MRI sagittal abdominal diameter is a stronger predictor of metabolic syndrome than visceral fat area or waist circumference in a high-risk vascular cohort

Michel R Hoenig

University of Queensland, Brisbane, Queensland, Australia

Objective: To determine whether sagittal abdominal diameter (SAD) is associated with the metabolic syndrome independently of visceral fat area (VFA) and waist circumference (WC).

Methods: Forty-three high-risk vascular patients were evaluated for metabolic syndrome criteria and underwent magnetic resonance imaging (MRI) to quantify SAD and VFA at the L4–L5 disc.

Comparisons: 1. Baseline differences in patients with and without the metabolic syndrome 2. Forward binary logistic regression analysis of predictors of the metabolic syndrome with SAD, VFA and WC as independents 3. Correlates of SAD.

Results: Patients with metabolic syndrome had greater SAD, VFA and WC than patients without the metabolic syndrome (P < 0.01). Of SAD, VFA and WC, only SAD was associated with metabolic syndrome on forward binary logistic regression; beta 0.68, Wald’s statistic 10.8 (P = 0.001) and c-statistic 0.89 (P < 0.001). A > 22.7 cm SAD threshold identified metabolic syndrome with a 91% sensitivity and 80% specificity. SAD correlated with waist circumference (r = 0.918), high-density lipoprotein-cholesterol (r = –0.363), triglyceride (r = 0.401), fasting glucose (r = 0.428) and the QUICK index of insulin sensitivity (r = –0.667) (all P < 0.05).

Conclusions: MRI-measured SAD is associated with the metabolic syndrome and renders the current gold standard of VFA redundant. This measure of obesity-related cardiovascular risk requires validation and evaluation in a prospective cohort.

Keywords: obesity, insulin resistance