The influence of body fat distribution on white matter integrity

Abstract

Objective: Obesity has become a great health problem and increases the risk for cardiovascular and metabolic diseases as well as for cognitive impairments including brain alterations in gray and white matter structure and function. The differentiation of adipose tissue in visceral adipose tissue and subcutaneous adipose tissue was found to be greatly relevant due to its different composition and consequent potential for metabolic complications. Hence, the objective of this study was to investigate the relationship between body fat distribution, especially visceral and subcutaneous adipose tissue, and white matter integrity.

Methods: Diffusion tensor imaging (DTI) of the brain and whole body magnetic resonance imaging were performed of 48 healthy young to middle-aged lean, overweight and obese participants. The collected data included participant’s sex, age, body mass index, total body volume, volume of total, subcutaneous and visceral adipose tissue, total intracranial volume and DTI data of the brain. By using a region-of-interest-based approach, the DTI parameters fractional anisotropy, mean diffusivity, axial diffusivity and radial diffusivity were analyzed and correlated with the body mass index, total adipose tissue, subcutaneous and visceral adipose tissue, controlling for age, sex, total intracranial volume and BMI.

Results: We found significant positive correlations between visceral adipose tissue and mean diffusivity and radial diffusivity values in the hippocampal part of the left cingulum (p < 0.005, corrected for number of tested regions) and marginally significant positive correlations in the forceps major and hippocampal part of the right cingulum (p < 0.05). Subcutaneous and total adipose tissue did not show significant correlations with DTI parameters.

Conclusion: Our DTI study contributed to the current knowledge of the relationship between visceral adipose tissue and white matter integrity. We conclude that increased visceral adipose tissue is associated with reduced white matter integrity in regions which are known to be important for emotional and cognitive functioning. Therefore we suggest that increased visceral adipose tissue may increase the risk for emotional and cognitive impairment. Still further longitudinal studies may determine causal impact of visceral adipose tissue and its clinical relevance.