Sagittal diameter minus subcutaneous thickness. An easy-to-obtain parameter that improves visceral fat prediction

Two groups of 99 and 98 women were studied to test if correcting sagittal diameter by subtracting the thickness of subcutaneous abdominal adipose tissue improves its degree of association with visceral adipose tissue. The first group (age, 40 +/- 14 years; body mass index [BMI], 36 +/- 6 kg/m2) was used to calculate the predictive equations for visceral adipose tissue. The second group (age, 43 +/- 14 years; BMI, 37 +/- 6 kg/m2) was used for cross-validation. Various anthropometric parameters were measured by ultrasound and computed tomography. Correlation coefficients with single-slice visceral adipose tissue area, after sagittal diameter was corrected by subtracting subcutaneous thickness, rose from 0.63 to 0.72 in the first group and from 0.64 to 0.71 in the second group. The standard error of residuals of the regression formula for visceral adipose tissue area was 10% lower with modified sagittal diameter than with sagittal diameter alone. During cross-validation, the standard error of differences was 5% lower with modified sagittal diameter. The visceral adipose tissue estimate was also less biased by the size of the area when sagittal diameter minus subcutaneous thickness was used. Results show that subtracting the thickness of abdominal subcutaneous adipose tissue from sagittal diameter significantly improves the predictive power of sagittal diameter for visceral adipose tissue and could be a useful tool for epidemiological studies.