People who tend to have negative perceptions may be more likely to develop Alzheimer's disease later in life than those who do not have such thoughts, a new study says.

Researchers from Yale's School of Public Health examined the brain autopsies of dementia-free individuals who took part in the Baltimore Longitudinal Study of Aging (BLSA).

They discovered that participants who held stereotypical ideas on fading memory and aging, such as grouchiness, absent-mindedness and the inability to learn new things, experienced a higher risk of developing brain changes that are often seen in Alzheimer's patients.

Through the help of magnetic resonance imaging (MRI), the team found that the participants' hippocampus, which is the part of the brain associated with memory, shrank by as much as three times compared to its normal volume.

Despite finding a link between stereotypes and Alzheimer's disease, the researchers said the study was not designed to determine a potential reason for this occurrence.

Prof. Becca Levy, one of the researchers involved in the study, pointed out that this could be caused by increasing stress levels as a result of having negative thoughts on aging. She said that stress is a known driving force for developing Alzheimer's disease.

"The positive message here is that our thinking about aging is modifiable," Levy said.

"It can be changed. So if we can reduce ageism, and promote more-positive views on getting older, it could perhaps be one way to reduce Alzheimer's risk."

Dr. Amy Kelley, an expert on aging from the Icahn School of Medicine, however, disagrees with the idea that stress alone causes the increase in disease risk.

Kelley said that while the findings of the study provide an interesting association between stress and Alzheimer's, it is still difficult to determine the exact cause of the disease because there are many other factors aside from stress that could be involved.

She added that people who tend to have more negative thoughts could also be less inclined to exercise or eat healthily, which could also play a role in increasing their risk of developing Alzheimer's disease.

The Alzheimer's Association (ALZ) said that approximately five million people living in the United States suffer from Alzheimer's. Most of these individuals are beyond 65 years old.

The findings of the Yale School of Public Health study are featured in the journal Psychology and Aging.

Photo: Michael Havens | Flickr

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