Why Measuring Waist Circumference in Addition to the BMI?
It is well-documented that obesity is associated with insulin resistance.82–88 However, obesity is remarkably heterogeneous as some obese patients are insulin sensitive whereas others are insulin resistant.89–91 Even some massively obese patients show a normal plasma lipoprotein-lipid profile despite their very significant excess of body fat.92,93 It is with this heterogeneity in mind that measuring an index of abdominal adiposity such as the waist circumference is clinically relevant, as it allows the identification of subgroups of abdominally obese patients who are more likely to be insulin resistant. Nevertheless, some investigators have argued that because BMI and waist circumference are strongly correlated (Figure 4), measuring waist circumference provides little additional information over BMI.94–96 To fully address this question, however, it is important to keep in mind that when heterogeneous samples of lean to obese individuals are studied, correlation coefficients between BMI