Immune Aging Accelerated By Stress

A new study demonstrates that stress from things like job strain, traumatic events, discrimination, and everyday occurrences can accelerate immune system aging. This can possibly increase people’s chances of cardiovascular disease, cancer and illness due to infections. The study could offer an explanation in disparities in health that are age related which include the diverse toll of the COVID-19 pandemic and determine possible avenues for intervention.

Because the worldwide population of aging people is increasing, the understanding of disparities in health that are age related is essential. The study helps to identify mechanisms connected to immune aging that is accelerated.

As we age, our immune system will naturally start a dramatic downturn which is a condition known as immunosenescence. As advanced age occurs, a person’s immune system will weaken and include many white blood cells that are not circulating and not enough that are naive and can take on new invaders.

The aging of the immune system is linked not only to cancer, but also with a heightened risk of cardiovascular disease, pneumonia, and reduced efficacy of aging organs.

The team wanted to see if they might be able to coax out a link between a life long exposure to stress, which is a known precursor to health that is poor, and declining intensity of the immune system.

They cross referenced and queried an enormous amount of data sets from the Univ. of Michigan and Retirement Study, which was a national study of the status of health, economic, marital and family position, and private and public support systems of Americans that were older.

To determine exposure to a variety of social stressors, the team studied answers from a national sampling of 5,744 individuals over age 50. A questionnaire was designed for the participants to answer that assessed respondents experiences with social stress that included chronic stress, life events that are stressful, ongoing discrimination and everyday discrimination.

Samples of blood from the participants were then analyzed through flow cytometry, a lab technique that classifies and counts blood cells as they flow one by one in a narrow stream by a laser.

As was expected, participants with a high stress score had older immune profiles with a lower percentage of disease fighters and a high percentage of white blood cells that were worn out. The association between stressful life events and fewer, ready to respond T cells, continued to be strong even following controlling of smoking, education, BMI, race, drinking and ethnicity.

T cells are critical components of immunity develop in the thymus gland, which is in front and above the heart. As we age, the tissue in the thymus gland diminshes and is replaced by fatty tissue which results in decreased production of immune cells. Earlier research has suggested that this process is sped up by lifestyle factors like low exercise, poor diet, which are both linked with social stress.

In the study, after the team statistically controlled for low exercise and poor diet, the association between stress and increased immune aging wasn’t as strong. This means people who go through more stress have poor exercise and diet habits, which partly explains why they have increased aging. Improving exercise and diet habits in older people might help counteract the immune aging linked with stress.

Also, CMV (cytomegaloovirus) may be a point for intervention. It is usually asymptomatic and a common virus in people and is known to have a powerful effect on increased immune aging. Similar to cold sores and shingles, CMV is mostly dormant but can occur when a person experiences high stress.

In the study, statistically controlling CMV positivity also decreased the link between accelerated immune aging and stress.

To view the original scientific study click below:
Social stressors associated with age-related T lymphocyte percentages in older US adults: Evidence from the US Health and Retirement Study