Recent Trends in Cigarette and HTP Use in Japan: A Scoping Review.

introductionThe emergence and rapid increase in sales and use of heated tobacco products (HTPs) in Japan provides a unique case study of their viability as a potentially lower-risk substitute for combustible cigarettes. This review investigates the relationship between HTP and cigarette use in Japan.

methodsWe searched PubMed and Web of Science for studies on HTP and cigarette use, including sales trends, prevalence, and transitions between HTPs and cigarettes from 2010 to 2024. We distinguish results by source of funding and survey design.

resultsOur review included 25 relevant studies, of which 21 reported HTP and/or cigarette prevalence and transitions and 4 reported sales trends. Cigarette sales and use rapidly declined during the national expansion of HTPs. HTP use increased substantially from 2015 to about 2019, then slowed through 2023. Trends from industry-sponsored studies were mostly in line with the government-sponsored estimates. Estimates from government-sponsored (mostly in-person) surveys indicate that cigarette use continuously declined from 2015 to 2023 as HTP growth increased, although at a slower pace since 2018. After decreasing cigarette prevalence from 2015 to 2018, online surveys reported high rates of dual cigarette-HTP use and comparatively low rates of smoking discontinuation from 2018 to 2023.

conclusionsThe rapid decline in cigarette use from 2015 to 2018 in Japan suggests that increasing HTP use may have contributed to this trend. After 2018, slowing HTP sales and mixed estimates of cigarette and HTP use raise uncertainty about the role of HTPs. As such, the evidence remains incomplete, limiting definitive conclusions. The current study highlights the challenges associated with distinguishing the impact of HTPs on displacing cigarettes. IMPLICATIONS: This review provides evidence that HTP use likely contributed to declines in cigarette use in Japan from 2015 to 2018, though recent trends are less conclusive. It highlights differences across data sources and survey types, which can affect how results are interpreted. The study adds to our understanding of how HTPs may or may not replace cigarettes over time and points to the need for better, more consistent data to track these trends.