Sagittal Abdominal Diameter: A Novel Anthropometric Measure for Predicting Visceral Fat and Associated Cardiometabolic Risk Factors in Children

Alternative waist-to-height ratios associated with risk biomarkers in youth with diabetes: comparative models in the SEARCH for Diabetes in Youth Study

BACKGROUND/OBJECTIVES

The waist-to-height ratio (WHtR) estimates cardiometabolic risk in youth without need for growth charts by sex and age. Questions remain about whether waist circumference measured per protocol of the National Health and Nutrition Examination Survey (WNHAHtR) or World Health Organization (WWHOHtR) can better predict blood pressures and lipid parameters in youth.

PARTICIPANTS/METHODS

WHtR was measured under both anthropometric protocols among participants in the SEARCH Study, who were recently diagnosed with diabetes (ages 5-19 years; N = 2 773). Biomarkers were documented concurrently with baseline anthropometry and again ~7 years later (ages 10-30 years; N = 1 712). For prediction of continuous biomarker outcomes, baseline WNHAHtR or WWHOHtR entered semiparametric regression models employing restricted cubic splines. To predict binary biomarkers (high-risk group defined as the most adverse quartile) linear WNHAHtR or WWHOHtR terms entered logistic models. Model covariates included demographic characteristics, pertinent medication use, and (for prospective predictions) the follow-up time since baseline. We used measures of model fit, including the adjusted-R2 and the area under the receiver operator curves (AUC) to compare WNHAHtR and WWHOHtR.

RESULTS

For the concurrent biomarkers, the proportion of variation in each outcome explained by full regression models ranged from 23 to 46%; for the prospective biomarkers, the proportions varied from 11 to 30%. Nonlinear relationships were recognized with the lipid outcomes, both at baseline and at follow-up. In full logistic models, the AUCs ranged from 0.75 (diastolic pressure) to 0.85 (systolic pressure) at baseline, and from 0.69 (triglycerides) to 0.78 (systolic pressure) at the prospective follow-up. To predict baseline elevations of the triglycerides/HDL cholesterol ratio, the AUC was 0.816 for WWHOHtR compared with 0.810 for WNHAHtR (p = 0.003), but otherwise comparisons between alternative WHtR protocols were not significantly different.

CONCLUSIONS

Among youth with recently diagnosed diabetes, measurements of WHtR by either waist circumference protocol similarly helped estimate current and prospective cardiometabolic risk biomarkers.

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.