Ectopic adipose tissue: association of obesity phenotypes with integral metabolic indices of obesity

Aim . To study the relationship and predictive value of integral metabolic indices of obesity in the identification of ectopic obesity. Material and methods . The study included 326 patients (146 men and 180 women, mean age 61±9 years). Anthropometric data, degree of obesity, body mass index (BMI), waist circumference (WC), sagittal abdominal diameter (SAD), body obesity index (BAI), visceral obesity index (VAI), lipid accumulation index (LAP), triglycerides-glucose index (TyG) was assessed. Perivascular adipose tissue (PVAT) volume, pericardial adipose tissue (PAT) volume and thickness of perirenal fat tissue (PRF) were assessed with CT. Results . Patients were divided into groups: with isolated ectopic obesity (iEO) (n=17); with isolated abdominal obesity (iAO) (n=74); with EO variants: pericardial (PCO) (n=31), perivascular (PVO) (n=22) or perirenal (PRO) (n=33) with AO; with mixed ectopic obesity and AO (mEO+AO) (n=117), and patients without obesity (n=32). Significantly higher BMI, WC, SAD, and BAI indices were found in individuals with PCO+AO, PRO+AO and mEO+AO. The highest values of LAP were found in groups: PCO+AO, PVO+AO, PRO+AO. There was a correlation between ectopic fat depots and WC (r=0,62 for PAT, r=0,55 for PVAT and r=0,39 for PRF, p=0,01) and SAD (0,429, 0,329 and 0,435, respectively, p=0,01). Correlation was established between PAT, PRF and LAP (0,425 and 0,319, respectively, p=0,01). The highest AUC values>0,8 had models of WC and SAD in identification of PCO (0,801 and 0,801, respectively) and PRO (0,826 and 0,826, respectively). For PCO, the cut-off point of WC was 100,5 cm (specificity 72,9%, sensitivity 70,2%, p=0,000), SAD — 25 cm (specificity 73%, sensitivity 70,2%, p=0,000). For PRO, the cut-off of WC was 101 cm (specificity 71,4%, sensitivity 72,7%, p=0,000), SAD — 25 cm (specificity 71,4%, sensitivity 72,7%, p=0,000). Conclusion . Еctopic fat depots are related to the risk of metabolic disorders. Potential informative value of simple and accessible integral metabolic indices was established. WC>100,5 cm, SAD>25 cm may indicate to the presence of PCO; WC>101 cm, SAD>25 cm — to the presence of PRO.