Objective: To determine if insulin-like growth factor 1 (IGF-1) is associated with strength and functional ability in healthy older men.
Design: Cross-sectional study.
Setting: San Francisco Department of Veterans Affairs Medical Center.
Participants: One hundred four ambulatory community-dwelling men.
Measurements: Serum IGF-1 levels were obtained. Measured variables included strength of the knee flexors and extensors, handgrip, score on the Physical Performance Test, body composition, and three tests of cognitive function.
Results: The subjects' mean age was 75.5 +/- 4.9 (SD) years (range 70-94 years), and their mean IGF-1 level was 134.7 +/- 43.6 ng/mL. The univariate association of age with the variables was much stronger than the univariate association of IGF-1 with the same variables. In multivariable models, age, but not IGF-1, was associated with the variables.
Conclusion: In this study of healthy older men, age is the most important variable in predicting functional decline. There was no association of IGF-1 levels to functional status independent of age.