400 Section - A Proposal for a Prospective Longitudinal DXA Cohort Study at the UK National Rehabilitation Centre: Bone Mineral Density Trajectories Following Moderate–Severe Traumatic Brain Injury

Objectives : To characterise baseline bone mineral density, and 12-month trajectories after moderate–severe traumatic brain injury (TBI), compare outcomes with matched orthopaedic controls, and evaluate the influence of endocrine dysfunction and osteoporosis therapy on BMD and fracture risk in a planned prospective cohort.

Design: This is a proposed prospective observational study at the UK National Rehabilitation Centre. Adults ≥18 years with moderate–severe TBI admitted for neurorehabilitation will undergo DXA scanning within 6 weeks of admission and at 6 and 12 months. Matched orthopaedic controls without neurological injury will be selected by age, sex, BMI, and mobility. Planned exclusion criteria include metabolic bone disease, chronic steroid use, bone malignancy, CKD stage 4–5, pregnancy, or surgical factors preventing DXA. Proposed assessments include endocrine profiling (vitamin D, PTH, thyroid and sex hormones), mobility measures, fragility fracture surveillance, and documentation of osteoporosis therapy. The primary outcome will be the percentage change in BMD over 12 months; secondary outcomes include baseline prevalence of low BMD, endocrine abnormalities, fracture incidence, and treatment response.


Results: As this is a proposed study, results are not yet available. Based on prior evidence, we expect a high baseline prevalence of low BMD in moderate–severe TBI and an early decline within 6 months. Endocrine abnormalities, particularly vitamin D deficiency and hypogonadism, are anticipated to correlate with reduced BMD and higher fracture risk. Patients receiving bisphosphonates may show greater BMD stability. Orthopaedic controls are expected to demonstrate comparatively preserved BMD.


Conclusion: This study will provide the first UK rehabilitation-based longitudinal DXA dataset focused on bone health after moderate–severe TBI. Findings are expected to support targeted DXA screening, early endocrine evaluation, and optimised fracture prevention in neurorehabilitation. The work aims to address a major evidence gap and establish a foundation for future TBI-specific bone health pathways.