Anticipating an Easier Day: Effects of Adult Day Services on Daily Cortisol and Stress

Author(s): Klein, L.C., Kim, K., Almeida, D.M., Femia, E.E., Rovine, M.J., and Zarit, S.H.

Published In: Gerontologist, 56 (2) 303-312

Study Aim/Purpose: This study investigates whether and how use of Adult Day Services (ADS) is associated with improved regulation of cortisol for caregivers. 

Summary of Methods: The study followed 158 family caregivers who lived with individuals with dementia who were attending ADS at least two days a week. After an initial in-person interview to collect background information, data was collected for eight consecutive days using a Daily Record of Behavior. Participants were called each evening to assess daily stress experiences and positive experiences, confirm ADS use or nonuse for that day, and daily wake-up time. Five daily saliva samples were analyzed to calculate: (1) cortisol awakening response (CAR), defined as the extent of change in cortisol levels from awakening to 30 minutes after awakening; and (2) total daily cortisol output, measured as cortisol area under the curve with respect to ground (AUC-G). To determine the between group effects of ADS use and non-ADS use days, participants were divided up into four quartiles (high, medium- high, medium and low) based on their cortisol results on non-ADS days. 

Summary of Results: The study found that caregivers had significantly fewer care-related stressors, more positive experiences, but also more noncare-related stressors on days of ADS use compared with days when they provided most or all of the care. Regarding effects of ADS on cortisol, ADS use was shown to have a positive effect on CAR. However, this effect varied based on caregivers’ level of CAR on non-ADS use days. Specifically, caregivers with a burned-out or flattened CAR and associated low AUC-G (both biomarkers associated with exhaustion and perceived fatigue) on non-ADS days displayed a more normative CAR and AUC-G response on ADS days. Restored cortisol regulation was also observed on ADS days among the high quartile group (i.e., caregivers with the highest CAR and AUC-G levels) on non-ADS days. No other covariants analyzed had significant effects on caregivers’ CAR, though total number of ADS days, caregiver’s age, and daily wake-up time had associations with their AUC-G level. 

Study Limitations (as cited by authors): The authors explain that there is likely selection bias in the study population given the intensive nature of the data collection. Additionally, although cortisol has been found to raise susceptibility to health problems, the authors point out that there are no clinical norms for risk. 

Authors’ Discussion/Conclusions: The authors conclude that ADS use provides partial relief from primary stressors of behavior problems as shown by the biomarker of cortisol level patterns. Future studies research is recommended to assess associations between daily stressor exposure and more than one kind of biomarker as well as the association between daily stress biomarkers and long-term health and well-being. To fully understand the health effects of respite care it is recommended that future research test the effects of daily ADS use and total ADS use across a period of time.