Dual-Energy X-Ray absorptiometry based differentiation of lipoedema and familial partial lipodystrophy from general obesity in women

BACKGROUND: Lipoedema and familial partial lipodystrophy (FPLD) are rare adipose tissue disorders frequently misclassified as common obesity. Clinical assessment and body mass index (BMI) alone may fail to capture regional fat distribution, delaying recognition and suboptimal management of metabolic complications. OBJECTIVE: To evaluate whether dual-energy X-ray absorptiometry (DXA)-derived regional fat distribution indices may provide complementary phenotyping information for distinguishing clinically characterized women with lipoedema, FPLD, general obesity, and normal adiposity. DXA-derived ratios and percentage fat mass were evaluated as exploratory, descriptive measures rather than definitive diagnostic markers, given known limitations of ratio-based and percentage-derived parameters. METHODS: This retrospective study included 72 women, equally allocated into four groups: lipoedema, FPLD, obesity, and normal-weight controls. All participants underwent whole-body DXA scanning to quantify total and regional fat parameters. Receiver operating characteristic (ROC) analyses assessed the discriminative performance of various indices. RESULTS: DXA revealed distinct adiposity patterns across groups. Lipoedema was best distinguished by a lower trunk fat mass (FM)/leg FM ratio (AUC: 0.964; p < 0.001). FPLD showed a centripetal fat distribution, notably via trunk FM/leg FM and trunk FM/limb FM ratios (both AUC: 0.860; p < 0.001). A total fat percentage ≥43.5% discriminated lipoedema from FPLD with near-perfect accuracy (AUC: 0.990). CONCLUSION: DXA-based assessment of regional fat distribution may provide supportive objective information for differentiating clinically selected women with lipoedema, FPLD, obesity, and normal adiposity; ratio-based and percentage-derived indices should be regarded as exploratory and hypothesis-generating rather than definitive diagnostic criteria. The applicability of these findings to male populations requires further investigation.