Reaching the Tipping Point: Identification of Thresholds at which Visceral Adipose Tissue May Steeply Increase in Youth

Objective: This study aimed to determine whether children and adolescents demonstrate, similarly to adults, a threshold of total percent body fat (%BF) above which the slope of visceral adipose tissue (VAT) rises. Methods: This cross-sectional study included 557 youth, aged 8 to 18 years, with a wide range of BMI values. Dual-energy x-ray absorptiometry was used to determine body composition (including VAT), and fasting blood was collected for measurement of lipids, glucose, insulin, and biomarkers. Segmented linear regression analysis identified the threshold for %BF unadjusted and adjusted for Tanner stage. Linear regression with robust variance estimation compared associations of risk factors and thresholds. Results: Thresholds of %BF were identified by sex (males = 33%, females = 38%), age (< 12 years = 34%; >= 12 years = 30%), and race (White/non-Hispanic = 31%; all other races/Hispanic = 38%) above which the slope of VAT was significantly steeper (all P < 0.001). The percentage of total body fat stored as VAT was higher above versus below these thresholds (all P < 0.001). Above threshold, but not below it, VAT was associated with triglycerides/high-density lipoprotein ratio, insulin, adiponectin, and blood pressure. Conclusions: The thresholds should be confirmed in longitudinal studies, and they may be useful in identifying youth at increased cardiometabolic risk in need of close clinical monitoring and/or intensive intervention to reduce excess adiposity.