Association between childhood trauma and accelerated telomere erosion in adulthood: A meta-analytic study

Defining and distinguishing early life stress, trauma, adversity, toxic and chronic stress and allostatic load: a descriptive review

AIMS

Various concepts are used to study the impact of stress on childhood development. These concepts are often used inconsistently or interchangeably. Our main objectives were to determine how selected stress concepts (chronic stress, toxic stress, allostatic load, early life stress, childhood adversity, childhood trauma and adverse childhood experiences; ACEs) are defined, operationalized and described, and to provide a theoretical context to aid the choice for a preferred concept in public health research.

METHODS

For this descriptive review, we systematically searched for literature published before 4 August 2021, on PubMed, Embase and PsycInfo. Two independent reviewers included studies. Exclusion criteria were: no systematic review, not peer reviewed, not published in English, selected stress concepts were no predetermined variable or a substantial topic in the discussion, full text was unobtainable or study described non-human or non-childhood populations. Data extraction forms were used. Descriptives were gathered, publication fields were identified through Journal Citation Reports categories, and verbatim descriptions were ordered in text and Venn diagrams.

RESULTS

Of 264 screened studies, 124 were included. ACEs, childhood adversity and childhood trauma were used most. ACEs were the main concept used most frequently (47.6%). A total of 11 of 14 public and environmental health journals used ACEs. All concepts refer to prolonged, repeated, interpersonal stress from 0 to 18 years, that can alter physiological systems. Four concepts were stressor oriented, two concepts focused on stress response and effect and one on the state of challenged homeostasis.

CONCLUSIONS

ACEs seem most fitting for public health setting, due to their operationalizability, large set of core experiences and widespread use.

Robust evidence supports a causal link between higher birthweight and longer telomere length: a mendelian randomization study

Background

Observational studies have suggested a potential relationship between birthweight and telomere length. However, the causal link between these two parameters remains undefined. In this study, we use Mendelian Randomization (MR). This method employs genetic variants as instrumental variables, to explore the existence of causal associations and elucidate the causal relationship between birth weight and telomere length.

Methods

We used 35 single nucleotide polymorphisms (SNPs) as instrumental variables for birth weight. These SNPs were identified from a meta-analysis involving 153,781 individuals. Furthermore, we obtained summary statistics for telomere length from a study conducted on 472,174 United Kingdom Biobank participants. To evaluate the causal estimates, we applied the random effect inverse variance weighted method (IVW) and several other MR methods, such as MR-Egger, weighted median, and MR-PRESSO, to verify the reliability of our findings.

Results

Our analysis supports a significant causal relationship between genetically predicted birth weight and telomer3e length. The inverse variance weighted analysis results for birth weight (Beta = 0.048; 95%CI = 0.023 to 0.073; p < 0.001) corroborate this association.

Conclusion

Our study provides robust evidence supporting a causal link between higher birth weight and longer telomere length.

Long-term effects of experiencing childhood parental death on mental and physical health: A NESDA study

Experiencing parental death during childhood is an adverse, potentially traumatic experience that may have substantial long-term effects on mental and physical well-being. The current study was based on data of the Netherlands Study of Depression and Anxiety to investigate mental health (i.e., depressive symptoms, anxiety symptoms, and suicidal ideation) and physical health outcomes (i.e., metabolic syndrome, telomere length, and perceived physical health) as well as health behaviour (i.e., smoking status, alcohol use, and physical activity) to provide more insight into the long-term outcomes after experiencing childhood parental death (CPD). For individuals who experienced CPD, we also investigated the role of loss-related factors in these associations, namely the age of the child when their parent passed away and gender of the deceased parent. Interviews and questionnaires were completed by adults between 18 and 65 years; 177 participants experienced CPD (mean age = 45.19, 61.6% female) and 2463 did not (mean age = 41.38, 66.6% female). Results showed no overall association between the experience of CPD and mental and physical health indices and health behaviour. Within the CPD group, experiencing CPD at a younger age was related to a higher likelihood of suicidal ideation. These findings seem to illustrate a general positive adjustment with regard to long-term health functioning after experiencing such an impactful life event. Future research should focus on individual differences in terms of adaptation, especially elucidating on contextual factors after the loss, such as the kind of support that is or is not provided by the surviving parent and/or other important individuals.

Childhood adversity, accelerated GrimAge, and associated health consequences

Childhood adversity is linked to psychological, behavioral, and physical health problems, including obesity and cardiometabolic disease. Epigenetic alterations are one pathway through which the effects of early life stress and adversity might persist into adulthood. Epigenetic mechanisms have also been proposed to explain why cardiometabolic health can vary greatly between individuals with similar Body Mass Index (BMIs). We evaluated two independent cross-sectional cohorts of adults without known medical illness, one of which explicitly recruited individuals with early life stress (ELS) and control participants (n = 195), and the other a general community sample (n = 477). In these cohorts, we examine associations between childhood adversity, epigenetic aging, and metabolic health. Childhood adversity was associated with increased GrimAge Acceleration (GAA) in both cohorts, both utilizing a dichotomous yes/no classification (both p < 0.01) as well as a continuous measure using the Childhood Trauma Questionnaire (CTQ) (both p < 0.05). Further investigation demonstrated that CTQ subscales for physical and sexual abuse (both p < 0.05) were associated with increased GAA in both cohorts, whereas physical and emotional neglect were not. In both cohorts, higher CTQ was also associated with higher BMI and increased insulin resistance (both p < 0.05). Finally, we demonstrate a moderating effect of BMI on the relationship between GAA and insulin resistance where GAA correlated with insulin resistance specifically at higher BMIs. These results, which were largely replicated between two independent cohorts, suggest that interactions between epigenetics, obesity, and metabolic health may be important mechanisms through which childhood adversity contributes to long-term physical and metabolic health effects.

Childhood Maltreatment and Leukocyte Telomere Length: Cardiac Vagal Activity Influences the Relation in Older Adults

OBJECTIVE

Childhood maltreatment is associated with shorter leukocyte telomere length (LTL). However, the influence of cardiac vagal control on this relation is unknown. We examined whether cardiac vagal control at rest and in response to stress moderates or cross-sectionally mediates the relationship between childhood maltreatment and LTL.

METHODS

Participants were 1179 men and women (aged 65 [7.2] years) suffering from coronary artery disease or non-cardiovascular chronic disease. They completed a childhood maltreatment questionnaire and underwent a stress protocol while electrocardiogram was monitored. High-frequency heart rate variability (HF-HRV) measures were obtained at rest, during stress, and after stress in absolute and normalized units (nu). LTL was measured using quantitative polymerase chain reaction. Mediation and moderation analyses were performed.

RESULT

HF-HRV and HF-HRV in normalized units (HFnu) measures did not mediate the childhood maltreatment-LTL relation. However, baseline HFnu ( p = .027) and HFnu reactivity ( p = .051) moderated the relation. Specifically, maltreatment was associated with significantly lower LTL among those with baseline HFnu at ( b = -0.059, p = .003) or below the mean ( b = -0.103, p < .001), but not among those with higher baseline HFnu. It was also associated with significantly lower LTL among participants who showed either blunted ( b = -0.058, p = .004) or increased HFnu ( b = -0.099, p = .001) responses to stress but not in those with large decreases in HFnu.

CONCLUSIONS

Childhood maltreatment was associated with lower LTL in those who showed a distinct cardiac vagal profile at baseline and in response to stress. The mechanisms and implications remain to be determined.

Decreased telomere length in a subgroup of young individuals with bipolar disorders: replication in the FACE-BD cohort and association with the shelterin component POT1

Bipolar disorder (BD) has been associated with premature cellular aging with shortened telomere length (TL) as compared to the general population. We recently identified a subgroup of young individuals with prematurely shortened TL. The aims of the present study were to replicate this observation in a larger sample and analyze the expression levels of genes associated with age or TL in a subsample of these individuals. TL was measured on peripheral blood DNA using quantitative polymerase chain reaction in a sample of 542 individuals with BD and clustering analyses were performed. Gene expression level of 29 genes, associated with aging or with telomere maintenance, was analyzed in RNA samples from a subsample of 129 individuals. Clustering analyses identified a group of young individuals (mean age 29.64 years), with shorter TL. None of the tested clinical variables were significantly associated with this subgroup. Gene expression level analyses showed significant downregulation of MYC, POT1, and CD27 in the prematurely aged young individuals compared to the young individuals with longer TL. After adjustment only POT1 remained significantly differentially expressed between the two groups of young individuals. This study confirms the existence of a subgroup of young individuals with BD with shortened TL. The observed decrease of POT1 expression level suggests a newly described cellular mechanism in individuals with BD, that may contribute to telomere shortening.

Early life adversity predicts an accelerated cellular aging phenotype through early timing of puberty

BACKGROUND

The current study examined if early adversity was associated with accelerated biological aging, and if effects were mediated by the timing of puberty.

METHODS

In early mid-life, 187 Black and 198 White (Mage = 39.4, s.d.age = 1.2) women reported on early abuse and age at first menstruation (menarche). Women provided saliva and blood to assess epigenetic aging, telomere length, and C-reactive protein. Using structural equation modeling, we created a latent variable of biological aging using epigenetic aging, telomere length, and C-reactive protein as indicators, and a latent variable of early abuse using indicators of abuse/threat events before age 13, physical abuse, and sexual abuse. We estimated the indirect effects of early abuse and of race on accelerated aging through age at menarche. Race was used as a proxy for adversity in the form of systemic racism.

RESULTS

There was an indirect effect of early adversity on accelerated aging through age at menarche (b = 0.19, 95% CI 0.03-0.44), in that women who experienced more adversity were younger at menarche, which was associated with greater accelerated aging. There was also an indirect effect of race on accelerated aging through age at menarche (b = 0.25, 95% CI 0.04-0.52), in that Black women were younger at menarche, which led to greater accelerated aging.

CONCLUSIONS

Early abuse and being Black in the USA may both induce a phenotype of accelerated aging. Early adversity may begin to accelerate aging during childhood, in the form of early pubertal timing.

Childhood maltreatment contributes to the medical morbidity of individuals with bipolar disorders

BACKGROUND

Individuals with bipolar disorders (BD) are at risk of premature death, mainly due to medical comorbidities. Childhood maltreatment might contribute to this medical morbidity, which remains underexplored in the literature.

METHODS

We assessed 2891 outpatients with BD (according to DSM-IV criteria). Childhood maltreatment was assessed using the Childhood Trauma Questionnaire. Lifetime diagnoses for medical disorders were retrospectively assessed using a systematic interview and checked against medical notes. Medical morbidity was defined by the sum of medical disorders. We investigated associations between childhood maltreatment (neglect and abuse) and medical morbidity while adjusting for potential confounders.

RESULTS

One quarter of individuals had no medical comorbidities, while almost half of them had at least two. Multivariable regression showed that childhood maltreatment (mainly abuse, but also sexual abuse) was associated with a higher medical morbidity. Medical morbidity was also associated with sex, age, body mass index, sleep disturbances, lifetime anxiety disorders and lifetime density of mood episodes. Childhood maltreatment was associated with an increased prevalence of four (i.e. migraine/headache, drug eruption, duodenal ulcer, and thyroid diseases) of the fifteen most frequent medical disorders, however with no difference in terms of age at onset.

CONCLUSIONS

This large cross-sectional study confirmed a high medical morbidity in BD and its association with childhood maltreatment. The assessment of childhood maltreatment in individuals with BD should be systematically included in routine care and the potential impact on physical health of psycho-social interventions targeting childhood maltreatment and its consequences should be evaluated.

Childhood maltreatment and leukocyte telomere length in men and women with chronic illness: an evaluation of moderating and mediating influences

BACKGROUND

Childhood maltreatment can result in lifelong psychological and physical sequelae, including coronary artery disease (CAD). Mechanisms leading to increased risk of illness may involve emotional dysregulation and shortened leukocyte telomere length (LTL).

METHODS

To evaluate whether (1) childhood maltreatment is associated with shorter LTL among older adults with CAD or other chronic illnesses; (2) sex and/or CAD status influence these results; and (3) symptoms of anxiety, depression, and stress moderate or mediate the association between childhood maltreatment and LTL, men and women (N = 1247; aged 65 ± 7.2 years) with and without CAD completed validated questionnaires on childhood maltreatment, symptoms of depression, anxiety, and perceived stress. LTL was measured using quantitative polymerase chain reaction. Analyses included bivariate correlations, hierarchical regressions, and moderation/mediation analyses, controlling for sociodemographic and lifestyle variables.

RESULTS

Childhood maltreatment was associated with significantly shorter LTL (r = -0.059, p = 0.038, b = -0.016, p = 0.005). This relation was not moderated by depression, anxiety, nor perceived stress, though there was mitigated evidence for absence of a maltreatment-LTL relation in men with CAD. Stress perception (but not anxiety or depression) partially mediated the relation between childhood maltreatment and LTL [Indirect effect, b = -0.0041, s.e. = 0.002, 95% CI (-0.0085 to -0.0002)].

CONCLUSIONS

Childhood maltreatment was associated with accelerated biological aging independently of patient characteristics. Emotional dysregulation resulting in chronic stress may contribute to this process. Whether stress management or other interventions may help prevent or slow premature aging in those who have suffered maltreatment requires study.

Adverse childhood experiences and personality functioning interact substantially in predicting depression, anxiety, and somatization

Etiological theories on the development of psychopathology often incorporate adverse childhood experiences (ACE) as an important contributing factor. Recent studies suggest personality functioning (PF; i.e., stability of the self and interpersonal relationships) as an important transdiagnostic construct that could be useful in better understanding when persons with ACE do (not) develop psychopathological symptoms. A representative sample of N = 2363 was assessed by questionnaires on ACE, PF (Level of Personality Functioning Scale-Brief Form 2.0), and current symptoms of depression, anxiety, and somatization (Brief Symptom Inventory 18). The interaction between ACE and PF on symptoms was investigated using multiple group models and Bayesian structural equation modeling. ACE were positively associated with psychopathology and PF impairments. The interaction effect between ACE and PF explained incremental variance in current symptoms, ranging from 26% for somatization to 49% for depression with the complete model explaining up to 91% of the latent variance in psychopathology. Our findings indicate a diathesis-stress model with PF as a resource or resilience that may buffer against the development of symptoms in the face of adversity. Treatments of depression and anxiety targeting self and interpersonal functioning therefore may lead to improvements in resilience and relapse prevention. [Correction added on 15 March 2023, after first online publication: Level of Personality Functioning Scale-Brief Form has been replaced to Level of Personality Functioning Scale-Brief Form 2.0 ].

No Mediation Effect of Telomere Length or Mitochondrial DNA Copy Number on the Association Between Adverse Childhood Experiences (ACEs) and Central Arterial Stiffness

Background

Adverse childhood experiences (ACEs) have been linked to increased cardiovascular disease (CVD) risk. Previous reports have suggested that accelerated biological aging—indexed by telomere length (TL) and mitochondrial DNA copy number (mtDNAcn)—may contribute to associations between ACEs and cardiovascular health outcomes. Here, we examine the potential mediating effects of TL and mtDNAcn on the association between ACEs and central arterial stiffness—an intermediate cardiovascular health outcome—as a novel pathway linking ACEs to CVD risk among young adults.

Methods and Results

One hundred and eighty‐five (n=102 women; mean age, 22.5±1.5 years) individuals provided information on ACEs. TL (kb per diploid cell) and mtDNAcn (copies per diploid cell) were quantified using quantitative polymerase chain reaction techniques. Central arterial stiffness was measured as carotid‐femoral pulse wave velocity (cfPWV; m/s). Multiple linear regression analyses were used to examine the associations between ACEs, TL, mtDNAcn, and cfPWV. ACEs were positively associated with cfPWV ( β =0.147, P =0.035). TL ( β =−0.170, P =0.011) and mtDNAcn ( β =−0.159, P =0.019) were inversely associated with cfPWV. Neither TL ( β =−0.027, P =0.726) nor mtDNAcn ( β =0.038, P =0.620) was associated with ACEs. Neither marker mediated the association between ACEs and cfPWV.

Conclusions

An increasing number of ACEs were associated with a faster cfPWV and thus, a greater degree of central arterial stiffness. ACEs were not associated with either TL or mtDNAcn, suggesting that these markers do not represent a mediating pathway linking ACEs to central arterial stiffness.

Early life trauma and adult leucocyte telomere length

BACKGROUND

Telomere length, a biomarker of cell division and cellular aging, has been associated with multiple chronic disease endpoints. Experienced trauma over the life course may contribute to telomere shortening via mechanisms of stress embodiment. However, it is unclear how patterns of co-occurring trauma during sensitive periods (e.g., early life) throughout the life course may influence telomere shortening. We examine the relationship between co-occurring early life trauma on adult telomere length and the extent to which adulthood trauma, socioeconomic position, and health and lifestyle factors may mediate this relationship.

METHODS

We use data from a sample of participants in the Sister Study (N = 740, analytic sample: n = 602), a prospective cohort of U.S. self-identified females aged 35-74 years at enrollment (2003-2009) for whom leukocyte telomere length was measured in baseline blood samples. Participants reported their experience of 20 different types of trauma, from which we identified patterns of co-occurring early life trauma (before age 18) using latent class analysis. We estimated the direct and indirect effects of early life trauma on leukocyte telomere length using structural equation modeling, allowing for mediating adult pathways.

RESULTS

Approximately 47 % of participants reported early life trauma. High early life trauma was associated with shorter telomere length compared to low early life trauma (β = -0.11; 95 % CI: -0.22, -0.004) after adjusting for age and childhood socioeconomic position. The inverse association between early life trauma and adult leukocyte telomere length was largely attributable to the direct effect of early life trauma on telomere length (β = -0.12; 95 %CI: -0.23, -0.01). Mediating indirect pathways via adult trauma, socioeconomic position, and health metrics did not substantively contribute the overall association.

CONCLUSIONS

These findings highlight the role of patterns of co-occurring early life trauma on shortened telomere length independent of adult pathways.

Association between Childhood Exposure to Family Violence and Telomere Length: A Meta-Analysis

The aims of this meta-analysis were to examine the association between childhood exposure to family violence and telomere length and the moderating variables that influence this association. Relevant works published on or before 1st September 2022 were identified through a search in five major databases in English and 19 articles (N = 18,977) finally met the inclusion criteria. A meta-analysis was conducted to compute the pooled effect size (correlation; r), and moderator analyses were performed using a random effects meta-analytic model. The studies yielded a significant inverse association between childhood exposure to family violence and telomere length, with a small effect size (r = -0.038, 95% CI [-0.070, -0.005], p = 0.025). Furthermore, the strength of this association was stronger in studies examining the co-occurrence of multiple types of violence than in those examining just one type (Q = 8.143, p = 0.004). These findings suggested that victims' telomere length may be negatively influenced by childhood exposure to family violence and that such impairment appears to be stronger for those who are exposed to multiple types of violence. Future studies are necessary to examine the moderating and mediating factors underlying the association between childhood exposure to family violence and telomere length.

Adverse and traumatic exposures, posttraumatic stress disorder, telomere length, and hair cortisol – Exploring associations in a high-risk sample of young adult residential care leavers

Background

Childhood adversities (CAs), potentially traumatic exposures (PTEs), and posttraumatic stress disorder (PTSD) are known to increase the risk for poor health outcomes, including diseases of aging and early mortality. Telomere length (TL) and hair cortisol concentrations (HCC) are biomarkers known to be associated with CA and PTEs, and PTSD, but there is considerable heterogeneity in findings.

Objectives

This study aims to investigate the association of CAs, PTEs, and PTSD with TL and HCC in a high-risk sample of young adults who were previously placed in youth residential care institutions throughout Switzerland.

Method

Our sample includes 130 participants (30.8% women, M _Age = 26.5 ± 3.7 years) with previous youth residential care placements (M_Placements= 3.9). CAs and PTEs, as well as PTSD, were assessed with self-reported questionnaires and semi-structured clinical interviews. Immune cell TL was measured with quantitative polymerase chain reaction (qPCR) in whole blood. Hair samples were collected for HCC measurement and assayed with high-sensitivity ELISA. Multivariate regression models were fitted to describe the associations between CAs, PTEs, and PTSD with TL and HCC, adjusting for covariates.

Results

In our high-risk sample, a higher burden of CAs, PTEs, Criterion A trauma, and PTSD was associated with longer TL. PTEs, Criterion A trauma, and PTSD were associated with lower HCC, however no significant associations between CAs and HCC were found. The magnitude of these effects varied depending on the dimensional or categorical nature of the stress-phenotype and the specific measure used.

Conclusions

Our findings are in contrast with many, but not all, previous studies of associations between adversity and both TL and HCC. For instance, our findings are in line with other studies that find a state of hypocortisolism in PTSD. Better measurement of adversities and trauma, multisystem biomarker approaches, and more research in larger high-risk samples at the upper end of the adversity-continuum is warranted.

•

In this high-risk sample,childhood adversities, potential traumatic exposures, criterion A trauma, or posttraumatic stress disorder (PTSD) was associated with longer telomere length (TL).

•

Potentially traumatic exposures, criterion A trauma, and PTSD were associated with lower hair cortisol concentrations.

•

The magnitude of these effects varied depending on the dimensional or categorical nature of the stress-phenotype and the specific measure used.

•

Hypocortisolism might explain findings of longer TL in participants with cumulated adverse and traumatic exposures.

•

Research in high-risk populations is strongly needed as results across the entire spectrum of adversity exposures may not generalize to the top end of the spectrum.

Associations between circadian misalignment and telomere length in BD: an actigraphy study

BACKGROUND

Life expectancy is significantly decreased in bipolar disorder (BD). This is associated with accelerated cellular aging which can be estimated by telomere length (TL). However, specific determinants of shorter TL in BD are under-explored. This study examines whether circadian misalignment (i.e. mismatch between preferred and actual phase of circadian activity rhythms) is associated with shorter TL in BD.

METHODS

Euthymic individuals with BD (n = 101) undertook 21 consecutive days of actigraphy recording and completed the Composite Scale of Morningness (CSM) to assess phase preference for activities (chronotype). Polymerase chain reaction was used to measure TL in blood. Cluster analysis identified circadian aligned/misaligned subgroups as defined by preferred (CSM score) and actual phases of activity (actigraphically determined onset of active and inactive periods). We tested for any associations between TL and clusters, with adjustments for between-cluster differences in socio-demographic and illness factors.

RESULTS

We identified three clusters: an "Aligned Morning" cluster (n = 31) with preferred and actual timing of activity in the morning, an "Aligned Evening" cluster (n = 37) with preferred and actual timing of activity in the evening and a "Misaligned" cluster (n = 32) with an evening chronotype, but an earlier objective onset of active periods. After adjustment for confounders, we found that TL was significantly associated with circadian misalignment and older age.

CONCLUSIONS

Circadian misalignment may partly explain shorter TL in BD and could contribute to accelerated aging in these individuals.

Telomere length and mitochondrial DNA copy number in bipolar disorder: identification of a subgroup of young individuals with accelerated cellular aging

The 10-15-years decrease in life expectancy observed in individuals with bipolar disorder (BD) has been linked to the concept of accelerated cellular aging. Telomere length (TL) and mitochondrial DNA copy number (mtDNAcn) have been proposed as markers of cellular aging and comparisons between individuals with BD and healthy controls (HC) sometimes led to conflicting results. Previous studies had moderate sample sizes and studies combining these two markers into a single analysis are scarce. Using quantitative polymerase chain reaction, we measured both TL and mtDNAcn in DNA (peripheral blood) in a sample of 130 individuals with BD and 78 HC. Regression analyses, receiver operating characteristic (ROC), and clustering analyses were performed. We observed significantly lower TL and mtDNAcn in individuals with BD as compared to HC (respective decrease of 26.5 and 35.8%). ROC analyses showed that TL and mtDNAcn highly discriminated groups (AUC = 0.904 for TL and AUC = 0.931 for mtDNAcn). In the whole population, clustering analyses identified a group of young individuals (age around 36 years), with accelerated cellular aging (both shorter TL and lower mtDNAcn), which consisted mostly of individuals with BD (85.5%). The subgroup of patients with young age but accelerated aging was not characterized by specific clinical variables related to the course of BD or childhood maltreatment. However, patients in this subgroup were more frequently treated with anticonvulsants. Further characterization of this subgroup is required to better understand the molecular mechanisms and the risk factors of accelerated cellular aging in BD.

Evidence for Revising the Adverse Childhood Experiences Screening Tool: a Scoping Review

The relationship between adverse childhood experiences (ACEs) and risky behavior, chronic illness, and premature mortality is well documented. Despite this evidence, screening for ACEs in primary care settings remains limited. Objections to widespread screening include concerns that the original ACE screening tool limited childhood adversities to family and household dysfunction. The purpose of this scoping review is to describe current knowledge for expanding ACEs categories and revising the formatting and scoring of the screening tool. With the assistance of a medical librarian, we used a two-step process to conduct a systematic search in three databases (CINAHL, OVID Medline, PsycINFO). Our aim was to focus on articles that expanded ACE categories and/or revised the scoring or formatting of the ACE tool. Eighteen articles (reporting 19 studies) met criteria. A minimum of two authors extracted the relevant characteristics of the studies independently and conferred to reach agreement. The majority of studies broadened ACEs to include community and systemic categories; three studies revised the formatting or scoring of the ACE tool. Exposure to community violence (ECV) was the most frequently added category (15), followed by economic hardship in childhood (EHC) (13); bullying (10); absence/death of parent or significant others (9); and discrimination (7). This evidence supports the expansion of ACE screening tools for assessment of childhood trauma and timely treatment.

Addressing the biological embedding of early life adversities (ELA) among adults through mindfulness: Proposed mechanisms and review of converging evidence

Early life adversities (ELA) are prevalent and have a profound and adverse impact across the lifespan, including on age-related health outcomes, yet interventions to remediate its adverse impact are scarce. This paper presents evidence for mindfulness training to reduce the elevated mental and physical health risks linked to ELA among adults by targeting biological mechanisms of ELA leading to these adverse health outcomes. We first provide a brief overview of ELA, its adverse health impacts, and mechanisms that might be responsible. Next, we review converging evidence that demonstrates that mindfulness training influences key biological pathways involved in ELA-linked negative health consequences, including (a) brain networks involved in self-regulation, (b) immunity and inflammation, (c) telomere biology, and (d) epigenetic modifications. Further, we review preliminary evidence from mindfulness-based trials that focused on populations impacted by ELA. We discuss limitations of this review and provide recommendations for future research. If effective, a mindfulness-based approach could be an important public health strategy for remediating the adverse mental and physical health consequences of ELA.

Examining the influence of adversity, family contexts, and a family-based intervention on parent and child telomere length

Background: Exposure to adversity, trauma, and negative family environments can prematurely shorten telomeres, the protective caps at the ends of chromosomes. Conversely, some evidence indicates that positive environments and psychosocial interventions can buffer the shortening of telomere length (TL). However, most work has examined individual aspects of the family environment as predictive of TL with little work investigating multiple risk and protective factors. Further, most research has not examined parent TL relative to child TL despite its heritability. Objective: In the current study, we examined interparental conflict, positive parenting, alcohol use, adverse childhood experiences (ACEs), and a family-based intervention as predictive of parent TL. We also examined interparental conflict, positive parenting, ACEs, and a family-based intervention as predictive of child TL. Method: Parents and adolescents from a sample of divorced families participated in either a 10-session family-based intervention, the New Beginnings Programme (NBP), or a 2-week active control condition. Approximately six years after the intervention, a subsample of parents (n = 45) and adolescents (n = 41) were assessed for TL. Parents reported on interparental conflict, ACEs, and alcohol use. Children reported on interparental conflict, positive parenting, and ACEs. In separate models, these constructs and the NBP intervention condition were examined as predictors of parent TL and child TL. Results: Findings indicated that the family-based intervention was associated with longer TL in parents. Also, positive parenting was associated with longer TL in children. Conclusions: These findings have important implications for the role of the family and family-based preventive interventions in buffering parent and child biological stress.

HIGHLIGHTS

Across multiple indices of psychosocial functioning, we found a family-based intervention associated with longer telomere length in parents and positive parenting associated with longer telomere length in children.

Prevalence of Childhood Sexual Abuse Among Women Using the Childhood Trauma Questionnaire: A Worldwide Meta-Analysis

Childhood sexual abuse (CSA) is a common form of childhood maltreatment. Several studies have shown that CSA adversely affects the physical and mental health. Numerous studies have evaluated the prevalence of CSA among females using various instruments. In this meta-analysis, we estimated the rate of CSA among women using the short form of the Childhood Trauma Questionnaire for the first time. Four databases (PsycINFO, PubMed, Cochrane Library, and Embase) were systematically searched for studies published as of April 2, 2018. Forty-eight articles (53 groups of samples) covering 22,224 individuals, including women, from 16 countries were selected. Using the random-effects model, the pooled overall rate of CSA was 24% (95% confidence interval [21%, 27%]). On subgroup analyses, the rate of female CSA in people with mental illness was higher than that in the general group; this result showed variability among different geographical regions.

Mental health benefits of a 1-week intensive multimodal group program for adolescents with multiple adverse childhood experiences

BACKGROUND

Adverse childhood experiences (ACEs) are associated with a wide range of diseases, unsafe behavior and shorter life expectancy. However, there is scarce evidence on effective interventions for children or adolescents who report multiple ACEs, including abuse, neglect and household dysfunction.

OBJECTIVE

The aim of this study was to evaluate the mental health outcomes of a multimodal program designed for adolescents with multiple ACEs.

PARTICIPANTS

Forty-four girls (aged 13-16 years, mean ACE score > 5) were randomized to an intervention group or a care-as-usual control group.

METHODS

The intervention included mindfulness-based practices, expressive arts and EMDR (Eye Movement Desensitization and Reprocessing Integrative) group treatment. We used questionnaires for adolescents to assess trauma (SPRINT, CPSS) and attention/awareness-related outcomes (MAAS-A) at baseline (T1), post-intervention (T2) and two-months post-discharge (T3).

RESULTS

Linear mixed effects model analyses showed significant Group by Time interactions on all the scales (F = 11.0, p = 0.015; F = 12.5 p < 0.001; and F = 6.4, p = 0.001, for SPRINT, CPSS and MAAS-A, respectively). After completing the program, the intervention group showed significant reduction in trauma-related outcomes (SPRINT, Δ%_(T2-T1) = -73%, p < 0.001; CPSS, Δ%_(T2-T1) = -26%, p < 0.001) while attention/awareness-related outcomes were improved by 57% (p < 0.001). These changes remained stable two months after discharge. SPRINT and CPSS scales were highly correlated (r = 0.833, p < 0.001) and outcomes from both trauma-related scales negatively correlated with mindfulness scores (MAAS-A/SPRINT, r = -0.515, p = 0.007; MAAS-A/CPSS, r = -0.553, p < 0.001).

CONCLUSIONS

Results presented here support this multimodal group intervention as a feasible and promising program for reducing the psychological burden in adolescents with a history of multiple ACEs.

Epigenetic studies in suicidal ideation and behavior

Most psychiatric disorders are associated with an elevated risk of suicide. Suicidal behavior is the product of the interaction of many risk factors, such as genetics and environmental factors. Hence, epigenetics research may help to understand the mechanisms leading to suicidal ideation and behavior. This review will discuss epigenetic studies in both suicidal ideation and behavior. Epigenetic modifications are likely to be important in both suicidal ideation and behavior. Most of the reviewed studies found significant epigenetic modifications linked with suicidal behavior rather than ideation. Although sizable research has been carried out on this topic, most studies have been done on small-scale samples, and future research is required in larger samples with better clinical characterization of suicide phenotypes to investigate these epigenetic modifications further.

Co-occurrence of preconception maternal childhood adversity and opioid use during pregnancy: Implications for offspring brain development

Understanding of the effects of in utero opioid exposure on neurodevelopment is a priority given the recent dramatic increase in opioid use among pregnant individuals. However, opioid abuse does not occur in isolation-pregnant individuals abusing opioids often have a significant history of adverse experiences in childhood, among other co-occurring factors. Understanding the specific pathways in which these frequently co-occurring factors may interact and cumulatively influence offspring brain development in utero represents a priority for future research in this area. We highlight maternal history of childhood adversity (CA) as one such co-occurring factor that is more prevalent among individuals using opioids during pregnancy and which is increasingly shown to affect offspring neurodevelopment through mechanisms beginning in utero. Despite the high incidence of CA history in pregnant individuals using opioids, we understand very little about the effects of comorbid prenatal opioid exposure and maternal CA history on fetal brain development. Here, we first provide an overview of current knowledge regarding effects of opioid exposure and maternal CA on offspring neurodevelopment that may occur during gestation. We then outline potential mechanistic pathways through which these factors might have interactive and cumulative influences on offspring neurodevelopment as a foundation for future research in this area.

Childhood adversities are associated with shorter leukocyte telomere length at adult age in a population-based study

Telomeres are repeat sequences and an associated protein complex located at the end of the chromosomes. They shorten with every cell division and are regarded markers for cellular aging. Shorter leukocyte telomere length (LTL) has been observed in many complex diseases, including psychiatric disorders. However, analyses focusing on psychiatric disorders are mainly based on clinical samples and the significance of shorter LTL on the population level remains uncertain. We addressed this question in a population-based sample from Finland (N = 7142). The survey was performed and the blood samples were collected in 2000-2001 to assess major public health problems and their determinants. DSM-IV diagnoses of major psychiatric illnesses were obtained by interview using the Composite International Diagnostic Interview. Information regarding their risk factors, including the number of self-reported childhood adversities, recent psychological distress, and sleep difficulties was collected by questionnaires. LTL was measured by qPCR. None of the studied psychiatric illnesses, sleep difficulties, or recent psychological distress associated with LTL. However, individuals with three or more childhood adversities had shorter LTL at adult age (β = -0.006, P = 0.005). Also, current occupational status was associated with LTL (β = -0.03, P = 0.04). These effects remained significant after adjusting for known LTL-associated lifestyle or sociodemographic factors. In conclusion, relatively common childhood adversities were associated with shorter LTL at adult age in a nationally representative population-based cohort, implying that childhood adversities may cause accelerated telomere shortening. Our finding has potentially important implications as it supports the view that childhood adversities have an impact on psychological and somatic well-being later in life.

The association of telomere length with substance use disorders: a systematic review and meta-analysis of observational studies

BACKGROUND AND AIMS

Several recent studies have investigated the relationship between telomere length and substance use disorders with inconsistent results. We aimed to assess this association and to identify moderators of the relationship.

METHODS

Systematic review and meta-analysis. Selection criteria were observational studies reporting telomere length in people with a substance use disorder compared with a control group. Studies focused solely on nicotine addiction, employing other study designs, and non-human studies were excluded. Study selection and data extraction were independently conducted by two researchers following a standardized protocol and included studies until December 2019. Standardized mean differences were used as the effect size index [d; 95% confidence interval (CI)] and random-effects models were used for the meta-analysis. Cochran's Q-statistic, I² index, visual inspection of the forest plot and a 95% prediction interval were applied to verify study heterogeneity. Subgroup analyses and meta-regressions were conducted to explore heterogeneity. Small study effects were examined using the 'funnel plot', the Egger test, Duval & Tweedie's trim-and-fill method and the precision-effect test-precision-effect estimate with standard error (PET-PEESE) method. The risk of bias and the quality of evidence were assessed.

RESULTS

Ten studies (12 analysis units with 2671 cases and 4532 controls) met the selection criteria. An overall effect size of moderate magnitude was found (d₊  = -0.63; 95% CI = -1.00 and -0.26; P = 0.0008). A potential small study effect was detected, as well as large heterogeneity between studies (Q-statistic P < 0.001, I²  = 97.3%). Selection of controls, reporting laboratory quality control procedures and total sample size significantly affected the effect size. The quality of the evidence was very low, based on risk of bias analysis and the grading of recommendations assessment, development and evaluation (GRADE) system.

CONCLUSIONS

People with substance use disorders appear to have shorter telomere length than controls; however, this finding should be interpreted with caution due to the poor quality of the evidence.

Mitochondria and early-life adversity

Early-life adversity (ELA), which includes maltreatment, neglect, or severe trauma in childhood, increases the life-long risk for negative health outcomes. Mitochondria play a key role in the stress response and may be an important mechanism by which stress is transduced into biological risk for disease. By responding to cues from stress-signaling pathways, mitochondria interact dynamically with physiological stress responses coordinated by the central nervous, endocrine, and immune systems. Preclinical evidence suggests that alterations in mitochondrial function and structure are linked to both early stress and systemic biological dysfunction. Early clinical studies support that increased mitochondrial DNA content and altered cellular energy demands may be present in individuals with a history of ELA. Further research should investigate mitochondria as a potential therapeutic target following ELA.

An integrative study of five biological clocks in somatic and mental health

Biological clocks have been developed at different molecular levels and were found to be more advanced in the presence of somatic illness and mental disorders. However, it is unclear whether different biological clocks reflect similar aging processes and determinants. In ~3000 subjects, we examined whether five biological clocks (telomere length, epigenetic, transcriptomic, proteomic, and metabolomic clocks) were interrelated and associated to somatic and mental health determinants. Correlations between biological aging indicators were small (all r < 0.2), indicating little overlap. The most consistent associations of advanced biological aging were found for male sex, higher body mass index (BMI), metabolic syndrome, smoking, and depression. As compared to the individual clocks, a composite index of all five clocks showed most pronounced associations with health determinants. The large effect sizes of the composite index and the low correlation between biological aging indicators suggest that one's biological age is best reflected by combining aging measures from multiple cellular levels.

Childhood Maltreatment in Bipolar Disorders

In this chapter, we will focus on childhood maltreatment and its role in the vulnerability to BD.We will review how childhood maltreatment and trauma not only predispose to the development of BD but also to a more unstable, pernicious, and severe clinical expression of the disorder. This environmental risk factor is suggested to be part of a multiple hit model of vulnerability, involving not only early stressors (prenatal and postnatal ones) but also interactions with the genetic background of individuals and with other stressors occurring later in life. We will also review how childhood maltreatment and trauma may modify the brain functioning and circuits and alter some biological pathways in BD, hence leading to psychopathology. Finally, we will briefly discuss the implications for clinical practice and treatment.

Social determinants of health, personalized medicine, and child maltreatment

This review begins with a brief summary of the importance of child maltreatment as a major public health problem, given its prevalence and the substantial human and economic costs involved. The focus then shifts to consideration of personalized medicine and child maltreatment, including genetic and genomics factors, as well as the role of social determinants of health. Research on epigenetics related to child abuse and neglect is presented, followed by that pertaining to a few specific social factors, such as poverty, parental depression and substance use, and domestic (or intimate partner) violence. The review ends with a discussion of interventions to help address social determinants of health with brief descriptions of several model programs, and thoughts concerning the role of personalized medicine in addressing child maltreatment in the foreseeable future. IMPACT: This paper synthesizes knowledge on social determinants of health and advances in genetics and genomics related to the prevention of child maltreatment. It provides examples of model approaches to addressing the prevention of child maltreatment in primary care practices.

Association between elder abuse and telomere shortening in older adults: A 2-year prospective study

BACKGROUNDS

Elder abuse is a public health issue associated with increased morbidity and mortality. Its impact on victims' health at the cellular level, however, remains unknown. This study assessed the association between abuse exposure and shortening of telomere length (TL), a promising molecular marker for biological aging, in older victims.

SETTING

The geriatric departments of three Grade-A hospitals in the People's Republic of China (PRC).

PARTICIPANTS

Six hundred Chinese older adults, including 300 abused victims and 300 non-abused controls were randomly drawn respectively from a larger sample of 467 abused and 518 non-abused older adults recruited at baseline. Participants were assessed for physical and psychological abuse exposure at baseline between September 2015 and February 2016 and assessed for TL 2 years after the abuse assessment.

MEASUREMENTS

TL was quantified using a quantitative PCR method and expressed as T/S ratio (the ratio of telomere repeat copy numbers to single-copy gene numbers). Physical and psychological abuse was measured using the Revised Conflicts Tactics Scale.

RESULTS

Adjusting for demographic, medical, and behavioral confounders, physical and psychological abuse exposure at baseline were independently associated with shorter TL at follow-up. The association was the most significant between multiple forms of abuse (physical and psychological) exposure and shorter TL.

CONCLUSION

This study provides the first evidence on the relationship between abuse and shortened TL in older victims, implying the potential effect of elder abuse on accelerated cellular aging. The findings suggest the importance of routinely assessing and intervening abuse in older adults by healthcare professionals, to promote and maintain physical health in older adults.

Physical and sexual abuse in childhood and adolescence and leukocyte telomere length: A pooled analysis of the study on psychosocial stress, spirituality, and health

Introduction

We examined whether abuse in childhood and/or adolescence was associated with shorter telomere length in a pooled analysis of 3,232 participants from five diverse cohorts. We also assessed whether religion or spirituality (R/S) could buffer deleterious effects of abuse.

Methods

Physical and sexual abuse in childhood (age <12) and adolescence (age 12–18) was assessed using the Revised Conflict Tactics Scale and questions from a 1995 Gallup survey. We measured relative leukocyte telomere lengths (RTL) using quantitative real time polymerase chain reaction. We used generalized estimating equations to assess associations of physical and sexual abuse with log-transformed RTL z-scores. Analyses were conducted in each cohort, overall, and stratified by extent of religiosity or spirituality and religious coping in adulthood. We pooled study‐specific estimates using random‐effects models and assessed between-study heterogeneity.

Results

Compared to no abuse, severe sexual abuse was associated with lower RTL z-scores, in childhood: -15.6%, 95% CI: -25.9, -4.9; p-trend = 0.04; p-heterogeneity = 0.58 and in adolescence: -16.5%, 95% CI: -28.1, -3.0; p-trend = 0.08; p-heterogeneity = 0.68. Sexual abuse experienced in both childhood and adolescence was associated with 11.3% lower RTL z-scores after adjustment for childhood and demographic covariates (95% CI: -20.5%, -2.0%; p-trend = 0.03; p-heterogeneity = 0.62). There was no evidence of effect modification by R/S. Physical abuse was not associated with telomere length.

Conclusions

Sexual abuse in childhood or adolescence was associated with a marker of accelerated biological aging, decreased telomere length. The lack of moderation by R/S may be due to inability to capture the appropriate time period for those beliefs and practices.

Epigenetic mechanisms activated by childhood adversity

Adverse childhood experiences (ACE) impair health and life expectancy and may result in an epigenetic signature that drives increased morbidity primed during early stages of life. This literature review focuses on the current evidence for epigenetic-mediated programming of brain and immune function resulting from ACE. To address this aim, a total of 88 articles indexed in PubMed before August 2019 concerning ACE and epigenetics were surveyed. Current evidence partially supports epigenetic programming of the hypothalamic-pituitary-adrenal axis, but convincingly shows that ACE impairs immune function. Additionally, the needs and challenges that face this area are discussed in order to provide a framework that may help to clarify the role of epigenetics in the long-lasting effects of ACE.

Maternal stress and social support prospectively predict infant inflammation

Maternal stress has been suggested to be a risk factor for offspring health, while social support has been shown to be a protective factor for offspring functioning. Currently, research has yet to investigate how both of these factors may relate to infant inflammatory processes and associated biological aging in the first years of life. In 48 mother-infant dyads, we investigated whether maternal parenting stress and social support when infants were 12 and 18 months of age were cross-sectionally associated with infant salivary C-reactive protein (sCRP) during these times. In addition, we investigated whether parenting stress and social support were prospectively associated with later sCRP and changes in sCRP from 12 to 18 months of age, as well as whether those changes in sCRP were associated with subsequent infant salivary telomere length (sTL), a marker of biological aging. Analyses revealed that while there were no cross-sectional associations between maternal factors and infant sCRP, maternal parenting stress and social support when infants were 12 months of age predicted infant sCRP at 18 months of age. Further, maternal social support predicted changes in infant sCRP from 12 to 18 months of age. We observed a null association between infant sCRP and sTL. Implications for the ways that maternal mental health and social support may impact biological mechanisms related to disease processes in infants are discussed.

The Impact of Environmental Chronic and Toxic Stress on Asthma

Several factors have been associated with the development of asthma and asthma-related morbidity and mortality. Exposures in the environment such as allergens and air pollutants have traditionally been linked to the risk of asthma and asthma outcomes. More recent literature has identified chronic psychosocial stress as an additional environmental exposure to consider in relation to asthma. Adverse childhood events (ACEs) and chronic and toxic stress have been associated with chronic diseases such as cardiovascular disease, cancer, and chronic obstructive pulmonary disease. Chronic stress has also been shown to result in biological changes such as expression of immunologic genes, changes in expression of the beta-adrenergic (B2AR) and the glucocorticoid receptor (GR-α) genes, cytokine regulation, and alterations in the hypothalamic pituitary axis and cortisol levels which all may affect asthma pathophysiology and therapeutic response among patients exposed to chronic stress. Recent research has revealed associations between ACEs and chronic and toxic stress and asthma risk in pre-conception to early childhood as well as morbidity and response to asthma treatments among pediatric and adult age groups. As some populations are more significantly impacted by asthma such as racial and ethnic minority groups, the influence of psychosocial stress has also been explored as a potential factor responsible for observed disparities in asthma prevalence and outcomes among these groups which also experience higher rates of psychosocial stress. Racial discrimination has specifically been shown to affect asthma-related outcomes among minority groups. Interventions to address the impact of chronic and toxic stress such as yoga and meditation have been shown to improve asthma outcome measures. Chronic and toxic stress is an important environmental exposure to further consider as we continue to explore the differences in underlying asthma pathophysiology leading to various disease phenotypes among patients and clinical/therapeutic response to interventions and treatments.

Stress and Psychiatric Disorders: The Role of Mitochondria

In seeking to understand mental health and disease, it is fundamental to identify the biological substrates that draw together the experiences and physiological processes that underlie observed psychological changes. Mitochondria are subcellular organelles best known for their central role in energetics, producing adenosine triphosphate to power most cellular processes. Converging lines of evidence indicate that mitochondria play a key role in the biological embedding of adversity. Preclinical research documents the effects of stress exposure on mitochondrial structure and function, and recent human research suggests alterations constituting recalibrations, both adaptive and nonadaptive. Current research suggests dynamic relationships among stress exposure, neuroendocrine signaling, inflammation, and mitochondrial function. These complex relationships are implicated in disease risk, and their elucidation may inform prevention and treatment of stress- and trauma-related disorders. We review and evaluate the evidence for mitochondrial dysfunction as a consequence of stress exposure and as a contributing factor to psychiatric disease.

Adverse Childhood Experiences: Implications for Offspring Telomere Length and Psychopathology

OBJECTIVE

Adverse childhood experiences (ACEs) are associated with mental and physical health risks that, through biological and psychosocial pathways, likely span generations. Within an individual, telomere length (TL), an established marker of cellular stress and aging, is associated with both ACE exposure and psychopathology, providing the basis for an emerging literature suggesting that TL is a biomarker of the health risks linked to early-life adversity both within and across generations. The authors tested the effect of maternal ACEs on both the trajectory of infant TL and infant social-emotional problems at 18 months of age.

METHODS

Pregnant women were recruited, and maternal scores on the Adverse Childhood Experience questionnaire were obtained, along with demographic and prenatal stress measures. Postnatal visits with 155 mother-infant dyads occurred when infants were 4, 12, and 18 months of age. At each visit, infant buccal swabs were collected for TL measurement, and mothers completed measures of maternal depression. Mothers also completed the Child Behavior Checklist at the 18-month visit. Mixed-effects modeling was used to test how maternal ACEs influenced infant TL trajectory. Linear regression was used to test the association between maternal ACEs and infant internalizing and externalizing behaviors. Finally, the interaction between telomere attrition from 4 to 18 months and maternal ACEs was examined as a predictor of infant scores on the Child Behavior Checklist.

RESULTS

Higher maternal ACEs were associated with shorter infant TL across infancy and higher infant externalizing behavioral problems at 18 months. No associations were found with internalizing behavioral problems. Telomere attrition from 4 to 18 months interacted with maternal ACEs to predict externalizing behaviors. In infants whose mothers reported higher scores on the Adverse Childhood Experience questionnaire, greater telomere attrition predicted higher externalizing problems, even when accounting for maternal postnatal depression and prenatal stress.

CONCLUSIONS

These data demonstrate an interactive pathway between maternal early-life adversity and infant TL that predicts emerging behavioral problems in the next generations.

The association of telomere length with substance use disorders: systematic review and meta-analysis protocol

BACKGROUND

The present protocol was designed for a systematic review and meta-analysis aimed at determining the association of telomere length with substance use disorders with the exclusion of nicotine addiction, and to identify potential moderators of the effect of telomere length. Such methodological information may provide guidance to improve the quality of future research on this important topic.

METHODS

Potential studies will be identified through electronic databases (PubMed/MEDLINE, EMBASE, PsycINFO, and Web of Science) up from inception onwards. The inclusion criteria will include published or unpublished observational studies (cohort, case-control, and cross-sectional studies) reporting telomere length in adult patients with substance use disorder compared with a control group. Non-human studies or other study designs such as reviews, case-only, family-based, and/or population studies with only healthy participants will be excluded, as well as those focused solely on nicotine addiction. The main outcome will be telomere length in adults with substance use disorder (primary) and, specifically, in those with alcohol use disorder (secondary). Two investigators will independently evaluate the preselected studies for possible inclusion and will extract data following a standardized protocol. Disagreements will be resolved by consensus. The risk of bias of all included studies will be assessed using the Newcastle-Ottawa Quality Assessment Scale for non-randomized studies. Data will be converted into standardized mean differences as effect size index, and random-effects models will be used for the meta-analysis. Cochran's Q statistic, I² index, and visual inspection of the forest plot will be used to verify study heterogeneity. Subgroup analyses and meta-regressions will be conducted to ascertain heterogeneity. Several sensitivity analyses will be conducted to address the influence of potential confounding factors. Publication bias will be examined using the "funnel plot" method with Duval and Tweedie's trim-and-fill method and Egger test.

DISCUSSION

This systematic review will assess the association of telomere length with substance use disorders aside from nicotine addiction.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42019119785.

Effect of alcohol use disorder on cellular aging

RATIONALE

Human telomeres consist of tandem repeats at chromosome ends which protect chromosomal DNA from degradation. Telomere shortening occurs as part of natural aging; however, life stressors, smoking, drug use, BMI, and psychiatric disorders could disrupt cell aging and affect telomere length (TL). In this context, studies have evaluated the effects of alcohol consumption on TL; however, results have been inconsistent, which may reflect diverse drinking cut-offs and categorizations.

OBJECTIVES

To help clarify this, the present study addresses the association of TL with alcohol use disorder (AUD), drinking behaviors, lifetime stress, and chronological age.

METHODS

TL was quantified as the telomere to albumin ratio (T/S ratio) obtained from peripheral blood DNA using the quantitative PCR assay, from 260 participants with AUD and 449 non-dependent healthy controls (HC) from an existing National Institute on Alcohol Abuse and Alcoholism (NIAAA) database.

RESULTS

AUD participants showed shorter TL compared to HC with both, age, and AUD, as independent predictors as well as a significant AUD with age interaction effect on TL. TL was also associated with impulsiveness in AUD participants. We did not observe an association between TL and chronicity of alcohol use, alcohol doses ingested, or childhood trauma exposures in either AUD or HC, although very few HC reported a history of childhood trauma.

CONCLUSION

Our results support previous findings of telomere shortening with chronic alcohol exposures and show both an effect of AUD on TL that is independent of age as well as a significant AUD by age interaction on TL. These findings are consistent with accelerated cellular aging in AUD.

Controlling for baseline telomere length biases estimates of the rate of telomere attrition

Longitudinal studies have sought to establish whether environmental exposures such as smoking accelerate the attrition of individuals' telomeres over time. These studies typically control for baseline telomere length (TL) by including it as a covariate in statistical models. However, baseline TL also differs between smokers and non-smokers, and telomere attrition is spuriously linked to baseline TL via measurement error and regression to the mean. Using simulated datasets, we show that controlling for baseline TL overestimates the true effect of smoking on telomere attrition. This bias increases with increasing telomere measurement error and increasing difference in baseline TL between smokers and non-smokers. Using a meta-analysis of longitudinal datasets, we show that as predicted, the estimated difference in telomere attrition between smokers and non-smokers is greater when statistical models control for baseline TL than when they do not, and the size of the discrepancy is positively correlated with measurement error. The bias we describe is not specific to smoking and also applies to other exposures. We conclude that to avoid invalid inference, models of telomere attrition should not control for baseline TL by including it as a covariate. Many claims of accelerated telomere attrition in individuals exposed to adversity need to be re-assessed.

Childhood maltreatment, behavioral adjustment, and molecular markers of cellular aging in preschool-aged children: A cohort study

OBJECTIVE

Childhood maltreatment is a major risk factor for the development of behavioral problems and poor physical and mental health. Accelerated cellular aging, through reduced telomere length and mitochondrial dysfunction, may be a mechanism underlying these associations.

METHODS

Families with (n = 133) and without (n = 123) child welfare documentation of moderate-severe maltreatment in the past six months participated in this study. Children ranged in age from 3 to 5 years, were racially and ethnically diverse, and 91% qualified for public assistance. Structured record review and interviews were used to assess a history of maltreatment and other adversities. Telomere length and mitochondrial DNA copy number (mtDNAcn) were measured from saliva DNA using real-time PCR. Measures were repeated at a six-month follow-up assessment. Repeated measures general linear models were used to examine the effects of maltreatment and other adversities on telomere length and mtDNAcn over time.

RESULTS

Maltreatment and other adverse experiences were significant positive predictors of both telomere length and mtDNAcn over time. Internalizing and externalizing behavior problems were also both significantly associated with telomere length, but only internalizing symptoms were associated with mtDNAcn.

CONCLUSIONS

This is the first study to show that mtDNAcn is altered in children with stress and trauma, and the findings are consistent with recent studies of adults. Surprisingly, children who experienced moderate-severe levels of maltreatment in the prior six months had longer telomeres, possibly reflecting compensatory changes in response to recent trauma. Telomere length and mtDNAcn were also associated with behavioral problems, suggesting that these measures of cellular aging may be causally implicated in the pathophysiology of stress-related conditions.

Accelerating research on biological aging and mental health: Current challenges and future directions

Aging is associated with complex biological changes that can be accelerated, slowed, or even temporarily reversed by biological and non-biological factors. This article focuses on the link between biological aging, psychological stressors, and mental illness. Rather than comprehensively reviewing this rapidly expanding field, we highlight challenges in this area of research and propose potential strategies to accelerate progress in this field. This effort requires the interaction of scientists across disciplines - including biology, psychiatry, psychology, and epidemiology; and across levels of analysis that emphasize different outcome measures - functional capacity, physiological, cellular, and molecular. Dialogues across disciplines and levels of analysis naturally lead to new opportunities for discovery but also to stimulating challenges. Some important challenges consist of 1) establishing the best objective and predictive biological age indicators or combinations of indicators, 2) identifying the basis for inter-individual differences in the rate of biological aging, and 3) examining to what extent interventions can delay, halt or temporarily reverse aging trajectories. Discovering how psychological states influence biological aging, and vice versa, has the potential to create novel and exciting opportunities for healthcare and possibly yield insights into the fundamental mechanisms that drive human aging.

Cumulative lifetime stress exposure and leukocyte telomere length attrition: The unique role of stressor duration and exposure timing

BACKGROUND

Stress exposure occurring across the lifespan increases risk for disease, potentially involving telomere length shortening. Stress exposure during childhood and adulthood has been cross-sectionally linked with shorter telomere length. However, few longitudinal studies have examined telomere length attrition over time, and none have investigated how stressor duration (acute life events vs. chronic difficulties), timing (childhood vs. adulthood), and perceived severity may be uniquely related to telomere length shortening.

METHODS

To address these issues, we administered a standardized instrument for assessing cumulative lifetime stress exposure (Stress and Adversity Inventory; STRAIN) to 175 mothers of children with Autism Spectrum Disorder or neurotypical children and measured their leukocyte telomere length (LTL) at baseline and 2 years later.

RESULTS

Greater count of lifetime stressors was associated with shorter LTL at baseline and greater LTL attrition over time. When separating lifetime stressors into acute life events and chronic difficulties, only greater count of chronic difficulties significantly predicted shorter baseline LTL and greater LTL attrition. Similarly, when examining timing of stressor exposure, only greater count of chronic childhood difficulties (age < 18) significantly predicted shorter baseline LTL and greater LTL attrition over the 2-year period in mid-life. Importantly, these results were robust while controlling for stressors occurring during the interim 2-year period. Post-hoc analyses suggested that chronic difficulties occurring during earlier childhood (0-12 years) were associated with greater LTL attrition. Cumulative stressor severity predicted LTL attrition in a parallel manner, but was less consistently associated with baseline LTL.

CONCLUSIONS

These data are the first to examine the effects of different aspects of cumulative lifetime stress exposure on LTL attrition over time, suggesting that accumulated chronic difficulties during childhood may play a unique role in shaping telomere shortening in midlife.

Adverse Childhood Experiences and Telomere Length a Look Into the Heterogeneity of Findings-A Narrative Review

Background: Adverse childhood experiences (ACEs) have been associated with poor mental and somatic health. Accumulating evidence indicates that accelerated biological aging-indexed by altered telomere-related markers-may contribute to associations between ACEs and negative long-term health outcomes. Telomeres are repeated, non-coding deoxyribonucleic acid (DNA) sequences at the end of chromosomes. Telomeres shorten during repeated cell divisions over time and are being used as a marker of biological aging. Objectives: The aim of the current paper is to review the literature on the relationship between ACEs and telomere length (TL), with a specific focus on how the heterogeneity of sample and ACEs characteristics lead to varying associations between ACEs and TL. Methods: Multiple databases were searched for relevant English peer-reviewed articles. Thirty-eight papers were found to be eligible for inclusion in the current review. Results: Overall, the studies indicated a negative association between ACEs and TL, although many papers presented mixed findings and about a quarter of eligible studies found no association. Studies with smaller sample sizes more often reported significant associations than studies with larger samples. Also, studies reporting on non-clinical and younger samples more often found associations between ACEs and TL compared to studies with clinical and older samples. Reviewing the included studies based on the "Stressor Exposure Characteristics" recently proposed by Epel et al. (2018) revealed a lack of detailed information regarding ACEs characteristics in many studies. Conclusion: Overall, it is difficult to achieve firm conclusions about associations of ACEs with TL due to the heterogeneity of study and ACE characteristics and the heterogeneity in reported findings. The field would benefit from more detailed descriptions of study samples and measurement of ACEs.

Associations between early life parent-child separation and shortened telomere length and psychopathological outcomes during adolescence

BACKGROUND

Given the ethical limitations of exposing children to experimentally manipulated adverse experiences, evidence of the effects of parent-child separation on subsequent psychopathology are based mostly on animal studies. Left-behind children phenomenon resulting from rural-urban mobility in China offers unique "natural experiments" to explore the long-term physical and mental health consequences of parent-child separation in childhood.

OBJECTIVE

To test the associations between parent-child separation with telomere length (TL) and psychopathology during adolescence.

METHOD

A total of 710 adolescents (age: M = 16.86, SD = 1.52) were recruited from local schools in rural area of Fuyang, one of the top inland areas for outward migration in Anhui province, China. Parent-child separation was collected through face to face interview. The MacArthur Health & Behavior Questionnaire (HBQ) was used to assess internalizing and externalizing symptoms. Quantitative polymerase chain reaction was used to measure buccal TL.

RESULTS

Nearly 60% (399/695) of the participants experienced separation from both parents. Childhood or persistent separation from parents was associated with increased internalizing symptoms (childhood: β = 0.13, 95% CI: 0.02, 0.23; persistent: β  = 0.23, 95% CI: 0.14, 0.31), increased externalizing symptoms (childhood: β = 0.17, 95% CI: 0.03, 0.32; persistent: β  = 0.23, 95% CI: 0.10, 0.35) and shorter telomere length (childhood: β = -0.16, 95% CI: -0.26, -0.05; persistent: β = -0.13, 95% CI: -0.22, -0.03). Shortened TL was estimated to explain 15.2% and 12.7% of the total effect of separation on internalizing and externalizing symptoms, while internalizing and externalizing symptoms explained 23.4% and 12.3% of the effect of separation on shortened TL.

CONCLUSION

Childhood and persistent parent-child separation, as experienced by rural left-behind children in China, associates with increased vulnerability for psychopathological symptoms and makers of cellular aging. The challenge for future research is to determine whether short telomere length is in fact a long-term consequence or an underlying vulnerability factor for future mental disorders.

Stress and Salivary Telomere Length in the Second Half of Life: A Comparison of Life-course Models

Background

Previous research has explored the relationship between childhood and adulthood stressful life events (SLEs) and adult salivary telomere length (TL), but no research to date has tested different life-course models in which stress in adulthood may fully, partly, or not mediate the relationship between childhood stress and adult TL.

Methods

To fill this gap, we elaborate over previous work by Puterman et al. (2016) and other standard models that do not account for the temporal order of stressors in childhood and adulthood, by using structural equation modeling (SEM) for a sample of 5,754 Health and Retirement Study (HRS) participants to compare the fit of three nested life-course models-social trajectory, early critical period, and cumulative risk.

Results

Results indicated that the social trajectory model, in which the association between childhood SLEs and TL in later adulthood is fully mediated by adulthood SLEs, fit the data better than the early critical period (no mediation) and cumulative risk (partial mediation) models.

Conclusion

In the social trajectory model, childhood SLEs are related to TL in later life only through adulthood SLEs. The direct physiological effect of childhood SLEs on TL in later life would be overestimated if adulthood SLEs are overlooked.