Association between dietary intake of iron and heart failure among American adults: data from NHANES 2009-2018.

Patients with heart failure (HF) often experience iron deficiency. Intravenous iron supplementation has been widely used in clinical practice to facilitate the treatment of HF. However, the association between dietary iron intake and HF still needs to be elucidated. This study aimed to evaluate the impact of dietary iron intake on HF in American adults. The data were extracted from the National Health and Nutrition Examination Survey (NHANES) 2009-2018. Iron dietary intake data were obtained from two 24-h dietary recall interviews. We examined baseline data and HF prevalence in different quartile groups of dietary iron intake (Q1-Q4). Two logistic regression models were established to evaluate the impact of Q4 (highest iron consumption) on the risk of HF. The study included 20,853 American adults (age ≥ 20 years). The participants with the highest iron intake (Q4) had the lowest prevalence of HF (Q1: 3.25%, Q2: 2.18%, Q3: 1.92%, Q4: 1.72%; P < 0.001). After adjusting for possible confounding factors, the highest iron intake (Q4) was significantly associated with a reduced risk of HF compared with that of Q1 (odds ratio 0.58, 95% confidence interval 0.41-0.82; P = 0.003). This association remained stable in subgroups of women, current smokers, and Hispanics other than Mexican Americans. This study revealed that the dietary intake of iron was negatively associated with HF in adults without exceeding the tolerable maximum daily intake of 45 mg/day.