Exploring the Role of Novel Aging-Focused Syndemic Conditions on HIV Risk and Quality of Life among HIV-Negative Older Sexual Minority Men - Project Summary Overview. This study addresses gaps in HIV and behavioral health research among older sexual minority men (OSMM). Specifically, this project assesses the relative severity and impact of contextually relevant age-related syndemic factors (age-related discrimination, internalized ageism, aging anxiety, sexual minority specific aging concerns, social isolation, economic marginalization, and perceived cognitive impairment) and traditional syndemic conditions (mental health via depression, PTSD, childhood sexual abuse; intimate partner violence; substance use) among OSMM.9,10 Background. With high prevalence and rising incidence rates, OSMM are uniquely burdened by HIV.1 This is particularly true for Florida (proposed study site), a state with one of the highest HIV incidence rates nationally.11 The framework for the study is based on three relevant theories. First, syndemic theory2 contends that HIV and quality of life (QOL) disparities are propagated by the synergistic co- occurrence of disease (e.g., health issues, substance use behaviors, sociocultural factors), some of which are unique to OSMM. Second, the minority stress model3,4 extends syndemic theory by positing that OSMM face enduring unique stressors resulting from their marginalized identities that perpetuate psychological adversity. Lastly, intersectionality theory5 posits that OSMM experience worse health outcomes compared to their younger SMM peers due to the compounding systems of oppression they face due to their multiple minoritized identities. Objectives & methods. This study’s three aims center on investigating the relative severity and impact of age-related psychosocial factors and traditional syndemic conditions in explaining HIV and health disparities among HIV-negative OSMM. Aim 1 examines the severity, frequency, and co-occurrence of theoretically linked psychosocial problems occurring in HIV-negative OSMM. Aim 2 assesses the influence of age-related psychosocial and traditional syndemic conditions on engagement in HIV prevention outcomes (condomless anal sex without PrEP, PrEP adherence) and QOL among this population of OSMM as well as a potential moderator of these relationships. Aim 3 utilizes tree-based-machine learning to explore interaction effects between the most influential age-related psychosocial factors and an additive index of traditional syndemic conditions on HIV risk and QOL outcomes. HIV-negative OSMM (N = 250) between the ages of 55 and 70 years will complete one psychosocial quantitative assessment. Data will be analyzed using tree-based- machine learning approaches and traditional regression models. Innovation and Impact. This dissertation study will identify age-related syndemic conditions unique to OSMM to better understand QOL, HIV, and behavioral health, among OSMM, an under-researched and multiple marginalized group. Findings gleaned will aid in the future development of HIV and behavioral health related tailored to OSMM and, as a dissertation, lay the groundwork for the PI’s programmatic research focused on HIV and behavioral health disparities among older sexual minorities. This proposal is relevant to the NIDA priorities (NOT-MD-19-001).