Stressful life event exposure is associated with combined physical and cognitive decline in older adults

Introduction Physical and cognitive impairment constitute large burdens of disease in older adults, but may be preventable through reduction of modifiable risk factors. While chronic stress has been linked to cognitive and physical function separately, few studies have accounted for combined decline. This study assessed associations between exposure to stressful life events (SLEs) and cognitive decline, physical decline, and combined physical and cognitive decline. Methods Data were taken from the Cardiovascular Risk Factors, Aging and Dementia (CAIDE) cohort study of community-dwelling older adults in Finland (n = 701). SLE exposure was assessed at baseline using a 32-item questionnaire. Cognitive function (mean z-score) was based on five cognitive tests, while physical function was based on self-reported mobility and ability to perform activities of daily living. Both were assessed at baseline and follow-up (mean 8.3 years). A combined physical-cognitive function score was created by multiplying the cognitive and physical function scores. Multivariate multiple linear regression was conducted to assess associations between SLE exposure and decline in physical/cognitive function over time. Results Greater lifetime SLE exposure was associated with cognitive decline only in the presence of simultaneous physical decline. Recent SLEs were associated with cognitive decline alone, while non-recent SLEs were associated with physical decline. Acute SLEs (sudden onset, short duration), especially those related to bereavement, were associated with cognitive and physical decline individually and combined, while chronic SLEs (extended duration) were not. Discussion Both physical and cognitive function should be accounted for to understand the role of chronic stress in aging. Associations appear to depend on stress type and timing, providing insight into the temporal dynamics linking stressor exposure, cognitive decline, and physical decline.