Exposure to social stress was associated with accelerated aging of the immune system, according to a recently published NIA-funded study. PNAS. The body’s immune system changes with age, but these changes are highly variable. The study, led by UCLA researchers, investigated whether social stressors promote weakened immune systems.
Researchers analyzed data from more than 5,500 participants in the Health and Retirement Study, a nationally representative longitudinal study of Americans age 50 and older. Researchers measured stress by analyzing responses to questions about exposure to different types of social stress, including: and other life events such as discrimination, trauma, and unemployment. They also analyzed the participant’s immune profile (a snapshot of immune system function) by drawing blood and measuring white blood cell levels, specifically his T lymphocytes (also called T cells). T cells are an important part of the immune system and help the body fight infections.
The results showed that exposure to social stress increases the proportion of T cells dedicated to fighting infections that have already been encountered, and decreases the proportion of T cells that can adapt to new challenges. indicates accelerated immunosenescence. The association between social stress and T cells remained even after controlling for education, smoking, alcohol use, BMI, and race/ethnicity.
Researchers found that the relationship between stress and accelerated immune aging was not as strong after controlling for lifestyle factors such as diet and exercise habits. These findings suggest that improving diet and exercise behavior in older adults may help offset stress-related immunosenescence.
Increased immunosenescence is associated with chronic disease, weakened responses to acute infections, increased risk of pneumonia, reduced vaccine effectiveness, and aging of organ systems. This study provides important insights into the influence of social stress on immunosenescence and highlights the important role of health behaviors and socio-environmental conditions. We also identify potential intervention points that could help address inequalities in aging.
This research was supported in part by NIA grants U01AG009740 and P30AG017265..
reference: Klopack ET, et al. Age-related T lymphocyte percentages and associated social stressors in older adults in the United States: Evidence from the American Health and Retirement Study. PNAS. 2022; 119(25). doi:10.1073/pnas.2202780119.