According to a new study from the USC, stress – in the form of traumatic events, work stress, daily stress and discrimination – accelerates the aging of the immune system and increases the risk of diseases such as cancer, cardiovascular disease and COVID-19. .
The study, published Monday in the National Academy of Sciences, will help explain age-related health imbalances, including an unequal number of pandemics, and identify possible interventions.
“As the number of older people in the world grows, it is important to understand the age-related health disparities. Age-related changes in the immune system play an important role in deteriorating health, “said lead author Eric Klopac, a postdoctoral researcher at the Leonard Davis School of Gerontology, USC.” This study will help identify the mechanisms involved in accelerated immune aging. “
As people age, the immune system naturally begins to decline sharply, which is called immunosensitivity. With age, a person’s immune profile weakens and contains very few new, “naive” white blood cells that are ready to accept too many obsolete leukocytes and new invaders.
Possible problems related to stress and the immune system
Immune aging is associated not only with cancer, but also with cardiovascular disease, increased risk of pneumonia, decreased effectiveness of vaccines and aging of the organ system.
But what are the stark differences in the health of people of the same age? USC researchers decided to see if they could find a link between lifelong stress – a known cause of ill health – and a weakened immune system.
They asked for a cross-reference from the University of Michigan Health and Retirement Survey, a nationwide study of the economic, health, family, marital status, and public and private support systems of older Americans.
To measure exposure to different types of social stress, the researchers analyzed responses from a national sample of 5,744 adults over the age of 50. They responded to a questionnaire designed to assess respondents’ social stress, including stressful life events, chronic stress, and everyday events. discrimination and lifelong discrimination.
Blood samples from the participants were then analyzed by flow cytometry, a laboratory method that counts and classifies blood cells as they pass one by one in a narrow stream in front of the laser.
As expected, people with high stress scores had older immune profiles, fewer people with new illnesses, and higher percentages of old leukocytes. The connection between ready-to-respond to stressful life events, or simple T-cells, remained strong even after control of knowledge, smoking, alcohol consumption, BMI, and race or ethnicity.
Some sources of stress cannot be controlled, but researchers say there may be ways to deal with it.
T cells, an important component of the immune system, mature in a gland called the thymus, located in front of and above the heart. As people get older, the tissue in their thyroid gland changes to fatty tissue, and the production of immune cells decreases. Past research has shown that this process is accelerated by lifestyle factors such as poor nutrition and lack of exercise, both of which are associated with social stress.
“In this study, after statistically controlled malnutrition and lack of exercise, the link between stress and accelerated immune aging was less strong,” Klopac said. “People who are more stressed tend to have poor eating and exercise habits, which partly explains why their immune system ages faster.”
Stress and the immune system: the effects of diet and exercise
Improving the diet and exercise behavior of older people can help compensate for the stress-related immune aging.
In addition, cytomegalovirus (CMV) may be targeted for intervention. CMV is a common, usually asymptomatic virus in humans and is known to have a strong immune-accelerating effect. Like tumors or cold sores, CMV is usually dormant, but can flare up, especially when a person is under severe stress.
Statistically monitoring CMV positivity in this study reduced the association between stress and accelerated immune aging. Therefore, widespread CMV vaccination may be a relatively simple and potentially potent intervention that can reduce the effects of stress on immune aging, the researchers said.
In addition to Klopac, other authors include Eileen Crimmins, a professor at the university and chair of the AARP in gerontology at the USC Leonard Davis School; and Steve Cole and UCLA Theresa Siman.
The study was supported by grants from the National Institute on Aging (P30AG017265, U01AG009740).
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