Sagittal abdominal diameter resembles waist circumference as a surrogate marker of insulin resistance in adolescents-Brazilian Metabolic Syndrome Study

Objective: To evaluate the association of the sagittal abdominal diameter (SAD) with insulin resistance (IR) and metabolic syndrome (MetS) components, and to compare SAD with waist circumference (WC). Subjects/Methods: This was a multicenter, cross-sectional study of 520 adolescents (10- to 18-years old). IR was assessed using the homeostasis model assessment of IR (HOMA-IR) and the hyperglycaemic clamp (n=76). Results: SAD and WC were positively correlated with HOMA-IR (r=0.637 and r=0.653) and inversely correlated with the clamp-derived insulin sensitivity index (ISI) (r=-0.734 and r=-0.731); P<.001. In the multivariable linear regression analysis, SAD was positively associated with HOMA-IR (B=0.046 +/- 0.003) and inversely associated with the clamp-derived ISI (B=-0.084 +/- 0.009) after adjusting for sex, age, and Tanner's stages (P<.001). When WC replaced the SAD, it was positively associated with HOMA-IR (B=0.011 +/- 0.001) and inversely associated with the clamp-derived ISI (B=-0.018 +/- 0.002); P<.001. The values of the areas under the curves (AUC) were 0.823 and 0.813 for SAD and WC, respectively. In Bland-Altman analysis, there were agreement between both, SAD and WC, with the clamp-derived ISI (mean=0.00; P>.05). The SAD and WC were positively associated with blood pressure, triglycerides, and uric acid, and inversely associated with high-density lipoprotein (HDL)-cholesterol after adjusting for sex, age, and Tanner's stages. Conclusion: The SAD was associated with IR and MetS components, with a good discriminatory power for detecting IR. When compared to WC, SAD showed equivalent results.