The relationship between grip strength and muscle mass (MM), inflammatory biomarkers and physical performance in community-dwelling very old persons

The main consequence of the loss of MM and muscle strength is limitations of physical performance and disability in older people. It is unclear whether a decline in functional capacity results from the loss of MM and/or the qualitative impairment of the muscle tissue. The aim of our research was to investigate the relationship between physical performance and grip strength, inflammatory markers and MM in a population of community-dwelling very old persons. This study is a cross-sectional analysis within the BELFRAIL-study, a cohort study of subjects aged 80 years and older (n=567). MM was assessed by bioelectrical impedance. Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) concentrations were determined on fasting blood samples. Logistic regression analysis was build using a low physical performance level evaluated according to Short Physical Performance Battery (SPPB) (dependent variable) and grip strength, pro-inflammatory status and MM (independent variables) adjusted for age and for the total number of chronic diseases. Low SPPB scores were associated with grip strength scores for women (OR 0.86 (95% CI 0.77-0.96)), and for men (OR 0.89 (95% CI 0.81-0.96)). The relationships between low SPPB and MM or inflammatory profile were not significant. Our results show that low physical performance remains associated with low grip strength even after considering other risk factors for sarcopenia in the oldest old and support the hypothesis that low muscle strength is a better indicator than low MM. The role of an inflammatory component in the age-related loss of muscle strength and function could not be confirmed.