Effect of Early Childhood Trauma on HPA Axis Dysregulation, Inflammatory Biomarkers, and Long-Term Health Outcomes Among Children in Conflict-Affected Zones of Borno State, North East Nigeria

Adverse childhood experiences (ACEs), particularly those arising from armed conflict and displacement, are increasingly recognised as biologically embedding adversity through dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis and immune-inflammatory pathways. In Borno State, where over a decade of armed conflict has created mass exposure to childhood trauma, the biological embedding of adversity has not been studied. This mixed-methods longitudinal study examines the relationship between ACE burden, HPA axis function, inflammatory biomarkers, and health outcomes at two-year follow-up in children aged 6 to 14 years residing in IDP camps and recovered communities of Maiduguri, Borno State. A total of 380 children completed the ACE-IQ adapted for Nigerian conflict contexts. Morning salivary cortisol, hair cortisol concentration, serum C-reactive protein, IL-6, and TNF-alpha were measured at baseline. Health outcomes at two-year follow-up included recurrent illness episodes, growth trajectory, and developmental functioning assessed by the Wechsler Intelligence Scale for Children. Children with four or more ACEs demonstrated blunted diurnal cortisol slopes (p less than 0.001) and 2.3-fold elevated IL-6 compared to low-ACE peers. Elevated baseline IL-6 predicted significantly poorer cognitive scores at two-year follow-up (beta negative 3.8, p less than 0.01). Hair cortisol concentrations were inversely correlated with height-for-age z-score trajectories. These findings provide the first biological evidence of HPA-inflammatory embedding of conflict-related childhood trauma in Nigeria, contributing a biological stress-embedding framework to paediatric adversity science in Africa. Keywords: adverse childhood experiences, HPA axis, inflammatory biomarkers, conflict, Borno State.