Serum leptin levels in patients with hyperlipidemias

Leptin is a protein hormone produced by adipocytes that reflects the body fat content. The aim of our study was to compare serum leptin levels in randomly selected untreated males and females with hypercholesterolemia and combined hyperlipidemia and in healthy control subjects matched for age and body mass index and to study the relations between leptin and serum lipids and lipoproteins. No statistically significant differences in serum leptin levels were found between the male control group (5.26 +/- 2.81 ng/mL(-1)) and the male group with hypercholesterolemia (8.16 +/- 3.85 ng/mL(-1)) or combined hyperlipidemia (7.51 +/- 4.83 ng/mL(-1)) and between the female control group (13.0 +/- 8.12 ng/mL(-1)) and the female group with hypercholesterolemia (15.36 +/- 8.89 ng/mL(-1)) or combined hyperlipidemia (18.63 +/- 10.15 ng/mL(-1)). Leptin concentration in male group with hypercholesterolemia did not differ significantly from the female control group; in the other male groups, leptin levels were significantly lower than those of the other female groups. Serum leptin levels in all studied groups except for the male group with hypercholesterolemia positively correlated with body mass index. Serum leptin levels correlated negatively with high-density lipoprotein cholesterol in the female group with hypercholesterolemia (r = -0.67, P < 0.01) and the male group with combined hyperlipidemia (r = -0.56, P < 0.01). A positive correlation between serum leptin and high-density lipoprotein cholesterol (r = 0.67, P < 0.01) and between leptin and lipoprotein (a) (r = 0.71, P < 005) was found in female group with combined hyperlipidemia. No other significant relationships between leptin and serum lipids or lipoproteins were found. We conclude that serum leptin levels in patients with hyperlipidemias do not significantly differ from those healthy control subjects matched by age and body mass index.