Stress and its impact on Alzheimer's

Perceived stress is said to have an impact on the incidence of Alzheimer's disease. (Photo: pixabay)

Feeling stressed increases the chance of older people developing mild cognitive impairment, which can lead to Alzheimer’s, says a report published in Alzheimer Disease & Associated Disorders.

Each year, around 470,000 Americans are diagnosed with Alzheimer’s disease. For many, the first sign is mild cognitive impairment - a pre-dementia condition that significantly increases the risk of developing Alzheimer's in the following months or years.

In the current study, researchers from Albert Einstein College of Medicine and Montefiore Health System - both in New York - looked at the connection between chronic stress and amnestic mild cognitive impairment (aMCI), which is the most common type of MCI, the main feature of which is memory loss. The team studied data collected from 507 people enrolled in the Einstein Aging Study (EAS), a community-based cohort of older adults.

Participants tested for a wide range of cognitive issues

Since 1993, the EAS has systematically recruited 507 adults aged 70 years and over who live in Bronx County, NY. Participants undergo annual assessments that include clinical evaluations, neuropsychological tests, psychosocial measures, medical history, assessments of daily-living activities and reports of memory issues and other cognitive complaints by participants and their relatives or caretakers.

In 2005, the EAS began assessing stress using the Perceived Stress Scale (PSS). The PSS is a widely used 14-item measure of psychological stress, designed to be sensitive to chronic stress. It measures stress perceived over the previous month due to ongoing life circumstances, possible future events and other causes. PSS scores range from 0-56, with higher scores indicating greater perceived stress.

The diagnosis of aMCI was based on standardized clinical criteria, including the results of recall tests and reports of forgetfulness from the participants or from others. All the participants were free from aMCI or dementia at their first PSS assessment. They then attended at least one follow-up evaluation each year for an average of 3.6 years.

Stress is associated with a higher incidence of aMCI

An aMCI diagnosis was made for 71 participants during the study. The higher the stress level, the greater the participants' risk for developing aMCI. For every 5-point increase in PSS scores, the risk of developing aMCI increased by 30%.
Participants were then divided into five groups, or quintiles, based on their PSS scores, ranging from high stress in the top quintile to low stress in the bottom one.

Participants in the highest-stress quintile were nearly 2.5 times more likely to develop aMCI than those in the remaining four quintiles combined (low stress). Participants in the high-stress group were also more likely to be female, to have a lower education level and higher levels of depression.

To confirm the role of stress in elevating the risk for aMCI, the researchers then assessed whether depression might also have contributed. Depression is associated with stress, cognitive impairment and Alzheimer's disease.
However, depression did not appear to affect the relationship observed between stress and the onset of aMCI significantly.

Mindy Katz, first author of the study, says:
"Perceived stress reflects the daily hassles we all experience, as well as the way we appraise and cope with these events. Perceived stress can be altered by mindfulness-based stress reduction, cognitive-behavioral therapies and stress-reducing drugs. These interventions may postpone or even prevent an individual's cognitive decline."

Since stress is treatable, the results suggest that detecting and treating stress in older people might help delay or even prevent the onset of Alzheimer's.

Author: Yvette Brazier / Dec. 2015
Text abridged and adapted / Jan. 2016
With kind permission to publish from MNT
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