Objective: Child maltreatment (CM) is a widespread problem associated with poor mental and physical health outcomes. The underlying mechanisms of this link are not always well understood, however certain biological changes observed in maltreated individuals may play a role in connecting experience and outcome. This review specifically focuses on two markers of biological embedding, DNA methylation (DNAm) and telomere length (TL) in maltreated children and youth. As biomarker changes are not uniform among maltreated children, we additionally discuss biological and environmental resilience factors that may contribute to variability. Methods: We conducted a systematic review of Medline, Embase and PsycInfo databases for studies examining DNAm and/or TL in maltreated children and youth. Methodological quality of the included articles was assessed using the Scottish Intercollegiate Guidelines Network (SIGN) checklists for cohort studies and randomized control trials. Data extraction focused on various factors including population and CM (type, chronicity, severity, and duration) characteristics. Results: The initial search returned 1,688 non-duplicate results, with 417 full text articles reviewed. Twenty-six articles from 16 studies were ultimately included of which 8 examined telomere length and 18 examined DNA methylation. Conclusions: While some heterogeneity of findings was found, evidence supports differential changes in both biomarkers associated with CM. This review enhances understanding of the constellation of biological changes related to CM and consideration of the important role of resilience factors in mitigating risk. Elucidating these factors may highlight targets for future study and intervention development. / Thesis / Master of Science (MSc) / Child maltreatment is a serious problem linked to poor mental and physical health outcomes. The mechanisms of these links are not always clear, however biological changes observed in some maltreated individuals may play a role. Here, we systematically review literature related to two biomarkers of interest in maltreated children, telomere length and DNA methylation. Findings are varied; however, overall, they support an association between child maltreatment and changes in both biomarkers. We additionally discuss factors that may confer resilience related to these changes to highlight potential targets for future study and interventions.

Introduction. La notion d'" embodiment " propose que chaque humain est à la fois un être social ainsi que biologique, intégrant le monde dans lequel il/elle vit. Nous faisons l'hypothèse que la position socioéconomique pendant l'enfance peut être biologiquement incorporée, conduisant à la production des inégalités sociales de santé entre les sous-groupes de population. La charge allostatique (CA) est un concept qui tente de capturer l'usure physiologique globale du corps liée à l'activation répétée des mécanismes physiologiques compensatoires en cas d'exposition à des stress chroniques. La CA pourrait permettre une meilleure compréhension des voies biologiques qui jouent un rôle potentiel dans la construction du gradient social de santé des adultes. Objectif. Pour explorer l'hypothèse d'incorporation biologique, nous avons examiné les voies de médiation entre les adversités psychosociales et la position socioéconomique précoces et la CA à 44 ans. Nous avons également confronté l'indice de CA à une mesure multidimensionnelle de santé latente à 50 ans. Méthodes. Les données sont issues de la cohorte Britannique de naissance de 1958 (n=18 000). La CA a été construite avec les données de l'enquête biomédicale conduite à 44 ans, comme une mesure physiologique synthétique, multi-système, à l'aide de 14 biomarqueurs représentant les systèmes neuroendocrinien, métabolique, immunitaire / inflammatoire et cardiorespiratoire. Résultats. L'ensemble de nos résultats suggèrent que la CA pourrait être un indice approprié pour capturer partiellement la dimension biologique des processus d'embodiment. Discussion. Comprendre comment l'environnement affecte notre santé en se " glissant sous la peau " et pénétrant dans les cellules, les organes et les systèmes physiologiques de notre corps est un principe clé dans la recherche en santé publique. Promouvoir le recueil de marqueurs biologiques dans des grandes études prospectives et représentatives est crucial pour continuer la recherche sur ce sujet. Les études de réplication pourraient faire partie des futures perspectives de recherche, pour comparer entre populations avec des contextes culturels différents pour observer si un index de CA peut être considéré comme "universel ". / Introduction. The notion of embodiment proposes that every human being is both a social and a biological organism that incorporates the world in which (s)he lives. It has been hypothesized that early life socioeconomic position (SEP) can be biologically embedded, potentially leading to the production of health inequalities across population groups. Allostatic load (AL) is a concept that intends to capture the overall physiological wear-and-tear of the body triggered by the repeated activation of compensatory physiological mechanisms as a response to chronic stress. AL could allow a better understanding of the potential biological pathways playing a role in the construction of the social gradient in adult health. Objective. To explore the biological embedding hypothesis, we examined the mediating pathways between early SEP and early adverse psychosocial experiences and higher AL at 44 years. We also confronted an AL index with a latent multidimensional and integrative measure of health status at 50y. Methods. Data are from the 1958 British birth cohort (n=18 000) follow-up to age 50. AL was operationalized using data from the biomedical survey collected at age 44 on 14 parameters representing the neuroendocrine, metabolic, immune-inflammatory and cardiovascular systems. Results. Overall, our results suggest that AL could be a suitable index to partially capture the biological dimensions of embodiment processes. Discussion. Understanding how human environments affect our health by 'getting under the skin' and penetrating the cells, organs and physiological systems of our bodies is a key tenet in public health research. Promoting the collection of biological markers in large representative and prospective studies is crucial to continue to investigate on this topic. Replication studies could be part of the future research perspectives, to compare with other cultural context and to observe if an AL index can be 'universal'.