Neuropathy and triglycerides/HDL ratio are associated with impaired bone health in type 2 diabetes

Background and aims: Diabetic neuropathy (DN) is widely acknowledged as a significant risk factor for fragility fractures in diabetes. However, it remains unclear whether DN contributes to fractures solely by heightening the risk of falls or if it also has a direct impact on bone mass and quality. Consequently, we aimed to explore the involvement of DN in bone pathology. Methods: We consecutively enrolled subjects with type 2 diabetes (T2D), without severe DN (Neuropathy disability score – NDS ≤9) and without previous history of fractures. Data on clinical (age, disease duration, body mass index –BMI) and biochemical features (HbA1c, blood glucose, lipid profile, renal function) were collected. Surrogate markers of insulin-resistance, namely triglycerides/HDL (TG/HDL) ratio and triglycerides/glucose (TyG) index were also estimated. NDS (evaluated by vibration perception, thermal perception, pin-prick sensation and Achilles tendon reflexes) was assessed, score ≥3 was used to diagnose DN. Finally, a DEXA scan was performed to evaluate bone mineral density (BMD) and trabecular bone score (TBS). Results: N.144 subjects with T2D were enrolled (72% male, 69[66-72] years). Subjects with DN (n=39, 27%) showed higher BMI (29.7[26.7-33.2]kg/m2 vs 27.7[25.5-30.8]kg/m2, p=0.036), fasting blood glucose (127[112-153]mg/dL vs 119[103-136]mg/dL, p=0.04), serum triglycerides (136[97-178]mg/dL vs 105[80-153]mg/dL, p=0.016), TG/HDL ratio (3.3[1.9-4.1] vs 2.4 [1.5-3.5], p=0.012) and TyG index (4.9±0.3 vs 4.7±0.3, p=0.003) compared to subjects without DN. Subjects with DN showed lower BMD at femoral neck (0.702[0.638-0.850]g/cm2 vs 0.789[0.717-0.860]g/cm2, p=0.035). The association between DN and low hip-neck BMD remains significant after multivariate correction (gender, age, BMI and metabolic control). No differences were found in total hip and lumbar BMD, as well as in TBS. A negative correlation between TG/HDL ratio and TBS was found (r=-0.215, p=0.013). Conclusion: In this study, we observed a significant association between DN and decreased BMD, the importance of additional research in this domain. Further, we confirm the contributory role of triglycerides and HDL in DN.