# Sex‐Specific Differences in Dietary Iron Intake and Sleep Disorder in NHANES 2005–2014 Population

## TL;DR

This study found that higher dietary iron intake is linked to fewer sleep disorders in women but not in men.

## Contribution

The study reveals a sex-specific relationship between dietary iron intake and sleep disorders, with a unique L-shaped association in women.

## Key findings

- Higher dietary iron intake is inversely associated with sleep disorders in women.
- There is an L-shaped relationship between iron intake and sleep disorders in women.
- No significant association was found between iron intake and sleep disorders in men.

## Abstract

The association between dietary iron intake and sleep disorder remains insufficiently understood. The aim of this research was to explore the relationship between dietary iron intake and sleep disorder. This research used data from the National Health and Nutrition Examination Survey conducted during the period from 2005 to 2014. Weighted logistic regression analyses were performed to detect the association between iron intake and sleep disorder. The participants had a mean age of 46.92 ± 0.29 years, and 51.19% were female. Overall, dietary iron intake showed a significant inverse association with sleep disorders (log2‐transformed iron intake: OR, 0.84; 95% CI: 0.74, 0.96). Per log2‐transformed unit increase in iron intake, the odds of sleep disorders decreased by 23% in women (OR: 0.77; 95% CI: 0.66, 0.91). However, dietary iron intake was not associated with sleep disorder in men (OR: 0.94; 95% CI: 0.81, 1.10). In addition, there was an L‐shaped relationship between iron intake with sleep disorder among women (p for non‐linearity = 0.01). This study demonstrated that higher dietary iron intake was inversely associated with sleep disorder exclusively in women.

This study reveals sex‐specific differences in the relationship between dietary iron intake and sleep disorder. Increased iron intake is associated with a lower prevalence of sleep disorders, with this correlation observed exclusively in women. The analysis also shows an L‐shaped association in women, indicating a threshold effect.