Attenuation of skeletal muscle and strength in the elderly: The Health ABC Study

Abstract

Although loss of muscle mass is considered a cause of diminished muscle strength with aging, little is known regarding whether composition of aging muscle affects strength. The skeletal muscle attenuation coefficient, as determined by computed tomography, is a noninvasive measure of muscle density, and lower values reflect increased muscle lipid content. This investigation examined the hypothesis that lower values for muscle attenuation are associated with lower voluntary isokinetic knee extensor strength at 60 degrees/s in 2,627 men and women aged 70-79 yr participating in baseline studies of the Health ABC Study, a longitudinal study of health, aging, and body composition. Strength was higher in men than in women (132.3 +/- 34.5 vs. 81.4 +/- 22.0 N x m, P < 0.01). Men had greater muscle attenuation values (37.3 +/- 6.5 vs. 34.7 +/- 7.0 Hounsfield units) and muscle cross-sectional area (CSA) at the midthigh than women (132.7 +/- 22.4 vs. 93.3 +/- 17.5 cm(2), P < 0.01 for both). The strength per muscle CSA (specific force) was also higher in men (1.00 +/- 0.21 vs. 0.88 +/- 0.21 N x m x cm(-2)). The attenuation coefficient was significantly lower for hamstrings than for quadriceps (28.7 +/- 8.7 vs. 41.1 +/- 6.9 Hounsfield units, P < 0.01). Midthigh muscle attenuation values were lowest (P < 0.01) in the eldest men and women and were negatively associated with total body fat (r = -0.53, P < 0.01). Higher muscle attenuation values were also associated with greater specific force production (r = 0.26, P < 0.01). Multivariate regression analysis revealed that the attenuation coefficient of muscle was independently associated with muscle strength after adjustment for muscle CSA and midthigh adipose tissue in men and women. These results demonstrate that the attenuation values of muscle on computed tomography in older persons can account for differences in muscle strength not attributed to muscle quantity.

Effect of bimagrumab on thigh muscle volume and composition in men with casting‐induced atrophy

“…Growing evidence suggests that the structural composition of a muscle is an important factor in its function 10. With ageing, muscle strength is lost at a faster rate than lean mass, pointing to additional determinants of impaired contractility in older adults 32.…”

“…Ageing is associated with a reduction in skeletal muscle mass, strength, and physical capacity, leading to impaired mobility, increased sedentary behaviour, and numerous adverse health effects 10. In such individuals, an acute episode of disuse atrophy (e.g.…”

Changes of gluteus medius muscle in the adult patients with unilateral developmental dysplasia of the hip

“…Muscle strength is proportional to not only the muscle volume or cross-sectional area (CSA) but also the muscle radiological density (RD), which may represent the actual amount of contractile muscle [34]. Thus we used CSA combined with muscular RD [17,35,36] to evaluate the atrophy of gluteus medius muscle.…”

Running‐wheel activity delays mitochondrial respiratory flux decline in aging mouse muscle via a post‐transcriptional mechanism

“…The loss of muscle strength, however, proceeds much faster than the loss of muscle mass (Goodpaster et al., 2006). This is in part attributed to neuromuscular coupling (Manini & Clark, 2012) and in part to intrinsic muscle characteristics such as intramuscular fat accumulation (Delmonico et al., 2009; Goodpaster et al., 2001; Marcus et al., 2012; Rivas et al., 2016) and mitochondrial function (Gouspillou, Bourdel‐Marchasson, et al. 2014; Hepple, 2016; Short et al., 2005).…”