Association of Negative Life Event Stress With Coagulation Activity in Elderly Alzheimer Caregivers

OBJECTIVE: Part of the excess coronary disease rate and overall mortality reported with caregiving stress could relate to a hypercoagulable state. Physiological responses to the chronic distress of caregiving may involve hyperactive sympathetic nervous system responses to superimposed stressors. We wondered whether negative life stress might affect hemostatic function in caregivers. METHODS: The three procoagulant measures thrombin-antithrombin III complex (TAT), fibrin D-dimer (DD), and von Willebrand factor (vWF) antigen were assessed in 54 spousal Alzheimer caregivers (mean age, 73 +/- 6 years). Subjects completed a semistructured interview (Psychiatric Epidemiologic Research Interview, PERI) that assessed for non-caregiving-related life stress (ie, number of negative life events) over the 4-week period before blood sampling. RESULTS: Caregivers reported an average of 2.6 negative life events (range, 0-6). The number of negative life events showed a direct association with plasma DD levels (p =.010). In multiple regression analyses, body mass index (BMI) and life stress were the only significant predictors of DD. Together, BMI, hypertension status, gender, and depression accounted for 23% of the variance in DD (p =.022). After these variables had been controlled for, life stress explained an additional 9% (p =.021) of the variance in DD. On the other hand, the number of life-events did not significantly predict TAT or vWF. CONCLUSIONS: The findings suggest that superimposed life stress on top of the chronic stress of Alzheimer caregiving may elicit a hypercoagulable state that could contribute to coronary disease and to increased overall mortality in this population.