Exploring the role of iron accumulation and muscle parameters as potential risk factors for sarcopenia

The link between iron accumulation and sarcopenia has become an increasingly important topic in aging and metabolic research. While there is a growing body of literature on this subject, the relationship remains poorly understood. Consequently, this study aims to explore the risk factors associated with sarcopenia by examining iron status through various iron biomarkers in conjunction with skeletal muscle parameters in individuals aged 60 to 80 years. In addition, we examine inflammation and physical performance as secondary risk factors that may contribute to sarcopenia in relation to iron status. Methods : We conducted a cross-sectional study using data collected during the year 2022–2023 from the affiliated hospital of Jiangsu University. Iron status was assessed using serum iron, serum ferritin, transferrin, total iron-binding capacity (TIBC), transferrin saturation. Skeletal muscle health was evaluated through measurements of total skeletal muscle mass (SMM), skeletal muscle index (SMI), body mass index (BMI) and both trunk and limb muscle mass. Inflammation was assessed by C-reactive protein (CRP) levels and white blood cell count. Physical performance was evaluated using handgrip strength and gait speed. Univariate and multivariate regression analyses were performed to explore the associations between these factors and sarcopenia. Results : A total of 102 participants were included. Significant associations were found between sarcopenia and several variables. Higher BMI and SMI were consistently protective against sarcopenia in both univariate and multivariate models (p < 0.05). Interestingly, the comparison Table 2 showed that CRP levels were significantly higher in participants with sarcopenia (1.7 ± 1.3 vs. 1.0 ± 0.7, p = 0.002), which aligns with the conventional understanding of inflammation's role in muscle degradation. However, it exhibited a paradoxical relationship, with higher levels linked to a lower risk of sarcopenia in both models. In the univariate regression, the odds ratio (OR) for CRP was 0.45 (95% CI: 0.25–0.84, p = 0.012), while in the multivariate regression, the OR was 0.51 (95% CI: 0.27–0.96, p = 0.037) This counterintuitive relationship suggests that further investigation into CRP's role in sarcopenia is needed. SMM and Weight showed a significant association in univariate regression (OR = 0.87, 95% CI: 0.79–0.95, p < 0.003) and (OR = 0.82, 95% CI: 0.75–0.90, p < 0.001) respectively. Although higher ferritin levels showed no significant association in the univariate analysis (p = 0.301), they were significantly associated with a slight increase in sarcopenia risk in the multivariate model (OR = 1.01[1.00; 1.02], P = 0.009). However, this finding requires further investigation. Other variables such age, transferrin did not show statistically significant associations with sarcopenia. Physical performance, measured by handgrips and gait speed, was assessed but not analyzed for statistical significance. Conclusion : These findings highlight the protective roles of BMI and SMI in reducing the risk of sarcopenia, while revealing the unexpected protective effect shown by CRP, challenging the traditional view of inflammation as a risk factor for sarcopenia and highlighting the complexity of its role in muscle health. Further research is needed to clarify the mechanisms underlying this relationship. Ferritin, an indicator of iron stores, showed a slight positive association with sarcopenia, suggesting that higher ferritin levels may marginally increase the risk, though this effect is small and warrants further investigation, especially after controlling for potential confounders. Although physical performance was measured, its role in sarcopenia was not a focus of this study.