Abstract
OBJECTIVES: Adolescent tobacco use often leads to adult smoking, yet longitudinal evidence in the Republic of Korea is limited. This study examined the annual incidence, current use, dual use patterns, and first product type among Korean adolescents using data from the Korean Youth Health Behavior Panel Survey (KYHPS). METHODS: Data from Waves 1-6 (2019-2024) of the KYHPS, comprising 5,051 students followed annually, were analyzed. Use patterns of conventional cigarettes, e-cigarettes, and heated tobacco products were assessed, accounting for longitudinal weights and complex survey design. RESULTS: Annual incidence of tobacco product use peaked at the transition to 10th grade (3.29%) and declined thereafter. Among 11th-grade girls, the prevalence of e-cigarette use (1.54%) surpassed that of conventional cigarettes (1.33%) for the first time. Of dual users, 36.3% initiated with e-cigarettes before transitioning to other tobacco products, suggesting a possible gateway effect of e-cigarettes. CONCLUSIONS: The transition from late middle to early high school is a critical intervention period for preventing adolescent tobacco initiation. Comprehensive tobacco control strategies encompassing all tobacco products are warranted.