Inflammation Mediates the Association between Recalled Childhood Maltreatment and Somatic Awareness: Results from a National Sample of U.S. Adults

Background/Purpose: Childhood maltreatment (CM) is associated with increased risk for numerous physical and mental health problems. Further, when these health problems occur, CM history is associated with an overall worse course of illness and/or greater risk for treatment resistance. Therefore, identifying novel targets for prevention and intervention is critical for reducing CM-related health disparities. CM has been linked to disrupted interoception, the body’s ability to recognize internal cues for self-regulation (e.g., sensitivity to pain, hunger, breathing, and heart rate). Social Safety Theory suggests that exposure to social threats increases activation of the body’s stress response, reflected in higher levels of circulating inflammatory markers that can affect brain functioning. Increased inflammation has been found to disrupt the brain’s role in bodily self-regulation. Thus, CM may contribute to disrupted interoception in part through inflammation; however, no study to date has tested whether inflammation mediates the association between CM and interoception.

Methods: Data from Wave 2 of the Midlife in the United States biomarker project (n=1,255) were used to test whether inflammation mediates the association between CM and interoception. CM was assessed continuously using the Childhood Trauma Questionnaire, which measures recalled emotional abuse, physical abuse, sexual abuse, emotional neglect, and physical neglect. Inflammation was measured continuously using interleukin-6 (IL-6), an inflammatory cytokine produced by immune cells during the stress response and able to target the brain by crossing the blood-brain-barrier. The somatic awareness subscale of the Mood and Anxiety Symptom Questionnaire measured the disrupted somatic sensitivity component of interoception. Regression-based mediation analysis followed the Baron and Kenney framework, with significance assessed using 2,000 bootstrap samples. Mediation analysis first focused on IL-6 as a potential mediator of overall CM on somatic awareness and then tested IL-6 as a mediator of CM subtypes. Analyses controlled for perceived stress, smoking status, alcohol consumption, race/ethnicity, sex, age, and household income.

Results: The sample had a mean age of 57.32 years (SD=11.55), was predominantly White (79%), and was 57% female. Regression models identified that overall CM was associated with greater somatic awareness (b=0.05, SE=0.01, p<0.001) and IL-6 (b=0.003, SE=0.001, p<0.05). When modeling jointly, both overall CM (b=0.05, SE=0.01, p<0.001) and IL-6 (b=0.59, SE=0.19, p<0.01) were associated with greater somatic awareness. Mediation analysis identified that IL-6 significantly mediated 2.70% of the association between CM and somatic awareness (z=0.002, p<0.05). After re-testing models using CM subtypes as joint predictors, only sexual abuse was found to be a predictor of both IL-6 (b=0.01, SE=0.005, p<0.01) and somatic awareness (b=0.09, SE=0.03, p<0.05). Mediation analysis found that IL-6 significantly mediated 7.87% of the association between sexual abuse and somatic awareness (z=0.009, p<0.05).

Conclusions/Implications: Findings underscore the importance of preventing CM and improving care for trauma-affected individuals. This includes screening for trauma exposure and somatic symptoms as well as delivering trauma-informed interventions targeting both psychological and physical symptoms. Interventions addressing chronic inflammation may be especially beneficial for individuals exposed to sexual abuse. Promoting safe, stable environments and expanding equitable access to mental health services remains critical for reducing CM-related disparities and advancing population health.