High Stress May Cause Alzheimer’s in Elderly

High levels of stress can increase the likelihood of elderly people developing mild cognitive impairment — usually a precursor to Alzheimer’s disease. These results are reported in a study titled “Influence of Perceived Stress on Incident Amnestic Mild Cognitive Impairment: Results From the Einstein Aging Study,” published in the journal Alzheimer Disease & Associated Disorders.

Researchers from the Albert Einstein College of Medicine and Montefiore Health System found that participants with very high stress levels were more than twice as likely to become impaired than those with lower stress levels. Because stress is treatable, these findings suggest that early stress detection and treatment in older people could help to delay or prevent AD onset.

Cognitive impairment and dementia are major causes of morbidity and mortality, and contribute substantially to healthcare expenditures for older adults worldwide. As populations are aging, the prevalence of Alzheimer’s disease (AD) and the pre-dementia states that precede it, such as amnestic mild cognitive impairment (aMCI), are expected to rise. Given the lack of effective disease-modifying treatments, emphasis is increasingly placed on early intervention through the identification of remediable risk factors and the development of preventive strategies.

Some previous studies have linked stress to increased rates of AD, however few have investigated the relationship between stress and aMCI onset (memory loss) in a community of older adults.

Researchers here wanted to determine whether perceived stress predicted incident aMCI, and whether the influence of stress on aMCI was independent of known aMCI risk factors, particularly demographic variables, depression, and apoli-poprotein genotype. “Our study provides strong evidence that perceived stress increases the likelihood that an older person will develop aMCI,” Richard Lipton, MD, senior author of the study, vice chair of neurology at Einstein and Montefiore, and professor in the Saul R. Korey Department of Neurology and the Edwin S. Lowe Chair of Neurology at Einstein, said in a recent news release. “Fortunately, perceived stress is a modifiable risk factor for cognitive impairment, making it a potential target for treatment.”

“Perceived stress reflects the daily hassles we all experience, as well as the way we appraise and cope with these events,” added the study’s first author, Mindy Katz, MPH, senior associate in the Saul R. Korey Department of Neurology at Einstein. “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.”

The team analyzed data retrieved from 507 people enrolled in the Einstein Aging Study (EAS), a longitudinal study of a community-based cohort of adults, ages 70 and older, from Bronx County, New York, that began in 1993. Participants undergo annual assessments, including a neuropsychological battery, clinical assessments, psychosocial measures, medical histories, demographics, standardized assessments of daily living activities, and self-reports and informant reports of memory and cognitive complaints. The EAS began assessing perceived stress via the Perceived Stress Scale (PSS) in 2005. PSS scores range from 0 to 56, with higher scores indicating greater perceived stress. All individuals assessed were free of aMCI or dementia at the initial PSS assessment, and had at least one subsequent annual follow-up. The mean follow-up period of this study was of 3.6 years.

During the study period, 71 of the 507 enrollees were diagnosed with aMCI. The results revealed that high levels of perceived stress were associated with a 30% greater risk of incident aMCI. Similar results were obtained even after researchers divided participants into five groups based on their PSS scores. Participants in the highest stress group were about 2.5 times more likely to develop aMCI than all those in the four groups with lower PSS scores. Highest stress group participants were also more likely to be less educated, female, and to report higher depression levels.

To understand if stress was an independent and increasing risk for aMCI, the team assessed whether depression (known to increase risks of stress, cognitive impairment, and AD) might have influenced the results. The data showed no significant relationship between stress and aMCI onset. Likewise, the impact of stress on cognitive status was unaffected if participants had at least one e4 allele of the APOE gene, known to increase the risk for late-onset AD.

“Perceived stress should be considered to be targeted in preventive interventions including mindfulness-based stress reduction, cognitive-behavioral therapies, and pharmacologic interventions that aim to reduce cognitive decline. Perceived stress can be easily measured using self-report instruments which can be easily implemented in a clinical setting,” the researchers concluded.