Anemia and Sleep Disturbances: Mechanisms, Evidence and Clinical Implications - a Narrative Review.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing observational studies and clinical trials without quantitative meta-analysis.
PubMed 42416773 · doi:10.26574/maedica.2026.21.2.524
What was done
The authors searched PubMed/MEDLINE, Embase, Scopus, Web of Science, and the Cochrane Library from database inception through February 2026 without language restrictions. They evaluated cross-sectional, prospective cohort, case-control, randomized controlled trials of iron therapy reporting sleep outcomes, and systematic reviews. The review examined the relationship between anemia subtypes (iron deficiency anemia [IDA] and non-IDA) and sleep outcomes, including subjective quality, sleep architecture, total sleep duration, sleep latency, efficiency, restless legs syndrome (RLS), periodic limb movements, insomnia, and sleep-disordered breathing. Findings were synthesized narratively due to marked heterogeneity across study definitions and methods.
What was found
IDA was consistently linked to higher Pittsburgh Sleep Quality Index (PSQI) scores, reduced total sleep duration, extended sleep-onset latency, lower sleep efficiency, and decreased slow-wave sleep. Restless legs syndrome occurred significantly more frequently in individuals with IDA, with serum ferritin levels of 50 to 75 µg/L identified as clinically relevant thresholds. In most reviewed randomized controlled trials, oral or intravenous iron supplementation significantly decreased RLS severity scores and improved sleep disturbances (reported as moderate-certainty evidence). No pooled effect sizes, odds ratios, or absolute numbers were provided in the abstract.
Why it matters
This paper consolidates evidence linking iron deficiency to common sleep complaints and restless legs syndrome. It provides clinicians with a mechanistic and evidence-based rationale to screen iron indices and consider iron repletion for patients presenting with sleep fragmentation and RLS.
Limits
The synthesis is narrative rather than a quantitative meta-analysis due to significant variability in anemia definitions, sleep assessments, and study populations. The abstract does not report the total number of included studies, overall participant sample size, or specific quantitative findings for non-IDA subtypes.
Cited by
- supports Low iron or ferritin levels cause sleep disruption.