ABSTRACT: PROJECT 3 The objective of this project is to estimate the public health impact of a federal flavored cigar ban on tobacco use, mortality and health disparities in the United States. This project will build a microsimulation model of individuals living in the US who are current, former, or potential users of cigars, cigarettes and e-cigarettes. The model can be used to track tobacco use over time, so the impact of a flavored cigar ban on smoking and mortality in the US population and in priority populations for tobacco control, such as among people who are Black or have lower incomes, can be estimated. The microsimulation model will be built in three phases corresponding to the specific aims. Specifically, using data from the nationally representative, longitudinal Population Assessment of Tobacco and Health study, we will estimate tobacco use transition probabilities over time, with a focus on the effects of cigar use on initiation, cessation, and dual/poly use of tobacco products (Aim 1). We will conduct a systematic review to compile data on cigar users’ tobacco use after a flavored cigar ban and elicit potential policy design effects from tobacco experts. Tobacco experts will be asked to develop plausible and distinct flavored cigar ban scenarios to simulate and compare, and quantify how key post-ban contextual factors (e.g., policy enforcement) affect the impact of the ban (Aim 2). Finally, using findings from Aims 1 and 2, and estimates from the literature, we will build a microsimulation model to estimate how tobacco use and mortality changes in the presence of a federal flavored cigar ban and in plausible moderating circumstances, such as with weak tobacco retailer compliance with a ban (Aim 3). This project will provide a comprehensive understanding of the potential public health impact of a flavored cigar ban, critical scientific evidence to counter likely legal challenges against a federal ban. We will also identify key threats to policy effectiveness for the Food and Drug Administration (FDA) to monitor and address in collaboration with local and state partners to maximize the public health benefits of the policy. This project addresses FDA research priorities to assess the impact of tobacco product characteristics (i.e., flavors) on initiation and cessation (Behavior, Aim 1) and to understand the public health impact of potential FDA regulatory action on tobacco use behavior and health (Impact Analysis, Aims 2 and 3). The University of North Carolina (UNC) Tobacco Centers of Regulatory Science (TCORS) has deep expertise in tobacco regulation and communications. The Center’s Integrative Theme is building the science for effective regulation of and communication about tobacco products disproportionately used by priority populations – flavored tobacco products.