Background: Insulin Sensitivity (IS) and Insulin Resistance (IR) mark the development of Type 2 Diabetes. Many reports have demonstrated that anthropometric indices can detect IS and IR, however ethnic variations can influence the optimal cutoff value. Therefore, the aim of this study was to determine the optimal cutoff value for Waist Circumference (WC), Body-Mass Index (BMI), Waist-To-Hip Ratio (WHR), Waist-To-Height Ratio (WHtR), and percent Body Fat (BF %) to determine IS and IR from subjects from central Mexico.
Methods: WC, BMI, WHR, WHtR, BF%, fasting plasma glucose, and insulin were determined in 569 subjects (male=286 & females=283; ages: 18-84). IR and IS were determined by the Homeostatic Model Assessment online calculator and Quantitative Insulin Sensitivity Check Index, respectively. The area under the Receiver Operating Characteristic curve (AUC) and Youden´s index for each anthropometric index was calculated to determine its cutoff value. Cutoff value´s efficiency was measured by determining the test´s accuracy.
Results: WC, BMI, WHtR and BF% negatively correlated IS and positively correlated to IR (p<0.0001). WHR did not correlate with IS nor IR. AUC analysis showed that WC, BMI, WHtR and BF% were acceptable test to determine IS and IR (IS: males: AUC=0.736-0.770 and females: AUC=0.648-0.666; IR: males: AUC=0.740-0.760 and females: AUC=0.681-0.709, p<0.001). Comparison of AUC demonstrated that WC, BMI, WHtR and BF% had similar efficiency to determine IS and IR. However, after determining the optimal cutoff value and using highest test accuracy, we determined the better indicators for IS was WHtR (cutoff=0.540, accuracy=76.8%) and BF% (cutoff=31.5%, accuracy=68.0%) and for IR was WC (cutoff=99.5 cm, accuracy=71.0%) and BMI (cutoff=31.6 kg/m2, accuracy=79.9%) for males and females, respectively.
Conclusion: When comparing multiple anthropometric indices, we determined that WHtR and WC for males and BF% and BMI for females were better indicators for determining IS and IR, respectively.