The stress of unemployment may
dampen healthy people’s immune system function -- but the good
news is that finding a job can restore its fighting power,
according to a new study.
Past research has linked chronic stress to impaired immune
function and a higher risk of infection and other illness. But
little is known about what happens to the immune system when
the stress subsides.
In the new study, researchers at the University of
California San Francisco followed 100 employed and 100
unemployed adults between the ages of 29 and 45 for 4 months.
The employed subjects were matched to the unemployed
subjects for factors such as gender, age, race and education
level. Individuals with chronic conditions or on medical
treatments that could affect the immune system, smokers and
intravenous drug users had been excluded from the study.
Each month, the researchers collected blood samples from
the participants to measure levels of "natural killer" cells,
an indication of the strength of their immune system.
The researchers found that, in general, the unemployed
group had weaker natural-killer activity than the working
group. However, 25 percent of the unemployed participants found
jobs during the study period, and their natural killer cells
subsequently got back on track.
"We believe this is the first study in humans to document
immune function recovery after the definable end of a chronic
stressor," Dr. Frances Cohen and her colleagues report in the
journal Psychosomatic Medicine.
Chronic stress may impair immune function through its
effects on the nervous system, according to the researchers.
The adrenal glands release the hormone norepinephrine in
response to stress, and in the test tube, norepinephrine has
been shown to reduce natural killer cells.
But the current findings suggest that immune function is
"resilient" in the face of long-term stress and can quickly
recover once the stressor is gone, Cohen’s team points out.
Study participants’ immune system recovery began within the
first month of their new employment, the study found.
Further studies, according to Cohen’s team, should
investigate immune system recovery from different types of
stressors, and try to figure out how that comeback happens.
SOURCE: Psychosomatic Medicine, April 2007.
