The results of their research were written up in the journal Annals of Neurology.
The U.S. researchers measured body mass index (BMI) and waist circumference, and waist-to-hip ratio, and used computer tomography (CT) based scanning devices to measure the amount of abdominal fat and magnetic resonance imaging (MRI) based scanning devices to measure total brain volume, temporal horn volume, white matter hyperintensity volume, and brain infarcts.
They found that as BMI increased, the volume of the brain decreased.
They also found that the more abdominal fat (which they called 'visceral fat around the central organs") a person has the more risk that person has of getting dementia.
The overall weight of a person did not seem to have this same correlation, only the amount of abdominal fat.
Page two concludes.
She adds, 'More importantly our data suggests a stronger connection between central obesity, particularly the visceral fat component of abdominal obesity, and risk of dementia and Alzheimer's disease."
Dr. Seshadr, who is also associated with Boston University's Alzheimer's Disease Center, concludes, "Our findings, while preliminary, provide greater understanding of the mechanisms underlying the link between obesity and dementia. Further studies will add to our knowledge and offer important methods of prevention."