ApoA1 and ApoB Are Associated with Fracture Risk in Patients with Type 1 Diabetes

Background: Individuals with type 1 diabetes (T1D) have an increased fracture risk, but no clear biomarkers have been linked to this risk. ApoA1 and ApoB were selected due to their association with metabolic disturbances in T1D. Copeptin was included given emerging evidence that ADH influences bone remodeling and glucose metabolism. The aim of this study was to identify biomarkers associated with fractures in patients with T1D. Methods: This prospective, population-based study included 473 individuals with T1D and 465 individuals without diabetes. Fasting blood samples were collected at baseline, and fracture outcomes were assessed after approximately 10 years. ApoA1, ApoB, CRP, GFR, copeptin, and HbA1c were analyzed. Cox regression was used to evaluate associations with fracture risk, and results were calculated per unit increase. Results: In total, 91 fractures occurred. A Kaplan-Meier analysis was performed to compare fracture risk between the control group and individuals with T1D. The results demonstrated a higher risk of fractures over time in patients with T1D compared to controls (p-value 0.037). When we divided the population by patient/control status, we found that, after adjustment for all investigated variables (HbA1c, GFR, CRP, copeptin, age, smoking, cortisone treatment, physical activity, lipid-lowering medication, and gender), both ApoA1 (HR 4.290, CI 1.871-9.837, p-value < 0.001) and ApoB (HR 7.625, CI 1.995-29.138, p-value 0.003) remained independently associated with fracture risk in the T1D group. Conclusions: Higher ApoA1 and ApoB levels are associated with increased fracture risk in individuals with T1D, independently of confounders. Additionally, individuals with T1D have a higher overall fracture risk compared to controls.