Higher levels of perceived stress appear to be associated with faster declines in two cognitive domains – episodic memory and visuospatial ability – among older African Americans without dementia, results from a longitudinal study of 467 participants suggest.
“To our knowledge, this is the first study to examine the relationship between perceived stress and cognition in specific cognitive domains in general and in a minority population in particular,” reported, of the Rush Alzheimer’s Disease Center and the department of behavioral sciences at Rush University, Chicago, and her associates.
Each participant took a battery of neuropsychological tests, including the MMSE, annually for up to 9 years. The participants’ stress levels were assessed using a 4-item version of Cohen’s Perceived Stress Scale (), “an index of the degree to which a person finds their lives unpredictable, uncontrollable, and overloading – characteristics central to the evaluation of stress” ( ).
Dr. Turner and her associates found that participants with a mean age and education level, and a PSS score 1 point above the mean experienced annual declines in episodic memory of 0.022 points (P = .047) and in visuospatial ability of 0.021 points (P = .017). No such associations were found for semantic or working memory or for perceptual speed.
The investigators said that the study did not pinpoint the mechanisms that link stress to cognition. “The well-established mechanism of hypothalamic-pituitary-adrenal-axis dysregulation in chronic stress may play a role,” they wrote. Another contributing factor could be inflammation, they said, citing research showing that discrimination is “a persistent stressor in African Americans and that perceived discrimination is associated with elevated levels of C-reactive protein.” Future studies are needed, they said, to test which mechanisms might be pathways between perceived stress and cognitive decline.
They cited several limitations. For example, because less educational attainment is associated with higher levels of stress and this cohort had achieved educational levels that were relatively high, this cohort’s reports of perceived stress might have been modest. In addition, “perception of stress is, by nature, a self-report measure,” the investigators wrote.
The National Institute on Aging and the Illinois Department of Public Health funded the study. Neither Dr. Turner nor her associates had any conflicts of interest.