Assessment of serum adiponectin and leptin levels in lean and overweight type 2 diabetes mellitus and their relation to insulin level

ABSTRACT

The purpose of this study was to assess the serum adiponectin and leptin levels in type 2 diabetic and to clarify the degree of association of adiponectin with insulin levels and diabetes mellitus independent of its association to obesity. A total of 169 type 2 diabetics [103 females and 66 males, mean age 51 +/- 10 years] and 85 healthy adults matching the same age with the patient group [43 females and 42 males, mean age 48 +/- 6.7 years] were enrolled in the study. The studied subjects were classified according to their BMI into; lean [BMI < 25 kg/m[2]] and overweight-obese group [BMI > 25 Kg/m[2]]. Accordingly, there were 4 groups group 1; lean diabetic [67 subjects], group 2; overweight-obese diabetic [102 subject], group 3; lean non-diabetic [36 subjects], group 4; overweight-obese non-diabetic [49 subjects]. Fasting insulin was assayed using RIA technique of DPC Diagnostics. Fasting serum leptin was measured by RIA using Kits purchased from Linco Research. Adiponectin was assayed using Elisa kit purchased from Quantikine [Catalog Number DRP300]. Adiponectin concentrations were lower in the overweight-obese non diabetic group compared to the lean non diabetic group [p value < 0.05], and the diabetic group compared to the non-diabetic group [p value < 0.001]. The same pattern was observed when we compared obese diabetics to obese non-diabetic groups [p value < 0.05], and lean diabetic and lean non-diabetic groups [p value < 0.001]. There was no significant difference of adiponectin levels between overweight-obese and lean diabetic groups [p value > 0.05]. Adiponectin was found to be positively correlated to FBS, PPS, and HDL and negatively correlated to BMI, total cholesterol, triglycerides, LDL, fasting insulin and leptin concentrations. Serum leptin concentrations are higher in both obese diabetic and non-diabetic groups compared to lean diabetic and non-diabetic groups [p value < 0.05, and < 0.05 respectively]. Leptin was positively correlated to BMI [p value < 0.001] and fasting insulin concentrations [p value < 0.001], and negatively correlated to adiponectin concentrations [p value < 0.01]. Serum adiponectin level is low in obese subjects and is consistently lower in diabetic patients in comparison to non diabetic subjects independent to BMI. The data suggest that serum adiponectin level is more related to insulin level than to the body weight