Muscle size, strength and physical performance and their associations with bone structure in the Hertfordshire Cohort Study

Sarcopenia is associated with a greater fracture risk; this relationship was originally thought to be explained by an increased risk of falls in sarcopenic individuals. However, in addition, there is growing evidence of a functional muscle-bone unit in which bone health may be directly influenced by muscle function. Since a definition of sarcopenia encompasses muscle size, strength and physical performance, we investigated relationships for each of these with bone size, bone density and bone strength to interrogate these hypotheses further in participants from the Hertfordshire Cohort Study. 313 men and 318 women underwent baseline assessment of health and detailed anthropometric measurements. Muscle strength was measured by grip strength and physical performance was determined by gait speed. Peripheral quantitative computed tomography (pQCT) examination of the calf and forearm was performed to assess muscle cross-sectional area (mCSA) at the 66% level, and bone structure (radius and tibia, 4% and 66% levels). Muscle size was positively associated with bone size (distal radius total bone area β = 17.5mm(2) /SD [12.0, 22.9]) and strength (strength strain index (β = 23.3mm(3) /SD [18.2, 28.4]) amongst women (p