Prevalence of low bone mineral density at axial sites and fracture risk in Bulgarian population

Background: Osteoporosis is a common chronic disease characterized by low bone mineral density (BMD) and microarchitectural deterioration of the bone, which are associated with increased risk of fragility fractures. Currently the most popular tool is the fracture risk assessment model FRAX to calculate the 10-year probability of major osteoporotic fractures (MOF) and hip fractures (HF). Objective: To investigate the prevalence of low BMD at axial sites and fracture risk in Bulgarian population. Methods: We retrospectively analyzed dual energy X-ray absorptiometry (DXA) scan results of 12 478 subjects. Scan results included BMD and T-score assessments of lumbar spine and femoral neck. FRAX major osteoprotic fracture (MOF) and FRAX hip fracture (HF) were assessed in subjects between 40 and 90 years using BMD values. Results: Of total 12478 subjects, 12119 were women and 359 were men. The mean age of the subjects was 61 years (yrs.) ± 10 yrs. The overall prevalence of low BMD at the lumbar spine was 6084/9336 subjects (65.2%). 3502/9336 subjects (37.5%) were considered as osteopenic and 2582/9336 subjects (27.7%) were considered as osteoporotic. The overall prevalence of low BMD at the femoral neck was 2036/3140 (64.8%). 1641/3140 subjects (52.3%) were classified as osteopenic and 395/3 140 subjects (12.6%) were classified as osteoporotic. The mean values of FRAX MOF and FRAX HF increased significantly with increasing the age interval. Conclusion: This study is the largest epidemiological research in Bulgaria up to date about the prevalence of low BMD at axial sites.