Exploring Associations and Mediating Factors between Multiple Trace Metals with Anemia in US Adults: Insight from NHANES 2017–2020

Abstract

Background: Anemia significantly contributes to the global disease burden, with its incidence potentially influenced by the trace metal content within the body. Objective: This study aims to examine the associations between trace metals and anemia risk, with a particular focus on investigating the potential mediating roles of iron status and inflammation in these associations. Methods: Five trace metals (Ni, Co, Mn, Se, and Mo) were examined in 1274 US adults, utilizing data from the National Health and Nutrition Examination Survey (NHANES) 2017–2020. The individual and combined effects of these metals on anemia were assessed using logistic regression, quantile g-computation (QGC), and Bayesian kernel machine regression (BKMR). A sex-stratified analysis was conducted to discern any gender-specific susceptibilities. Additionally, mediation analysis was employed to explore the potential mediating roles of iron status and inflammation in the associations between these metals and anemia. Results: Increased risks of anemia were positively associated with Co and Ni levels but negatively correlated with Se and Mn levels (all with p < 0.05). The trace metal mixture was negatively associated with anemia, with the highest weights of Co and Se in different directions in both the QGC and BKMR models. In the sex-specific analysis, we observed less pronounced protective effects from trace metals in females. Moreover, the mediating proportion of the iron status and inflammation in these relationships ranged from 10.29% to 58.18%. Conclusion: Our findings suggest that the trace element mixture was associated with decreased anemia risk, among which Se was a protective factor while Co was a risk factor, and females were more susceptible. The effects of these trace metals on anemia may be mediated by the iron status and inflammation.