From obesity to dementia

Dementia associated with obesity resembles Alzheimer’s disease, according to a new study from Montreal. Brain atrophy is similar in both cases.

“The first risk factor for dementia and Alzheimer’s is a family history of these diseases”, explains the main author of the study published Tuesday in the Journal of Alzheimer’s Disease, Alain Dagher of the McGill University Neuro. “The second is obesity. The more obese a person is, the greater the loss of gray matter. »

The Montreal researchers had already demonstrated that obesity can lead to the accumulation of amyloid β plaques in the brain, associated with Alzheimer’s. Using the records of 1300 UK patients from the UK Biobank database, they found similar thinning of the right temporoparietal cortex and left prefrontal cortex in obese and Alzheimer’s patients. These were imperceptible changes on cognitive tests.

“The next step is to see if we can make changes in the cortex if we treat obesity,” says the neurologist from The Neuro. There are now pharmacological treatments, developed for diabetes, which are very effective for obesity. » The D^r Dagher thinks we could also see if treating the consequences of obesity, such as high blood pressure and diabetes, lowers the risk of dementia.

Two potential biases of the study are the absence of data on the presence of the APOE genetic mutation, which is associated with Alzheimer’s disease, and the possibility that sicker patients are underrepresented in the database. It is also possible that susceptibility to brain atrophy leads to obesity.

This last possibility is put forward by the author of one of the studies cited by the study of D^r Dagher, Michael Lev, of Harvard University. “More and more studies show that eating disorders and obesity are closely linked to specific brain characteristics. »

The author of another study cited by the Neuro study, Suzanne De La Monte, of Brown University, adds that the risk of dementia is only high for obese people, not for people who are are overweight. “This new study confirms animal data, says Dr.^D From LaMonte. The inflammation caused by obesity seems to have terrible effects on the brain. »