According to a new study, the stress in the form of traumatic events, job strain, everyday stress, and prejudice increases immune system aging, potentially raising a person’s risk of cancer, cardiovascular disease, and illness from infections such as Covid-19.
The researchers from the University of Southern California analyzed responses from a national sample of 5,744 persons over the age of 50 to determine exposure to various forms of social stress.
Their experiences with social stress, including stressful life events, chronic stress, everyday discrimination, and lifetime discrimination, were compared to blood samples analyzed using flow cytometry, a lab technique that counts and classifies blood cells as they pass one by one in front of a laser.
People with higher stress levels had older-looking immune profiles, with lower percentages of new disease fighters and higher percentages of worn-out white blood cells, as expected.
The scientists found in an article published in the Proceedings of the National Academy of Sciences that the link between stressful life events and less ready to respond, or naive, T cells remained strong even after controlling for education, smoking, drinking, BMI, and race or ethnicity (PNAS).
T-cells, an important component of immunity, develop in the thymus gland, which is located just in front of and above the heart. As people age, the tissue in their thymus diminishes and is replaced with fatty tissue, leading in a decrease in immune cell production.
Previous study suggests that this process is hastened by lifestyle factors such as poor diet and lack of exercise, both of which are linked to social stress.
Improving nutrition and exercise habits in older persons may help counteract the immunological ageing caused by stress.
“After correcting for poor diet and lack of exercise in this study, the link between stress and accelerated immunological ageing was not as robust,” said lead study author Eric Klopack, a postdoctoral scholar at the University.
“What this suggests is that people who are more stressed tend to have inferior food and exercise habits, which may explain why they have more accelerated immunological ageing,” he noted.