source: Neuromuscular Disorders
M. Sframeli, G. Vita, A. Catalano, M. Distefano, M. La Rosa, C. Barcellona, C. Bonanno, G. Nicocia, C. Profazio, N. Morabito, C. Lunetta, G. Vita, S. Messina
Low bone mineral density (BMD) and increased fracture risk are frequently observed in Duchenne muscular dystrophy (DMD). Our aim was to explore BMD and bone turn over and to evaluate their main determinants in a cohort of DMD subjects. BMD at lumbar spine, detected by DXA and expressed as Z-score values, C-terminal telopeptide of procollagen type I (CTX) and osteocalcin (BGP), as bone resorption and formation markers respectively, and sclerostin were assessed. Prevalent fragility fractures were recorded. Left Ventricular Ejection fraction (LVEF %) and Forced Vital Capacity (FVC %) were evaluated. Thirty-one patients [median age 14 (12 to 21.5) yr.] were studied. Ambulant subjects showed significantly higher Z-score values in comparison with not ambulant ones, and subjects with prevalent clinical fractures had significantly lower Z-score values in comparison to subjects without fractures. Z-score values were positively correlated with FVC (r = 0.50; p = 0.01), but not with GCs use, and FVC was positively associated with BGP (r = 0.55; p = 0.02). In not ambulant subjects, Z-score values were associated with BMI (r = 0.54; p = 0.02) and sclerostin was associated with age (r = 0.44; p = 0.05). At a stepwise multiple regression analysis, age, BMI, FVC and sclerostin levels were retained in the model as independent predictors of BMD. Our data confirm low BMD values in DMD subjects, especially in not ambulant ones, irrespective of the use of GCs, and identify, for the first time, FVC and sclerostin as main determinants of BMD in this cohort. Therefore, a multidisciplinary setting, focusing on rehabilitative and respiratory care, is warranted to reduce bone complications in DMD.
University of Messina, Italy; NEMO SUD Clinical Centre for Neuromuscular Disorders, Italy