Conceptual Frameworks of Transitions in Use of Cigarettes, Heated Tobacco Products, and E-cigarettes

Background: In South Korea's multiproduct tobacco market, concurrent use of and transitions among combustible cigarettes (CC), e-cigarettes (EC), and heated tobacco products (HTP) has created diverse use states and transition patterns.However, inconsistent definitions limit comparability across studies.Methods: The current use of CC, EC, and HTP was encoded as a three-digit binary state (1=current use; 0=non-current use), generating eight mutually exclusive use states.All 64 possible transitions between consecutive observations were enumerated, classified using rule-based criteria, and represented through conceptual diagrams.Results: The eight use states were grouped into the following four categories: non-use, exclusive use, dual use, and triple use.The 64 transitions were further organized into the following eight mutually exclusive types: initiation, cessation, switching, entry into concurrent use, escalation, de-escalation, composition change, and maintenance.Conclusion: This framework establishes a standardized taxonomy for characterizing tobacco use states and transitions in South Korea and has the potential to enhance the design, reporting, and comparability of empirical research.