Association between red blood cell distribution width-related indicators and cataracts: differences in males and females

Hemoglobin (Hb), red blood cell distribution width (RDW), albumin, and their binding indicators: Hb-to-RDW ratio (HRR) and the RDW-to-albumin ratio (RAR), are serum biomarkers linked with systemic inflammation and nutritional status. Nevertheless, the relationships between these biomarkers and cataract prevalence, as well as potential gender-specific differences, remain unclear. We performed a cross-sectional analysis of 8,210 NHANES participants from the survey conducted between 2005 and 2008. We utilized weighted multifactor logistic regression, smooth curve fitting approaches, and restricted cubic splines to investigate RDW-related indicators and their relationship with cataract prevalence. We further applied subgroup analysis to assess stability in different populations. Lastly, we evaluated the discriminative performance of the model for prevalent cataract surgery using receiver operating characteristic (ROC) curves. After adjusting for all covariates, RAR was significantly associated with the prevalence of cataract surgery [adjusted OR (95% CI) = 1.28 (1.03, 1.59)]. RDW showed a modest positive association [adjusted OR (95% CI) = 1.08 (1.00, 1.18)]. Conversely, HRR exhibited a linear negative correlation with cataract prevalence [HRR: adjusted OR 95% CI = 0.41 (0.19, 0.90)], with notable interactions identified within age and gender subgroups. Gender-stratified analyses indicated different exposure–response patterns between males and females. ROC curve analysis indicated that RDW demonstrated a moderate discriminatory ability for cataract prevalence. Decreased HRR and increased RDW and RAR were associated with a higher prevalence of cataracts. The observed gender-specific associations highlight the need for further prospective studies to clarify the clinical relevance of these biomarkers across different populations.