Care Transitions and Adult Day Services Moderate the Longitudinal Links between Stress Biomarkers and Family Caregivers' Functional Health.

backgroundStress biomarkers have been linked to health and well-being. There are, however, few studies on how dysregulation in the hypothalamic-pituitary-adrenal axis and sympathetic nervous system actually affects functional health of family caregivers of persons with dementia. Further, it is not clear whether and how factors affecting caregiving stressor exposures such as care transitions and adult day services (ADS) use may affect such association.

objectiveFirst, to examine the association of daily stress biomarkers and functional health over time among family caregivers of persons with dementia. Second, to examine effects of care transitions and ADS use on the association between baseline stress biomarkers and functional health over time.

methodsAt baseline, caregivers provided 5 saliva samples each day during an 8-day diary study, where all caregivers were having a varying number of ADS days per week. There were 2 longitudinal follow-ups at 6 and 12 months on ADS use, care transitions, and caregivers' functional health. The average daily total output across days was computed at baseline for salivary cortisol, the sulfated form of dehydroepiandrosterone (DHEA-s), and salivary alpha amylase (sAA), which were used as predictors of caregivers' longitudinal functional limitation trajectories. Care transitions and total number of ADS days per week at baseline were considered as moderators of the associations between stress biomarkers and health over time.

resultsThe associations between functional limitation trajectories and daily total outputs of cortisol and sAA were modified by ADS use and care transitions. Among caregivers who experienced a transition, and who used less than average ADS days per week, lower daily cortisol total output and lower daily sAA total output were associated with increasing functional limitations. Caregivers who experienced a transition but used greater than average ADS days per week did not show such patterns of association. No significant effect was found for DHEA-s.

conclusionThe study contributes to an important but largely unanswered question regarding implications of stress biomarkers on functional health. Assessments of the association between stress biomarkers and health among family caregivers of persons with dementia need to consider changes in stressor exposures over time, such as care transitions and ADS use.