Objectives: Both pre-frailty and frailty are linked with impaired executive function (EF) but the mechanism underlying this relationship is not known. Williams and colleagues' model posits EF affects health outcomes via stress regulation. This model was utlized to test indicators of stress regulation as mediators of the relationship between EF and pre-frailty in older adults.
Setting: Academic general clinical research centers.
Participants: 690 community-dwelling older adults ≥ 50 years of age.
Measurements: Pre-frailty was measured using a modified form of the Fried Frailty measure. EF was assessed via telephone-based neurocognitive assessments. Indicators of stress regulation included: stress exposure (measured by perceived stress), reactivity and recovery (measured by heart rate) and restoration (measured by serum interleukin-6 and sleep quality).
Results: 396 individuals were classified as non-frail, 277 as pre-frail, and 17 as frail. Pre-frail and non-frail individuals were included in data analyses. Compared to non-frail individuals, pre-frail were older and exhibited poorer EF, higher levels of stress exposure and poorer stress restoration. Poorer EF was associated with greater stress exposure, less stress reactivity, longer stress recovery and poorer stress restoration. The total effect of the relationship between EF and pre-frailty was significant with significant indirect effects supporting stress exposure and restoration as mediators of the relationship.
Conclusion: Stress exposure and restoration appear to mediate the relationship between EF and pre-frailty. Longitudinal studies are needed to clarify the direction of causality and determine whether stress regulation processes are appropriate targets for interventions aiming to prevent declines in EF and the development of pre-frailty.