Higher uric acid serum levels are associated with better muscle function in the oldest old: results from the Mugello study

Background: Sarcopenia is the progressive loss of muscle mass and strength that occurs with advancing age and plays a pivotal role in the causal pathway leading to frailty, disability and, eventually, to death among older per- sons. As oxidative damage of muscle proteins has been shown to be a relevant contributory factor, in this study we hypothesized that uric acid (UA), a powerful endogenous antioxidant, might exert a protective effect on mus- cle function in the oldest old and we tested our hypothesis in a group of nonagenarians who participated in the Mugello Study. Methods: 239 subjects, 73 men and 166 women, mean age 92.8 years ± SD 3.1, underwent the assessment of UA serum level and isometric handgrip strength, a widely used clinical measure of sarcopenia. Results: Mean UA serum level was 5.69 mg/dL ± SD 1.70 and mean handgrip strength was 15.0 kg ± SD 6.9. After adjusting for relevant confounders, higher UA serum levels remained independent positive predictors of isomet- ric handgrip strength (β 1.24 ± SE(β) 0.43, p = 0.005). Conclusion: Our results show that higher UA serum levels are associated with better muscle function in the oldest old and, accordingly, might slow down the progression of sarcopenia.