Endocrine Abstracts

The aim of the study was to evaluate the degree of muscle dysfunction and relationship of trunk muscle strength and body composition in patients with osteoporotic vertebral fractures (VFs). Methods. Study comprised 90 men and woman 40-80 years old with primary osteoporosis. Study group (n=60) included patients with at least 1 VF (confirmed by X-rays), control group (n=30) consisted of osteoporotic patients of the same age, BMI and BMD without any fracture. Trunk muscles strength was measured with tenzodynamometry at Back-Check Dr. Wolff diagnostic unit. Body composition was evaluated by DXA Total Body. Muscle function was evaluated with Up-and-go test, 10-meters-walk test, testa for static and dynamic of back and abdomen muscles. Results. Patients with VFs had a significant muscle strength deficiency in trunk flexors (TF) −40.9% and extensors (TE) −18.1% with an adequate function of the left (LLF) and right lateral flexors (RLF). Patients in study group had lower muscle strength vs controls in TF (15.6±9.8 vs 27.7±9.9 kg, P<0.001), TE (14.6±8.9 vs 21.3±8.4 kg, P<0.001), LLF (13.1±7.2 vs 24.1±8.9 kg, P<0.001) and RLF (13.4±7.4 vs 24.3±7.7 kg, P<0.0001). No significant difference in functional tests results were registered (P>0.05). Body composition analyses showed differences between study and control groups in relative skeletal muscle index (RSMI, 6.5±1.2 vs 7.5±2.1 kg/m², P=0.02) and fat mass (29717±8367.4 vs 35464±9127.4 g, P=0.01). There was no significant difference in soft tissue mass and lean (muscle) mass between groups. Strength of all studied trunk muscles strongly negatively correlated with the number of VFs (P<0.001) and positively correlated with femoral neck BMD (g/m²), fat mass, soft tissue mass and lean mass (P<0.001), but not with age and RSMI (P>0.05). Conclusions. Patients with VFs have a decrease in trunk muscles strength and lower RSMI, mass and % of body fat in compared with patients without fractures. Number of VFs, low BMD, fat mass, soft tissue mass and lean mass are the main factors of trunk muscle dysfunction in osteoporotic patients. Functional tests showed less specificity for estimation of muscle function than tenzodynamometry.