Los Angeles, California, USA
  1. Correspondence to Dr Jessica Barrington-Trimis, Department of Preventive Medicine, University of Southern California, Los Angeles, CA 90089, USA; jtrimis{at}


Background Tobacco 21 (T21) laws, which raise the minimum legal age of sale of tobacco products to 21, have been proposed and implemented in states and cities across the USA. However, limited data are available on the effect of T21 laws on youth tobacco purchasing behaviours and access to tobacco products.

Methods Participants in a population-based prospective cohort in southern California completed questionnaires before (n=1609, age=18–19 y) and after (n=1502, age=19–20 y) T21 was implemented in California (June 2016). We examined the prevalence of past 30-day cigarette and e-cigarette use, and among past 30-day users, purchase location of tobacco products before (pre-) versus after (post-) T21. We also examined whether, post-T21, participants were refused purchase of tobacco products due to their age, and the perceived relative ease of purchasing cigarettes and e-cigarettes (vs pre-T21).

Results Negligible changes in cigarette and e-cigarette use were observed pre-T21 versus post-T21. At both time points, the majority of past 30-day users purchased cigarettes from gas stations and e-cigarettes from vape shops. Post-T21, the proportion of participants who reported purchasing cigarettes at gas stations decreased. Post-T21, most past 30-day cigarette or e-cigarette users were not refused purchase of cigarettes (65.4%) or e-cigarettes (82.0%) in the past 30 days, despite being under 21; half of the participants felt it was harder to purchase cigarettes (54.3%) and e-cigarettes (43.6%) post-T21.

Conclusion Post-T21, few participants were refused purchase of any tobacco product, despite the illegality of such sales. Better enforcement of T21 is needed to improve the efficacy of T21 legislation.

  • addiction
  • electronic nicotine delivery devices
  • public policy

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  • Contributors SS: principal author responsible for the majority of the manuscript text. SS, JB-T, JBU and TBC: collectively developed the conceptualisation of the manuscript’s specific aims. FL: conducted the analyses prepared the tables. FL, TBC, JBU, SC, AL, RM and JB-T: provided feedback on drafts.

  • Funding Research reported in this publication was supported by grant numbers P50CA180905 and U54CA180905 from the National Cancer Institute at the National Institutes of Health (NIH) and the Food and Drug Administration (FDA) Center for Tobacco Products (CTP), grant number K01DA042950 from the National Institute for Drug Abuse at NIH, and grant number 27-IR-0034 from the Tobacco Related Disease Research Program (TRDRP).

  • Disclaimer The funding agencies had no role in the design and conduct of the study; collection, management, analysis and interpretation of the data; preparation, review or approval of the manuscript; and decision to submit the manuscript for publication.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval The study obtained ethics approval from the University of Southern California institutional review board (protocol #: HS-13-00708) and participants gave informed consent before taking part.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data are available upon reasonable request. De-identified participant data are available upon reasonable request to the corresponding author (JBT).