Ultrasound measurements of intraabdominal fat estimate the metabolic syndrome better than do measurements of waist circumference

Background: We recently developed an ultrasound technique to estimate intraabdominal fat (IAF). This method is more accurate than measurement of waist and hip circumferences and is simpler and less expensive than computed tomography or magnetic resonance imaging. Objective: We compared the associations of ultrasound and waist-circumference (WC) measurements of IAF with other components of the metabolic syndrome. Design: IAF was determined in 600 consecutive participants in the Secondary Manifestations of Arterial Disease (SMART) study. The mean (+/-SD) age was 56.1 +/- 12.6 y, 30.0% of participants were women, and the mean body mass index (BMI; in kg/m(2)) was 26.6 +/- 4.1. Results: IAF increased with age (ultrasound: r=0.28; WC: r=0.25; P < 0.001 for both). Higher IAF, as measured by ultrasound but not by WC, was independently associated with higher metabolic risk factors. The correlation coefficients between IAF measured by ultrasound and plasma glucose, total cholesterol, HDL cholesterol, and triacylglycerol were 0.13, 0.16, -0.13, and 0.25, respectively (all P < 0.001; adjusted for age, sex, and BMI). The corresponding coefficients for IAF measured by WC were 0.17 (P < 0.001) and 0.01, -0.06, and 0.05 (all NS). Conclusions: These results confirm the findings of computed tomography and magnetic resonance imaging investigations. When IAF is measured by ultrasound, the associations are more pronounced than when WC measurements are used and are independent of BMI. This suggests that IAF can be more reliably assessed by ultrasound measurements than by WC measurements.