Relationship between age-associated endocrine deficiencies and muscle function in elderly women: a cross-sectional study

Abstract

Objective: muscle receptors and selected anabolic effects have been identified for both insulin-like growth factor I (IGF-D and 1,25-dihydroxyvitamin D (l,25(OH)2D3). The aim of the present study was to test the hypothesis that the decreasing concentrations of these endocrine factors might be involved in the decline in muscle function that characterizes normal human ageing. Design: cross-sectional study. Study participants: a community-based sample of 245 healthy elderly women aged 70-90 years. Exclusion criteria were diseases or medications known to affect muscle function or the somatotrophic axis. Measurements: knee extension strength was evaluated using an isokinetic dynamometer. A standardized questionnaire was used to assess habitual physical activity. IGF-I and 1,25(OH)2D3 were measured by radioimmunoassay. Vitamin D binding protein (DBP) was measured by single radial immunodiffusion and the free 1,25(OH)2D3 concentration calculated as the molar ratio of total 1,25(OH)2D3 to DBP Results: the differences in isometric and isokinetic strength over the age range were equivalent to losses of 0.9-2.4% per year. However, no relationship was found between the somatotrophic axis or vitamin D status and knee extension strength, despite markedly decreasing concentrations of circulating IGF-I and free I ,25(OH)2D3 with age. Conclusion: levels of circulating IGF-I and free 1,25(OH)2D3 appear not to be involved in the loss of muscle function that characterizes normal human ageing.

Neuromuscular and Psychomotor Function in Elderly Subjects Who Fall and the Relationship With Vitamin D Status

“…Bischoff et al (24) found that although 25OHD and 1,25(OH) 2 D 3 were found to correlate with leg extension power in men, only 1,25(OH) 2 D 3 correlated with extensor power in women. These results conflict with Boonen et al, (25) who did not observe a relationship between free 1,25(OH) 2 D 3 and knee extensor strength in a cross-sectional study of 245 elderly women. Cellular levels of vitamin D may be more important measures with respect to muscle function than serum levels, but unfortunately these are difficult to measure.…”

Circulating levels of IGF1 are associated with muscle strength in middle-aged- and oldest-old women

“…A significant positive relationship has been shown between low plasma IGF1 and functional outcome, such as impaired physical performance and self-reported difficulties with mobility tasks (10,32,33). However, physical performance has also been found to be negatively associated with IGF1 serum levels (13,35,(43)(44)(45). Our findings regarding functional performance and ADL disability are also conflicting with higher IGF1 serum levels being associated with slower walking speed in oldest-old men and a positive association between serum levels of IGFBP3 and ADL in oldest-old women.…”

Chronic inflammation and the effect of IGF-I on muscle strength and power in older persons

“…Moreover, Fernandez-Celemin and Thissen (13) demonstrated that IL-6 controls IGF-I biological activity through a stimulation of hepatic IGFBP-4 gene expression. In humans, contrasting findings on the potential role of IGF-I on muscle function have been reported (9,7,17,19,20,25,26). In fact, a cross-sectional study in 245 healthy elderly women showed that plasma IGF-I levels did not explain the age-associated decline of muscle function, a phenomenon that is considered part of normal human ageing (7).…”