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

Abstract

Objective: In aging populations, poor handgrip strength has been associated with physical disability and mortality. IGF1 is an important mediator of muscle growth and regeneration affecting muscle function. We studied the relationship between circulating levels of IGF1, its binding protein 3 (IGFBP3), and handgrip strength and physical performance in middle-aged-and oldest-old subjects. Design: Cross-sectional analysis in two different cohorts composed of middle-aged-(nZ672, mean 63.9G6.7 years) and oldest-old subjects (nZ272, all 89 years). Methods: Handgrip strength, functional performance and ability, and serum levels of IGF1 and IGFBP3 were measured in all subjects and analyzed by linear regression for men and women separately. Results: IGF1 and IGFBP3 levels declined with chronological age and were positively associated with handgrip strength in middle-aged-and oldest-old women (both, P!0.05), but not in men of either age group. Furthermore, higher serum levels of IGF1 were associated with slower walking speed in oldestold men (PZ0.012), and serum levels of IGFBP3 were positively associated with activities of daily living in the oldest-old women (PZ0.002). Conclusion: The significant relationship between IGF1 levels and muscle strength found in women but not in men suggests a gender-specific influence of IGF1 on muscle strength. Further studies are necessary to test the relationship with physical performance.

Gender differences in the association between grip strength and mortality in older adults: results from the KORA-age study

“…Our results suggest that older women are more sensitive to muscle strength alterations throughout ageing, probably as a result of sex differences in muscle mass as well as hormonal factors [25, 26]. It seems to be particularly important for the weakest to enhance their levels of muscular strength and build up muscle mass early in life, where targeted preventative efforts may be launched, to reduce their risk of premature death.…”

Serum levels of bioactive IGF1 and physiological markers of ageing in healthy adults

“…It is well-known that serum total IGF concentrations are related with age and several indices of physiological ageing such as body composition, strength, mobility and mortality (14,16,18,27,28). However, the measurement of IGF1 by immunoassay does not take the modifying effect of the IGFBPs on IGF1 action into consideration and therefore we found it relevant to compare total IGF1 and bioactive IGF1 in healthy subjects.…”

“…Moreover, total IGF1 levels are associated with strength, mobility and mortality in women (18,19). The production of GH is three times higher in women compared with men, despite the fact that circulating IGF1 concentrations are only marginally higher in women (20)), which indicates a relative GH resistance in women.…”

Serum concentrations of insulin-like growth factor-1, members of the TGF-beta superfamily and follistatin do not reflect different stages of dynapenia and sarcopenia in elderly women

“…On the other hand IGF-1 levels decrease during muscle atrophy (Frystyk, 2010;Goldspink et al, 2010). There is strong evidence to include IGF-1 in a set of blood-based biomarkers for the diagnosis of dynapenia and/or sarcopenia since several studies have shown that weak physical performance is associated with lower levels of circulating IGF-1 (Blain et al, 2012;Taekema et al, 2011).…”