Sex-Specific Differences in Dietary Iron Intake and Sleep Disorder in NHANES 2005-2014 Population

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.