Association of hemoglobin-to-red blood cell distribution width ratio and depression in older adults: A cross sectional study

The association between hemoglobin-to-red blood cell distribution width ratio (HRR) and the depression in old adults was not clear. We extracted data on depression, general characteristics, lifestyle, medical history, drug use, and blood indicators from the National Health and Nutrition Examination Survey 2005–2018 to investigate the relationship between HRR and depression. A total of 4141 individuals were evaluated, among whom 266 (6.4 %) were identified as having depression. HRR was significantly lower in the low depression group, and Spearman correlation analysis revealed an inverse association between HRR and depression scores (r = −0.148, P < 0.001). Multiple linear regression showed that HRR was associated with depression after adjusted for general characteristics, life style, medical history, drug use and blood indicators (P = 0.010). ROC analysis demonstrated that in participants with depression, the area under the curve (AUC) for HRR was 0.612, surpassing both Hb(0.586) and RDW(0.401). These findings were statistically significant (P < 0.05). Only participants aged 65–79 years are selected for this study and this was a cross-sectional study that can only represent an association between HRR and depression, but not a cause-and-effect relationship. HRR, being more potent than Hb or RDW, emerges as an independent risk factor for depression. It has the potential to facilitate early depression detection, aiding in the prevention of clinical deterioration or relapses, and could also serve as a viable treatment target.