Low Socioeconomic Status (and associated scarcity of resources, early exposure to infections, and nutritional stress), unpredictability (familial conflict), and abuse can all have lasting effects on people’s mental and physical health when they occur in early childhood. Some of these risk factors (e.g. early life exposure to infection and nutritional stress) affect men more than women and some (e.g. maltreatment and abuse) affect the long-term physical and mental health of women more than men (Gassen et al. 2021). There is some indication that adverse childhood experiences irreversibly change the trajectory of important developmental processes, and the fact there are prominent sex differences, suggests that sex hormones play an important role in the process.
A study by Jeffrey Gassen et al. examined the relationship between various stressors in early life and adult immune function. The measures of childhood stressors were retrospectively reported by participants and the measures of immune function were determined using immune function assays (measured the ability of natural killer cells to destroy tumor cells, efficiency of phagocytes in ingesting E. coli bioparticles, and the extent of white cell proliferation and cytokine release caused by mitogens).
Researchers found that lower childhood SES for men was associated with the inefficiency in two measures of immune function; namely, lower phagocytosis of E. coli bioparticles, lower natural killer cell efficiency (NK cell cytotoxicity), and associated with higher levels of testosterone. For women, childhood SES was not associated with any of these measures of immune function. Also, lower SES was associated with a higher tendency to release proinflammatory cytokines in the absence of overt immunological stimulation (many diseases like COVID-19 become fatal due to exaggerated inflammatory response). Neither childhood unpredictability, nor exposure to adverse childhood experiences were related to any of the immunological measures, testosterone levels, nor did they interact with participant sex to impact any of these outcomes.
In line with previous findings, the study suggests that early life situations have an irreversible effect on adult health, particularly for men. The fact that higher testosterone levels co-occur with reduced immune function suggests, the authors write, that sex hormones may play a role in determining how much of the bodily resources are invested in the immune system during critical periods of development. Read more about the study here.
