E-cigarette, cannabis, hookah and tobacco use patterns in fee-paying South African high schools

Background. Monitoring adolescent substance use is crucial for informing public health strategies. However, in South Africa (SA), recent large-sample data on the use and co-use of tobacco, nicotine and cannabis among youth remain scarce. Objectives. To describe the use and co-use of cannabis, hookah, tobacco cigarettes and electronic cigarettes (e-cigarettes/vapes) among SA high-school learners, and to examine how these patterns vary by school-based characteristics, including grade, school fee category and school gender composition. Methods. A cross-sectional survey was administered to 25 149 learners in grades 8 - 12 from 52 fee-paying high schools across eight provinces. Learners reported their past-30-day use of cannabis, hookah, tobacco cigarettes and e-cigarettes/vapes. Key outcomes included current use of each individual product, any one of the four products, as well as dual-usage patterns. Multilevel logistic regressions examined associations between school grade, fee category (lower-, mid-, or high-fee), gender composition (co-educational, all boys, all girls) and the odds of single, any and dual product use. Results. Among sampled learners, 19.39% (95% confidence interval (CI) 18.91 - 19.88) reported current use of any product. Vape use was most prevalent (16.83%, 95% CI 16.37 - 17.30), followed by cannabis (5.13%, 95% CI 4.86 - 5.41), hookah (3.16%, 95% CI 2.95 - 3.39) and tobacco cigarettes (2.08%, 95% CI 1.91 - 2.27). Dual use was especially common among vape users, with more than one-third (34.31%, 95% CI 32.88 - 35.77) reporting concurrent use of at least one other product: 22.06% (95% CI 20.83 - 23.35) cannabis, 13.50% (95% CI 12.50 - 14.58) hookah and 10.13% (95% CI 9.25 - 11.08) tobacco cigarettes. Usage rates were highest among learners in Grade 12, in co-educational schools and in lower-fee schools. Multivariable regression analyses showed that advanced grade level was significantly associated with increased odds of current use across all product types. Compared with learners in all-boys schools, those in co-educational schools had significantly higher odds of cannabis use (odds ratio (OR) 1.53, p<0.05) and dual use (OR 1.42, p<0.1), while learners in all-girls schools had significantly lower odds of any product use (OR 0.75, p<0.05) and of vape use (OR 0.73, p<0.05). Regression results further revealed significantly elevated odds of hookah use and dual use among learners attending lower- and middle-fee schools compared with learners in high-fee schools. Conclusion. The widespread use of e-cigarettes, along with dual use among e-cigarette users, in fee-paying high schools signals a significant public health concern, underscoring the need for comprehensive interventions. Elevated hookah and dual use in lower-fee schools, along with increased cannabis and dual use in co-educational settings, underscore the need for targeted interventions to address context-specific vulnerabilities among SA adolescents.