Objective: The first objective was to determine the associated sensitivity (true positives) and specificity (false positives) associated with the use of waist circumference (WC) to predict specific visceral adipose tissue (VAT) levels. Because WC is a strong correlate of VAT, and, a WC of 100 cm and a VAT area of 130 cm2 (L4-L5) have been suggested as thresholds for increased disturbances in insulin-glucose homeostasis and lipid metabolism, we assessed the sensitivity and specificity when using a WC of 100 cm to identify a VAT of 130 cm2 or greater. A second objective was to evaluate the effects of diet and exercise induced weight loss on VAT and WC to establish the utility of using WC to follow reductions in VAT.
Research design and methods: The sensitivity between WC and VAT was assessed using 50 male (BMI: 30.9 +/- 4.7, age: 41.0 +/- 11.2 y) and 49 female (BMI: 33.3 +/- 5.0, age: 36.9 +/- 7.4 y) subjects. The effects of weight loss on WC and VAT were evaluated in a subgroup of 20 male and 38 female subjects. VAT was measured by magnetic resonance imaging.
Results: The sensitivity associated with the prediction of a VAT of 130 cm2 or greater using a WC of 100 cm was high (83%), however, so too was the incidence of false positives (38%). Significant (p < 0.01) correlations were obtained between concurrent reductions in VAT and WC for both the male (r = 0.69) and female (r = 0.47) groups. For the two groups combined, regression analysis indicated that a 1 cm reduction in WC was associated with a 4% reduction in VAT mass (p < 0.01).
Conclusions: The misclassification of individuals with VAT accumulation above 130 cm2 suggest that WC alone lacks the sensitivity required to identify specific VAT values. The diet and exercise induced reductions in visceral adiposity are positively related to corresponding reductions in WC for both genders is a positive result, and demonstrates the potential utility of using WC to follow changes in the AT depot that conveys the greatest health risk.