Stress — in the form of traumatic events, job stress, everyday stress and discrimination — accelerates the aging of the immune system, which can increase a person’s risk of developing cancer, cardiovascular disease and diseases caused by infections like COVID-19, according to a new study from the University of Southern California. .
The research, published Monday in the Proceedings of the National Academy of Sciences, could help explain age-related disparities in health, including the disproportionate losses to the epidemic, and identify potential points of intervention.
“With the world getting older, it is essential to understand age-related health disparities. Age-related changes in the immune system play a critical role,” said lead study author Eric Klopack, a postdoctoral researcher in the Leonard Davis School of Gerontology at USC. in declining health.” “This study helps elucidate the mechanisms involved in accelerating immune aging.”
As people get older, the immune system naturally begins to drop dramatically, a condition called immunodeficiency. With age, a person’s immune system weakens, and this includes too many circulating, worn-out white blood cells, and too few “naive” new white blood cells ready to face new invaders.
Possible problems related to stress and the immune system
Immune aging is not only associated with cancer, but also with cardiovascular disease, increased risk of pneumonia, decreased efficacy of vaccines and organ system aging.
But what explains the drastic health differences in adults of the same age? University of Southern California researchers decided to see if they could discover the link between lifetime exposure to stress – a known factor contributing to poor health – and decreased activity in the immune system.
They inquired and expressed large data sets from the University of Michigan Health and Retirement Study, a national longitudinal study of the economic, health, marital, family, and public and private support systems of older Americans.
To measure exposure to different types of social stress, researchers analyzed the responses of a national sample of 5,744 adults over the age of 50. They answered a questionnaire designed to assess respondents’ experiences with social stressors, including stressful life events, and chronic stress, each day. Discrimination and discrimination for life.
Then blood samples from the participants were analyzed through flow cytometry, a laboratory technique that counts and ranks blood cells as they pass one by one in a narrow stream in front of the laser.
As expected, people with higher stress scores had older-looking immune profiles, with lower proportions of new disease fighters and higher proportions of worn-out white blood cells. The association between stressful life events and fewer ready-to-response or naive T cells remains strong even after controlling for education, smoking, drinking, body mass index, and race or ethnicity.
It may be impossible to control some sources of stress, but researchers say there may be a workaround.
T cells – an important component of immunity – mature in a gland called the thymus, which is located just in front of and above the heart. As people age, tissue in the thymus shrinks and is replaced by fatty tissue, resulting in decreased production of immune cells. Previous research suggests that this process is accelerated by lifestyle factors such as poor diet and low exercise, both of which are linked to social stress.
“In this study, after statistical control of poor diet and low exercise, the association between stress and accelerated immune aging was not as strong,” Klopak said. “What this means is that people with more stress tend to have poorer diet and exercise habits, which partly explains why their immune aging is accelerated.”
Stress and the immune system: the impact of diet and exercise
Improving diet and exercise behaviors in older adults may help offset stress-related immune aging.
In addition, cytomegalovirus (CMV) may be a target for intervention. Cytomegalovirus (CMV) is a common and asymptomatic virus in humans that is known to have a powerful effect in accelerating immune aging. Like shingles or cold sores, CMV is dormant most of the time but can flare up, especially when a person is under severe stress.
In this study, statistical control of CMV positivity also reduced the association between stress and accelerated immune aging. Therefore, widespread CMV vaccination could be a relatively simple and powerful intervention that could reduce the immune-aging effects of stress, the researchers said.
In addition to Klupac, other authors include Eileen Crimmens, University Professor and AARP Chair in Gerontology at USC Leonard Davis. and Steve Cole and Teresa Seaman of the University of California.
The study was supported by grants from the National Institute on Aging (P30AG017265, U01AG009740).
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