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


METHODS
Cross-sectional analysis in two different cohorts composed of middle-aged- (n = 672, mean 63.9 ± 6.7 years) and oldest-old subjects (n = 272, 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 oldest-old men (P = 0.012), and serum levels of IGFBP3 were positively associated with activities of daily living in the oldest-old women (P = 0.002).


CONCLUSIONS
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.
Department of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, The Netherlands. d.g.taekema@lumc.nl
Diana G
DG
Taekema
Carolina H Y
CH
Ling
Gerard Jan
GJ
Blauw
Carel G
CG
Meskers
Rudi G J
RG
Westendorp
Anton J M
AJ
de Craen
Andrea B
AB
Maier
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D012737:Sex Factors; D016138:Walking / Q000502:physiology
D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I