It is commonly acknowledged that as people grow older, their immune systems naturally deteriorate, a condition known as “immunosenescence.”
Immunosenescence is a term that describes the gradual deterioration of the immune system that occurs as a result of natural aging. The period is characterized by excessively worn-out white blood cells circulating and not enough new white blood cells ready to combat new invaders.
The ongoing COVID-19 pandemic, for instance, has a substantially greater death rate among the elderly than the young. However, you may know people who are quite old but in excellent health, or vice versa, someone who is youthful but susceptible to diseases. This condition has been associated with an increased risk of cancer, heart disease, and pneumonia, as well as decreased vaccine effectiveness and organ system aging.
New research led by the University of Southern California (USC) has concluded that stress caused by a variety of factors, including job strain, traumatic events, everyday stressors, or discrimination – may accelerate the aging of the immune system, increasing people’s risk of cardiovascular disease, cancer, or severe illness from infections such as Covid-19. These findings may help explain age-related health disparities, such as the differential impact of the coronavirus epidemic, and uncover potential therapeutic approaches.
The study, published in the journal Proceedings of the National Academy of Sciences on Monday, June 13, 2022, could help explain discrepancies in age-related health, including the pandemic’s disproportionate toll, and suggest potential intervention spots.
“As the world’s population of older individuals grows, it’s more important than ever to understand the differences in age-related health conditions. Lead study author Eric Klopack, a postdoctoral scholar at the USC Leonard Davis School of Gerontology, said, “Age-related alterations in the immune system play a significant role in worsening health.” “This research sheds light on the mechanisms behind immunological aging,” he explains further.
Health issues that could arise as a result of an aging immune system
Immune aging is linked to cancer, cardiovascular disease, increased pneumonia risk, vaccine efficacy, and organ aging, among other things.
Why are there such stark disparities in immunological profiles among people of the same age?
Researchers at USC wanted to explore if they could find a link between lifetime stress exposure, a known driver of poor health, and immune system strength decline. They combed through massive data sets from the University of Michigan’s Health and Retirement Study, a national longitudinal study of the economic, health, marital, family status, and older Americans’ public and private support systems.
The research summary
The researchers assessed responses from a national sample of 5,744 persons over age 50 to determine their exposure to various types of social stress. They completed a survey measuring their social stress experiences, including stressful life events, chronic stress, everyday discrimination, and lifetime discrimination.
Flow cytometry, a lab technique that counts and classifies blood cells as they pass one by one in a narrow stream in front of a laser, was used to evaluate blood samples from participants with higher stress ratings.
The researchers discovered a higher percentage of worn-out white blood cells, implying that stress hastens immunological aging. Poor diet and lack of exercise have been linked to social stress and appear to have a role in these issues.
As expected, people with higher stress levels had immunological profiles that appeared to be older, with fewer percentages of new disease fighters and higher percentages of worn-out white blood cells. Even after controlling for smoking, education, BMI, drinking, and ethnicity or race, the link between stressful life events and less ready-to-respond or naive T cells remained strong.
Some sources of stress may be uncontrollable, but…
T-cells, an essential component of immunity, mature in the thymus gland, located just in front of and above the heart. The tissue in the thymus diminishes with age and is replaced by fatty tissue, decreasing immune cell production. According to previous studies, lifestyle factors such as poor food and lack of exercise were linked to social stress and were found to speed up this process.
“The link between stress and accelerated immunological aging was not as strong in this study after statistically correcting for poor food and low exercise,” Klopack added. “This suggests that people who are more stressed have inferior food and exercise habits, which may explain why their immune systems age more quickly.”
Diet and exercise can prevent the aging of the immune system
Improving a person’s diet and exercise habits as they age may help counteract the immunological aging that comes with stress.
Furthermore, cytomegalovirus (CMV), a common asymptomatic human virus, could be a target for intervention. It is believed to have a strong influence on boosting immune aging. CMV, like shingles or cold sores, is usually latent but can flare up at any time, especially when a person is highly stressed.
Statistically correcting for CMV positive in this study also attenuated the link between stress and immunological aging. As a result, the authors concluded that widespread CMV immunization could prove to be a specific and effective intervention for reducing the immunological aging consequences of stress.