February 1, 2003

Alzheimer Caregiver's Stress May Trigger Risky Blood Clots

Stressful circumstances beyond the routine duress faced by those who care for a demented loved one can increase the chances of excessive blood clotting, new research suggests, and may help explain why the caregiver role can create a serious health risk.

Previous studies have shown that the health of some of those who care for a spouse with Alzheimer's disease is worse than among the elderly in the general population because the chronic strain of caregiving makes them more vulnerable than noncaregivers to premature death and certain types of heart disease.

The researchers explain that their results are consistent with the theory that the chronic stress of caregiving may sensitize those who care for a beloved Alzheimer's patient to be more reactive to and to suffer more negative effects from "other life stressors … which may have little or nothing to do with caregiving" and affect the elderly population in general. The study, which was conducted by Igor Grant, M.D., and Roland von Känel, M.D., of the University of California, San Diego, and colleagues, is reported in the January-February issue of Psychosomatic Medicine.

Specifically, the authors note, the study indicates that serious life stress may cause excessive blood clotting in the caregivers. This hypersensitivity to factors that trigger clotting, they observe, can play a crucial role in clogging and blockage of the coronary arteries, the major vessels that carry blood to the heart.

"Such a mechanism might contribute to [the] excess mortality [seen] in this highly stressed population," the authors explain.

The researchers studied 54 men and women who provided home care for a spouse with Alzheimer's disease. They gathered information from each participant on stressful life circumstances during the previous four weeks that were unrelated to the caregiving role, such as the death of a child from cancer. The research team also evaluated each participant for depression, gathered information on the caretakers' health and use of medications and obtained a blood sample to measure levels of three indicators of excessive blood clotting.

The researchers found that caretakers who reported a higher number of recent negative life events were likely to have higher blood levels of one of these substances, called fibrin D-dimer (DD). According to the researchers, increases in DD, even within the normal range, have been seen to predict coronary events such as heart attacks in apparently healthy individuals as well as those already diagnosed with coronary artery disease.

The number of negative life events was far higher among the female participants than among the male participants, the researchers observed. In addition, the women showed more signs of depression than the men did. But even when the researchers factored out the influences of gender and depression on DD levels, they found that a higher number of unrelated life stressors remained a strong predictor of elevated DD.

Primary funding for the research was provided by the National Institute on Aging of the U.S. National Institutes of Health. The Swiss National Science Foundation and the Novartis Foundation in Switzerland provided additional support for Dr. von Känel.

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