McArdle disease (muscle glycogen phosphorylase deficiency) is a genetic condition associated with exercise intolerance, but how it affects lean mass (LM) and bone mineral content (BMC) and density (BMD) in patients is unknown. We compared these variables between McArdle patients and age-/sex-matched healthy controls and assessed their potential association with physical activity levels in patients.
A case–control, cross-sectional design was used to examine LM, BMC, and BMD by using dual-energy x-ray absorptiometry in 136 young adults of both sexes (36 McArdle patients (33 ± 15 yr) and 103 controls (34 ± 11 yr)). Physical activity was assessed using the International Physical Activity Questionnaire.
McArdle patients had significantly lower LM values in whole-body and regional sites compared with their corresponding controls, whereas no differences were found (except for the trunk) when physically active patients (n = 23) were compared with controls. All bone-related variables were significantly lower in patients than in controls (average difference of 13% for BMC and 7.6% for BMD). By contrast, no significant differences at the lumbar spine, pelvis, and femur sites were found between physically active patients and controls.
We report on a previously undescribed condition in McArdle patients, poor bone health, which warrants further attention because it can occur in relatively young adults. An active lifestyle can at least partly alleviate this disorder presumably because of its beneficial effect on LM.
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1GENUD Toledo Research Group, Universidad de Castilla–La Mancha, Toledo, SPAIN; 2CIBER of Frailty and Healthy Aging (CIBERFES), Madrid, SPAIN; 3Department of Sport and Computer Science, Section of Physical Education and Sports, Faculty of Sport, Universidad Pablo de Olavide, Sevilla, SPAIN; 4Research Institute Hospital 12 de Octubre, Madrid, SPAIN; 5Department of Neurosciences, Institut d’Investigació en Ciències de la Salut Germans Trias i Pujol I Campus Can Ruti, Universitat Autònoma de Barcelona, Badalona, SPAIN; 6CIBER of Rare Disorders (CIBERER), Madrid, SPAIN; and 7School of Research and Doctorate Studies, Universidad Europea de Madrid, Madrid, SPAIN
Address for correspondence: Ignacio Ara, Ph.D., GENUD Toledo Research Group, Universidad de Castilla-La Mancha, Avda Carlos III s/n, 45071 Toledo, Spain; E-mail: firstname.lastname@example.org.
Submitted for publication April 2017.
Accepted for publication August 2017.
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