Muscle function and age are associated with loss of bone mineral density in Duchenne muscular dystrophy.

INTRODUCTION

Patients with Duchenne muscular dystrophy (DMD) demonstrate decreased bone mineral density (BD). It is not clear which factors exert the greatest impact on BD loss in these patients.

METHODS

In 63 patients with DMD, serum cytokines (interleukin [IL]-1, IL-6, and tumor necrosis factor-beta [TNF-β]), C-reactive protein (CRP), creatine kinase (CK), muscle function (by Vignos scale), body composition, and total BD (the latter 2 measured by dual-energy X-ray absorptiometry, or DEXA) were determined.

RESULTS

The main factors associated with BD loss were muscle function (34.0%; β = -0.139; P < 0.023) and age (36.7%; β = -0.151; P = 0.004). Cytokines, CRP, body fat mass, and CK did not contribute to BD loss.

DISCUSSION: Muscle function and age contribute to BD loss in DMD. We propose that a cut-off of at least 6 points for the Vignos scale and at least 10.5 years of age predict a Z-score of less than or equal to -2.0. Muscle Nerve 59:417-421, 2019.