Association between dietary iron intake and stroke in U.S. adults: a cross-sectional study

The present investigation sought to examine the association between iron consumption from diet and stroke incidence in the adult population of the U.S.

We analyzed adults from the 2011-2018 National Health and Nutrition Examination Survey (NHANES). Dietary iron intake was assessed using two 24-hour dietary recalls, with the average value used for subsequent studies. The diagnosis of stroke is assessed using a medical condition questionnaire (MCQ),though no stroke subtype was recorded. The association between dietary iron consumption and stroke probability was evaluated using logistic regression modeling. Nonlinear associations were investigated via the application of restricted cubic splines(RCS).

The research involved 5,817 adult individuals. The analysis using multivariable-adjusted regression models revealed a significant correlation between iron consumption from dietary sources and stroke accident incidence among the adult population. Analysis of dietary iron consumption demonstrated that participants with moderate intake levels (Q3: 12.49-17.76 mg/day) exhibited a 35% lower cerebrovascular risk relative to the lowest consumption group (Q1: < 8.67 mg/day). This protective association was statistically confirmed by the multivariable-adjusted model (OR = 0.65, 95% CI:0.43-0.98; p = 0.0413), suggesting optimal neuroprotective benefits occur at intermediate dietary iron concentrations. The threshold effect analysis demonstrated that participants with daily iron intake below 8.09 mg exhibited a 17% reduction in cerebrovascular event risk (OR = 0.83, 95% CI:0.75-0.91; p < 0.0001), suggesting a significant dose-response relationship at lower consumption levels.

This research revealed a non-linear, L-shaped association between dietary iron intake and the likelihood of stroke among U.S. adults. For individuals consuming less than 8.09 mg/day, higher iron intake was correlated with a reduced risk of stroke. Nonetheless, additional prospective investigations are required to clarify and confirm this relationship.