E-cigarette sales to school-uniformed adolescents in China: a randomized clinical trial

Importance: Electronic cigarettes (e-cigarettes) are appealing to adolescents, but sale of e-cigarettes to individuals younger than 18 years is prohibited in China. The effect of school uniforms on e-cigarette sales to adolescents has not been explored. Objective: To study e-cigarette sales to adolescents wearing school uniforms compared with those wearing casual attire. Design, Setting, and Participants: This 2-arm randomized clinical trial involved adolescent mystery shoppers wearing school uniforms or casual attire who attempted to purchase e-cigarettes. The trial was conducted across 36 major metropolitan areas in China from July 29 to September 3, 2023. Adolescent buyers aged 18 to 19 years were randomly assigned to wear 1 of the 2 attire types. A 1:1 matching of e-cigarette and cigarette stores was also performed. Intervention: Adolescent buyers attempting to purchase e-cigarettes while wearing school uniforms were the intervention group, and those in casual attire served as the control group. Main Outcomes and Measures: The primary outcome was successful purchase of e-cigarettes. Secondary outcomes assessed whether sellers verbally inquired about the buyer's age, requested an identification (ID) card for age verification, or dissuaded the buyers from using e-cigarettes. Multivariable logistic regression models identified factors associated with outcomes by attire type, adjusted for buyer, seller, and store characteristics. Results: The final analytical sample included 1089 visits to e-cigarette stores (543 by adolescents in school uniforms and 546 by those in casual attire) and 1059 visits to cigarette stores. Of the e-cigarette stores visited, 85.4% (95% CI, 80.3%-89.4%) posted external advertising, 39.4% (95% CI, 35.9%-43.0%) were located in shopping malls, 90.8% (95% CI, 87.7%-93.2%) displayed age-of-sale signs, and only 15.0% (95% CI, 9.7%-22.5%) exhibited health warnings specifically for e-cigarettes. The overall success rate of adolescents purchasing e-cigarettes without age verification was 78.3% (95% CI, 75.8%-80.6%), significantly lower than the 94.5% (95% CI, 91.3%-96.6%) success rate for purchasing cigarettes without age verification. Adolescents wearing school uniforms had significantly lower odds of successfully purchasing e-cigarettes (adjusted odds ratio [AOR], 0.39; 95% CI, 0.23-0.66) than those in casual attire and were more likely to be asked about their age (AOR, 9.18; 95% CI, 6.46-13.06), requested to show an ID card (AOR, 6.68; 95% CI, 4.53-9.87), and dissuaded from using e-cigarettes (AOR, 1.79; 95% CI, 1.30-2.47). Additionally, when sellers requested ID cards, the probability of successful e-cigarette purchases was significantly lower than when they did not (AOR, 0.02; 95% CI, 0.01-0.03). Conclusions and Relevance: In this randomized clinical trial of e-cigarette sales, e-cigarettes remained widely sold to adolescents without age verification in China, but wearing a school uniform appeared to reduce adolescents' ability to purchase e-cigarettes.