Vascular Health and Cutaneous Sensation are Predictive of Upper Limb Bone Loss in People with Stroke: A 2-Year Longitudinal Study

Objectives: Secondary osteoporosis is common post-stroke. Despite the importance of fracture prevention in this population, stroke-related factors which lead to bone loss over time remain relatively understudied. This study aimed to assess changes in distal radius bone properties after stroke and examine their association with clinical assessments of stroke-related impairment. Design: Forty-five people with chronic stroke (age = 60.7 ± 7.2 years; post-stroke onset = 6.4 ± 4.2 years, 20 = women) and 45 healthy controls (age = 57.7 ± 6.3 years; 17 = women) completed this longitudinal study. Methods: Bone properties and failure load of the bilateral distal radius were measured at baseline and at 2-year follow-up using high-resolution peripheral quantitative computed tomography. Brachial artery blood flow volume and cutaneous hand sensation were measured by Doppler ultrasound and Semmes-Weinstein monofilaments, respectively. Results: Relative changes in cortical area and thickness (Cohen’s d = 0.51–0.59, 95%CI = 0.08–1.01) and estimated bone stiffness and failure load (Cohen’s d = 0.49–0.63, 95%CI = 0.07 − 1.05) were significantly greater for the stroke group than the controls (non-dominant side). On the paretic side, the decline in trabecular bone density (− 2.29%), cortical volumetric bone mineral density (vBMD) (− 0.53%), cortical thickness (− 3.61%), cortical area (− 3.45%), and increase in trabecular area (1.06%) were 2 to 4-fold greater than their corresponding precision error at follow-up. Among these, change in cortical vBMD (standardized Beta = 0.39, p = 0.004) and cortical thickness (standardized Beta = 0.34, p = 0.012) contributed most to the decrease in paretic radius failure load. Additionally, both arterial blood flow volume (ΔF = 5.31, p = 0.027) and light touch sensation (ΔF = 4.26, p = 0.046) at baseline were significant predictors of failure load decline. Conclusions: Deterioration in paretic radius bone strength was largely attributed to changes in cortical bone properties among people with chronic stroke. Autonomic dysfunction, evidenced by compromised vascular health, as well as reduced cutaneous sensation at baseline, may be associated with greater decline in radius bone strength.