Posted by Annapaola Prestia Laboratory of Epidemiology Neuroimaging and Telemedicine, IRCCS Centro San Giovanni di Dio FBF, The National Centre for Research and Care of Alzheimer’s and Mental Diseases, Brescia, Italy
Obesity and overweight are often defined by the body mass index (BMI), which associates with metabolic and cardiovascular disease, and possibly with dementia as well as variations in brain volume. However, body fat distribution and abdominal obesity, as measured by waist circumference, is more strongly correlated with cardiovascular and metabolic risk than is BMI. While prior studies have revealed negative associations between gray matter tissue volumes and BMI, the relationship with respect to waist circumference remains largely unexplored.
In the present study, the researchers analyzed the whole brain images of 115 carefully screened healthy subjects using an optimized voxel-based morphometry approach to determine and clarify the effects of BMI and waist circumference on regional gray matter volume. Further, follow-up analyses were additionally performed to examine the modulating effects of gender and age variables. The study observed widespread reductions of gray matter volume in association with BMI and waist circumference in bilateral prefrontal cortex, anterior temporal cortex, inferior parietal cortex and cerebellar and midbrain hypothalamic regions. Waist circumference, which estimates abdominal fat, was associated with more spatially extensive reductions in gray matter volume than BMI, particularly in females. Results from this study support that regional reductions in gray matter are associated with obesity and point to a stronger association between abdominal obesity and diminished gray matter than with BMI, particularly in females. This may suggest that abdominal obesity is a more relevant risk factor for cardiovascular or metabolic disease, and potentially also for neurodegenerative disorders.