Childhood life events, immune activation and the development of mood and anxiety disorders: the TRAILS study

Mind-body therapies and their interplay with the immune system in children and adolescents: a protocol for a systematic review and meta-analysis

BACKGROUND

Chronic inflammation is a critical public health concern that, in children and adolescents, increases the long-term risk of a variety of different health issues. While mind-body therapies like yoga, meditation, and acupuncture have shown promise in modulating immune responses in adults, their safety and effectiveness in pediatric populations remain underexplored. This protocol outlines the methodology for a systematic review and meta-analysis aimed at evaluating the effects of mind-body therapies on immune modulation in children and adolescents.

METHODS

This systematic review and meta-analysis will follow PRISMA 2020 guidelines. We will include randomized controlled trials, non-randomized controlled trials, cohort studies, and case-control studies that examine the relationship between mind-body therapies and immune markers in pediatric populations. Electronic searches will be conducted in MEDLINE, Embase, PsycINFO, CINAHL, Web of Science, and the Cochrane Library, supplemented by trial registries. Risk of bias will be assessed using the Cochrane Risk of Bias Tool (RoB 1), the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I), and the Newcastle-Ottawa Scale (NOS). Two independent reviewers will screen studies, extract data, and assess study quality, with a third reviewer resolving any discrepancies. Results will be synthesized both narratively and through meta-analysis using R software.

DISCUSSION

The review will evaluate the effectiveness and safety of mind-body therapies on immune markers in children and adolescents. The synthesized evidence will guide clinical practice and public health policies in integrating mind-body therapies into pediatric care. The findings will also provide a foundation for future research and policymaking in this area.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42024546585.

Longitudinal Measurement Invariance of the ASEBA Youth/Adult Self-Reports Across the Transition From Adolescence to Adulthood

The ability to quantify within-person changes in mental health is central to the mission of clinical psychology. Typically, this is done using total or mean scores on symptom measures; however, this approach assumes that measures quantify the same construct, the same way, each time the measure is completed. Without this quality, termed longitudinal measurement invariance, an observed difference between timepoints might be partially attributable to changing measurement properties rather than changes in comparable symptom measurements. This concern is amplified in research using different forms of a measure across developmental periods due to potential differences in reporting styles, item-wording, and developmental context. This study provides the strongest support for the longitudinal measurement invariance of the Anxiety Scale, Depression/Affective Problems: Cognitive Subscale, and the Attention Deficit Hyperactivity Disorder (ADHD) Scale; moderate support for the Depression/Affective Problems Scale and the Somatic Scale, and poor support for the Depression/Affective Problems: Somatic Symptoms Subscale of the Dutch Achenbach System of Empirically Based Assessment Youth Self-Report and Adult Self-Report in a sample of 1,309 individuals (N = 1,090 population-based, N = 219 clinic-based/referred to an outpatient clinic before age 11 years) across six waves of data (mean ages = 11 years at Wave 1 and 26 years at Wave 6).

Associations Between Growth Differentiation Factor 15 and Anxiety and Depression in the General Population: The Akershus Cardiac Examination 1950 Study

OBJECTIVE

Several studies suggest a bidirectional association between inflammation, and anxiety and depression. Elevated inflammatory cytokines generate and aggravate neuroinflammation, which may play a part in developing psychological symptoms. Growth differentiation factor 15 (GDF-15) is a novel biomarker possibly reflecting fibrosis and inflammation. The aim of the current study was to investigate the associations between levels of GDF-15 and symptoms of anxiety and depression in the general population.

METHODS

We measured GDF-15 in middle-aged persons participating in the Akershus Cardiac Examination 1950 Study. Symptoms of anxiety and depression were assessed using the Hospital Anxiety and Depression Scale (HADS), with HADS ≥8 denoting significant symptoms. We used multivariable regression analysis to assess the associations between GDF-15 and HADS, adjusting for levels of C-reactive protein (CRP), demographics, and comorbidities.

RESULTS

A total of 3638 participants had valid assessment of HADS and measurements of GDF-15 and CRP. The mean age was 63.9 (SD 0.65) years, and 48.8% were women. In adjusted models, levels of GDF-15 were associated with the continuous HADS-D score (β = 0.27, 95% confidence interval [CI] = 0.12 to 0.43) and HADS-D score ≥8 (odds ratio = 1.41, 95% CI = 1.12 to 1.78), but not with the continuous HADS-A score (β = 0.06, 95% CI = -0.12 to 0.24) or HADS-A score ≥8 (odds ratio = 1.06, 95% CI = 0.88 to 1.27).

CONCLUSIONS

Levels of GDF-15 are independently associated with symptoms of depression in the general population. Our results reinforce the notion that inflammation may be a contributing factor for the development of clinical depression.

REGISTRATION

ClinicalTrials.gov identifier NCT01555411 (Akershus Cardiac Examination [ACE] 1950 Study), https://clinicaltrials.gov/study/NCT01555411.

Interpersonal violence exposure and inflammation during adolescence and young adulthood

Exposure to violence increases young peoples' risk of developing mental and physical health problems. Chronic stress-related upregulation of innate immune system activity and the development of low-grade inflammation may partially underlie this health risk. However, much of the previous research has been limited to cross-sectional studies utilizing between-person analytic designs, susceptible to confounding by unmeasured factors. In this six-wave panel study of N=157 female adolescents and young adults, we tested within-person associations between interpersonal violence exposure and multiple measures of inflammatory activity. Ex vivo culture studies suggested that participants' immune cells were more reactive to microbial stimulation and less sensitive to inhibition by glucocorticoids after violence. Numbers of circulating monocyte cells increased after violence, but serum levels of interleukin-6 and c-reactive protein did not. Findings from this within-person analysis suggest that violence exposure up-regulates innate immune system activity during adolescence and young adulthood in ways that may increase mental and physical health risk.

Recent advances in understanding the neurobiology of pediatric functional neurological disorder

INTRODUCTION

Functional neurological disorder (FND) is a neuropsychiatric disorder that manifests in a broad array of functional motor, sensory, or cognitive symptoms, which arise from complex interactions between brain, mind, body, and context. Children with FND make up 10%-20% of presentations to neurology services in children's hospitals and up to 20% of adolescents admitted to hospital for the management of intractable seizures.

AREAS COVERED

The current review focuses on the neurobiology of pediatric FND. The authors present an overview of the small but growing body of research pertaining to the biological, emotion-processing, cognitive, mental health, physical health, and social system levels.

EXPERT OPINION

Emerging research suggests that pediatric FND is underpinned by aberrant changes within and between neuron-glial (brain) networks, with a variety of factors - on multiple system levels - contributing to brain network changes. In pediatric practice, adverse childhood experiences (ACEs) are commonly reported, and activation or dysregulation of stress-system components is a frequent finding. Our growing understanding of the neurobiology of pediatric FND has yielded important flow-on effects for assessing and diagnosing FND, for developing targeted treatment interventions, and for improving the treatment outcomes of children and adolescents with FND.

APOE Genotype, ApoE Plasma Levels, Lipid Metabolism, and Cognition in Monozygotic Twins with, at Risk of, and without Affective Disorders

Background: Lipids influence brain function and mental health. Understanding the role of apolipoproteins in affective disorders could provide valuable insights and potentially pave the way for novel therapeutic approaches. Methods: We examined the apolipoprotein E genotype and ApoE-levels, lipid profiles, and the correlation with cognition in 204 monozygotic (MZ) twins with unipolar or bipolar disorder in remission or partial remission (affected, AT), their unaffected co-twins (high-risk, HR), and twins with no personal or family history of affective disorder (low-risk, LR). Results: The APOE genotype was not associated with affective disorders. No significant group differences in ApoE levels were found between the three risk groups. Post hoc analysis group-wise comparisons showed higher ApoE levels in the AT than HR twins and in the concordant AT twin pairs relative to the discordant twin pairs. Within the discordant twin pairs, higher ApoE levels were observed in the affected twins (AT = 39.4 mg/L vs. HR = 36.8 mg/L, p = 0.037). Limitations: The present study could benefit from a larger sample size. We did not assess dietary habits. Conclusions: The results did not support our main hypothesis. However, exploratory post hoc analysis suggests a role for plasma ApoE and triglycerides in affective disorders. Future research is needed.

Antagonism of the brain P2X7 ion channel attenuates repeated social defeat induced microglia reactivity, monocyte recruitment and anxiety-like behavior in male mice

Chronic stress is linked to increased anxiety. Repeated social defeat (RSD) in mice causes anxiety that is dependent on activated neurons, reactive microglia, and accumulation of monocytes in the brain. This response requires interactions between the immune system and central nervous system (CNS). Neuronal activation within threat appraisal regions is a key response to RSD, however, it is unclear how microglia become activated. One potential explanation is that microglia express a purinergic non-selective ligand gated adenosine-triphosphate (ATP) receptor 7 (P2X7). Activation of P2X7 promotes the release of chemokines and cytokines, and recruitment of monocytes to the brain. Thus, the purpose of this study was to determine if a novel P2X7 antagonist blocked neuronal and microglia interactions and the corresponding anxiety following RSD. Male mice were administered (i.p.) a P2X7 antagonist, JNJ-54471300, prior to each cycle of RSD. Fourteen hours after RSD, behavioral deficits including social avoidance and anxiety-like were determined. Moreover, several immune parameters were assessed. RSD caused neuronal activation in stress-responsive regions, monocyte production and release, splenomegaly, and social avoidance. These parameters were unaffected by P2X7 antagonism. RSD-associated proportional area of Iba-1+ microglia, monocyte accumulation in the brain, IL-1β mRNA expression in enriched myeloid cells, plasma IL-6, and anxiety-like behavior were ameliorated by P2X7 antagonism. Gene expression analysis in the hippocampus and amygdala showed regional specific responses to RSD and some were reversed with P2X7 antagonism. Overall, blocking P2X7 activation attenuated RSD-induced microglia reactivity with corresponding reduction in neuroinflammation, monocyte accumulation, and anxiety-like behavior in male mice.

A systematic literature review on the humanistic burden of cytomegalovirus

OBJECTIVE

Cytomegalovirus (CMV) infection is typically asymptomatic in healthy individuals; however, certain populations are vulnerable to infection and may develop serious sequelae. CMV infection may also have a broad impact on humanistic outcomes, including patient health status and quality of life (QoL). We conducted a systematic literature review (SLR) to describe the global humanistic burden of CMV and congenital CMV (cCMV) infections across all age groups.

METHODS

Medline, Embase, and LILACS were searched to identify studies on humanistic outcomes following CMV infection, including health status/QoL and any outcomes in domains such as auditory, cognitive ability, developmental status, intelligence, language, memory, mental health, motor performance, social communication, speech, and vocabulary. The SLR included articles published from 2000-2020 and focused geographically on Australia, Europe, Israel, Japan, Latin America, and North America.

RESULTS

Sixty-three studies met the inclusion criteria. In general, individuals with symptomatic cCMV infection experience a greater burden of disease and more substantial impact on QoL versus those with asymptomatic cCMV infection. Children with hearing loss due to cCMV infection, both symptomatic and asymptomatic, showed improved auditory outcomes following cochlear implantation. Newborns, infants, and children with cCMV infections had worse cognitive outcomes in psychological development, sequential and simultaneous processing, phonological working memory, and attention control versus age-matched controls without cCMV infection. CMV infection was also associated with cognitive decline in elderly populations.

CONCLUSIONS

CMV infection can have substantial, lifelong, heterogenous impacts on humanistic outcomes, including health status and QoL, which should be considered when developing and implementing treatment and prevention strategies.

Trajectories of stressful life events and long-term changes in mental health outcomes, moderated by family functioning? the TRAILS study

PURPOSE

We assessed the association between trajectories of stressful life events (SLEs) throughout adolescence and changes in mental health from childhood to young adulthood. Further, we assessed whether family functioning moderated this association.

METHODS

Data of the first six waves of the TRAILS study (2001-2016; n = 2229) were used, a cohort followed from approximately age 11 to 23. We measured SLEs (death of a family member or other beloved one, delinquency, moving, victim of violence, parental divorce, and sexual harassment) at ages 14, 16 and 19. Family functioning was measured at all six time points using the Family Assessment Device (FAD), and mental health was measured through the Youth/Adult Self-Report at ages 11 and 23. Latent class growth analyses (LCGA) were used to examine longitudinal trajectories and associations.

RESULTS

We identified three SLE trajectories (low, middle, high) throughout adolescence, and found no significant associations between these trajectories and changes in mental health from childhood to young adulthood. Family functioning and SLE trajectories were significantly associated, however, the association of SLE trajectories and changes in mental health was not modified by family functioning. Mental health problems at age 11 increased the likelihood of high SLE trajectories during adolescence, and of experiencing negative family functioning.

CONCLUSION

Experiencing SLEs throughout adolescence does not have a direct impact on changes in mental health from childhood to young adulthood, but early adolescence mental health problems increase the likelihood of experiencing SLEs.

Specific Associations Between Type of Childhood Abuse and Elevated C-Reactive Protein in Young Adult Psychiatric Rehabilitation Participants

BACKGROUND

Early-life adversity such as childhood emotional, physical, and sexual trauma is associated with later-life psychiatric and chronic medical conditions, including elevated inflammatory markers. Although previous research suggests a role for chronic inflammatory dysfunctions in several disease etiologies, specific associations between childhood trauma types and later-life inflammation and health status are poorly understood.

METHODS

We studied patients (n = 280) admitted to a psychiatric rehabilitation center. Self-reported histories of childhood emotional, physical, and sexual trauma were collected with a standard instrument. At the time of admission, we also assessed individuals' body mass index and collected blood samples used to examine inflammatory marker C-reactive protein (CRP) levels.

RESULTS

The prevalence of all 3 types of abuse was relatively high at 21% or more. Fifty percent of the sample had elevations in CRP, with clinically significant elevations in 26%. We found that compared with a history of emotional or physical abuse, a history of childhood sexual trauma was more specifically associated with elevated CRP. This result held up when using linear regressions to examine the contribution of body mass index.

LIMITATION

Our sample was relatively young, with an average age of 27.2 years and minimal representation of ethnic and racial minority participants.

CONCLUSION

Relative to childhood emotional and physical trauma, childhood sexual trauma may lead to elevated inflammatory responses, as confirmed in our finding of an association between CRP and sexual abuse. Future studies need to assess the causal link between childhood sexual trauma and poorer health outcomes later in life.

The neuroimmunology of social-stress-induced sensitization

Myriad clinical findings provide links between chronic stressors, inflammation, and mood disorders. Furthermore, traumatic or chronic exposure to psychological stressors may promote stress sensitization, in which individuals have long-term complications, including increased vulnerability to subsequent stressors. Post-traumatic stress disorder (PTSD) is a clinically relevant example of stress sensitization. PTSD alters neuronal circuitry and mood; however, the mechanisms underlying long-term stress sensitization within this disorder are unclear. Rodent models of chronic social defeat recapitulate several key physiological, immunological, and behavioral responses associated with psychological stress in humans. Repeated social defeat (RSD) uniquely promotes the convergence of neuronal, central inflammatory (microglial), and peripheral immune (monocyte) pathways, leading to prolonged anxiety, social withdrawal, and cognitive impairment. Moreover, RSD promotes stress sensitization, in which mice are highly sensitive to subthreshold stress exposure and recurrence of anxiety weeks after the cessation of stress. Therefore, the purpose of this Review is to discuss the influence of social-defeat stress on the immune system that may underlie stress sensitization within three key cellular compartments: neurons, microglia, and monocytes. Delineating the mechanisms of stress sensitization is critical in understanding and treating conditions such as PTSD.

Association of interleukin-8 and risk of incident and recurrent depression in long-term breast cancer survivors

BACKGROUND

In cancer patients, an interleukin (IL)-8 gene variant that leads to higher production of IL-8, is associated with lower risk of depressive symptoms. In non-cancer adults, higher levels of IL-8 correlate with lower severity of depressive symptoms, decreased risk of suicide, and improved treatment response in females, but not males. This study evaluates the prospective association between circulating levels IL-8 and incident and recurrent major depressive disorder in breast cancer survivors.

METHODS

In this single site, prospective cohort study with protocol modification extending follow-up from 24- to 32 months, recruitment occurred between September 2013 and January 2018, and follow-up was completed February 2021. Participants were identified from a Kaiser Permanente of Southern California health plan-based sample of 219 breast cancer survivors, who were two or more years since diagnosis of early stage breast cancer (TNM 0-II), aged 55 to 85 years, with no major depression or health events in last year. Circulating levels of IL-8 were obtained at enrollment. Primary outcome was time to incident or recurrent major depressive disorder as diagnosed by interview and DSM-5 criteria.

RESULTS

Among 219 participants (mean age, 70 years; 100% female; 16 [7.3%] Asian, 42 [19.2%] Black, 161 [73.5%] White), 84% completed 24 months follow-up. After protocol modification, 59% completed 32 months follow-up. Median follow-up was 28.5 months. The primary endpoint occurred in 27 participants (12.4%, 5.7 events /100 person years; 95% CI 2.7 - 8.8). Higher IL-8 was associated with lower risk of incident and recurrent depression (hazard ratio, HR, 0.52, 95% CI 0.26 - 1.05). Among those with levels of IL-8 in the highest quartile, the primary endpoint occurred in 2 participants (3.6%; 1.6 events/100 person years; 95% CI 1.3 - 1.9), as compared to 25 participants in the pooled lower quartiles (15.2%; 7.2 events/100 persons years; 95%CI 7.0 - 7.4; rate difference, 5.6 per 100 person years, 95%CI 5.2 - 5.9; HR, 0.21, 95%CI 0.05 - 90, multivariable adjusted HR, 0.20, 95%CI 0.05 - 0.88).

CONCLUSIONS

Among breast cancer survivors, higher IL-8 at enrollment was associated with a decreased risk of incident and recurrent major depression. These findings provide insights into mechanisms of depression risk and development of novel therapies for depression prevention, and suggest that testing for IL-8 may have prognostic value in identifying resilience or risk of depression.

Cytokine alterations in pediatric internalizing disorders: Systematic review and exploratory multi-variate meta-analysis

Pediatric internalizing disorders are prevalent and characterized by a maladaptive cognitive, emotional response to a perceived stressor. The hypothesized effect of this response is observable changes in behavior mediated by homeostatic inflammatory cytokines. The aim of this study was to synthesize the literature and analyze the effect of cytokines on pediatric internalizing disorders. Influential moderating variables, including mean body mass index, fasting status at blood collection, participant sex, cytokine type, mean age, percentage of sample medicated, and diagnosis, were also assessed. A systematic literature search was performed in electronic databases (Medline, PubMed, and PsycINFO) from January 1, 1980 to June 15, 2022. Case-control studies of pediatric internalizing disorders, specifically anxiety and depression, were reviewed for their association with peripheral cytokine levels. Meta-analyses were performed using a random effects multi-variate model and effect sizes were calculated using Hedge's g for IL-2, CRP, IL-6, TNF-α, IL-1β, IFN-γ, and IL-10. Thirty-three studies were reviewed and 28 studies were included in the meta-analysis (n = 1322 cases and n = 3617 controls). Peripheral cytokine levels were elevated in pediatric internalizing disorders compared to controls (Hedge's g = 0.19, p < 0.001). In the moderator analyses, depression diagnosis (Hedge's g = 0.18, p = 0.009) and non-fasting blood collection (Hedge's g = 0.20, p = 0.006) were significant. The meta-analytic findings are limited by methodological variation between studies, high heterogeneity, and low statistical power. Despite this, the findings suggest that elevated peripheral cytokine levels may play a role in the etiology and/or symptom maintenance of pediatric internalizing disorders.

Psychological Stress During Childhood and Adolescence and Its Association With Inflammation Across the Lifespan: A Critical Review and Meta-Analysis

Psychological stress during childhood and adolescence increases risk of health problems across the lifecourse, and inflammation is implicated as an underlying mechanism. To evaluate the viability of this hypothesis, we used meta-analysis to quantify the association between childhood/adolescent stress and inflammation over the lifecourse. Furthermore, we addressed three unresolved conceptual questions: (a) Does the strength of this association change over the lifecourse? (b) Are different types of childhood/adolescent stressors differentially associated with inflammation? (c) And which components of the inflammatory response are involved? A systematic search identified 187 articles reporting 922 associations. Meta-analyses were conducted using a three-level multilevel approach and controlled for study quality, conversion confidence, and whether effect sizes were unadjusted or adjusted (n = 662, 72%). Results indicated a small but reliable overall adjusted association ( r ^ = .04 ) . The magnitude of the association strengthened across the lifecourse-effect sizes were smallest in studies that measured inflammation in childhoodr ^ = .02 and became progressively larger in studies of adolescencer ^ = .04 and adulthoodr ^ = .05 , suggesting the impact of early stress strengthens with time. By contrast, effect sizes did not vary by adversity type (socioeconomic disadvantage, maltreatment, other interpersonal stressors, and cumulative exposure across stressors), or component of inflammation (circulating biomarkers of low-grade inflammation vs. cytokine responses to microbial stimuli). Implications and future directions are discussed.

Childhood Violence Exposure, Inflammation, and Cardiometabolic Health

Exposure to interpersonal violence during childhood, a severe and often traumatic form of social stress, is an enduring problem that an emerging body of work suggests may be relevant to cardiometabolic health and the progression of cardiovascular disease (CVD) across the life course. Less is known about this association causally, and consequently, the biological mechanisms that may confer risk for, and resilience to, poor health outcomes in the aftermath of violence are not well understood. Drawing on recent theoretical insights and empirical research in both humans and non-human animal models, the current paper articulates a hypothesis for one way that childhood violence could get "under the skin" to influence CVD. Based on this emerging literature, one plausible way that childhood violence exposure could increase susceptibility to CVD in later life is by sensitizing stress-response neurobiology and immune processes that regulate and promote inflammation, which is a key pathogenic mechanism in CVD. This is inherently a developmental process that begins in early life and that unfolds across the life course, although less is known about the specific mechanisms through which this occurs. The goal of this paper is to articulate some of these plausible mechanisms and to suggest areas for future research that aims to reduce the burden of disease among individuals who are exposed to violence.

Associations of High-Sensitivity C-Reactive Protein and Interleukin-6 with Depression in a Sample of Italian Adolescents During COVID-19 Pandemic

INTRODUCTION

Many studies highlighted the role of inflammation in the pathogenesis of depression, although not for every patient nor for every symptom. It is widely shared that stressors can increase inflammation and lead to depressive symptoms. Little is known about the symptom-specificity of the inflammation-depression link in adolescence, which we aimed to explore. The single symptom analysis is a core feature of the recent network approach to depression, supposing that psychiatric disorders consist of co-occurring symptoms and their tendency to cause each other.

PATIENTS AND METHODS

We recruited 52 adolescents diagnosed with a Depressive Disorder during the COVID-19 stressful period. We used regression analysis to measure associations between high sensitivity C-Reactive Protein (hs-CRP) and Interleukin-6 (IL-6) and depressive symptoms assessed by the Children's Depression Inventory 2 (CDI 2). For the study of symptom specificity, we selected 13 items from the CDI 2 Self Report corresponding with the DSM-5 diagnostic criteria for Major Depressive Disorder and we coded them as dichotomous variables to perform a regression analysis.

RESULTS

We found that a higher CDI 2-Parent Version total score was significantly predicted by higher hs-CRP (coefficient 3.393; p 0.0128) and IL-6 (coefficient 3.128; p 0.0398). The endorsement of the symptom self-hatred, measuring the DSM-5 symptom "feelings of worthlessness", was significantly predicted by hs-CRP (OR 10.97; 95% CI 1.29-93.08; p 0.0282).

CONCLUSION

A novel symptom-specificity emerged, with hs-CRP significantly predicting the endorsement of the symptom self-hatred, recognized as a core feature of adolescent depression, following the network theory. We considered it a possible phenotypic expression of one depression endophenotype previously causally linked to inflammation. Due to the limited sample size, these preliminary findings require confirmation with future research focusing on the relationship between inflammation and self-hatred and other central nodes of the depression network, representing an opportunity for targeting interventions on crucial symptoms.

Inflammation and depression in young people: a systematic review and proposed inflammatory pathways

Depression onset peaks during adolescence and young adulthood. Current treatments are only moderately effective, driving the search for novel pathophysiological mechanisms underlying youth depression. Inflammatory dysregulation has been shown in adults with depression, however, less is known about inflammation in youth depression. This systematic review identified 109 studies examining the association between inflammation and youth depression and showed subtle evidence for inflammatory dysregulation in youth depression. Longitudinal studies support the bidirectional association between inflammation and depression in youth. We hypothesise multiple inflammatory pathways contributing to depression. More research is needed on anti-inflammatory treatments, potentially tailored to individual symptom profiles.

Associations between childhood maltreatment and oxidative nucleoside damage in affective disorders

Background

Childhood maltreatment is an established risk factor for incident unipolar disorder and bipolar disorder. It is separately observed that affective disorders (AD) are also associated with higher nucleoside damage by oxidation. Childhood maltreatment may induce higher levels of nucleoside damage by oxidation and thus contribute to the development of AD; however, this relation is only sparsely investigated.

Methods

In total, 860 participants (468 patients with AD, 151 unaffected first-degree relatives, and 241 healthy control persons) completed the Childhood Trauma Questionnaire (CTQ). The association between CTQ scores and markers of systemic DNA and RNA damage by oxidation as measured by urinary excretion of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoGuo) levels, respectively, was investigated.

Results

In multiple regression models adjusted for sex- and age, 8-oxodG and 8-oxoGuo levels were found to be higher in individuals who had experienced more childhood maltreatment. These associations persisted in models additionally adjusted for body mass index, alcohol, and current smoking status. Emotional abuse, sexual abuse, and emotional neglect were principally responsible for the foregoing associations.

Conclusions

Our findings of an association between childhood maltreatment and oxidative stress markers suggest that childhood maltreatment overall, notably emotional abuse and emotional neglect, is associated with enhanced systemic damage to DNA and RNA in adulthood. Further, individuals with AD reported a higher prevalence of childhood maltreatment, which may induce higher levels of nucleoside damage by oxidation in adulthood, possibly leading to increased risk of developing AD. Longitudinal studies are needed to clarify this relationship further.

Promoting brain health through physical activity among adults exposed to early life adversity: Potential mechanisms and theoretical framework

Adverse childhood experiences such as abuse, neglect, and poverty, profoundly alter neurobehavioral development in a manner that negatively impacts health across the lifespan. Adults who have been exposed to such adversities exhibit premature and more severe age-related declines in brain health. Unfortunately, it remains unclear whether the negative effects of early life adversity (ELA) on brain health can be remediated through intervention in adulthood. Physical activity may represent a low-cost behavioral approach to address the long-term consequences of ELA on brain health. However, there has been limited research examining the impact of physical activity on brain health among adults with a history of ELA. Accordingly, the purpose of this review is to (1) review the influence of ELA on brain health in adulthood and (2) highlight evidence for the role of neurotrophic factors, hypothalamic-adrenal-pituitary axis regulation, inflammatory processes, and epigenetic modifications in mediating the effects of both ELA and physical activity on brain health outcomes in adulthood. We then propose a theoretical framework to guide future research in this area.

The longitudinal associations of inflammatory biomarkers and depression revisited: systematic review, meta-analysis, and meta-regression

The innate immune system is dysregulated in depression; however, less is known about the longitudinal associations of depression and inflammatory biomarkers. We investigated the prospective associations of depression and inflammatory biomarkers [interleukin-6 (IL-6), Tumor Necrosis Factor-Alpha (TNF-α), and C-reactive protein (CRP)] in community samples, both unadjusted and adjusted for covariates. The review, registered with PROSPERO, searched for published and unpublished studies via MEDLINE/PsycINFO/PsycARTICLES/EMBASE/Proquest Dissertation. Standardized Fisher transformations of the correlation/beta coefficients, both unadjusted and adjusted for covariates, were extracted from studies examining the prospective associations of depression and inflammatory biomarkers. Systematic review conducted in January, 2019 included 38 studies representing 58,256 participants, with up to 27 studies included in random-effects meta-analysis. Higher CRP/IL-6 were associated with future depressive symptoms, and higher depressive symptoms were associated with higher future CRP/IL-6 in both unadjusted and adjusted analyses - this is the first meta-analysis reporting an adjusted association of IL-6 with future depression. The adjusted prospective associations of depression with CRP/CRP with depression were substantially attenuated and small in magnitude. No significant associations were observed for TNF-α. No conclusive results were observed in studies of clinical depression. Meta-regression indicated that the association of CRP and future depression was larger in older samples and in studies not controlling for possible infection. Small, prospective associations of depression and inflammatory biomarkers are observed in both directions, particularly for IL-6; however, the strength and importance of this relationship is likely obscured by the heterogeneity in depression and profound study/methodological differences. Implications for future studies are discussed.

Mapping relationships between ADHD genetic liability, stressful life events, and ADHD symptoms in healthy adults

Attention-deficit/hyperactivity disorder (ADHD) symptoms are continuously distributed in the general population, where both genetic and environmental factors play roles. Stressful life events (SLEs) have been associated with ADHD diagnosis, but the relationship between ADHD genetic liability, SLEs, and ADHD symptoms in healthy individuals is less clear. Using a sample of 1,531 healthy adults (average age 26.9 years; 55.8% female), we investigated relationships between ADHD polygenic risk scores (ADHD-PRSs), SLEs, and ADHD symptoms in a general population sample. Confirming earlier findings in an overlapping sample, all SLE-measures assessed (lifetime SLEs, recent SLEs, and childhood trauma (CT)) were significantly correlated with total ADHD, inattention (IA), and hyperactivity-impulsivity (HI) scores (r² range = .08-.15; all p < .005). ADHD-PRSs was associated with HI (R²_best-fit  = .37%), lifetime SLEs (R²_best-fit  = .56%), and CT (R²_best-fit  = .40%). Mediation analyses showed that lifetime SLEs partially mediated the association between ADHD-PRSs and HI (indirect effect: β = 68.6, bias corrected accelerated 95% confident interval (BCa95%CI) [11.9, 131.0], p = .016, proportion mediated (P_M ) =19.5%), with strongest effects contributed by CT (β = 34.4, BCa95%CI [0.4, 76.5], p = .040, P_M  = 9.8%). On the other hand, HI partially mediated the association between the ADHD-PRSs and lifetime SLEs (β = 42.9, BCa95%CI [7.3, 83.9], p = .014, P_M  = 18.8%). Our study observed a complex relationship of genetic and environmental risk factors contributing to ADHD symptoms in the healthy adult population.

Investigating whether depressed youth exhibiting elevated C reactive protein perform worse on measures of executive functioning, verbal fluency and episodic memory in a large, population based sample of Dutch adolescents

Cognitive functioning is disrupted during a depressive episode and cognitive dysfunction persists when depression is in remission. A subtype of depressed individuals who exhibit elevated inflammatory biomarkers may be at particular risk for cognitive dysfunction. We examined whether an elevated inflammatory biomarker (C-reactive protein: CRP) in acute and/or remitted depression was associated with specific deficits in executive functioning, episodic memory, and verbal fluency. Data were drawn from a population-based sample of Dutch adolescents (N = 1066; 46% male) recruited at the age of 11 and followed over the course of eight years. We tested whether adolescents with either, (i) a history of depression (Wave 1-3) or (ii) current depression (Wave 4), and elevated levels of C-reactive protein measured in blood at Wave 3 performed worse on cognitive assessments at Wave 4. Eight measures of cognitive functioning were hypothesized to load on to one of three dimensions of cognitive functioning (executive functioning, episodic memory, and verbal fluency) within a structural equation model framework. Higher levels of CRP were associated with worse future executive functioning in adolescents with and without current/prior depression. A current depression diagnosis also was associated with worse executive functioning. There was consistent evidence linking low socioeconomic status and health-related covariates (high body mass index/sedentary behavior) with worse performance across multiple measures of cognitive functioning and, importantly, the association of depression/CRP and executive functioning was no longer significant when controlling for these covariates. Future studies may benefit from investigating whether specific depressogenic behaviors (e.g., sedentary behavior/substance use) mediate a relationship between depression and worse executive functioning, potentially via a prospective pathway through elevated inflammation.

Towards precision medicine: What are the stratification hypotheses to identify homogeneous inflammatory subgroups

Diverse lines of research testify a link, presumably causal, between immune dysregulation and the development, course and clinical outcome of psychiatric disorders. However, there is a large heterogeneity among the patients' individual immune profile and this heterogeneity prevents the development of precise diagnostic tools and the identification of therapeutic targets. The aim of this review was to delineate possible subgroups of patients on the basis of clinical dimensions, investigating whether they could lead to particular immune signatures and tailored treatments. We discuss six clinical entry points; genetic liability to immune dysregulation, childhood maltreatment, metabolic syndrome, cognitive dysfunction, negative symptoms and treatment resistance. We describe the associated immune signature and outline the effects of anti-inflammatory drugs so far. Finally, we discuss advantages of this approach, challenges and future research directions.

Adverse childhood experiences and early life inflammation in the Avon longitudinal study of parents and children

BACKGROUND

Adverse childhood experiences (ACEs) have been associated with poorer health across the life course. Previous studies have used cumulative risk scores (ACE scores) or individual ACEs but these two approaches have important shortcomings. ACE scores assume that each adversity is equally important for the outcome of interest and the single adversity approach assumes that ACEs do not co-occur. Latent class analysis (LCA) is an alternative approach to operationalising ACEs data, identifying groups of people co-reporting similar ACEs. Here we apply these three approaches for ACEs operationalisation with inflammation in childhood with the aim of identifying particular ACEs or ACE combinations that are particularly associated with higher inflammation in early life.

METHODS

Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC) we compare ACE scores, single adversities and LCA-derived ACE clusters in their relationships with Interleukin-6 at age 9 (n = 4935) and C-Reactive Protein (CRP) at age 9 (n = 4887). ACEs included were parental separation/divorce, parental alcohol problems, parental mental health problems, parental offending, inter-parental violence, parental drug misuse, and physical, emotional and sexual abuse.

RESULTS

Two thirds of the sample reported at least one ACE. Mother's mental health problems was the most frequently reported ACE (32.3 %). LCA identified four ACE classes - 'Low ACEs' (81.1 %), 'Maternal mental health problems' (10.3 %), 'Maternal mental health problems and physical abuse' (6.3 %) and 'Parental conflict, mental health problems and emotional abuse' (2.4 %). Parental separation/divorce was associated with higher IL-6. Parental alcohol problems, paternal mental health problems, parental convictions and emotional abuse were associated with lower levels of IL-6. Associations for paternal mental health problems and emotional abuse were only observed for boys. ACE score and LCA-derived ACE classes were not associated with differences in IL-6. Girls in the 'Maternal mental health problems' cluster had lower CRP levels.

CONCLUSIONS

Specific adversities and adversity combinations are important for differences in childhood inflammation. Some associations were only observed for girls or boys.

Early childhood risk exposures and inflammation in early adolescence

There is now reliable evidence that early psychosocial stress exposures are associated with behavioral health in children; the degree to which these same kinds of stress exposures predict physical health outcomes is not yet clear. We investigated the links between economic adversity, family and caregiving stress in early childhood and several markers of immune function in early adolescence. The sample is derived from the Family Life Project, a prospective longitudinal study of at-risk families. Socio-demographic and psychosocial risks have been assessed at regular intervals since the children were first assessed at 2 months of age. When the children were early adolescents, we conducted an in-depth health assessment of a subsample of families; blood samples were collected from venipuncture for interleukin(IL)-6, Tumor Necrosis Factor (TNF)-alpha, and C-reactive protein (CRP), as well as glucocorticoid resistance. Results indicated limited but reliable evidence of an association between early risk exposure and inflammation in adolescence. Specifically, caregiver depressive symptoms in early childhood predicted elevated CRP almost a decade later, and the prediction was significant after accounting for multiple covariates such as socio-economic adversity, health behaviors and body mass index. Our findings provide strong but limited evidence that early stress exposures may be associated with inflammation, suggesting one mechanism linking early stress exposure to compromised behavioral and somatic health.

Herpes simplex virus: global infection prevalence and incidence estimates, 2016

Objective

To generate global and regional estimates for the prevalence and incidence of herpes simplex virus (HSV) type 1 and type 2 infection for 2016.

Methods

To obtain data, we undertook a systematic review to identify studies up to August 2018. Adjustments were made to account for HSV test sensitivity and specificity. For each World Health Organization (WHO) region, we applied a constant incidence model to pooled prevalence by age and sex to estimate the prevalence and incidence of HSV types 1 and 2 infections. For HSV type 1, we apportioned infection by anatomical site using pooled estimates of the proportions that were oral and genital.

Findings

In 2016, an estimated 491.5 million people (95% uncertainty interval, UI: 430.4 million–610.6 million) were living with HSV type 2 infection, equivalent to 13.2% of the world’s population aged 15–49 years. An estimated 3752.0 million people (95% UI: 3555.5 million–3854.6 million) had HSV type 1 infection at any site, equivalent to a global prevalence of 66.6% in 0–49-year-olds. Differing patterns were observed by age, sex and geographical region, with HSV type 2 prevalence being highest among women and in the WHO African Region.

Conclusion

An estimated half a billion people had genital infection with HSV type 2 or type 1, and several billion had oral HSV type 1 infection. Millions of people may also be at higher risk of acquiring human immunodeficiency virus (HIV), particularly women in the WHO African Region who have the highest HSV type 2 prevalence and exposure to HIV.

Associations of nitric oxide with obesity and psychological traits among children and adolescents in Taiwan

BACKGROUND

Findings concerning nitric oxide (NO) in children and adolescents with obesity are scant.

OBJECTIVE

This study examined the links of NO with obesity and psychological traits (ie, self-concept, anxiety, depression, anger and disruptive behaviour) in children and adolescents in Taiwan.

METHODS

A total of 564 first, fourth and seventh graders (314 children with overweight/obesity and 250 children with normal weight) completed an in-hospital health examination in 2010. All students received a physical examination, underwent blood sample collection and completed a questionnaire. Multiple linear regression analyses were performed for analyses.

RESULTS

Among the fourth and seventh graders (P=.003 and.001, respectively), the students with overweight/obesity displayed significantly higher levels of NO than those with normal weight; however, no difference was observed in males and females. In multiple linear regression models, a high level of anxiety was independently associated with low NO levels (β=-1.33, 95% confidence interval -2.24 to -0.41) in first graders who with overweight/obesity. No association between NO levels and psychological traits was evident among students with normal weight.

CONCLUSIONS

Our results enrich the limited data and suggest that NO may be associated with obesity and psychopathology and should be a concern in the pathophysiology of childhood mental health and obesity.

Frequency of stressful life events and associations with mental health and general subjective health in the general population

Aim

We aim to determine the frequency of stressful life events (SLEs) and investigate the association of single and aggregated SLEs with mental health and general subjective health, which has not been reported for an aging representative sample to date.

Subjects and methods

A total of 12,947 participants (35–74 years old) of the Gutenberg Health Study (GHS) in Germany were analyzed. SLEs were analyzed at the item and aggregated level with unweighted and weighted sum scores. Additionally, the survey included measures of mental health, general subjective health and demographics. Descriptive analyses were stratified by sex, age and socioeconomic status.

Results

Multivariate analyses of variance with SLE at the item level revealed large main effects for sex (ηp2 = 0.30) and age (ηp2 = 0.30); a moderate effect was found for socioeconomic status (ηp2 = 0.08). Interaction effects of sex with age and SES were also significant, but with negligible effect sizes. Regression analyses revealed similar results for unweighted and weighted SLE sum scores controlling for sociodemographic variables, supporting the detrimental relations among cumulated SLEs, depression (β = 0.18/0.19) and anxiety (β =0.17/0.17), but not general health. Mental health indicators showed the highest correlations with single SLEs such as change of sleep habits or personal finances. Severe SLEs according to proposed weight scores showed no or only weak associations with mental health.

Conclusion

Representative data support a more distinct impact of SLEs on mental health than on general health. Single SLEs show strong associations with mental health outcome (e.g., change of sleep habits). The low associations between severe single SLEs and mental health merit further attention.

Exposure to common infections and risk of suicide and self-harm: a longitudinal general population study

Common infectious agents, such as Toxoplasma gondii (T. gondii) and several human herpes viruses, have been linked to increased risk of self-harm. The aim of this study was to investigate the associations between self-harm and seropositivity to T. gondii, Epstein-Barr virus (EBV), Herpes Simplex virus Type 1 (HSV-1), and Cytomegalovirus (CMV). IgM and IgG antibodies to these infections were measured in the Health 2000 project nationally representative of the whole Finnish adult population, and 6250 participants, age 30 and over, were followed for 15 years via registers. In addition, lifetime suicidal ideation and suicide attempts based on medical records and interview were assessed within a subsample of 694 participants screened to a substudy for possible psychotic symptoms or as controls. Among the 6250 participants, 14 individuals died of suicide and an additional 4 individuals had a diagnosis of intentional self-harm during follow-up. Serological evidence of lifetime or acute infections was not found to be associated with these suicidal outcomes. However, in the subsample, those seropositive for CMV had fewer suicide attempts compared to those seronegative, adjusting for gender, age, educational level, childhood family size, regional residence, CRP, and screen status (OR for multiple attempts = 0.40, 95% confidence interval 0.20‒0.83, p = 0.014). To conclude, common infections were not associated with risk of death by suicide or with self-harm diagnoses at a 15-year follow-up in the general population sample. Our finding of an increased number of suicide attempts among persons seronegative for CMV calls for further research.

Stress-system activation in children with chronic pain: A focus for clinical intervention

Accumulating evidence indicates that psychological and neurophysiological processes interconnect and interact to activate the body's stress system and to trigger and maintain functional somatic symptoms. This study used the Early Life Stress Questionnaire, Depression Anxiety Stress Scales and biological markers (heart rate, heart rate variability, skin conductance, C-reactive protein (CRP) titre, respiratory rate, and accuracy and reaction time in an emotion-face identification task), to examine childhood adversity, psychological distress and stress-system activation in 35 children and adolescents (23 girls and 12 boys, 9-17 years old) disabled by chronic pain (vs two groups of age- and sex-matched healthy controls). Patients reported more early-life stress (U = 798.5, p = .026) and more psychological distress (U = 978, p < .001). They showed activation of the autonomic system: elevated heart rate (U = 862.5, p = .003), elevated electrodermal activity (U = 804.5, p = .024) and lower heart rate variability in the time domain (U = 380.5, p = .007) and frequency domain (U = 409.5, p = .017). The group showed an upward shift of CRP titres (with 75th and 90th CRP percentiles of 4.5 and 10.5 mg/L, respectively), suggesting the activation of the immune-inflammatory system. Elevated CRP titres were associated with elevated heart rate (p = .028). There were no differences in respiratory rate or in accuracy and reaction time in the emotion-face identification task. The results indicate that interventions for children and adolescents with chronic pain need a multidisciplinary mind-body approach that concurrently addresses psychological distress, physical impairment and stress-system dysregulation.

A healthy peer status: Peer preference, not popularity, predicts lower systemic inflammation in adolescence

In adolescence, sensitivity to peers is heightened, which makes peer experiences highly salient. Recent work suggests that these experiences may influence individuals' immune system functioning. Although there is a need to investigate which types of developmental salient social experiences affect inflammation, no studies have examined the role of peer status in inflammatory activity so far. This study is the first to examine the unique role of different types of peer status (i.e., peer preference and peer popularity) on systemic inflammation in adolescence, and the extent to which this association is moderated by early childhood adversity. Participants were 587 Dutch adolescents from the TRacking Adolescents´ Individual Lives Survey (TRAILS). Data were collected when participants were 11 (SD = .56), 13 (SD = .53) and 16 (SD = .71) years old, respectively. At age 11, early childhood adversity (e.g., hospitalization, death within the family) between 0-5 years was assessed via parent interviews. At age 13, peer preference and peer popularity were assessed with peer nominations of classmates. At age 16, high sensitive C-reactive protein (hsCRP), a marker of low-grade systemic inflammation, was assessed with a venipuncture blood draw. Results showed that adolescents who were rated low on peer preference at age 13 exhibited higher levels of hsCRP at age 16. Importantly, these effects remained after controlling for several covariates, including age, sex, peer victimization, smoking behavior, SES, fat percentage, physical activity and temperament. Additionally, we found a positive effect of peer popularity on hsCRP that depended on early childhood adversity exposure. This suggests that for those adolescents who experienced little early childhood adversity, high levels of peer popularity were associated with high levels of hsCRP. Overall, these findings suggest that it is important to take into account the independent roles of peer preference and peer popularity, as specific types of peer status, to better understand adolescent systemic inflammation.

Blood CRP levels are elevated in children and adolescents with functional neurological symptom disorder

There is accumulating evidence that patients with functional neurological symptom disorder (FND) show activation of multiple components of the stress system-the hypothalamic-pituitary-adrenal axis, autonomic nervous system, and brain regions involved in arousal- and emotion-processing. This study aims to examine whether the immune-inflammatory component of the stress system is also activated. C-reactive protein (CRP) blood titre levels were measured in 79 children and adolescents with FND. CRP values ≥ 2 mg/L suggest low-grade inflammation. CRP values > 10 mg/L suggest a disease process. Sixty-six percent of subjects (n = 52) had CRP titres ≥ 2 mg/L. The upward shift in the distribution of CRP levels suggested low-grade inflammation (median CRP concentration was 4.60 mg/L, with 75th and 90th percentiles of 6.1 and 10.3 mg/L, respectively). Elevated CRP titres were not explained by sex, pubertal status, BMI, or medical factors. Confounder analyses suggested that history of maltreatment (χ² = 2.802, df = 1, p = 0.094, φ = 0.190; β = 2.823, p = 0.04) and a diagnosis of anxiety (χ² = 2.731, df = 1, p = 0.098, φ = 0.187; β = 4.520, p = 0.061) contributed to elevated CRP levels. Future research will need to identify the origins and locations of immune cell activation and the pathways and systems contributing to their activation and modulation. Because functional activity in neurons and glial cells-the brain's innate effector immune cells-is tightly coupled, our finding of elevated CRP titres suggests activation of the immune-inflammatory component of the brain's stress system. A more direct examination of inflammation-related molecules in the brain will help clarify the role of immune-inflammatory processes in FND.

Early childhood family instability and immune system dysregulation in adolescence

Exposure to stress is one way in which social disadvantages during childhood may alter biological and psychological systems with long-term consequences. Family social and economic conditions are critical for early childhood development and exposure to difficult family conditions may have lasting physiological effects. However, there is little research linking early childhood conditions with physiological indicators of stress and system dysregulation in adolescence. In this study, we assess how family social and economic instability that occurred in early childhood (birth to age 5) is associated with immune system dysregulation in adolescence, as indicated by DNA shedding of the Epstein-Barr virus (EBV). We utilize a biomarker of EBV obtained through saliva, a non-invasive method of collecting immune-system biomarkers, in 674 adolescents 11-17 years old. Multivariable regression results indicated that experiences of moving into a new parent/caregiver household or moving in with a grandparent during early childhood was associated with an estimated 100% increase in EBV DNA shedding among prior EBV-infected adolescents. Other measures of early childhood family instability, total number of family structure changes and economic insecurity, were marginally significant. Contemporaneous family conditions were not associated with adolescents' EBV DNA shedding.

Screening for childhood adversity: the what and when of identifying individuals at risk for lifespan health disparities

Existing research on childhood adversity and health risk across the lifespan lacks specificity regarding which types of exposures to assess and when. The purpose of this study was to contribute to an empirically-supported framework to guide practitioners interested in identifying youth who may be at greatest risk for a lifelong trajectory of health disparities. We also sought to identify the point in childhood at which screening for adversity exposure would capture the largest group of at risk individuals for triage to prevention and intervention services. Participants (n = 4036) collected as part of the Midlife in the United States study reported their medical status and history including physical (cardiovascular disease, hypertension, obesity, diabetes, cancer) and mental health (depression, substance use problems, sleep problems). Participants indicated whether they were exposed to 7 adversities at any point in childhood and their age of exposure to 19 additional lifetime adversities before the age of 18. Parent drug abuse, dropping out or failing out of school, being fired from a job, and sexual assault during childhood exhibited the largest effect sizes on health in adulthood, which were comparable to the effects of childhood maltreatment. Childhood adversity screening in early adolescence may identify the largest proportion of youth at risk for negative health trajectories. The results of this descriptive analysis provide an empirical framework to guide screening for childhood adversity in pediatric populations. We discuss the implications of these observations in the context of prevention science and practice.

The association between herpes virus infections and functional somatic symptoms in a general population of adolescents. The TRAILS study

Background

FSS have been suggested to follow activation of the immune system, triggered by herpes virus infections. The aim of this study was to find out whether herpes virus infections were associated with the experience of FSS in adolescents, and whether this association was mediated by hsCRP, as a general marker of immune activation.

Methods

This study was performed in TRAILS, a large prospective population cohort of 2230 adolescents (mean age: 16.1 years, SD = .66, 53.4% girls). FSS were assessed using the somatic complaints subscale of the Youth Self-Report. FSS were analyzed as total scores and divided in two group clusters based on previous studies in this cohort. Levels of hsCRP and antibody levels to the herpes viruses HSV1, HSV2, CMV, EBV and HHV6 were assessed in blood samples at age 16. Also a value for pathogen burden was created adding the number of viruses the adolescents were seropositive for. Multiple regression analysis with bootstrapping was used to analyze the association between viral antibodies and pathogen burden, hsCRP and FSS scores.

Results

Antibody levels and pathogen burden were not associated with FSS total scores or FSS scores in both symptom groups. hsCRP was associated with the total FSS score (B = .02, 95% CI: .004 to .028, p = .01) and FSS score in the symptom group of headache and gastrointestinal complaints (B = .02, 95% CI: .001 to .039, p = .04).

Conclusion

Our study showed no association between herpes virus infections and FSS in general or specific FSS symptom clusters. A role for inflammatory processes in FSS development was supported by the significant association we found between hsCRP levels and FSS, especially in the symptom group of headache and gastrointestinal complaints.