Relation between serum high molecular weight adiponectin and serum ferritin or prohepcidin in patients with type 2 diabetes

An increase of serum ferritin, an indicator of body iron store, is associated with insulin resistance and with an increased risk of type 2 diabetes in the general population. A low serum adiponectin is also associated with insulin resistance. Recently, hepcidin was identified as a regulator of iron metabolism. We investigated whether serum adiponectin was associated with serum ferritin or prohepcidin, a precursor of hepcidin, in healthy subjects and patients with type 2 diabetes. We studied 65 healthy subjects and 104 patients with type 2 diabetes. A serum ferritin concentration ≥ 300 ng/ml for men or ≥ 150 ng/ml for women was defined as hyperferritinemia. Serum ferritin was significantly higher and serum prohepcidin was significantly lower in diabetic patients than in control subjects. Serum total and high molecular weight (HMW) adiponectin correlated negatively with serum ferritin in control subjects or diabetic patients, while serum total and HMW adiponectin correlated positively with serum prohepcidin in diabetic patients, but not in control subjects. Serum total and HMW adiponectin were lower in patients with hyperferritinemia than in those without it. In conclusion, serum ferritin was increased in type 2 diabetic patients, while serum prohepcidin was decreased. A high serum ferritin was associated with insulin resistance, and with low serum total and HMW adiponectin in patients with type 2 diabetes.