Background

The purpose of this study was to find an independent relationship between waist circumference/waist-to-hip ratio which estimates abdominal fat and fasting insulin/atherogenic index which is a predictor of coronary heart disease in obese women.

Methods
The subjects were 80 obese (BMI≥25 kg/m²) women. Whole body fat was estimated by body fat mass, % body fat using bioelectrical impedence, and by BMI. Abdominal fat was measured by waist circumference (WC) and waist-to-hip ratio. Fasting insulin was examined and atherogenic index was defined asthe ratio of serum total cholesterol to HDL-cholesterol. Independent association between abdominal fat and insulin/AI was analyzed using partial correlation, multiple regression and Hotelling t-test.

Results
Among subjects, 85.7% of obese women had WC greater or equal to 80 cm. The mean BMI was 30.3 kg/m². The partial correlations between whole body fat and insulin/AI were not significantly different from the partial correlations between abdominal fat and insulin/AI. When age and height were adjusted, partial correlations between abdominal fat and insulin were 0.38 and 0.39. The partial correlations were reduced to 0.15∼0.29 after further adjusting for whole body fat. Age and height-adjusted partial correlations between abdominal fat and AI were 0.34 and 0.36. The partial correlations were reduced to -0.11∼0.17 when whole body fat was additionally adjusted. Whole body fat explained 9.9∼13.7% for variability of insulin; abdominal fat explained 14.2% and 15.9%. Whole body fat explained 12.5∼12.8% for variability of AI and abdominal fat explained 11.9%.

Conclusion
Most of the obese women showed abdominal obesity. Abdominal fat did not seem to be independently associated with fasting insulin and atherogenic index.