PROJECT SUMMARY/ABSTRACT Interstitial cystitis/bladder pain syndrome (IC/BPS) is a multifactorial, chronic syndrome involving urinary frequency, urinary urgency, and bladder discomfort (1) that affects an estimated 10 million patients in the United States(2). Although understandings of IC/BPS pathophysiology remain limited, published studies have found several comorbidities, including vulvodynia and anxiety comorbidities prevalent in IC/BPS (4, 5). Research suggests that these comorbidities, in turn, exacerbate IC/BPS symptoms and are associated with poor functioning, adjustment, prognosis, and treatment response rates. The research within this proposal builds upon our previous analyses and those of the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network. Our cohort of 400 IC/BPS patients at Boston Children's Hospital has been followed for 15 years and provides an extraordinary opportunity for an epidemiological study of the various conditions co-occurring with IC/BPS. We will also comprehensively phenotype a large online cohort of patients with IC/BPS through surveys and systematic analysis of patient social media posts via “social listening”, which could be methodologically advantageous in identifying environmental factors when triangulated with patient surveys influencing IC/BPS comorbidities. The hypothesis underlying this proposal is that extensive phenotyping will elucidate the depth and breadth of co-occurring disorders in IC/BPS and uncover factors that play a role in the development of the disorders. Based on this hypothesis, our aims are to: 1) identify the prevalence of conditions in demographically distinct cohorts (e.g, anxiety, depression, vulvodynia) and potential environmental influencers (e.g., family discord, poverty, pollution); 2) comprehensively and rigorously phenotype a subset of these patients with the use of PROMIS and PhenX toolkit surveys for comorbid conditions; and 3) characterize the impact of health disparities on IC/BPS, with particular attention paid to health disparities affecting African Americans with IC/BPS. As this project leverages existing cohorts and conducts phenotyping via telemedicine, it is a cost-effective approach to better characterizing phenotypes and elucidating the architecture and epidemiology of dimensional phenotypes in IC/BPS.