Serum albumin is associated with skeletal muscle in elderly men and women

Serum albumin concentrations decrease with age and values < 38 g/L are associated with increased morbidity mortality, and disability in the elderly. It is not clear to what extent the decreases are associated independently with changes in metabolism, dietary intake, physical activity, morbidity, or body composition. We examined associations of serum albumin with age, protein and energy intakes, physical activity, morbidity, and muscle mass in 275 men and women aged 60-95 y. Serum albumin was measured with the bromcresol green procedure. Usual dietary intake and physical activity were quantified through questionnaires. Morbidity was ascertained from medical history, questionnaire, and examination. Muscle mass was estimated from dual-energy X-ray absorptiometry. In multivariate analyses, serum albumin was associated significantly with muscle mass after age, protein intake, physical activity, and comorbidity were controlled for in men and women. This study suggests that decreases with age in serum albumin concentrations are associated with muscle loss (sarcopenia) in the elderly. This association is independent of other factors that may affect muscle mass and albumin concentration. We suggest that the increased risk of disability with low serum albumin concentrations observed in the elderly may actually reflect an association with sarcopenia.