Association between muscle quality index and inflammatory markers in patients aged 50 to 60 with Dynapenia or Sarcopenia.

Abstract

Introduction

Dynapenia and sarcopenia are musculoskeletal conditions characterized by decreased muscle mass, strength, and function, prevalent in older adults. Factors such as hormonal changes, physical inactivity, the presence of comorbidities, and systemic inflammation contribute to their development. This inflammation alters muscle metabolism, increasing the risk of disability and mortality. In turn, muscle quality—which involves more than just muscle size or strength—is essential for functionality and physical performance. Both muscle quality and inflammatory markers are relevant indicators for identifying individuals at risk of functional decline.

General Objective

To evaluate the association between the Muscle Quality Index (MQI) and inflammatory markers in adults aged 50 to 60 years diagnosed with dynapenia or sarcopenia.

Materials and Methods

An analytical cross-sectional study was conducted in patients diagnosed with dynapenia or sarcopenia, treated at the LGII National Rehabilitation Institute. The muscle mass index (MMI) of the dominant arm and leg was determined using: maximum knee extension torque by isokinetic dynamometry, handgrip strength with a dynamometer, and segmental lean mass by bioimpedance. The MMI calculation was based on the formula of Jansen et al.

The inflammatory markers interleukin-6 (IL-6) and C-reactive protein (CRP) were quantified in blood samples. Data distribution was assessed using the Shapiro-Wilk test. To analyze the relationship between MMI and inflammatory markers, Pearson's correlation coefficient (for normally distributed data) and Spearman's rank correlation coefficient (for non-normally distributed data) were used.

Results

The sample consisted of 56 participants, of whom 73.2% were women with a mean age of 53.9 ± 3.2 years. 71.4% presented with dynapenia, 28.5% with sarcopenia, and 82.1% reported no comorbidities. No significant correlation was found between arm or leg muscle mass index (MMI) and IL-6 or CRP levels. A weak and non-significant inverse correlation was observed between leg MMI and log CRP (r = -0.146, p = 0.282), as well as between arm MMI and log CRP (r = -0.123, p = 0.365). A weak and non-significant positive correlation was also detected between leg MMI and 1/IL-6 (r = 0.105, p = 0.515), and between arm MMI and 1/IL-6 (r = 0.228, p = 0.152).

Conclusion

In middle-aged adults with dynapenia or sarcopenia and no comorbidities, no association was found between low-grade systemic inflammation and muscle function. However, further exploration of the impact of potential comorbidities on elevated inflammatory markers and their effect on muscle performance in this age group is suggested.