Association between dietary iron intake from natural food sources and the likelihood of abdominal aortic calcification in US adults: a population-based study

Abstract Background This study aimed to investigate the relationship between dietary iron intake and risk of abdominal aortic calcification (AAC) in middle-aged and older US adults. Methods We analyzed data from the 2013-2014 National Health and Nutrition Examination Survey (NHANES). Multivariate linear and logistic regression models were employed to evaluate the association between dietary iron intake and AAC score, as well as the likelihood of both AAC and severe AAC. To investigate potential non-linear dose-response relationships, we performed restricted cubic spline (RCS) modeling. In addition, stratified analyses and interaction tests were conducted to assess the effect modification by relevant covariates. Results A total of 2640 participants were included in the final analysis.The mean AAC score was 1.47 ± 0.14, with a prevalence of AAC and severe AAC of 27.79% and 8.12%, respectively. An inverse association was observed between dietary iron intake and both AAC score (β = − 0.03; 95% CI: − 0.04 to − 0.02) and the likelihood of severe AAC (OR = 0.98; 95%CI: 0.95 to 0.99). Notably, participants in the highest tertile of dietary iron intake exhibited a 0.56-unit decrease in mean AAC score (β = -0.56, 95% CI:-1.24 to -0.13) and a significant 60% decrease in the risk of severe AAC (OR = 0.40, 95%CI: 0.20 to 0.81). However, no statistically significant association was found between dietary iron intake and the overall risk of AAC. Subgroup analyses and interaction tests indicated that AAC scores were significantly influenced by age, alcohol consumption, and smoking status. Moreover, a history of stroke was significantly associated with increased risk of severe AAC. Conclusion We observed that higher dietary iron intake was inversely associated with AAC score and the risk of severe AAC. Our findings suggested that clinicians need to focus on dietary iron intake in patients at risk for AAC.