Behavioral, Lifestyle, and Cultural Risk Factors for Bone Quality and Osteoporosis in the PROSPECT Cohort - PROJECT SUMMARY Data on osteoporosis (OP) among adults living in the US territory of Puerto Rico (PR) is limited. However, evidence suggests that adults in PR may be at high risk of OP (12% for lumbar spine, 8.7% for femoral neck), although the few studies that exist are small, outdated, or rely on self-report. This is supported by data in Puerto Rican (PR) adults from the US mainland showing increased risk for OP compared to non-Hispanic White adults. OP is a serious musculoskeletal disease increasing risk of fragility fracture, morbidity, and mortality. Diet is a known modifiable preventative factor for OP, but evidence for recommendations remains unclear. Psychological stress has been proposed as a novel risk factor for bone health through dysregulation of the hypothalamic-pituitary adrenal and sympathomedullary axes, but most evidence is from animal studies. This relationship may be further modified by diet, which is related to stress and OP. Trabecular bone score (TBS), a low-cost indicator of bone quality, has not been examined in adults in PR. Adults living in PR may be susceptible to poor bone health, as this population has low dietary quality and high psychosocial stressors due to social and environmental inequities compounded by climate-related disasters. A Dietary Approaches to Stop Hypertension (DASH) diet has been shown to be most protective against OP in PR adults from the US mainland. Adults in PR consume both healthy (legumes, dairy, locally sourced fruit/vegetables, seafood) and unhealthy foods (sugary beverages, refined grains, French fries, SPAM), which may differ from PR diets on the US mainland. Developing culturally relevant, effective prevention strategies for OP has been hindered by a major gap in PR: the lack of rigorously collected data on OP and risk factors. Thus, our central hypothesis is that OP is prevalent and that psychophysiological stress and dietary factors are related to bone health among adults in PR. The proposed ancillary study will build on the Puerto Rico Osteoporosis Study of Psychosocial, Environmental and Chronic Disease Trends (PROSPECT), an ongoing investigation of risk factors for CVD in adults 30-75 y in PR. Adults (n=1000) aged > 45 y, who complete their 4-y PROSPECT visit, will be invited to complete additional measures including bone mineral density (BMD), TBS, and questionnaires. Our project aims to: 1) quantify BMD and TBS in PROSPECT, and to compare prevalence of OP to national data and data for US mainland PR adults; 2) assess dietary intake and biomarkers in relation to bone outcomes; and 3) quantify measures of psychophysiological stress and assess their relationships to bone outcomes in PROSPECT. This ancillary study is time sensitive, as PROSPECT will start its 4-y follow up in May 2024, providing a unique opportunity to add OP as an outcome, capitalizing on existing data from the parent study. The proposed study will provide timely data to inform clinical and public health efforts to prevent bone loss and OP for the population of PR. This study will answer new lines of inquiry on the interconnections between diet, stress, and bone outcomes that will serve as a foundation for populations with high prevalence of OP.