There are various studies documenting the association of serum leptin (Lep) with other variables including serum tumor necrosis factor-alpha (TNF-α), total cholesterol (TC), serum testosterone (ST) and interleukin-6 (IL-6) in HT [17,18,19,20] and OW-related HT (OHT) [21,22,23]. Here, LEP is linked to hematocrit.