PROJECT SUMMARY The Clinical Core is located at Tulane University School of Medicine (SOM). The overall objective of the Core is to recruit 300 human subjects, including 150 subjects with hip osteoporotic fracture (OF) and 150 controls without OF, for Projects 1-3 during the first 4 years. All the case and control subjects are at least 55 years old. The control subjects will be closely matched with hip OF cases for age, sex, weight, and ethnicity. Recruitment plan: Recruitment of the 150 subjects with new hip OF (75 men and 75 women in each group) will occur at Tulane Health System (THS). THS consists of three major Tulane SOM affiliated hospitals and an additional 25 medical clinics in the greater New Orleans area. Per our system records, THS treats >120 hip OF patients with age ≥ 55 years old in recent years. Study clinicians will identify new hip OF patients who are ≥55 years in age and have a unilateral hip fracture (with the other side normal) and will refer them for participation in the proposed study. The control subjects will be recruited from our ongoing large-scale Louisiana Osteoporosis Study (LOS). Currently, LOS has >5,500 subjects (age ≥55 years) without any fracture history. Most of them (>95%) signed informed consent forms to allow re-contact for future research opportunities. For the recruited hip OF subjects, we will screen for potentially matched control subjects through the ongoing LOS recruitment and the extensive LOS archive. For all the case and control subjects who are willing to participate, we will confirm their eligibility, consent subjects, perform clinical examination, and collect specimens. Steps in clinical examination and specimen collection: For all consented eligible case and control subjects, we will collect their epidemiological information by three questionnaires. We will conduct DXA (dual energy X-ray absorptiometry) scan at spine, hip, and whole body, to derive bone mineral density (BMD) and trabecular bone score (TBS), and perform QCT scan at spine and hip for vBMD/finite element analyses (FEA). For each subject, we will collect 50ml fasting blood (for Proj 1-3), 10ml urine (for biobanking), and ~0.5g stool (for Proj 1) samples. For each subject, we will also collect bone samples by bone biopsy at os ilium for isolation of osteoblasts, and 10ml bone marrow samples by bone marrow aspiration for isolation of bone marrow mesenchymal stem cells (BMSCs) for Project 2. All the collected specimens will be immediately transferred for subsequent processing (e.g., stool DNA extraction, plasma preparation, bone cell isolation) in Projects 1-3, respectively. The PI’s group has had a long history of successful recruitment for clinical and epidemiological studies. The services provided by this Core are routine in our Tulane Center for Biomedical Informatics and Genomics (CBG) and have been successful for all of our previous and ongoing NIH projects (e.g., P50AR055081, R01AR050496, R01AR064421, R01AR059781, and U19AG05537...