Purpose: To investigate the effects of two interventions on physiologic markers (biomarkers) associated with chronic psychological stress in a care-giving population. Subjects are participants in the Balance Study that compares the effects of mindfulness-based stress reduction (MBSR) to an active control group of caregiver education and social support on the psychological well-being of spousal and family caregivers of dementia patients.
Methods: Four biomarkers associated with chronic stress were selected based on strong evidence of abnormal levels in caregiver populations and biological significance. Biomarkers selected include interleukin 6 (IL-6, a pro-inflammatory cytokine), D-dimer (a blood coagulation breakdown product), DHEA-S (dihydroepiandrosterone-sulfate, an adrenal steroid hormone), and telomere length (a measure of DNA turnover). Blood was drawn prior to and at the conclusion of the intervention. D-dimer, DHEAS, IL-6 levels, and telomere length were measured. An additional blood draw is scheduled for 6 months post-intervention.
Results: Preliminary analysis did not show signifi cant changes of biomarker levels as a result of either intervention; therefore, caregiver data were pooled to examine average levels in this care-giving group (n=25, 100% female, median age 56, age range 42-75 years). Average baseline biomarker levels were D-dimer=0.43 + 0.09 (n=21), DHEAS=0.80 + 0.15 (n=20), and IL-6=2.4 + 0.47 (n=13). No significant differences were found between baseline and post-intervention levels in the pooled data, although IL-6 levels increased and DHEAS levels decreased from baseline. There were no significant correlations between biomarkers at either baseline or post intervention. Age did correlate with DHEAS at baseline (P<.05), but this relationship was not significant at post-intervention.
Conclusions: Our inability to identify a change in the 4 biomarkers selected is likely due to the low sample size. The Balance Study is still in active recruitment and currently conducting additional interventions. In the future, correlations between biomarkers and caregiver-perceived stress, sleep quality, and other measures of psychological well-being will be examined. + 0.09 SEM ug/mL (n=25), DHEAS=0.69 + 0.10 ƒ Êg/mL (n=25), and IL-6=1.6 + 0.29 pg/mL (n=24); telomere data is still pending. Average postintervention levels were: D-dimer=0.43