- Stressed adults tend to have poorer eating and exercise habits.
- A stressful event and chronic stress have been associated with a lower percentage of immune system cells called “naïve CD4 cells.”
Work, income, marriage, raising children… there are many sources of stress. “Exposure to this nervous tension is a risk factor for accelerated aging. Immune aging plays a role in immune health and tissue-specific aging and may contribute to an increased risk of ill health in people experiencing high levels of psychosocial stress,” wrote researchers from the University of California in the United States in a study published in the journal Proceedings of the National Academy of Sciences (PNAS).
As part of this research, scientists were trying to determine if there was a link between exposure to stress throughout life and a decline in the immune system. “This study elucidates the mechanisms of accelerated immune aging,” said the authors.
For the purposes of the work, they recruited 5,744 adults over the age of 50. Participants completed a questionnaire about their experiences of social stress, including distressing life events, chronic stress, and daily or lifetime discrimination. Blood samples from the subjects were then analyzed using flow cytometry, an analysis technique that allows rapid characterization and enumeration of cells.
A link between stress and immune senescence
According to the results, adults with higher stress scores displayed older immune profiles with lower proportions of disease-fighting fresh cells and higher proportions of worn-out white blood cells. The association between stressful life events and decreased T-cell count, a key component of immunity, remained strong even after accounting for education, smoking, alcohol consumption, or BMI.
“The results identify psychosocial stress as a factor contributing to accelerated immune aging by depleting naïve T cells.”, we can read in the study. The team pointed out that immune aging is associated with cancer, cardiovascular disease, increased risk of pneumonia, reduced vaccine effectiveness and aging of organ systems.