TFRC and obesity due to melanocortin 4 receptor deficiency: In this cross-sectional study of a national representing population, we ought to elucidate the association of sTfR and cardiovascular diseases, and our data suggested: 1) higher sTfR levels were associated with higher prevalence for cardiovascular diseases; 2) serum sTfR levels were associated with several cardiovascular risk factors including obesity, hypertension, diabetes, and insulin resistance.