Reduced cortical thickness associated with visceral fat and BMI

Abstract

Structural brain imaging studies have shown that obesity is associated with widespread reductions in gray matter (GM) volume. Although the body mass index (BMI) is an easily accessible anthropometric measure, substantial health problems are more related to specific body fat compartments, like visceral adipose tissue (VAT). We investigated cortical thickness measures in a group of 72 healthy subjects (BMI range 20-35 kg/m(2), age range 19-50 years). Multiple regression analyses were performed using VAT and BMI as predictors and age, gender, total surface area and education as confounds. BMI and VAT were independently associated with reductions in cortical thickness in clusters comprising the left lateral occipital area, the left inferior temporal cortex, and the left precentral and inferior parietal area, while the right insula, the left fusiform gyrus and the right inferior temporal area showed a negative correlation with VAT only. In addition, we could show significant reductions in cortical thickness with increasing VAT adjusted for BMI in the left temporal cortex. We were able to detect widespread cortical thinning in a young to middle-aged population related to BMI and VAT; these findings show close resemblance to studies focusing on GM volume differences in diabetic patients. This may point to the influence of VAT related adverse effects, like low-grade inflammation, as a potentially harmful factor on brain integrity already in individuals at risk of developing diabetes, metabolic syndromes and arteriosclerosis.

Keywords: Cortical thickness; MR imaging; Obesity; Visceral adipose tissue.

Figures

Fig. 1

Lateral and inferior views of the reductions in cortical thickness in relation to BMI adjusted for sex, age, total surface area and education. Significant clusters in the left inferior temporal and left inferior parietal cortex (a) and right precentral gyrus (b). Scatter plots represent the association between BMI and the averaged cortical thickness of each subject in the corresponding clusters representing the left inferior temporal cortex (c) and the right precentral gyrus (d). The t-value and the corresponding p-value are depicted.

Fig. 2

(a) Lateral and inferior views of the reductions in cortical thickness in relation to visceral adipose tissue adjusted for sex, age, total surface area and education. Significant clusters in the left fusiform gyrus (a) and the right inferior temporal and mid-insular region (b). Scatter plots represent the association between VAT and the averaged cortical thickness of each subject in the cluster representing the left inferior temporal cortex (c) and the right mid-insular gyrus (d). The t-value and the corresponding p-value are depicted.

Fig. 3

Lateral view of the reductions in cortical thickness in relation to VAT adjusted for BMI, sex, age, total surface area and education. A significant cluster in the left transverse temporal gyrus extending into the superior temporal gyrus and mid-insula. Scatter plot represents the association between VAT and the averaged cortical thickness in the corresponding area in each subject. The t-value and the corresponding p-value are depicted.