<h4>Aims</h4>To clarify the relationship between serum ferritin (SF) levels and diabetic retinopathy (DR) and to analyze the mediating role of the neutrophil-to-albumin ratio (NAR).<h4>Methods</h4>A total of 1,884 middle-aged and elderly patients (aged ≥ 45 years) with type 2 diabetes mellitus (T2DM) were included in this study. The gene discussed is ALB; the disease is diabetes mellitus.