Introduction: Idiopathic intracranial hypertension (IIH) occurs in young obese women (>90%) but little is known about the metabolic characteristics in these patients. We aimed to characterise IIH fat distribution, metabolic phenotype and evaluate alterations following weight loss.
Methods: IIH and matched (BMI/sex) healthy obese controls were recruited. Metabolic indices (fasting lipid, glucose, insulin), anthropological measures and body composition were assessed (dual energy X-ray absorptiometry). IIH patients then underwent a therapeutic diet over 3 months followed by re-evaluation. The diet is a previously validated and nutritionally complete very low calorie total meal replacement liquid (Lipotrim, Howard Foundation, Cambridge, UK), providing 425 Kcal/day.
Results: IIH patients (n=29) had a similar centripetal fat distribution to simple obesity patients (n=47), which is contrary to previous reports of fat distribution measured by waist hip ratios. Lipid and glucose profiles were similar in IIH and normal obesity. Weight loss intervention resulted in a significant loss in body weight (−14.2±7.8%), BMI (−5.8±3.0 kg/m2), and waist circumference (−9.8±5.4 cm) (all P<0.001). Importantly, weight loss resulted in significant amelioration of clinical signs and symptoms of IIH, namely a decrease in intracranial pressure (−8.3±4.1 cm H2O; P<0.001). Following weight loss intervention there was a significant reduction in total fat mass (−9.10±4.7 kg; P<0.001). Interestingly, fat loss occurred predominantly from the truncal regions compared to the limbs (−4.7±37 vs −1.1±2.1; P<0.01).
Conclusions: Fat distribution in IIH patients is centripetal, akin to simple obesity. Clinical resolution of IIH is associated with preferential loss of truncal fat, potentially suggesting a pathogenic role for central adiposity in IIH.