[Comparison of serum leptin levels of non-diabetic and diabetic obese subjects and its relationship to anthropometric indices]

ABSTRACT

Leptin, the product of the ob gene, plays a significant role in the pathogenesis of obesity and type 2 diabetes mellitus. The aim of this study was to compare serum leptin level in non-diabetic and type 2 diabetic obese subjects and assess its relationship to anthropometric indices. This cross-sectional study was performed on 35 obese subjects with type 2 diabetes and 35 non-obese, non-diabetics. Fasting lipid profiles were measured using enzymatic methods. The NycoCard HbA1c Kit was used to measure HbA1c. Serum leptin, insulin and glucose levels were measured by an enzyme immunoassay, using a commercially available kit and glucose oxidase methods respectively. The insulin resistance index was calculated by homeostasis model assessment [HOMA-IR]. The mean of insulin resistance index [HOMA-IR], HbA1c, diastolic blood pressure, triglyceride and fasting glucose in diabetics were significantly higher than in non-diabetic subjects [P < 0.05]. Serum leptin levels were significantly lower in diabetics than in non-diabetics [21.51 +/- 2.18 vs. 30.36 +/- 2.46] and were significantly higher in women than in men [31.85 +/- 17.96 vs.12.80 +/- 9.02] in the diabetic and [36.11 +/- 10.99 vs. 23.55 +/- 15.72] in non-diabetic groups. There was a direct and significant correlation between serum leptin levels with hip circumference [r= 0.450, p= 0.04] in diabetics and [r=0.590, p=0.000] in non-diabetics, and between leptin and BMI [r= 0.666, p= 0.000] in diabetic and [r= 0.490, p= 0.003] in non-diabetic groups. Since the mean serum leptin level is lower in obese diabetes, compared to non-diabetics, further studies are required to clarify the mechanisms of lower leptin levels in obese diabetic subjects: