A-13 Free Communication/Slide - Aging and Skeletal Muscle: JUNE 2, 2010 9:30 AM - 11:30 AM: ROOM: 324
Serum concentrations of dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) decrease by ∼80% during the adult lifespan. Because DHEA is androgenic, it is possible that low DHEA levels in older age may contribute to age-related reductions in muscle strength and mass.
PURPOSE: To determine if DHEA replacement therapy in sedentary older (65-75y) men and women increases muscle strength and mass.
METHODS: Sedentary subjects were randomized to 1y oral DHEA supplementation (50 mg/d; n=63) or placebo (n=63). Isometric and isokinetic (60 and 180 deg/s) knee flexor and extensor strength were measured with dynamometry. Isotonic strength (1RM) was measured on 6 commonly used strength exercises. Whole body lean mass was measured with DXA and thigh muscle volume by magnetic resonance imaging. DHEAS, IGF-1, and testosterone were measured in serum.
RESULTS: DHEA supplementation increased serum DHEAS (6-fold increase), IGF-1 (+6%) and testosterone (+24%) (all p≤0.01 vs. placebo). Muscle strength did not change in either group based on results from isometric tests (knee extension + flexion: DHEA, +2.3±4.43 N·m; placebo, -0.02±4.64 N·m, p=0.70) isokinetic tests (sum of knee extension and flexion for both velocities: DHEA, +11.36±7.93 Nm; placebo, -1.03±6.25, p=0.33) or isotonic tests (sum of 6 exercises: DHEA, +8.3±5.9 kg; placebo, +2.0±5.5 kg, p=0.42). Strength results were similar in men and women. No differences between groups occurred for changes in lean mass (DHEA, +0.4±0.2 kg, placebo, -0.1±0.1 kg, p=0.42) or thigh muscle volume (DHEA, +6±16 cm3, placebo, -15±12 cm3, p=0.32). Results were similar in men and women for thigh muscle volume. However, while DHEA supplementation did not affect lean mass in men, DHEA supplementation increased lean mass in women (+0.6±0.3 vs. -0.3±0.2 kg, p=0.006). No correlations were found between the magnitude of change in serum androgens (DHEAS, IGF-1, testosterone) and changes in strength, muscle size, or lean mass.
CONCLUSIONS: In sedentary older adults, one year of DHEA replacement therapy increases serum androgen levels but does not affect lower extremity strength or muscle volume. However, in women, DHEA replacement may have a modest beneficial effect on whole body lean mass.
Grants: NIH AG020076, NIH GCRC RR00036, NIH CNRU DK56341. EPW Supported by AG00078, DK080886.