Cerebrospinal fluid opening pressure: The effect of body mass index and body composition

Objectives: Idiopathic intracranial hypertension (IIH) is strongly related to obesity. The relationship between intracranial pressure, body mass index (BMI), percentage body fat and distribution of body fat in non-IIH patients remains less clear. The aim of this study was to examine the relationship between intracranial pressure and body type in non-IIH patients. Patients and Methods: Lumbar puncture manometry was used to measure cerebrospinal fluid opening pressure (CSFOP). BMI, in addition to neck, waist and hip circumferences were calculated. Air displacement plethysmography (BODPOD) was used to assess body composition. Results: Data was collected from 100 subjects. 11 subjects with conditions known to cause raised intracranial pressure were excluded from analysis. According to Pearson correlation factors displaying a significant relationship with CSFOP included: BMI (R = 0.635, p < 0.0001); waist circumference (R = 0.498, p < 0.0001), hip circumference (R = 0.513, p < 0.0001) and percentage body fat (R = 0.435, p < 0.001). Multivariate analysis indicated that BMI was the only independent factor which predicted CSFOP. Sub-analysis according to gender indicated that BMI was predictive in females and percentage body fat was predictive in males. We did not identify any differences in BMI, percentage body fat or distribution of body fat in 7 IIH patients and 7 wtmatched non-IIH patients. Conclusion: BMI and percentage body fat both positively correlated with CSFOp, but BMI was more predictive in women and percentage body fat was more predictive in men. We did not find a relationship between distribution of body fat and CSFOP.