Project Summary The acceptance and use of electronic nicotine delivery systems (ENDS) within the African-American (AA) community may widen tobacco-related health disparities such as gingival inflammation (GI), the precursor to periodontal disease. However, how and why ENDS use may pose GI risk is unclear as there is a lack of comprehensive data on smoking behaviors, exposure, and disease outcomes in AA ENDS users. We hypothesize that AA ENDS users may be more susceptible to ENDS-mediated oral health outcomes due to variations in ENDS preference, usage, and biological responses. To address this hypothesis, we will establish a behavior-exposure-toxicity-disease paradigm utilizing aims specifically designed to evaluate behaviors (Aim 1), common ENDS products (Aim 2), and susceptibility (Aim 3). This innovative approach will facilitate the identification of risk factors and biomarkers that can be applied to disease prevention strategies. In Aim 1, we will recruit cohorts of current AA and Caucasian ENDS users and never-tobacco users to evaluate patterns of ENDS usage behaviors, oral health, and risk factors. In this aim, we will employ questionnaires and mobile ecological momentary assessments coupled with real-time monitoring to examine ENDS puff topography within each group. By using this mixed methods approach, we will limit recall bias and also capture moment to moment phenomena that may occur differentially in these two ENDS user groups. To elucidate the role of specific group and product-based ENDS exposure scenarios we will utilize an in vitro air liquid interface cellular model system in Aim 2. Using specific group exposure scenarios (identified by puff topography characterization in Aim 1) and established protocols for comparative toxicity assessments we will identify differential biomarkers associated with ENDS aerosol exposures. Specifically, this will include comparisons of cellular responses induced by differing ENDS generation products and brands as well as usage patterns. In Aim 3, we will utilize a molecular epidemiology approach to assess the impact of differential exposures in our AA and Caucasian ENDS cohorts by using participant saliva and gingival cells to identify biomarkers of oxidative stress, DNA damage, and other indicators commonly found in GI. Specifically, we aim to establish a pathway between ENDS preference, puff topography, and toxicological pathways contributing GI development that may be exacerbated in the AA population. Our project outcomes will be a biomarker panel that may provide critical insight into ENDS-mediated GI susceptibility in AA.