CRP and sarcopenia: Among the four immune activation biomarkers, CRP showed a positive correlation with sarcopenia (SMD = 0.35, 95% CI (0.06, 0.64), K = 26, N = 8137, I2 = 96.0%) and the SO population (SMD = 1.71, 95% CI (0.2, 3.23), K = 7, N = 1154, I2 = 98.7%) compared to individuals with normal muscle function (Figure 3a,b).