Modelling the Population Health Impacts of Heated Tobacco Products in Japan

Abstract

Few data are available on the health impact of tobacco heating products (THPs) at the population level. We used systems dynamics modelling to estimate effects in the established THP market in Japan. We projected effects of THP use in overall mortality up to 2100 and compare those projections against a baseline scenario based on smoking rates pre-THP launch, i.e., smoking only. The model was informed using data from publicly available sources and the literature, including population size, yearly deaths and smoking prevalence with initialisation year (2004) and, births and migration from 2004 to 2065. Transitions between products were estimated from cross-sectional population surveys in Japan. Potential life-years saved with the introduction of THPs was 13 million by 2100 compared with smoking only. In worst-case scenario, population health gains would be seen with THPs risk 10–50% lower risk than smoking. Assuming equal risk for dual use and smoking, THP risk would need to be at least 10% lower than smoking to achieve a population health benefit by 2100. In credible scenarios, substantial population health gains will follow the introduction of THPs in Japan in a relatively short time frame.

Investigating the health effects of 3 coexisting tobacco and nicotine products using system dynamics population modeling: An Italian population case study

“…Sensitivity assessments present 1000 projections drawn using the transitions’ 95% confidence intervals from either the E-Cigarette scenario based on USA data (Brouwer et al, 2020) and THP scenario based on Japan data (Camacho et al, 2021). Reductions in life years lost (as life years saved for brevity) for the E-Cigarette and THP scenarios are displayed in figures 3 and 4.…”

“…The definition of product use status for e-cigarettes are based on usage in the previous 30 days while the e-cigarette transition probabilities are estimated from a Markov multistate transition model based on data approximately at one-year intervals (Brouwer et al, 2020). The THP transition probabilities (Camacho et al, 2021) are also based on one-year intervals with product status definitions according to use in the last year. For e-cigarette initiation, this could mean that short-term experimental use of an e-cigarette may be overlooked.…”

“…Details about the data inputs and multiple assumptions required to inform the three-product model can be found in Supplementary File 1 . For the two-product model implementations, in order to provide more useful projections than modellers’ best estimates, we used published transition data between smoking and e-cigarettes estimated for the USA population (Brouwer et al, 2020) and transitions between THP and smoking estimated for the Japanese population (Camacho et al, 2021). In the E-Cigarette scenarios, e-cigarettes are considered to be in the Italian market from 2010 while THP products are introduced in scenarios from 2014.…”