Serum Resistin Concentrations are Higher in Human Obesity but Independent from Insulin Resistance

Although obesity may be linked to resistin, the role of resistin in humans is still controversial. Conflicting results of the associations between resistin and BMI and measures of insulin resistance were reported. In view of the yet unexplained role of resistin in human obesity, the aim of this study was to examine correlations between serum resistin concentrations and the degree of human obesity and insulin sensitivity. For this purpose, we investigated 2 homogenous groups of obese and non obese humans, in whom the presence of obesity was the solely differentiating factor. The WHO definition of obesity was used. Study group consisted of 136 obese subjects (75 women and 61 men) and 48 non-obese controls (31 women, 17 men) aged 48.0 +/- 10.1, and 48.8 +/- 13.4 yrs, respectively. Results: Obese subjects showed higher resistin concentrations than non obese controls (24.89 +/- 9.73 ng/mL, median 26.61 vs. 15.34 +/- 4.68 ng/mL, median 14.76, P<0.0001). Resistin concentrations correlated with BMI in the whole cohort (r=0.4296, P<0.0001), but not in obese and non-obese subjects separately (r=0.1418, P=0.0997; r=0.2712, P=0.0623, respectively). Moreover, serum resistin was not influenced by insulin resistance in either group examined. Conclusion: Although concentrations of resistin differ between obese and non-obese humans, no relationship between resistin concentration and insulin resistance has been found. Correlations between resistin and BMI are present only in a mixed population but disappear in non obese and obese subjects when analyzed separately.