Diagnostic Central Obesity Indexes Cut – Off Point Values Determined with Dual-Energy X-Ray Absorptiometry in Cushing’s and Obese Women

Aim: The aim of this study was to develop quantiative criteria for defining visceral obesity and to establish dual-energy X-ray absorptiometric (DXA) diagnostic cut-off points (CP) for normal and abnormal values of the central obesity indexes (COI) that best differentiate extreme visceral obesity in Cushing’s syndrome (CS) from non CS obese and non obese women.

Material and Methods: COI_1–4 values calculated as a ratio of android to gynoid tissue mass, fat mass and their % were determined in 4 groups, each consisting of 18 women: 1^st group of CS, 2nd group of obese women (O₁) not different according to their age and BMI from CS, 3^rd group of obese women (O2) with BMI of 35 ± 1.2 kg and 4^th group of non obese healthy women (C) with normal BMI. Diagnostic accuracy (DG) of CP values of COI_1m-4m indexes of abdominal obesity and CP values of COI_1n-4n indexes of normal body fat distribution (BFD) was determined.

Results: COI_1-4 indexes values were highly significantly different among the 4 examined groups and were significantly highest in CS patients and lowest in group C (p < 0.0001). COI1m-4m CP values differentiated extreme visceral, abdominal obesity in CS with highest DG as well as COI1n-4n CP values differentiated normal BFD in group C. COI_1m CP of 0.55 best differentiated CS from O1 for DG of 100%. COI2n of 0.38 best differentiated C from CS and O₂ for highest DG of 100% compared to O1 because of the significantly higher BMI and COI_1n-4n values in O₂ that were associated with more pronounced abdominal obesity and highly significantly positive correlation with BMI.

Conclusions: DXA cut-off point values of indexes COI_1m-4m and COI_1n-4n were established as diagnostic indexes and criteria useful in discovering extreme abdominal and normal BFD. COI_1m CP value of 0.55 was discovered as a diagnostic criterion of extreme abdominal obesity and COI_2n of 0.38 as a diagnostic criterion of normal BFD that excluded abdominal obesity. The other indexes COI_1m-4m and COI_1n-4n CP values had also high DG in discovering abdominal and normal body fat distribution.