Does 25(OH)D deficiency affect muscle elasticity, physical function, pain, and quality of life? A shear-wave elastography-based cross-sectional study

In this cross-sectional study of 80 young adults, 25(OH)D deficiency (< 20 ng/mL) was associated with lower SWE-measured muscle elasticity (FCR, BB, and TA), and reduced fingertip pinch strength. When women and men were evaluated separately, muscle elasticity values were lower in the low 25(OH)D group in both sexes. Muscle elasticity showed strong correlations with 25(OH)D and accurately discriminated deficiency (AUC 0.935-0.957) in this young cohort. Vitamin D is a key biological regulator in maintaining bone mineralization and muscle function by regulating calcium and phosphorus metabolism, promoting muscle protein synthesis, and supporting muscle cell growth and differentiation. To assess muscle elasticity using shear-wave elastography (SWE) in young adults with low and adequate 25-hydroxyvitamin D [25(OH)D] and explore the diagnostic usefulness of SWE in distinguishing 25(OH)D deficiency. A cross-sectional study. Physical Medicine and Rehabilitation and Radiology Departments in the Selcuk University Faculty of Medicine Hospital. Eighty participants (18–45 years) were included in two groups regarding 25(OH)D levels. Participants with serum 25(OH)D levels( < 20 ng/mL and those with ≥ 20 ng/mL) were classified as Groups I( n = 40) and II( n = 40). Muscle elasticity of flexor carpi radialis (FCR), short head of biceps brachii (BB), and tibialis anterior (TA) was measured using SWE (kPa). Group I consisted of 21 women and 19 men, while Group II consisted of 22 women and 18 men. The groups were similar in demographic characteristics, physical activity, and SF-36 scores. FCR-kPa, BB-kPa, and TA-kPa were lower in Group I ( p < 0.001). When women and men were evaluated separately, FCR, BB, and TA muscle elasticity values were significantly lower in both sexes in the low 25(OH)D group (all p < 0.001). Fingertip pinch strength was lower in the dominant and non-dominant hands in Group I ( p = 0.001; p = 0.023). AUC values for predicting 25(OH)D deficiency were FCR: 0.94 (cut-off 23.5 kPa), BB: 0.957 (26.5 kPa), and TA: 0.935 (23.75 kPa). Serum 25(OH)D showed a strong positive correlation with elasticity measurements ( r = 0.870–0.916; p < 0.001). Low 25(OH)D levels were found to be associated with lower elasticity values, as measured by SWE, in FCR, BB, and TA muscles in women and men.