Adverse childhood experiences and neuroendocrine biomarker changes in Mexican preschool children

Adverse Childhood Experiences (ACEs) are highly prevalent and associated to severe health outcomes in the Mexican adult population. However, their biological correlates during early childhood remain poorly understood. We conducted a cross-sectional study in Mexican children, aged 3-5 years, to examine the association between neuroendocrine biomarker hair levels related to hypothalamic-pituitary-adrenal (HPA) axis (cortisol, cortisone, and DHEA) and the number and type of ACEs in this population. Additionally, we analyzed the effect of sociodemographic characteristics of the population (age, sex and urbanity stratum). The study included 237 children and 226 caregivers from the national ACESMEXICO cohort. Caregivers provided self-reported sociodemographic and child-related information, and hair samples from 178 children were analyzed for neuroendocrine biomarkers. The Pediatric ACEs and Related Life-Events Screener (PEARLS) was used to gather ACEs data. Linear regression models adjusted by age, sex and urbanity stratum, tested associations between cumulative ACEs categories and individual ACEs, and log-tansformed steroid levels. Children with two ACEs had higher cortisone levels compared with those with none, whereas the ≥ 3 ACEs group showed a marginal increase. These findings suggest a threshold response. Children with parents who abused drugs showed higher cortisol hair levels even when controlling for total ACEs. Elevated DHEA levels were associated with economic difficulties, rural living, younger age, and male sex, independent of the number of ACEs. These findings provide novel evidence that associates ACEs with neuroendocrine alterations in Mexican preschool children, highlighting rural-urban disparities. Exposure to adversities such as parental substance use significantly altered stress-related hormone levels, particularly among girls, emphasizing the need for gender- and context-sensitive approaches to childhood adversity interventions.