Stressors — in the form of traumatic events, job strain, everyday stressors, and discrimination — accelerate immune system aging, potentially increasing a person’s risk of cancer, cardiovascular disease and illness from infections such as COVID-19, according to a study from the University of Southern California.

As people age, the immune system naturally begins a dramatic downgrade, a condition called immunosenescence. With advanced age, a person’s immune profile weakens, and includes too many worn-out white blood cells circulating and too few fresh, “naive” white blood cells ready to take on new invaders, the researchers explain

But what accounts for drastic health differences in same-age adults? The team sought to tease out a connection between lifetime exposure to stress — a known contributor to poor health — and declining vigor in the immune system.

To measure exposure to various types of social stress, the researchers analyzed responses from a national sample of 5,744 adults over the age of 50 who answered a questionnaire designed to assess their experiences with social stress, including stressful life events, chronic stress, everyday discrimination and lifetime discrimination. Blood samples from the participants were also analyzed.

As expected, people with higher stress scores had older-seeming immune profiles, with lower percentages of fresh disease fighters and higher percentages of worn-out white blood cells. The association between stressful life events and fewer naive T cells remained strong even after controlling for education, smoking, drinking, BMI and race or ethnicity.

Some sources of stress may be impossible to control, but previous research suggests that people who experience more stress tend to have poorer diet and exercise habits, which partly explains why them have more accelerate immune aging, according to the study authors. They suggest that improving diet and exercise behaviors in older adults may help offset stress-associated immune aging.

To read the full article, "Social stressors associated with age-related T lymphocyte percentages in older US adults: Evidence from the US Health and Retirement Stud," click here