Any oncologist can testify to the difficulties facing family members of patients with cancer. A recent study out of Canada examines the “biologic cost” of caring for a patient with cancer. This was a small study in which the researchers compared saliva and blood samples from 18 primary caregivers of people who had just been diagnosed with brain tumors with those from 19 volunteers. They also used questionnaires to measure perceived stress and depressive symptoms in the caregivers and the volunteers, who were all followed for one year.

Salivary amylase was used as a proxy for studying activation of the sympathetic nervous system (a.k.a. adrenaline, responsible for the “fight or flight” response). Normally, this enzyme in saliva declines sharply after awakening and then rises throughout the day. As expected, this diurnal rhythm was preserved over time in the healthy volunteers. Caregivers, on the other hand, experienced loss of this normal rhythm over time and then gradual recovery. C-reactive protein is a measure of systemic inflammation and high levels are a well-documented risk factor for cardiovascular disease. At the study entry, levels were similar in caregivers and volunteers; however, over time, the caregivers demonstrated increase in CRP. In fact, half of them developed CRP levels >3 mg/L, a level considered to be a marker for high risk of cardiovascular disease. CRP levels did not reach a plateau but continued to increase over the year of the study. Over time, caregivers also demonstrated lower expression of anti-inflammatory signaling molecules.

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