Introduction: Abdominal subcutaneous adipose tissue (SAT) is subdivided into two depots by the fascia of Scarpa. The deep SAT (dSAT) and superficial SAT (sSAT) are morphologically and metabolically distinct, with dSAT reportedly being more similar to visceral adipose tissue (VAT) in terms of elevating the risk for obesity-related complications. Conversely, sSAT appears to be more similar to lower-body SAT. The relationship between dSAT and metabolic disease has been studied in adults, but to our knowledge, no such studies have investigated children and adolescents.
Methods: 203 subjects were included (males n=107, obesity n=182, age 14.1±2.1 years) from childhood obesity clinics in Uppsala, Sweden and Salzburg, Austria. Each participant underwent an oral glucose tolerance test (OGTT) after an overnight fast and magnetic resonance imaging (MRI) in close chronological proximity to the OGTT. Clinical MRI systems (1.5-T, Philips Medical System, Amsterdam, Netherlands) were used. Volumes of VAT and SAT were determined using a fully automated segmentation method, from slices centered on L2-L3. dSAT and sSAT were assessed through manual segmentation of T1-weighted images by tracking the fascial plane using the software ImageJ. One single operator performed all manual measurements. Statistical analyses were carried out in RStudio. dSAT and sSAT were both normalized against total SAT for all calculations. To assess the relationship between SAT depots and insulin secretion, standardized major axis regressions were calculated through males and females.
Results: There was a positive correlation between total SAT volume and fasting insulin in both males (R2=0.18, P=8.41x10-6) and females (R2=0.06, P=0.02). The correlation between dSAT and fasting insulin was also positive in males (R2=0.16, P=1.94x10-5) and non-significantly so in females (R2=0.01, P=0.28), while the correlation between sSAT and fasting insulin was negative in both sexes (males R2=0.20, P=1.37x10-6; females R2=0.09, P=0.003). The same pattern was seen in 120 min insulin (significant only in males). No significant relationships were found between SAT depots and glucose at fasting or 120 min.
Conclusion: SAT is associated with hyperinsulinemia in adolescents, and the relationship appears to be driven by the deep, rather than the superficial, depot. Although seen in both sexes, the association is more pronounced in males than in females. Accumulation of deep subcutaneous adipose tissue seems to be related to metabolic risk.
15 Sep 2022 - 17 Sep 2022