Childhood trauma leaves a lasting mark on biological systems, study finds

A study of 13-year-olds in Portugal found that children exposed to selected adverse experiences by 10 years of age tend to show increased allostatic burden in adolescence. Additional adverse experiences by age 13 further amplify this association. The paper was published in Brain, Behavior, and Immunity.

Adverse childhood experiences (ACEs) are potentially traumatic events that occur during childhood and can have lasting effects on health and well-being. They typically include experiences such as abuse, neglect, and household dysfunction before the age of 18. Examples include physical, emotional, or sexual abuse, emotional or physical neglect, and exposure to domestic violence. They also include growing up in a household with substance abuse, mental illness, parental incarceration, or parental separation.

Research shows that the more ACEs a person experiences, the higher their risk for mental and physical health problems later in life. High ACE exposure has been associated with depression, anxiety, substance misuse, and increased risk of chronic diseases.

One key mechanism is chronic activation of the stress response, which can affect brain development and immune functioning. However, not everyone who experiences ACEs develops negative outcomes, because protective factors such as supportive relationships and stable environments can promote resilience.

Study author Armine Abrahamyan and her colleagues wanted to estimate the allostatic load of 13-year-olds and evaluate whether exposure to ACEs during the first decade of life may be associated with it. Allostatic load is the cumulative physiological “wear and tear” on the body that results from repeated or chronic activation of the stress response systems.

Over time, this prolonged stress-related activation can dysregulate multiple biological systems—such as cardiovascular, metabolic, immune, and renal systems—thereby increasing the risk for various physical and mental health problems.

The authors of this study analyzed data from Generation XXI, a population-based birth cohort from Porto, Portugal. This group initially consisted of 8,647 children born in 2005 and 2006 in the public maternity wards of the Porto metropolitan area. However, by 13 years of age, only 54% of the group still provided their data to researchers. The analyses presented in the paper were based on an analytic sample of 3,787 participants, of which 1,979 were boys.

At 10 and 13 years of age, participating children completed an assessment of adverse childhood experiences (a questionnaire adapted from the Adverse Childhood Experiences Study and from the Child and Adolescent Survey of Experiences: Child Version). At age 13, they also provided blood samples, underwent anthropometric measurements, and had their blood pressure and heart rate measured. The measure of allostatic load was based on a combination of data about the functioning of the cardiovascular system, metabolic system, immune and inflammatory systems, and renal function.

The results showed that while the total score of adverse experiences at age 10 was not associated with a higher allostatic load at age 13, specific individual traumas—such as parental separation or divorce before age 10—were. Furthermore, participants with a higher total accumulation of adverse childhood experiences by age 13 showed a significantly higher overall allostatic load at that same age.

Parental separation and divorce, difficulties in school, or household alcohol/drug use that occurred between participants’ age of 10 and 13 were associated with higher allostatic load at age 13. Overall, the metabolic and immune systems tended to be the most responsive to adverse childhood experiences.

“These findings suggest that adolescents exposed to selected ACEs at age 10 showed increased AL [allostatic load] burden, with cumulative ACEs by age 13 further amplifying this association,” the study authors concluded.

The study contributes to the scientific understanding of the links between overall health and adverse childhood experiences. However, it should be noted that almost half of the initial number of participants dropped out of the study by the last measurement period. This could have affected the results, potentially underestimating the true magnitude of the physical toll, as adolescents from more disadvantaged backgrounds (who often face higher adversity) were more likely to drop out.

The paper, “Adverse childhood experiences and physiological wear-and-tear in adolescence: Findings from the Generation XXI cohort,” was authored by Armine Abrahamyan, Milton Severo, Michelle Kelly-Irving, Liane Correia-Costa, Mariana Amorim, Sara Soares, and Sílvia Fraga.