Association of Body Mass Index and Fracture Risk Varied by Affected Bones in Patients with Diabetes A Nationwide Cohort Study

Background: Body mass index (BMI) is a risk factor for the type 2 diabetes (T2DM), and T2DM accompanies various complica-tions, such as fractures. We investigated the effects of BMI and T2DM on fracture risk and analyzed whether the association var-ied with fracture locations.Methods: This study is a nationwide population-based cohort study that included all people with T2DM (n= 2,746,078) who re-ceived the National Screening Program during 2009-2012. According to the anatomical location of the fracture, the incidence rate and hazard ratio (HR) were analyzed by dividing it into four categories: vertebra, hip, limbs, and total fracture.Results: The total fracture had higher HR in the underweight group (HR, 1.268; 95% CI, 1.228 to 1.309) and lower HR in the obese group (HR, 0.891; 95% CI, 0.882 to 0.901) and the morbidly obese group (HR, 0.873; 95% CI, 0.857 to 0.89), compared to reference (normal BMI group). Similar trends were observed for HR of vertebra fracture. The risk of hip fracture was most promi-nent, the risk of hip fracture increased in the underweight group (HR, 1.896; 95% CI, 1.178 to 2.021) and decreased in the obesity (HR, 0.643; 95% CI, 0.624 to 0.663) and morbidly obesity group (HR, 0.627; 95% CI, 0.591 to 0.665). Lastly, fracture risk was least affected by BMI for limbs. Conclusion: In T2DM patients, underweight tends to increase fracture risk, and overweight tends to lower fracture risk, but as-sociation between BMI and fracture risk varied depending on the affected bone lesions.