Background: Fragility fractures are one of the most common causes of hospitalisation globally [1]. FRAX™ scores are calculated based on risk factors for fragility fractures and help guide risk factor management [2]. However, it does not distinguish between risk factors specific to typical fragility fractures (hip, spine and distal radius fractures) and atypical fractures (fractures of other bones). Objectives: Our study looked to distinguish specific risk factors associated with typical and atypical fractures. Methods: The study analysed a cohort of patients from an NHS Foundation Trust in the North West of England that sustained any fracture and were referred for dual-energy X-ray absorptiometry (DEXA) between April 2004 and January 2024. The site of fracture, various demographics and other potential risk factors were recorded, and patients were allocated to the typical or atypical group. Differences between the two groups were analysed using 2-sample T-tests and chi-squared tests and fitted to a logistical model. A stepwise multiple logistic model was then fitted to see which variables remained associated with each fracture group when the other variables were accounted for. Results: 20,862 patients were referred for DEXA scanning in the study period, of whom 17184 (82.37%) were female and 3678 (17.63) were male. 10,613(51.87%) had typical fractures and 10,249 (49.13%) were had atypical fractures. Analysis of 17 variables (including the 12 FRAX™ variables), as shown in Tables 1 and 2, found the following were significantly associated with an increased risk of typical fractures: female gender; taller height; increased weight; higher BMI; higher percentage body fat; higher left femur T-score; family history of fracture; secondary osteoporosis and coeliac disease. Whereas the following variables were significantly associated with an increased the risk of atypical fractures: older age at scan; history of previous fracture; secondary osteoporosis and vitamin D deficiency. When analysed in our multi-variate model, higher left femur T-score (OR 1.37; CI 1.25-1.50) and total fat percentage (OR 0.00; CI 0.99-0.99) remained as significant risk factors associated with typical fractures, while history of fracture (OR 1.41; CI 1.19-1.67); age (OR 1.01; CI 1.00-1.01) and vitamin D deficiency (OR 1.25; CI 1.25-1.50) remained as significant risk factors of atypical fractures. Conclusion: Our data suggests that there are different risk factors for typical and atypical fragility fractures. History of fracture and age, which are also included in FRAX™ scoring, are strong predictive risk factors for atypical fragility fractures. REFERENCES: [1] The global burden of fractures; Cauley, Jane A; The Lancet Healthy Longevity, Volume 2, Issue 9, e535 - e536. [2] Watts NB. The Fracture Risk Assessment Tool (FRAX®): applications in clinical practice. J Womens Health (Larchmt). 2011 Apr;20(4):525-31. DOI: 10.1089/jwh.2010.2294. Epub 2011 Mar 25. PMID: 21438699. Table 1 Categorical Variables Total number of patients Number of patients with typical fractures (%) Number of patients with atypical fractures (%) P value Odds Ratio 95% Confidence interval Female 17184 8818 83.09% 8366 16.91% 0.006* 0.90 0.84-0.97 Smoker (previous or current) 5944 3069 51.63% 2875 48.37% 0.166 0.96 0.90-1.02 Steroid use(previous or current) 2218 1133 51.08% 1085 48.92% 0.835 0.99 0.91-1.08 Rheumatoid arthritis 1205 601 49.87% 604 50.12% 0.476 1.04 0.93-1.17 History of previous fracture 2762 1230 44.53% 1532 55.47%