Type and developmental timing of childhood adversity predicts psychopathology symptoms in a South African birth cohort.

Background: Childhood adversity is widespread globally and is one of the strongest predictors of later psychopathology. However, the differential effects of type and timing of childhood adversities on childhood psychopathology remain unclear, highlighting the need to explore which life-course hypotheses (sensitive periods, accumulation of exposure, and/or recency of exposure) best explain these associations. Of particular importance, there is a lack of research in low- and middle-income countries (LMIC), where children experience higher rates of adversity relative to children in high-income countries (HIC).

Strengthening Rigor and Reproducibility in Epigenome-Wide Association Studies of Social Exposures and Brain-Based Health Outcomes.

Purpose Of Review: Studies examining the effects of social factors on the epigenome have proliferated over the last two decades. Social epigenetics research to date has broadly demonstrated that social factors spanning childhood adversity, to neighborhood disadvantage, educational attainment, and economic instability are associated with alterations to DNA methylation that may have a functional impact on health. These relationships are particularly relevant to brain-based health outcomes such as psychiatric disorders, which are strongly influenced by social exposures and are also the leading cause of disability worldwide.

Stress reactivity moderates the association between stressful life events and depressive symptoms in adolescents: Results from a population-based study.

Background: A large body of evidence links stressful life events with depression. However, little is understood about the role of perceived impact in this association.

Methods: We performed regression analysis to investigate whether self-reported stress reactivity (derived by regressing the impact-weighted life event score on the unweighted score) moderated the association between stressful life events and depressive symptoms in adolescents from the Avon Longitudinal Study of Parents and Children cohort (n = 4791), controlling for age at outcome, sex, ethnicity, and maternal education.

Maximizing insights from longitudinal epigenetic age data: simulations, applications, and practical guidance.

Background: Epigenetic age (EA) is an age estimate, developed using DNA methylation (DNAm) states of selected CpG sites across the genome. Although EA and chronological age are highly correlated, EA may not increase uniformly with time. Departures, known as epigenetic age acceleration (EAA), are common and have been linked to various traits and future disease risk.

Technical variability across the 450K, EPICv1, and EPICv2 DNA methylation arrays: lessons learned for clinical and longitudinal studies.

DNA methylation (DNAm) is the most commonly measured epigenetic mechanism in human populations, with most studies using Illumina arrays to assess DNAm levels. In 2023, Illumina updated their DNAm arrays to the EPIC version 2 (EPICv2), building on prior iterations, namely the EPIC version 1 (EPICv1) and 450K arrays. Whether DNAm measurements are stable across these three generations of arrays has yet not been investigated, limiting the ability of researchers-especially those with longitudinal data-to compare and replicate results across arrays.

Maximizing Insights from Longitudinal Epigenetic Age Data: Simulations, Applications, and Practical Guidance.

Background: Epigenetic Age (EA) is an age estimate, developed using DNA methylation (DNAm) states of selected CpG sites across the genome. Although EA and chronological age are highly correlated, EA may not increase uniformly with time. Departures, known as epigenetic age acceleration (EAA), are common and have been linked to various traits and future disease risk.

DNA methylation as a possible mechanism linking childhood adversity and health: results from a 2-sample mendelian randomization study.

Childhood adversity is an important risk factor for adverse health across the life course. Epigenetic modifications, such as DNA methylation (DNAm), are a hypothesized mechanism linking adversity to disease susceptibility. Yet, few studies have determined whether adversity-related DNAm alterations are causally related to future health outcomes or if their developmental timing plays a role in these relationships.

Examining the epigenetic mechanisms of childhood adversity and sensitive periods: A gene set-based approach.

Background: Sensitive periods are developmental stages of heightened plasticity when life experiences, including exposure to childhood adversity, have the potential to exert more lasting impacts. Epigenetic mechanisms, including DNA methylation (DNAm), may provide a pathway through which adversity induces long-term biological changes. DNAm shifts may be more likely to occur during sensitive periods, especially within genes that regulate the timing of sensitive periods.

Intersection of Epigenetic and Immune Alterations: Implications for Fetal Alcohol Spectrum Disorder and Mental Health.

Prenatal alcohol exposure can impact virtually all body systems, resulting in a host of structural, neurocognitive, and behavioral abnormalities. Among the adverse impacts associated with prenatal alcohol exposure are alterations in immune function, including an increased incidence of infections and alterations in immune/neuroimmune parameters that last throughout the life-course. Epigenetic patterns are also highly sensitive to prenatal alcohol exposure, with widespread alcohol-related alterations to epigenetic profiles, including changes in DNA methylation, histone modifications, and miRNA expression.

Associations between indicators of socioeconomic position and DNA methylation: a scoping review.

Background: Socioeconomic position (SEP) is a major determinant of health across the life course. Yet, little is known about the biological mechanisms explaining this relationship. One possibility widely pursued in the scientific literature is that SEP becomes biologically embedded through epigenetic processes such as DNA methylation (DNAm), wherein the socioeconomic environment causes no alteration in the DNA sequence but modifies gene activity in ways that shape health.

Association of Maternal Stress and Social Support During Pregnancy With Growth Marks in Children's Primary Tooth Enamel.

Importance: Exposure to maternal psychosocial stressors during the prenatal and perinatal periods can have major long-term mental health consequences for children. However, valid and inexpensive biomarkers are currently unavailable to identify children who have been exposed to psychosocial stress and the buffers of stress exposure.

Objective: To assess whether a growth mark in tooth enamel, the neonatal line, is associated with exposure to prenatal and perinatal maternal psychosocial factors.

Sensitive period-regulating genetic pathways and exposure to adversity shape risk for depression.

Animal and human studies have documented the existence of developmental windows (or sensitive periods) when experience can have lasting effects on brain structure or function, behavior, and disease. Although sensitive periods for depression likely arise through a complex interplay of genes and experience, this possibility has not yet been explored in humans. We examined the effect of genetic pathways regulating sensitive periods, alone and in interaction with common childhood adversities, on depression risk.

Childhood Emotional Neglect and Adolescent Depression: Assessing the Protective Role of Peer Social Support in a Longitudinal Birth Cohort.

Childhood adversities have been shown to increase psychopathology risk, including depression. However, the specific impact of childhood emotional neglect on later depression has been understudied. Moreover, few studies have investigated relational protective factors that may offset the risk of depression for children who experienced emotional neglect.

Genetic susceptibility for major depressive disorder associates with trajectories of depressive symptoms across childhood and adolescence.

Background: Early-onset depression during childhood and adolescence is associated with a worse course of illness and outcome than adult onset. However, the genetic factors that influence risk for early-onset depression remain mostly unknown. Using data collected over 13 years, we examined whether polygenic risk scores (PRS) that capture genetic risk for depression were associated with depressive symptom trajectories assessed from childhood to adolescence.

A Structured Approach to Evaluating Life-Course Hypotheses: Moving Beyond Analyses of Exposed Versus Unexposed in the -Omics Context.

The structured life-course modeling approach (SLCMA) is a theory-driven analytical method that empirically compares multiple prespecified life-course hypotheses characterizing time-dependent exposure-outcome relationships to determine which theory best fits the observed data. In this study, we performed simulations and empirical analyses to evaluate the performance of the SLCMA when applied to genomewide DNA methylation (DNAm). Using simulations (n = 700), we compared 5 statistical inference tests used with SLCMA, assessing the familywise error rate, statistical power, and confidence interval coverage to determine whether inference based on these tests was valid in the presence of substantial multiple testing and small effects-2 hallmark challenges of inference from -omics data.

Prenatal Alcohol Exposure: Profiling Developmental DNA Methylation Patterns in Central and Peripheral Tissues.

Prenatal alcohol exposure (PAE) can alter the development of neurobiological systems, leading to lasting neuroendocrine, neuroimmune, and neurobehavioral deficits. Although the etiology of this reprogramming remains unknown, emerging evidence suggests DNA methylation as a potential mediator and biomarker for the effects of PAE due to its responsiveness to environmental cues and relative stability over time. Here, we utilized a rat model of PAE to examine the DNA methylation profiles of rat hypothalami and leukocytes at four time points during early development to assess the genome-wide impact of PAE on the epigenome and identify potential biomarkers of PAE.