Associations Between Muscle Mass, Muscle Morphology and Bone Health in Older Men With Sarcopenia: A Cross-sectional Study

Abstract

Background: The aim of this study was to explore the association between muscle mass, morphology, bone mineral density, and physical function in community-dwelling older men with sarcopenia.Methods: A total of 151 men, 60 years or older were included in this study. Body composition was measured by dual-energy X-ray absorptiometry (DXA). Low bone mineral density was diagnosed if T-score was equal to or below -1.0 SD of mean young men reference range. Sarcopenia was diagnosed according to European Working Group on Sarcopenia in Older People (EWGSOP) criteria: low muscle mass and low muscle strength or low physical performance. Physical performance was evaluated by short physical performance battery. Microbiopsy of musculus vastus lateralis was performed with disposable muscle microbiopsy system. The perimeter and cross-section area of muscle fibers were calculated using image analysis software in whole slide images; type of fiber and their distribution were evaluated as well. Relationship between variables were examined using Spearman’s and Pearson’s correlations. The level of significance (p-value) of < 0.05 was considered as statistically significant.Results: Mean age of the subjects was 72.9 ± 8.02 years. Sarcopenia was diagnosed in 45 (29.8%) men. In the sarcopenia group, 25 muscle biopsies were examined. The average muscle fiber length was 217.47 ± 25.22 microm and average fiber cross-sectional area was 2446 ± 608.87 microm2. In 9 sarcopenic men with T-scores equal or below -2.5, the muscle fiber area had a significant correlation with balance test (r = 0.73, p = 0.025). Multiple significant correlations were found between bone mineral density, lean mass, appendicular lean mass, arm and leg lean mass, gait speed, balance test and handgrip strength.Conclusions: In men with sarcopenia, low lean muscle mass was associated with low femoral neck and hip BMD, and lower muscle strength. In sarcopenic men with osteoporosis, lower muscle fiber area was associated with lower scores of balance test.Trial registration: study protocol has been approved by Lithuanian regional biomedical research ethics committee (No. 158200-03-208-75).