Serum Iron Levels, Dietary Iron Intake, and Supplement Use in Relation to Metabolic Syndrome in Adolescents: A Cross-Sectional Study

The objective of this study was to investigate the potential associations between serum iron levels, dietary iron intake, and iron supplementation, and the prevalence of metabolic syndrome (MetS) in adolescents A cross-sectional analysis was conducted, utilizing data from adolescents participating in the 2003-2018 cycle of the National Health and Nutrition Examination Survey (NHANES). Odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) pertaining to serum iron, dietary iron, and iron supplementation were derived through multivariate logistic regression models. Additionally, a restricted cubic spline (RCS) regression model was applied to explore the nonlinear relationship between dietary iron and serum iron concerning MetS. The study encompassed 4858 American adolescents aged 12 to 19, among whom 413 (8.5%) manifested MetS. The study cohort exhibited an average age of 15.52 years, comprising 2551 males (52.51%) and 2307 females (47.49%). Relative to individuals in the lowest serum iron quartile, those in the highest quartile for serum iron (OR = 0.33, 95% CI 0.21-0.50), the highest quartile for dietary iron (OR = 0.53, 95% CI 0.32-0.89), and those utilizing iron supplements (OR = 0.61, 95% CI 0.37-0.99) evinced a diminished prevalence of MetS, even post adjustment for potential confounding variables. A non-linear relationship was discerned between serum iron and MetS, exhibiting a statistically significant negative correlation when serum iron concentrations exceeded the inflection point (serum iron = 8.66 mu mol/L, P for nonlinear < 0.001). This investigation reveals that higher levels of serum iron, increased dietary iron intake, and the use of iron supplements are linked to a lower prevalence of MetS in US adolescents. These findings suggest that dietary modifications could play a role in promoting the health of adolescents.