Influence of waist circumference on the metabolic risk associated with impaired fasting glucose: effect of weight loss after gastric bypass.

BACKGROUND

Impaired fasting glucose (IFG) is a pre-diabetic state defined as a fasting plasma glucose (FPG) between 100 and 125 mg/dl. However, individuals in this group do not exhibit the same atherogenic risk.

METHODS

The atherogenic profile of subjects with IFG >110 mg/dl (IFG110, n = 96) or <110 mg/dl (IFG100, n=131) were compared and the potential differential impact of the waist circumference analyzed. In addition, the same clinical variables were measured in 18 morbidly obese patients (8 males, 10 females; BMI 45.3 +/- 1.9 kg/m2) before and after weight loss following Roux-en-Y gastric bypass (RYGBP), in order to analyze the influence of the reduction in waist circumference on the improvement of the metabolic risk factors.

RESULTS

Individuals in the IFG110 group showed decreased HDL-cholesterol levels together with an increased total cholesterol to HDL ratio (TC/HDL), accompanied by elevated homocysteine concentrations and white blood cell (WBC) count, and higher waist circumference (P<0.05 for all). Significant correlations between waist circumference and HDL-cholesterol (r=-0.200, P<0.05), TC/HDL (r=0.190, P<0.05), WBC count (r=0.299, P<0.05), and QUICKI (r=-0.375, P<0.0001) were observed. An almost 3-fold increase in the prevalence of T2DM in subjects in the IFG110 group as compared to IFG100 was observed. In the group of patients who underwent RYGBP, the reduction in waist circumference was significantly associated with the improvement in insulin sensitivity as evidenced by the QUICKI index (r=-0.582, P<0.05) and the reduction in TC/HDL (r=0.595, P<0.05).

CONCLUSION

Waist circumference is related to metabolic risk factors associated with increased levels of IFG. Our data support that individuals with IFG >110 mg/dl and a high waist circumference should undergo an OGTT to exclude the presence of diabetes.