The study includes longitudinal urine collection, HR-pQCT assessment of tibial bone density and microarchitecture, DXA assessment of body composition, anthropometric measurements, risk-factor assessments, and integrated analysis of imaging, clinical, and proteomic data using advanced statistical techniques. Doctoral degree completed by the start date in biomedical engineering, biological science, kinesiology, biochemistry, bone biology, biostatistics, medical imaging, bioinformatics, or a closely related field.