Serum soluble transferrin receptor concentrations are increased in central obesity. Results from a screening programme for hereditary hemochromatosis in men with hyperferritinemia

Abstract

Background: A decrease in the serum concentrations of the soluble transferrin receptor (sTfR) is considered a good index of tissue iron. Because obesity is associated with hyperferritinemia and this is considered a sign of iron overload, a decrease in sTfR would be expected for the obese. We evaluated whether obese men with hyperferritinemia, detected in a genetic screening programme for hereditary hemochromatosis (HH), have lower serum concentrations of sTfR than their non-obese counterparts.

Methods: 75 men (age: 55.4+/-12.4 years) with hyperferritinemia (serum ferritin--SF > 200 microg/L) and no known conditions of iron overload were evaluated for body mass index (BMI), waist circumference (WC), blood pressure, traditional indices of iron status, sTfR, fasting plasma glucose, lipid profile, insulin resistance (HOMA-IR), highly-sensitive C-reactive protein, hepatic enzymes and HFE gene mutations of HH.

Results: sTfR correlated with BMI (r=0.289; p=0.014) and with WC (r=0.420; p<0.001). Thirty-two subjects were obese (BM > or = 30 kg/m(2)) and had a significantly higher sTfR (2.95 (2.22-3.28) vs 2.28 (1.88-2.91) mg/L; p=0.013), hemoglobin (157+/-12 vs 152+/-11 gr/L; p=0.049) and HOMA-IR (1.38 (1.04-2.69) vs 1.02 (0.60-1.55) mg/L; p=0.009) than the non-obese. WC explained separately more variability of the sTfR than BMI (r(2)=0.177; p=0.002 and r=0.077; p=0.042, respectively), after adjusting for potential confounders.

Conclusion: An increase in serum concentrations of sTfR is associated with central obesity in men with hyperferritinemia.