Is serum ferritin high in patients with diabetic retinopathy? A controlled study

It is suggested that an excessive absorption and storage of dietary iron might contribute in the pathogenesis of type II diabetes mellitus and its complications. However, previous studies had methodological problems including design, lack of matched controls and unspecified inclusion criteria. The aim of the study was to evaluate the relationship between diabetic retinopathy and serum ferritin levels in well-defined diabetic patients and controls. The study population comprised of 3 groups: patients with type II diabetes mellitus and severe diabetic retinopathy, diabetic patients without retinopathy, and non-diabetic, non-retinopathy patients. The groups were well matched by age, gender and hemoglobin levels, whereas diabetes characteristics and treatment differed. Serum iron, transferrin and ferritin levels were compared between the patients' groups. Twenty-two patients had diabetes and retinopathy, 29 patients had diabetes without retinopathy and 40 were non-diabetic, non-retinopathy patients. Serum iron or ferritin levels did not differ significantly between the 3 groups. Also, there was no correlation between HbA_1c level and serum iron or ferritin levels between the 2 diabetic patients' groups. Our findings suggest that iron does not have a major role in the development of diabetes mellitus or diabetic retinopathy.