Serum albumin in relation to change in muscle mass, muscle strength, and muscle power in older men

Objectives: To investigate the relationship between serum albumin and change in muscle mass, grip strength, and leg power.

Design: Prospective cohort.

Setting: Six U.S. academic medical centers.

Participants: Community-dwelling men aged 65 and older participating in the Osteoporotic Fractures in Men (MrOS) Study.

Measurements: Serum albumin was measured at baseline in 5,534 participants. Baseline serum albumin was examined in relation to change in appendicular skeletal muscle (ASM) mass, grip strength, and leg power after 2 and 4.6 years. Two-year change in serum albumin was examined with respect to simultaneous change in these outcomes in 1,267 participants.

Results: Baseline serum albumin <40 g/L was not associated with 2- or 4.6-year change in ASM mass, grip strength, or leg power before or after adjustment for confounders. There was no association between serum albumin change and change in grip strength. A statistically significant trend was observed between serum albumin change and change in ASM mass, but there was substantial overlap across confidence intervals (CIs). Participants with a marked decrease (>3 g/L) and mild decrease (1-2 g/L) in serum albumin over 2 years exhibited a modest change of -8.9 W (95% CI = -25.6 to -7.8 W) and -6.3 W (95% CI = -21.2 to -8.5 W) of leg power, respectively (P for trend = .02), compared with those with no decrease in albumin concentration.

Conclusion: Serum albumin demonstrated modest and inconsistent trends with loss of muscle mass and function. Low serum albumin within the normal range is not a risk factor for this process in elderly men.