Acute procoagulant stress response as a dynamic measure of allostatic load in Alzheimer caregivers

Allostasis designates processes of bodily adaption to stressful challenges, whereas allostatic load means the costs of wear and tear to the body as a consequence of inefficient allostasis. In distressed dementia caregivers, an acute procoagulant stress response might be one dynamic mediator of allostatic load relevant to cardiovascular endpoints. An interviewer assessed the number of negative life-events independent from caregiving over 4 weeks in 37 spousal Alzheimer caregivers (M age SD = 72 +/- 6 years). Baseline procoagulability scores and procoagulability scores in response to a 15-min speech task included plasma thrombin/antithrombin III complex, D-dimer von Willebrand factor, tissue-type plasminogen activator and plasminogen activator inhibitor 1 levels. Allostatic load was defined as the difference in procoagulability scores from baseline to speech, using standardized (z-score) transformations. Speech stress significantly increased heart rate (p = .017), systolic blood pressure (p = .002), and diastolic blood pressure (p < .001). The number of negative life-events (M +/- SD 2.8 +/- 2.0) correlated with allostatic load (r = .367, p = .026). After controlling for age and smoking, which together explained 32% of the variance in the allostatic load (R-2 = .324), F(2, 34) = 8.14, p = .001, the number of negative life-events accounted for an additional 13% of that variance (DeltaR(2) = .125), DeltaF(1, 33) 7.49, p = .010. The finding is compatible with the concept of allostasis and allostatic load, suggesting that higher combined caregiving and life distress levels are associated with more dysfunctional hemostatic responses to acute mental stress. The acute procoagulant stress response might constitute a dynamic mediator of allostatic load in Alzheimer caregivers.