Researchers from the University of California claim to have identified a gene that explains the link between obesity and dementia.
There has been a long-established link between mid-life obesity and the later development of dementia, according to the Alzheimer's Society.
Now an article published in the Proceedings of the National Academy of Sciences journal has found that it is genetic.
A specific gene, carried by 46 per cent of western Europeans, which is known to increase the likelihood of a person becoming obese, also alters brain structure, facilitating the development of dementia, the study claims.
Commenting on the findings, head of research at the Alzheimer's Society Dr Susanne Sorensen said: "We've known for some time that there's a link between obesity in mid life and the development of Alzheimer's disease.
"However, this study suggests that healthy people who carry a specific DNA sequence associated with obesity could be at a greater risk of developing dementia."
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