Turns out, being skinny may not be all it’s cracked up to be as a recent study has found a link between a lower weight and early Alzheimer’s disease.

Researchers at Brigham and Women’s Hospital (BWH) and Massachusetts General Hospital (MGH) found an association between lower weight and more extensive deposits of the Alzheimer’s-associated protein beta-amyloid in the brains of cognitively normal older individuals.

The association was seen in particular among individuals carrying the APOE4 gene variant, which is known to increase the risk of Alzheimer’s.

“Elevated cortical amyloid is believed to be the first stage of the preclinical form of Alzheimer’s disease, so our findings suggest that individuals who are underweight late in life may be at greater risk for this disease,” said senior author Gad Marshall.

He added, “Finding this association with a strong marker of Alzheimer’s disease risk reinforces the idea that being underweight as you get older may not be a good thing when it comes to your brain health.”

While the concept of a preclinical version of Alzheimer’s disease is theoretical and not yet being used to guide clinical diagnosis or treatment, the current hypothesis involves three stages. Individuals at stage 1 are cognitively normal but have elevated amyloid deposits; stage 2 adds evidence of neurodegeneration, such as elevated tau deposits or characteristic loss of certain brain tissues, with no cognitive symptoms; and stage 3 adds cognitive changes that, while still in a normal range, indicate a decline for that individual.