Potential early biomarkers of sarcopenia among independent older adults

Objectives: There are no tools or biomarkers for a quantitative analysis of sarcopenia. Study design: Cross-sectional study of the diagnosis of sarcopenia in 200 independent adults aged 70 years or over. Main outcome measures: Sarcopenia was defined as loss of muscle mass together with low strength and/or loss of physical performance. We considered different clinical parameters and assayed potential blood biomarkers (cell energetic metabolism, muscle performance, inflammation, infection and oxidative stress). Results: The prevalence of sarcopenia was 35.3% in women and 13.1% in men, and it was significantly associated with advanced age, a low functional performance in the lower extremities, deficient weekly consumption of kilocalories, risk of malnutrition, and drug use for the digestive system. A close relationship was found between sarcopenia, pre-frailty and depressed mood. With these confounding variables, we observed that products of lipid peroxidation were closely associated with sarcopenia in independent older adults (frail participants and those with severe dependence had been excluded from the sample). The best multivariate model proposed was able to predict 67.6% of the variance in sarcopenia, with a power of discrimination of 93.5%. Additional analyses considering lipid levels, fat mass, dyslipidemia, use of lipid-lowering drugs and hypertension confirmed this close association between lipid peroxidation and sarcopenia. Conclusions: Given the difficulty in the diagnosis of sarcopenia in clinical practice, we suggest the use of blood circulating products of lipid peroxidation as potential biomarkers for an early diagnosis of sarcopenia in independent older adults.