Assessing the Likelihood and Magnitude of a Population Health Benefit Following the Market Introduction of a Modified-Risk Tobacco Product: Enhancements to the Dynamic Population Modeler, DPM(+1).

Researchers and those responsible for evaluating and implementing policies intended to reduce population harm must assess the potential for both intended and unintended consequences associated with those policies. Such assessments should be based on the combined dimensions of magnitude, and thus likelihood, of shifts in exposure patterns needed to produce a population benefit or harm, and magnitude of the expected population benefit or harm. In response to this assessment need, we provide a conceptual description of the dynamic population modeler, DPM(+1), as well as illustrative analyses that estimate the effects on all-cause mortality, life expectancy, and quality of life-adjusted life expectancy if exposure patterns in the population shift from a higher risk product (e.g., cigarettes) to a lower, or modified, risk tobacco product (MRTP) in specified ways. Estimates from these analyses indicate that, within a single birth cohort, switching completely from cigarette smoking to MRTP use is more likely to lead to a population-level survival benefit than initiating tobacco use with an MRTP instead of cigarettes. This is because tobacco initiation rarely occurs beyond young adulthood, whereas continuing smokers exist in all subsequent age categories, leading to a greater cumulative effect. In addition, complete switching to MRTP use among a small proportion of smokers in each age category offsets the survival deficit caused by unintended shifts in exposure patterns, such as MRTP initiation among never tobacco users followed by transitioning to cigarette smoking and/or cigarette smokers switching to MRTP use instead of quitting.