Markers of inflammation and their association with muscle strength and mass: A systematic review and meta-analysis

Background: Chronic inflammation has been associated with sarcopenia and its components skeletal muscle strength and muscle mass. The aim of this systematic review and meta-analysis was to determine the relationship between systemic inflammation, muscle strength and/or muscle mass in adults. Methods: An electronic search using keywords such as 'acute phase proteins, cytokines and sarcopenia, muscle mass, muscle strength' was conducted via Pubmed, Web of Science and Embase from inception until the 30th of June 2020. A meta-analysis using correlation data was performed to determine the overall relationship between inflammation and muscle strength and muscle mass in adults. Results: Overall, 168 articles; 149 cross-sectional articles (n = 76,899 participants, 47.0 % male) and 19 longitudinal articles (n = 12,295 participants, 31.9 % male) met inclusion criteria. Independent of disease state, higher levels of C reactive protein (CRP), Interleukin (IL)-6 and Tumor necrosis factor (TNF)alpha were associated with lower handgrip and knee extension strength (CRP; r = 0.10, p < 0.001, IL-6; r = -0.13, p < 0.001, TNF alpha; r = -0.08, p < 0.001 and CRP; r = -0.18, p < 0.001, IL-6; r = -0.11, p < 0.001, TNF alpha; r = -0.13, p < 0.001 respectively) and muscle mass (CRP; r = -0.12, p < 0.001, IL-6; r = -0.09, p < 0.001, TNF alpha; r = -0.15, p < 0.001). Furthermore, higher levels of systemic inflammatory markers appeared to be associated with lower muscle strength and muscle mass over time. Conclusion: Higher levels of circulating inflammatory markers are significantly associated with lower skeletal muscle strength and muscle mass.