HRR was significantly negatively associated with sleep disorders, sleep problems, and depression, with depression mediating 10.59% and 23.14% of the association between HRR and sleep disorders and sleep problems, respectively.
Higher hemoglobin-to-red cell distribution width ratio (HRR) was significantly negatively associated with sleep disorders in US adults.
Higher HRR was significantly negatively associated with sleep problems in US adults.
Higher HRR was significantly negatively associated with depression in US adults.
Depression mediated a statistically significant but partial portion of the association between HRR and sleep disorders.
Depression mediated a larger portion of the association between HRR and sleep problems than it did for sleep disorders.
The study used restricted cubic spline (RCS) modeling and threshold effect analysis in addition to multivariable logistic regression to characterize the HRR–sleep quality relationship.
The study population consisted of 20,823 participants drawn from ten years of NHANES survey cycles.
This research suggests that a blood marker called the hemoglobin-to-red cell distribution width ratio (HRR) — calculated by dividing a person's hemoglobin level by a measure of variation in red blood cell size — is linked to sleep quality. Using data from over 20,000 American adults surveyed between 2005 and 2014, the study found that people with higher HRR values were significantly less likely to report sleep disorders or general sleep problems. Higher HRR was also associated with lower likelihood of depression. These associations held up after accounting for a wide range of other health and demographic factors. The study also explored whether depression plays a role in the pathway connecting HRR to sleep quality. The analysis found that depressive symptoms accounted for about 11% of the link between HRR and sleep disorders, and about 23% of the link between HRR and sleep problems. This suggests that while depression partially explains why lower HRR relates to worse sleep, the majority of the association operates through other mechanisms not yet identified. This research suggests that HRR — a simple ratio derivable from routine blood tests — may serve as a useful indicator of sleep health risk. Because both hemoglobin levels and red cell distribution width can be influenced by nutrition, inflammation, and chronic disease, these findings point to potential biological pathways connecting blood health to sleep and mental health. However, since this was an observational study relying on self-reported sleep measures, it cannot establish that low HRR directly causes poor sleep.
Liao Z, Zhou Z. (2026). Association between the hemoglobin-to-red cell distribution width ratio and poor sleep quality in US adults.. Acta psychologica. https://doi.org/10.1016/j.actpsy.2026.106461