Autonomic, neuroendocrine, and immune responses to psychological stress: the reactivity hypothesis

Associations between adolescent perceived loneliness and hair cortisol concentration

INTRODUCTION

Adolescents experience high levels of loneliness, which is linked to poor health in adulthood. Loneliness may contribute to poor health through chronic dysregulation of the hypothalamic-pituitary-adrenal axis. In this analysis, we examined the associations between survey- and ecological momentary assessment (EMA)-based measures of loneliness and hair cortisol concentrations (HCC) in a sample of 1102 adolescents and assessed sex differences in this relationship.

METHODS

Data came from wave 1 of the Adolescent Health and Development in Context study. We conducted a series of multivariable linear regression models to examine the associations between loneliness and HCC. Models were adjusted for adolescent and caregiver demographics, adolescent clinical factors, adolescent hair care practices, and adolescent lifetime mental health diagnosis and current psychotropic medication use. An interaction term between sex and loneliness was added to assess for effect moderation.

RESULTS

In our sample, the mean HCC was 1.35 pg/mg (SD=1.1). The mean for the unstandardized survey loneliness measure was 1.79 (SD=0.79) for the total analytic sample. The unstandardized mean for the EMA loneliness measure was - 0.02 (SD=2.1) for the total analytic sample. In model one testing the bivariate linear relationship between loneliness and HCC, higher loneliness via survey and EMA measures was associated with lower HCC (Survey: b= - 0.10, SE=0.03, p=.004; EMA: b= - 0.09, SE=0.03, p=.005). In model two, higher loneliness remained significantly associated with lower HCC (Survey: b= - 0.07, SE=0.03, p=.023; EMA: b= - 0.07, SE=0.03, p=.037), after controlling for the following covariates: sociodemographic factors, pubertal development and BMI, corticosteroid use, hair care practices, season of collection and assayed hair length. In model 3, youth lifetime mental health diagnosis and current psychotropic medication use were added into the regression model, and higher loneliness remained significantly associated with lower HCC (Survey: b= - 0.07, SE=0.03, p=.029; EMA: b= - 0.07, SE=0.03, p=.039). There was no effect modification by sex (Survey: b=0.04, SE=0.06, p=.552; EMA: b= - 0.01, SE=0.06, p=.843).

CONCLUSIONS

In our analysis, both survey- and EMA-reported loneliness measures were associated with lower HCC. No evidence of an interaction between sex and loneliness was observed. Future research is needed to validate these findings and investigate longitudinal relationships among adolescent loneliness, stress physiology, and downstream health sequelae.

When virtual reality becomes psychoneuroendocrine reality: A stress(or) review

This review article was awarded the Dirk Hellhammer award from ISPNE in 2023. It explores the dynamic relationship between stressors and stress from a historical view as well as a vision towards the future of stress research via virtual reality (VR). We introduce the concept of a "syncytium," a permeable boundary that blurs the distinction between stress and stressor, in order to understand why the field of stress biology continues to inadequately measure stress alone as a proxy for the force of external stressors. Using Virtual Reality (VR) as an illustrative example to explicate the black box of stressors, we examine the distinction between 'immersion' and 'presence' as analogous terms for stressor and stress, respectively. We argue that the conventional psychological approaches to stress measurement and appraisal theory unfortunately fall short in quantifying the force of the stressor, leading to reverse causality fallacies. Further, the concept of affordances is introduced as an ecological or holistic tool to measure and design a stressor's force, bridging the gap between the external environment and an individual's physiological response to stress. Affordances also serve to ameliorate shortcomings in stress appraisal by integrating ecological interdependencies. By combining VR and psychobiological measures, this paper aims to unravel the complexity of the stressor-stress syncytium, highlighting the necessity of assessing both the internal and external facets to gain a holistic understanding of stress physiology and shift away from reverse causality reasoning. We find that the utility of VR extends beyond presence to include affordance-based measures of immersion, which can effectively model stressor force. Future research should prioritize the development of tools that can measure both immersion and presence, thereby providing a more comprehensive understanding of how external stressors interact with individual psychological states.

Quantifying the accuracy of inter-beat intervals acquired from consumer-grade photoplethysmography wristbands using an electrocardiogram-aided information-based similarity approach

Objective. Although inter-beat intervals (IBI) and the derived heart rate variability (HRV) can be acquired through consumer-grade photoplethysmography (PPG) wristbands and have been applied in a variety of physiological and psychophysiological conditions, their accuracy is still unsatisfactory.Approach.In this study, 30 healthy participants concurrently wore two wristbands (E4 and Honor 5) and a gold-standard electrocardiogram (ECG) device under four conditions: resting, deep breathing with a frequency of 0.17 Hz and 0.1 Hz, and mental stress tasks. To quantitatively validate the accuracy of IBI acquired from PPG wristbands, this study proposed to apply an information-based similarity (IBS) approach to quantify the pattern similarity of the underlying dynamical temporal structures embedded in IBI time series simultaneously recorded using PPG wristbands and the ECG system. The occurrence frequency of basic patterns and their rankings were analyzed to calculate the IBS distance from gold-standard IBI, and to further calculate the signal-to-noise ratio (SNR) of the wristband IBI time series.Main results.The accuracies of both HRV and mental state classification were not satisfactory due to the low SNR in the wristband IBI. However, by rejecting data segments of SNR < 25, the Pearson correlation coefficients between the wristbands' HRV and the gold-standard HRV were increased from 0.542 ± 0.235 to 0.922 ± 0.120 for E4 and from 0.596 ± 0.227 to 0.859 ± 0.145 for Honor 5. The average accuracy of four-class mental state classification increased from 77.3% to 81.9% for E4 and from 79.3% to 83.3% for Honor 5.Significance.Consumer-grade PPG wristbands are acceptable for HR and HRV monitoring when removing low SNR segments. The proposed method can be applied for quantifying the accuracies of IBI and HRV indices acquired via any non-ECG system.

Autonomic nervous system flexibility for understanding brain aging

A recent call was made for autonomic nervous system (ANS) measures as digital health markers for early detection of Alzheimer's disease and related dementia (AD/ADRD). Nevertheless, contradictory or inconclusive findings exist. To help advance understanding of ANS' role in dementia, we draw upon aging and dementia-related literature, and propose a framework that centers on the role of ANS flexibility to guide future work on application of ANS function to differentiating the degree and type of dementia-related brain pathologies. We first provide a brief review of literature within the past 10 years on ANS and dementia-related brain pathologies. Next, we present an ANS flexibility model, describing how the model can be applied to understand these brain pathologies, as well as differentiate or even be leveraged to modify typical brain aging and dementia. Lastly, we briefly discuss the implication of the model for understanding resilience and vulnerability to dementia-related outcomes.

Do Mental Health Changes in Nature Co-occur with Changes in Heartrate Variability and Executive Functioning? A Systematic Review

PURPOSE OF REVIEW

Given the global burden of mental health issues, new solutions are needed to promote mental health. Nature exposure represents a promising option to promote mental health, but the mechanisms are poorly understood. Recent frameworks have argued that changes in mental health in nature are caused by activity changes in the vagus nerve, which connects the heart and the brain, and that these changes also improve executive functioning (EF) abilities. This suggests that changes in mental health symptomology in nature should be accompanied by changes in vagus nerve activity, as well as changes in executive functioning. Yet, little work has systematically examined co-variation of these outcomes in empirical studies. The present manuscript systematically examines whether changes in mental health in nature are accompanied by changes in vagus nerve activity (approximated by heartrate variability) and changes in executive functioning.

RECENT FINDINGS

There is compelling evidence that spending time in nature can increase heartrate variability, improve mental health, and improve executive functioning. However, despite strong theoretical claims that these three outcomes should be linked after spending time in nature settings, few studies directly examine such co-occurrence. The study systematically examines whether studies that considered both mental health and executive functioning (n = 6) showed co-occurring effects in response to nature exposure. Similarly, the study also considers if studies examining mental health and heartrate variability (n = 6) showed similarly directional effects following nature exposure. This systematic review concludes with discussion about the limited number of studies (n =1) that include all three measures. We find mixed results of co-occurrence with these variables, suggesting that the relationship between these three constructs in nature may be more nuanced than current theory suggests. Perhaps more importantly, our results demonstrate that there is very little existing work linking changes in mental health to changes in EF and vagal tone. We conclude with justification for why it may be beneficial for researchers to include all three metrics as well as guidance on how to do so.

Individual differences in social homeostasis

The concept of “social homeostasis”, introduced by Matthews and Tye in 2019, has provided a framework with which to consider our changing individual needs for social interaction, and the neurobiology underlying this system. This model was conceived as including detector systems, a control center with a setpoint, and effectors which allow us to seek out or avoid additional social contact. In this article, we review and theorize about the many different factors that might contribute to the setpoint of a person or animal, including individual, social, cultural, and other environmental factors. We conclude with a consideration of the empirical challenges of this exciting new model.

Coordination of autonomic and endocrine stress responses to the Trier Social Stress Test in adolescence

Dysregulations in autonomic and endocrine stress responses are linked to the emergence of psychopathology in adolescence. However, most studies fail to consider the interplay between these systems giving rise to conflicting findings and a gap in understanding adolescent stress response regulation. A multisystem framework-investigation of parasympathetic (PNS), sympathetic (SNS), and hypothalamic pituitary adrenal (HPA) axis components and their coordination-is necessary to understand individual differences in stress response coordination which contribute to stress vulnerabilities. As the first investigation to comprehensively evaluate these three systems in adolescence, the current study employed the Trier Social Stress Test in 72 typically developing adolescents (mean age = 13) to address how PNS, SNS, and HPA stress responses are coordinated in adolescence. Hypotheses tested key predictions of the Adaptive Calibration Model (ACM) of stress response coordination. PNS and SNS responses were assessed via heart rate variability (HRV) and salivary alpha amylase (sAA) respectively. HPA responses were indexed by salivary cortisol. Analyses utilized piecewise growth curve modeling to investigate these aims. Supporting the ACM theory, there was significant hierarchical coordination between the systems such that those with low HRV had higher sAA and cortisol reactivity and those with high HRV had low-to-moderate sAA and cortisol responsivity. Our novel results reveal the necessity of studying multisystem dynamics in an integrative fashion to uncover the true mechanisms of stress response and regulation during development. Additionally, our findings support the existence of characteristic stress response profiles as predicted by the ACM model.

Metabolomics Based on Peripheral Blood Mononuclear Cells to Dissect the Mechanisms of Chaigui Granules for Treating Depression

Chaigui granules were a traditional Chinese medicine (TCM) preparation with antidepressant effects derived from a famous antidepressant prescription. It was of great significance to clarify the antidepressant mechanism of Chaigui granules for the clinical application of this drug. In this study, a chronic unpredictable mild stress (CUMS) depression model was successfully established, and behavioral indicators were used to evaluate the antidepressant effect. Second, the CD4+, CD8+, and CD4+/CD8+ levels were detected in peripheral blood. Meanwhile, the amount of inflammatory cytokines was determined in serum. Correspondingly, LC/MS-based peripheral blood mononuclear cell (PBMC) metabolomics was used to investigate vital metabolic pathways participating in the antidepressive effects of Chaigui granules. Finally, bioinformatics technology was further employed to discover the potential antidepressant mechanism of Chaigui granules regulating the immune system. The results suggested that the administration of Chaigui granules significantly improved CUMS-induced depressive symptoms. Chaigui granules could improve immune function by regulating T lymphocyte subsets, increasing anti-inflammatory cytokine levels of IL-2 and IL-10, and reducing pro-inflammatory cytokine levels of TNF-α, IL-1β, and IL-6. In addition, metabolomics results of PBMCs showed that Chaigui granules improved 14 of the 25 potential biomarkers induced by CUMS. Metabolic pathway analyses indicated that purine metabolism was the critical metabolic pathway regulated by Chaigui granules. Furthermore, correlation analysis indicated that 13 key biomarkers were related to immune-related indicators. The metabolite-gene network of 13 key biomarkers was investigated by using bioinformatics. The investigation showed that 10 targets (5'-nucleotidase ecto; 5'-nucleotidase, cytosolic IB; 5'-nucleotidase, cytosolic II; etc.), mainly belong to the purine metabolism, might be potential targets for Chaigui granules to exert their antidepressant effects by improving immune function impairment. Together, our results suggested that Chaigui granules might exert antidepressant effects by improving immune function and regulating the purine metabolic pathway in PBMCs. This work used PBMCs metabolomics as an entry point to study the antidepressant mechanism of Chaigui granules, which provided a new way to elucidate the mechanism of a traditional Chinese medicine prescription.

Childhood adversity modulation of central autonomic network components during cognitive regulation of emotion in major depressive disorder and borderline personality disorder

Adverse childhood experiences (ACEs) have lifelong effects on emotional behavior and are frequent in Borderline Personality Disorder (BPD) and Major Depressive Disorder (MDD). The Central Autonomic Network (CAN), which modulates heart rate variability (HRV), comprises brain regions that mediate emotion regulation processes. However, it remains unclear the effect of ACEs on CAN dynamics and its relationship with HRV in these disorders. We studied the effects of ACEs on the brain and HRV simultaneously, during regulation of psychological stress in 19 BPD, 20 MDD and 20 healthy controls (HC). Participants underwent a cognitive reappraisal task during fMRI with simultaneous ECG acquisition. ACEs exposure was associated with increased activity of CAN and salience network components in patients with MDD compared to BPD during cognitive reappraisal. A brain-autonomic coupling was found in BPD relative to HC during emotion regulation, whereby greater activity of left anterior cingulate and medial superior frontal gyrus areas was coupled with increased HRV. Results suggest that ACEs exposure is associated with a distinct activation of the CAN and salience network regions governing responses to psychological stress in MDD compared to BPD. These alterations may constitute a distinctive neurobiological mechanism for abnormal emotion processing and regulation related to ACEs in MDD.

Understanding the cross-talk between mediators of infertility and COVID-19

COVID-19 is the ongoing health emergency affecting individuals of all ages around the globe. Initially, the infection was reported to affect pulmonary structures. However, recent studies have delineated the impacts of COVID-19 on the reproductive system of both men and women. Hence, the present review aims to shed light on the distribution of SARS-CoV-2 entry factors in various reproductive organs. In addition, impacts of COVID-19 mediators like disrupted renin angiotensin system, oxidative stress, cytokine storm, fever, and the mental stress on reproductive physiology have also been discussed. For the present study, various keywords were used to search literature on PubMed, ScienceDirect, and Google Scholar databases. Articles were screened for relevancy and were studied in detail for qualitative synthesis of the review. Through our literature review, we found a multitude of effects of COVID-19 mediators on reproductive systems. Studies reported expression of receptors like ACE-2, TMPRSS2, and CD147 in the testes, epididymis, prostrate, seminal vesicles, and ovarian follicles. These proteins are known to serve as major SARS-CoV-2 entry factors. The expression of lysosomal cathepsins (CTSB/CTSL) and/ neuropilin-1 (NRP-1) are also evident in the testes, epididymis, seminal vesicles, fallopian tube, cervix, and endometrium. The binding of viral spike protein with ACE-2 was found to alter the renin-angiotensin cascade, which could invite additional infertility problems. Furthermore, COVID-19 mediated cytokine storm, oxidative stress, and elevated body temperature could be detrimental to gametogenesis, steroidogenesis, and reproductive cycles in patients. Finally, social isolation, confinement, and job insecurities have fueled mental stress and frustration that might promote glucocorticoid-mediated subnormal sperm quality in men and higher risk of miscarriage in women. Hence, the influence of COVID-19 on the alteration of reproductive health and fertility is quite apparent.

Predicting Hair Cortisol and Cortisone Concentration in Postpartum Women through Repeated Measurements of Perceived Stress

To investigate whether hair cortisol (HCC) and hair cortisone (HCNC) can be predicted by repeated stress reports from postpartum women in different mental health conditions (non-depressed, ND, adjustment disorder, AD, postpartum depression, PPD), 240 mothers (mean age 31.8 years; SD = 4.7) were monitored from within 1 to 6 days of childbirth over a period of three months. HCC and HCNC in 3 cm hair samples were assessed via triple mass spectrometry after liquid chromatographic separation. Every second day, participants reported their stress levels online. The summed perceived stress scores were not found to be predictive of HCC. However, perceived stress predicted a decrease in HCNC (r_Spearman = -0.153, p = 0.035) and an increase in the HCC/HCNC ratio (r_Spearman = 0.304, p < 0.001) in the ND group. With AD in the first few weeks after childbirth, an inverse effect appeared for HCNC (r_Spearman = 0.318, p = 0.011), suggesting an overall downregulation of the HPA axis owing to the stressful experience of adjusting to the new situation. No effects were found for mothers developing PPD. The indirect results of HPA-axis activity are better indicators of the experience of psychological stress in postpartum women than the absolute HCC value.

Cardiovascular Stress Reactivity and Health: Recent Questions and Future Directions

OBJECTIVE

High cardiovascular reactions to psychological stress are associated with the development of hypertension, systemic atherosclerosis, and cardiovascular disease. However, it has become apparent that low biological stress reactivity also may have serious consequences for health, although less is known about the mechanisms of this. The objectives of this narrative review and opinion article are to summarize and consider where we are now in terms of the usefulness of the reactivity hypothesis and reactivity research, given that both ends of the reactivity spectrum seem to be associated with poor health, and to address some of the key criticisms and future challenges for the research area.

METHODS

This review is authored by the members of a panel discussion held at the American Psychosomatic Society meeting in 2019, which included questions such as the following: How do we measure high and low reactivity? Can high reactivity ever indicate better health? Does low or blunted reactivity simply reflect less effort on task challenges? Where does low reactivity originate from, and what is a low reactor?

RESULTS

Cardiovascular (and cortisol) stress reactivity are used as a model to demonstrate an increased understanding of the different individual pathways from stress responses to health/disease and show the challenges of how to understand and best use the reconstruction of the long-standing reactivity hypothesis given recent data.

CONCLUSIONS

This discussion elucidates the gaps in knowledge and key research issues that still remain to be addressed in this field, and that systematic reviews and meta-analyses continue to be required.

Low self-reported stress despite immune-physiological changes in paramedics during rescue operations

Despite the high stress levels, paramedics seem to ignore or even negate the stress. This can be detrimental and lead to stress-related diseases. Therefore, we investigated the divergence between physiological and psychological stress responses of paramedics. Participants were 16 paramedics and 17 white-collar workers. We assessed psychological stress parameters, cortisol awakening response (CAR), and quantified immune parameters. In paramedics, electrocardiogram (ECG) was measured during one complete 24-hour shift. Our results revealed that CAR was higher in paramedics compared to controls. An alteration of immune parameters was observed even during days of free time. Also, ECG recordings showed acute stress in paramedics during rescue situations. Questionnaires revealed that rescue-service specific stressors affect psychological outcomes. However, paramedics reported significantly less mental stress and higher levels of depersonalization than controls. Taken together, our results suggest higher stress in paramedics compared to controls. However, paramedics negate their daily stress. Our findings underline therefore the importance to develop stress-management interventions for paramedics including sensitization for their stress reactions.

Externalizing and Internalizing Problems: Associations with Family Adversity and Young Children's Adrenocortical and Autonomic Functioning

The development of child mental health problems has been associated with experiences of adversity and dysregulation of stress response systems; however, past research has largely focused on externalizing or internalizing problems (rather than their co-occurrence) and single physiological systems in high-risk adolescent samples. The present study examined whether cumulative family adversity, functioning in the hypothalamic-pituitary-adrenal axis (i.e., cortisol) and the parasympathetic nervous system (i.e., respiratory sinus arrhythmia [RSA]), and their interactions, predicted trajectories of co-occurring externalizing and internalizing problems among young children. Participants included 338 socioeconomically and racially diverse children (M age = 5.32 years, SD = .32; male = 51.8%) from a community sample. Family adversity (assessed with six measures) and child daily cortisol output and resting RSA were assessed in kindergarten. Parents, teachers, and children reported on children's externalizing and internalizing psychopathology up to three times from kindergarten to grade 1. Latent class growth analyses identified stable trajectories of externalizing and internalizing psychopathology. Trajectories were combined to create groups: co-occurring externalizing and internalizing (13.1%), externalizing-only (14.0%), internalizing-only (11.3%), and low problems (61.3%). Family adversity and resting RSA significantly positively predicted co-occurring group membership. Tests for interactions showed adversity did not significantly interact with physiological indicators to predict group membership. However, the two physiological systems interacted, such that higher and lower daily cortisol predicted internalizing group membership for children with lower and higher resting RSA, respectively. Findings support the importance of considering family context and multiple physiological systems to inform understanding of the development of mental health problems, and their co-occurrence, in early childhood.

The autonomic nervous system in its natural environment: Immersion in nature is associated with changes in heart rate and heart rate variability

Stress Recovery Theory (SRT) suggests that time spent in nature reduces stress. While many studies have examined changes in stress physiology after exposure to nature imagery, nature virtual reality, or nature walks, this study is the first to examine changes in heart rate (HR) and vagally mediated HR variability, as assessed by Respiratory Sinus Arrythmia (RSA), after a longer duration of nature exposure. Consistent with SRT, we hypothesized that immersion in nature would promote stress recovery, as indexed by an increase in RSA and a decrease in HR. We also predicted that exposure to nature would improve self-reported mood. We used a within-subjects design (N = 67) to assess changes in peripheral physiology before, during, and after a 5-day nature trip. Results demonstrated a significant decrease in RSA and a significant increase in HR during the trip compared to before or after the trip, suggesting that immersion in nature is associated with a shift toward parasympathetic withdrawal and possible sympathetic activation. These results were contrary to our hypotheses and may suggest increased attentional intake or presence of emotions associated with an increase in sympathetic activation. We also found an improvement in self-reported measures of mood during the trip compared to before or after the trip, confirming our hypotheses and replicating previous research. Implications of this study are discussed in the context of SRT.

Effect of Supplementation with Saccharomyces Boulardii on Academic Examination Performance and Related Stress in Healthy Medical Students: A Randomized, Double-Blind, Placebo-Controlled Trial

In recent years, bacterial probiotic dietary supplementation has emerged as a promising way to improve cognition and to alleviate stress and anxiety; however, yeast probiotics have not been tested. The aim of the present study was to determine whether 30-day supplementation with Saccharomyces boulardii enhances academic performance under stress and affects stress markers. The trial was retrospectively registered at clinicaltrials.gov (NCT03427515). Healthy medical students were randomized to supplement their diet with Saccharomyces boulardii CNCM I-1079 or placebo before sitting for an academic examination, which served as a model of stress. The grades of a final examination adjusted to subject knowledge tested in non-stressful conditions was used as a primary outcome measure. Psychometrically evaluated state anxiety, cortisol and metanephrine salivary levels, and pulse rate were tested at a non-stressful time point before the intervention as well as just before the stressor. Fifty enrolled participants (22.6 ± 1.4 years of age, 19 males) completed the trial in the Saccharomyces and placebo arms. Supplementation with Saccharomyces did not significantly modify examination performance or increase in state anxiety, salivary cortisol, and metanephrine. However, the intervention resulted in higher increase in pulse rate under stress as compared to placebo by 10.4 (95% CI 4.2–16.6) min⁻¹ (p = 0.0018), and the effect positively correlated with increase in salivary metanephrine (Pearson’s r = 0.35, 95% CI 0.09–0.58, p = 0.012). An intention-to-treat analysis was in line with the per-protocol one. In conclusion, supplementation with Saccharomyces boulardii CNCM I-1079 appears largely ineffective in improving academic performance under stress and in alleviating some stress markers, but it seems to increase pulse rate under stress, which may hypothetically reflect enhanced sympathoadrenal activity.

Role of neuroimmune circuits and pruritus in psoriasis

Psoriasis is a chronic inflammatory skin disease presenting with an array of clinical phenotypes, often associated with pruritus. Environmental and psychological stressors can exacerbate psoriasis symptoms and provoke flares. Recent studies suggest a dysfunctional hypothalamic-pituitary-adrenal (HPA) axis in some patients with psoriasis that can result in immune dysregulation. The immune system, in turn, can communicate with the nervous system to induce, maintain or aggravate psoriasis. In the skin, peripheral sensory as well as autonomic nerves control release of inflammatory mediators from dendritic cells, mast cells, T cells or keratinocytes, thereby modulating inflammatory responses and, in case of sensory nerves, pruritus. In response to the environment or stress, cytokines, chemokines, proteases, and neuropeptides fluctuate in psoriasis and influence immune responses as well as nerve activity. Furthermore, immune cells communicate with sensory nerves which control release of cytokines, such as IL-23, that are ultimately involved in psoriasis pathogenesis. Nerves also communicate with keratinocytes to induce epidermal proliferation. Notably, in contrast to recent years the debilitating problem of pruritus in psoriasis has been increasingly appreciated. Thus, investigating neuroimmune communication in psoriasis will not only expand our knowledge about the impact of sensory nerves in inflammation and pruritus and give new insights into the impact of environmental factors activating neuroimmune circuits or of stress in psoriasis, but may also lead to novel therapies. This review summarizes the relevant literature on the role of neuroimmune circuits, stress and how the central HPA axis and its peripheral equivalent in the skin, impact psoriasis.

Stress hypothesis overload: 131 hypotheses exploring the role of stress in tradeoffs, transitions, and health

Stress is ubiquitous and thus, not surprisingly, many hypotheses and models have been created to better study the role stress plays in life. Stress spans fields and is found in the literature of biology, psychology, psychophysiology, sociology, economics, and medicine, just to name a few. Stress, and the hypothalamic-pituitaryadrenal/interrenal (HPA/I) axis and sympathetic nervous system (SNS), are involved in a multitude of behaviors and physiological processes, including life-history and ecological tradeoffs, developmental transitions, health, and survival. The goal of this review is to highlight and summarize the large number of available hypotheses and models, to aid in comparative and interdisciplinary thinking, and to increase reproducibility by a) discouraging hypothesizing after results are known (HARKing) and b) encouraging a priori hypothesis testing. For this review I collected 214 published hypotheses or models dealing broadly with stress. In the main paper, I summarized and categorized 131 of those hypotheses and models which made direct connections among stress and/or HPA/I and SNS, tradeoffs, transitions, and health. Of those 131, the majority made predictions about reproduction (n = 43), the transition from health to disease (n = 38), development (n = 23), and stress coping (n = 18). Additional hypotheses were classified as stage-spanning or models (n = 37). The additional 83 hypotheses found during searches were tangentially related, or pertained to immune function or oxidative stress, and these are listed separately. Many of the hypotheses share underlying rationale and suggest similar, if not identical, predictions, and are thus not mutually exclusive; some hypotheses spanned classification categories. Some of the hypotheses have been tested multiple times, whereas others have only been examined a few times. It is the hope that multi-disciplinary stress researchers will begin to harmonize their naming of hypotheses in the literature so as to build a clearer picture of how stress impacts various outcomes across fields. The paper concludes with some considerations and recommendations for robust testing of stress hypotheses.

Maternal Affect During a Challenging Mother-Child Interaction: The Effects of Broad Autism Phenotype and Respiratory Sinus Arrhythmia Reactivity in Mothers of Children With and Without Autism Spectrum Disorder

Respiratory sinus arrhythmia (RSA) is proposed to index cognitive and behavioral inflexibility. Broad autism phenotype (BAP) traits are prevalent in family members of children with autism spectrum disorder (ASD). The study investigated whether RSA and BAP traits in mothers of typically developing (TD) children and mothers of children with ASD influence maternal affect. It was hypothesized that these factors would interact to influence mother-child interactions. Twenty-three mother-child dyads participated in a challenging interaction while measuring mother's RSA. Results indicated that mothers of children with ASD show different RSA reactivity than mothers of TD children. Furthermore, preliminary analyses revealed RSA reactivity moderated the relationship between mothers' rigidity and maternal affect during this interaction. Implications for future research and interventions are discussed.

Are Psycho-Behavioral Factors Accounting for Longevity?

The general objective of this article is to critically review the state of the art regarding current factors accounting for aging, longevity and successful longevity. There are two major constructs which most authors are employing to account for longevity: genetic or intrinsic components versus environmental or extrinsic factors. This classification has important flaws: (i) From an epigenetic standpoint, such a polar classification could lead to misconceptions since both factors are interdependent through lifelong interactions. (ii) There are no specifications regarding these “environmental” factors, which include a broad heterogeneity of conditions (physical, economic, social, and cultural aspects as well as behavioral ones such as lifestyle) but do not include personal conditions, such as psychological characteristics. The review of the new paradigm called successful aging yields an important set of psycho-behavioral factors, and although population indexes such as Disability Free Life Expectancy (DFLE) or Healthy Life expectancy (HLE) have been developed, authors do not take into consideration healthy or successful longevity as a potential prolongation of the new paradigm of active or successful aging. There is a broad corpus of research literature supporting the importance of psycho-behavioral (PB) factors intervening in the ways of aging, specifically intelligence and cognitive functioning, positive emotion and control, personality traits, psychosocial, physical conditions, and lifestyles, all of which are highly associated with active aging, health, longevity, and survival. The importance of these factors accounting for longevity, and successful longevity must be taken into consideration as a pending issue in gerontology.

Social-evaluative threat: Stress response stages and influences of biological sex and neuroticism

Social-evaluative threat (SET) - when the self could be negatively judged by others - can cause pronounced responses in the different stress systems: threat/challenge appraisal, the sympathetic (SNS) and parasympathetic (PNS) nervous systems, experienced motivation and affect, and the hypothalamus-pituitary-adrenal (HPA) axis. Here, we utilize a four-stage stress response model to shed light on the complex associations between different stress responses, where earlier stages are hypothesized to predict later stages. Additionally, we take into account important moderators, such as biological sex (controlling for menstrual cycle phase), personality traits (neuroticism and extraversion), and baseline stress levels. Thirty-seven men and 30 women in their luteal phase participated in an impromptu public speaking task to induce SET. Stress responses in four different stages were measured using: self-reported appraisal (threat or challenge, stage 1: S1), cardiovascular measures (pre-ejection period as SNS index, respiratory sinus arrhythmia as PNS index, S2), self-reported motivation and affect (state approach motivation, state anxiety, S3) and endocrine measures (cortisol as HPA index, S4). Stress reactivity was calculated by subtracting individual peaks from baseline. Results showed that SET induced pronounced stress reactivity in stages two to four. Against expectations, self-reported appraisal (S1) or motivation and affect (S3) did not predict later stress reactivity. As hypothesized, increased SNS (but not PNS) reactivity (S2) predicted increased HPA reactivity (S4). Bayesian model comparison confirmed the absence of sex differences in stress reactivity, likely due to controlling for menstrual cycle phase and sex differences in neuroticism levels. Higher trait neuroticism predicted blunted SNS (S2) and HPA (S4) reactivity, while higher baseline stress levels predicted blunted stages two and three reactivity overall. In conclusion, this rigorously controlled experiment partly supports and partly contradicts previous findings regarding associations between stress response stages, and offers new insight into the causes of blunted HPA responses in women.

Stress adaptation in older adults with and without cognitive impairment: an fMRI pattern-based similarity analysis

BACKGROUND

The capacity to adapt to environmental stressors is essential for older adults' health and well-being. It is unclear how cognitive impairment may disrupt the capacity. Here we examined the relationship between self-perceptions of stress and the neurobiological response to a laboratory model of stress adaptation in amnestic mild cognitive impairment (aMCI), a group at high risk for dementia.

RESULTS

aMCI group and cognitively healthy controls did not differ in neurobiological acute stress recovery (indexed by similarity in neural patterns at baseline and after recovery from cognitive challenges). However, compared to controls, aMCI group had significantly lower scores on PSS-PW. Notably, higher PSS-PW was associated with greater acute neural recovery in controls, but not aMCI.

METHODS

We assessed self-perceptions of stress adaptation with the Perceived Stress Scale subscales, measuring perceived helplessness (i.e., negatively worded items, PSS-NW) and self-efficacy (i.e., positively worded items, PSS-PW) in response to stress. At a subsequent laboratory fMRI visit, we indexed neurobiological stress adaptation by assessing and comparing functional network connectivity at baseline and immediately following, and after recovery from, cognitive challenges.

CONCLUSIONS

Studying stress adaptation in aMCI may shed light on pathways that contribute to the onset and progress of cognitive deterioration in aging.

Stressing the accuracy: Wrist-worn wearable sensor validation over different conditions

Wearable sensors are promising instruments for conducting both laboratory and ambulatory research in psychophysiology. However, scholars should be aware of their measurement error and the conditions in which accuracy is achieved. This study aimed to assess the accuracy of a wearable sensor designed for research purposes, the E4 wristband (Empatica, Milan, Italy), in measuring heart rate (HR), heart rate variability (HRV), and skin conductance (SC) over five laboratory conditions widely used in stress reactivity research (seated rest, paced breathing, orthostatic, Stroop, speech task) and two ecological conditions (slow walking, keyboard typing). Forty healthy participants concurrently wore the wristband and two gold standard measurement systems (i.e., electrocardiography and finger SC sensor). The wristband accuracy was determined by evaluating the signal quality and the correlations with and the Bland-Altman plots against gold standard-derived measurements. Moreover, exploratory analyses were performed to assess predictors of measurement error. Mean HR measures showed the best accuracy over all conditions. HRV measures showed satisfactory accuracy in seated rest, paced breathing, and recovery conditions but not in dynamic conditions, including speaking. Accuracy was diminished by wrist movements, cognitive and emotional stress, nonstationarity, and larger wrist circumferences. Wrist SC measures showed neither correlation nor visual resemblance with finger SC signal, suggesting that the two sites may reflect different phenomena. Future studies are needed to assess the responsivity of wrist SC to emotional and cognitive stress. Limitations and implications for laboratory and ambulatory research are discussed.

Female primary and secondary psychopathic variants show distinct endocrine and psychophysiological profiles

Research with predominantly male samples supports primary and secondary developmental pathways to psychopathy that are phenotypically indistinguishable on aggressive and antisocial behavior. The aim of this study was to examine whether female variants of psychopathy show divergent endocrine (i.e., cortisol, dehydroepiandrosterone [DHEA], testosterone, and their ratios) and psychophysiological (i.e., heart rate variability [HRV]) reactivity to social provocation. We also tested whether variants differed on reactive aggression when performing a competitive reaction time task against the fictitious participant who previously insulted them. Latent profile analyses on 101 undergraduate women oversampled for high psychopathic traits identified a high-anxious, maltreated secondary variant (n=64) and a low-anxious primary variant (n=37). Although variants did not differ on aggression, secondary variants showed higher cortisol, testosterone, cortisol-to-DHEA ratios, and HRV following social provocation relative to primary variants. Findings suggest that the neurobiological mechanisms underpinning aggression in psychopathy may differ between women on primary versus secondary developmental pathways.

Supportive hand-holding attenuates pupillary responses to stress in adult couples

BACKGROUND

Social relationships, particularly marriage, have been shown to ameliorate the potentially pathogenic impact of stressful events but prior research has been mostly aimed at downstream effects, with less research on real-time reactivity. Pupillometry is an innovative procedure that allows us to see the effects of acute stress in real time. The muscles that control pupil size are linked to the autonomic nervous system, so that when stressed, the pupils dilate; this occurs within 200ms. This quick response allows us to see the immediate effects of acute stress on the autonomic nervous system (ANS), and the real-time effects of social support in buffering stress.

PURPOSE

The purpose of this study is to examine the dampening effects of received social support on the ANS's pupillary response.

METHODS

Eighty individuals (40 couples) were randomly assigned to either a spousal support (i.e., spouse hand-holding) or non-support condition (i.e., alone) and administered a Stroop task while pupil dilation was measured.

RESULTS

The Stroop task elicited a stress reaction in terms of pupil dilation in response to the incongruent task trials. Participants in the support condition showed accelerated habituation to the stress task (p < .001), and less pupil reactivity (p < .001) providing evidence for buffering effects of social support via spousal presence and hand-holding.

CONCLUSIONS

These results reveal the speed at which stress-buffering occurs, suggesting that pupillometry could be a good method to address the immediate dampening effects of social support.

Sexual orientation and salivary alpha-amylase diurnal rhythms in a cohort of U.S. young adults

Sexual minorities in the United States are at elevated risk of prejudice, discrimination, and violence victimization due to stigma associated with their sexual orientation. These stressors may contribute to physiological stress responses and changes in the regulation of the sympathetic nervous system (SNS). To date, no studies have examined the associations among minority sexual orientation, recent stressful events, and diurnal salivary alpha-amylase (sAA) patterns. The present study included 1663 young adults ages 18-32 years (31% men, 69% women) from the Growing Up Today Study, a prospective cohort of U.S. youth. Participants provided five saliva samples over the course of one day to estimate diurnal sAA patterns. Sexual orientation groups included completely heterosexual with no same-sex partners (CH; referent), mostly heterosexual/completely heterosexual with same-sex partners, and gay/lesbian/bisexual (LB or GB). Sex-stratified multilevel models were fit to evaluate the association of sexual orientation with diurnal patterns of log sAA. The association of recent stressful events was also evaluated. Among women, sexual minorities scored significantly higher than CH on perceived stress and number of stressful events in the past month (p < 0.05). Among men, sexual minorities scored higher than CH on perceived stress but not recent stressful events. In multivariable models, recent stressful events were not associated with sAA patterns, but significant sexual orientation group differences in sAA diurnal rhythm were observed among women though not among men. Compared to CH women, LB showed a blunted awakening response and elevated sAA levels across the day, both indicators consistent with SNS dysregulation. Findings suggest dysregulation of stress physiology in LB women, but not other sexual minority women or men, relative to same-sex heterosexuals. Observed dysregulation may relate to exposure among LB women to chronic stressors associated with sexual orientation stigma, although these relations and differences by sex warrant further study.

Exploring the multidimensional complex systems structure of the stress response and its relation to health and sleep outcomes

To gain a comprehensive understanding of the multidimensional complex systems structure of the stress response and related health outcomes, we utilized network analysis in a sample of 328 healthy participants in two steps. In a first step, we focused on associations between measures of basal hypothalamic-pituitary-adrenal axis functioning and subjective stress perceptions. In a second step, we linked these diverse stress-related measures to biomarkers and self-reports of health and sleep. Overall, measures clustered depending on their method of assessment, with high correlations between different saliva-based indices of diurnal cortisol regulation, between cortisol and cortisone levels in hair, between different biological health indicators (systemic inflammatory activity and body mass index), between state (experience sampling) and trait (questionnaire-based) self-reports of stress and wellbeing, and between different self-reports of sleep. Bridges between clusters suggested that if individuals perceive stress throughout their daily lives this is reflected in their total salivary cortisol output possibly contributing to long-term cortisol accumulation in hair. Likewise, earlier awakening time may contribute to cortisol accumulation in hair via an influence on awakening cortisol processes. Our results show that while meaningful connections between measures exist, stress is a highly complex construct composed of numerous aspects. We argue that network analysis is an integrative statistical approach to address the multidimensionality of the stress response and its effects on the brain and body. This may help uncover pathways to stress-related disease and serve to identify starting points for prevention and therapeutic intervention.

Loneliness, HPA stress reactivity and social threat sensitivity: Analyzing naturalistic social challenges

Loneliness has been linked to poor health through an increased activation of threat surveillance mechanisms, such as the hypothalamic-pituitary-adrenal axis (HPA). The socio-cognitive model (Cacioppo & Hawley) proposes that lonely people have an increased social threat sensitivity which activates the HPA axis. The current study examined the impact of loneliness on HPA stress reactivity and social threat sensitivity in response to naturally occurring social challenges. Participants (N = 45) were prospective undergraduates attending a 3-day university preparation programme over the summer, prior to commencing their university studies. Cortisol levels and perceived stress were measured before and after an ice breaker session on Day 1 and a lecture session on Day 3. Social threat sensitivity was also measured on the first and third day. When meeting unfamiliar peers in the ice breaker session, HPA stress reactivity was evident, but it was not markedly different in those who reported high levels of loneliness than those with low levels. The high loneliness group had higher levels of perceived stress and increased social threat sensitivity than the low loneliness group on both testing days. The findings show partial support for the socio-cognitive model of loneliness because increased threat sensitivity was demonstrated in the high loneliness group. The findings indicate that lonely people do not respond in a physiologically different way to specific social challenges, but they typically report higher social threat sensitivity and higher perceived stress than their non-lonely peers.

Evidence establishing a link between prenatal and early-life stress and asthma development

PURPOSE OF REVIEW

The objective of this review is to provide an update on our evolving understanding of the effects of stress in pregnancy and during early development on the onset of asthma-related phenotypes across childhood, adolescence, and into early adulthood.

RECENT FINDINGS

Accumulating evidence over the past 2 decades has established that prenatal and early-life psychological stress and stress correlates (e.g., maternal anxiety or depression) increase the risk for childhood respiratory disorders. Recent systematic reviews and meta-analyses including numerous prospective epidemiological and case-control studies substantiate a significant effect of prenatal stress and stress in early childhood on the development of wheeze, asthma, and other atopic-related disorders (eczema and allergic rhinitis), with many studies showing an exposure-response relationship. Offspring of both sexes are susceptible to perinatal stress, but effects differ. The impact of stress on child wheeze/asthma can also be modified by exposure timing. Moreover, coexposure to prenatal stress can enhance the effect of chemical stressors, such as prenatal traffic-related air pollution, on childhood respiratory disease risk. Understanding complex interactions among exposure dose, timing, child sex, and concurrent environmental exposures promises to more fully characterize stress effects and identify susceptible subgroups. Although the link between perinatal stress and childhood asthma-related phenotypes is now well established, pathways by which stress predisposes children to chronic respiratory disorders are not as well delineated. Mechanisms central to the pathophysiology of wheeze/asthma and lung growth and development overlap and involve a cascade of events that include disrupted immune, neuroendocrine, and autonomic function as well as oxidative stress. Altered homeostatic functioning of these integrated systems during development can enhance vulnerability to asthma and altered lung development.

SUMMARY

Mechanistic studies that more comprehensively assess biomarkers reflecting alterations across interrelated stress response systems and associated regulatory processes, in both pregnant women and young children, could be highly informative. Leveraging high-throughput systems-wide technologies to include epigenomics (e.g., DNA methylation, microRNAs), transcriptomics, and microbiomics as well as integrated multiomics are needed to advance this field of science. Understanding stress-induced physiological changes occurring during vulnerable life periods that contribute to chronic respiratory disease risk could lead to the development of preventive strategies and novel therapeutic interventions.

High heart rate reactors display greater decreases in tear SIgA concentration following a novel acute stressor

Tear secretory immunoglobulin-A (SIgA) is a putative biomarker of common-cold risk with potential utility in non-invasive diagnostics. As SIgA secretion at the ocular surface is under strong autonomic control, we investigated the relationship between HR reactivity and tear SIgA responses to novel experiential stress. Thirty-two healthy participants undertook a 60 s zip-line ride to evoke acute stress and a seated-rest control trial in a randomised-crossover design. We recorded heart rate (HR) continuously and collected unstimulated tear samples 5 min pre-, 2 min post- and 20 min post-stress/control. Stress increased HR and state anxiety whereas tear SIgA concentration decreased 44% post-stress vs.

CONTROL

Higher peak HR values during stress uniquely explained 21% of the variance in tear SIgA reactivity to stress (p < 0.01); high HR reactors displayed greater decreases in tear SIgA concentration. We conclude that physiological arousal increases immune reactivity to acute stress and highlight tear SIgA as a minimally-invasive, physiologically relevant biomarker of immune reactivity.

Well-Being and Safety Among Inpatient Psychiatric Staff: The Impact of Conflict, Assault, and Stress Reactivity

Psychiatric staff are faced with multiple forms of hostility, aggression, and assault at work, collectively referred to as workplace violence, which typically is activated by patients but can also come from coworkers and supervisors. Whether workplace violence adversely affects staff well-being may be related not only to its presence, but also to an individual's stress reactivity. At a large public psychiatric hospital, an online survey was completed by 323 clinical care staff, of whom 69.5 % had experienced physical assault in the previous 12 months. Staff well-being (depression, anger, and physical health) and staff safety concerns were adversely affected by conflicts with other staff members and by individual reactivity to social conflict and to assault. To improve staff well-being, in addition to safety protocols, interventions should target staff relationships, personal health maintenance practices, and individual coping skills for dealing with adverse workplace experiences.

Effects of transportation, relocation, and acclimation on phenotypes and functional characteristics of peripheral blood lymphocytes in rhesus monkeys (Macaca mulatta)

Nonhuman primates from domestic sources constitute a small, but critical, proportion of animals studied in research laboratories. Many of these nonhuman primates are raised at one facility and subsequently transported/relocated to another facility for research purposes. We examined the effects of transport, relocation, and acclimation on the phenotype and function of peripheral blood mononuclear cells (PBMCs) in a group of rhesus monkeys that were transported by road for approximately 21 hours from one facility to another. Using a panel of human antibodies and a set of standardized human immune assays, we evaluated the phenotype of lymphocyte subsets by flow, mitogen-specific immune responses of PBMCs in vitro, and levels of circulating cytokines and cortisol in plasma at various time points including immediately before transport, immediately upon arrival, and after approximately 30 days of acclimation. Analyses of blood samples revealed that CD3+ T-cell and CD20+ B-cell populations had decreased significantly immediately after relocation but had recovered within 30 days after arrival at the new facility. Similarly, circulating cortisol and cytokine levels in plasma were significantly higher immediately after relocation; and by the 30-day time point, these differences were no longer significant. However, immune assays of PBMCs indicated that mitogen-specific responses for proliferation, interferon γ (IFN-γ), and perforin were significantly higher after relocation and 30 days of acclimation. These findings have implications on the research participation of transported and relocated nonhuman primates in immunologic research studies, suggesting that 30 days is not sufficient to ensure return to baseline immune homeostasis. These data should be considered when planning research studies in order to minimize potential confounding factors associated with relocation and to maximize study validity.

NIAID, NIEHS, NHLBI, and MCAN Workshop Report: The indoor environment and childhood asthma-implications for home environmental intervention in asthma prevention and management

Environmental exposures have been recognized as critical in the initiation and exacerbation of asthma, one of the most common chronic childhood diseases. The National Institute of Allergy and Infectious Diseases; National Institute of Environmental Health Sciences; National Heart, Lung, and Blood Institute; and Merck Childhood Asthma Network sponsored a joint workshop to discuss the current state of science with respect to the indoor environment and its effects on the development and morbidity of childhood asthma. The workshop included US and international experts with backgrounds in allergy/allergens, immunology, asthma, environmental health, environmental exposures and pollutants, epidemiology, public health, and bioinformatics. Workshop participants provided new insights into the biologic properties of indoor exposures, indoor exposure assessment, and exposure reduction techniques. This informed a primary focus of the workshop: to critically review trials and research relevant to the prevention or control of asthma through environmental intervention. The participants identified important limitations and gaps in scientific methodologies and knowledge and proposed and prioritized areas for future research. The group reviewed socioeconomic and structural challenges to changing environmental exposure and offered recommendations for creative study design to overcome these challenges in trials to improve asthma management. The recommendations of this workshop can serve as guidance for future research in the study of the indoor environment and on environmental interventions as they pertain to the prevention and management of asthma and airway allergies.

The effects of acute psychological stress on circulating and stimulated inflammatory markers: A systematic review and meta-analysis

Inflammatory reactivity to acute laboratory stress is thought to reflect individual differences in responsivity to environmental stressors and may confer future health risk. To characterize this response, we conducted a meta-analysis of 34 studies that measured circulating inflammatory markers and 15 studies that measured stimulated production of inflammatory markers before and after exposure to laboratory challenge. Results showed significant stress-related increases in circulating interleukin (IL)-1β (d=0.66, p<0.001), IL-6 (d=0.35, p<0.001), IL-10 (d=0.69, p<0.001), and tumor necrosis factor(TNF)-α (d=0.28, p<0.001), but not IL-1ra, IL-2, interferon-γ, or C-reactive protein. There were sufficient data to assess the time course of IL-6, IL-1β, and TNF-α reactivity. IL-6 increased from baseline to measures taken 40-50, 60-75, 90, and 120min following stress, with the largest effect at 90min post-stress (d=0.70, p<0.001). IL-1β increased from baseline to 20-30, 40-50, and 60-70min following stress, with the largest effect between 40 and 50min post-stress (d=0.73, p=0.02). For TNF-α, there was a significant increase from baseline to 31-50min post stress (d=0.44, p=0.01), but not at later times. There was no difference in magnitude of IL-6 reactivity as a function of type of stress (social-evaluative versus other). For stimulated inflammatory markers, results showed stress-related increases in IL-1β when measured 20-120min post-stress (d=1.09, p<0.001), and in IL-4 and interferon-γ when measured 0-10min post stressor (d=-0.42, p<0.001 and d=0.47, p<0.001). These results extend findings from a prior meta-analysis (Steptoe et al., 2007) to show reliable increases in circulating IL-6, IL-1β, IL-10 and TNF-α and stimulated IL-1β, IL-4 and interferon-γ in response to acute stress. It is possible that these responses contribute to associations between exposure to life challenges and vulnerability to inflammatory disease.

Validation of autonomic and endocrine reactivity to a laboratory stressor in young children

The validation of laboratory paradigms that reliably induce a stress response [including hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS) activation], is critical for understanding how children's stress-response systems support emotional and cognitive function. Early childhood research to date is markedly limited, given the difficulty in establishing paradigms that reliably induce a cortisol response. Furthermore, research to date has not included a control condition or examined concurrent ANS reactivity. We addressed these limitations by characterizing the extent to which a modified matching task stressor paradigm induces HPA and ANS activation, beyond a closely matched control condition. Modifications include an unfamiliar and unfriendly assessor to increase the stressful nature of the task. Results validate the matching task as a laboratory stressor, with significant differences in HPA and ANS responsivity between conditions. The Stressor group exhibited a cortisol increase post-stressor, while the Control group was stable over time. Children in both conditions exhibited reduced parasympathetic activity to the first-half of the task, but in the second-half, only children in the Stressor condition, who were experiencing exaggerated signals of failure, exhibited further parasympathetic decline. The Stressor condition induced higher sympathetic activity (versus Control) throughout the task, with exaggerated second-half differences. Within the Stressor condition, responsivity was convergent across systems, with greater cortisol reactivity correlated with the magnitude of parasympathetic withdrawal and sympathetic engagement. Future research employing the matching task will facilitate understanding the role of HPA and ANS function in development.

Alexithymia and Immune Dysregulation: A Critical Review

Alexithymia presents a deficit in identifying and expressing emotions, paucity of fantasies, and an externally oriented cognitive style. Numerous recent studies have documented that alexithymia is significantly related to dysregulation of immune functions. These findings implicate that stressors related to alexithymia could underlie the process of immune dysregulation that likely presents a significant risk factor in pathogenesis of several psychosomatic illnesses. In this article various findings on immune dysregulation in alexithymia are reviewed and discussed.

Impact of Maternal Lifetime Interpersonal Trauma on Children's Asthma: Mediation Through Maternal Active Asthma During Pregnancy

OBJECTIVE

Traumatic stressors, including child abuse and/or interpersonal violence over a woman's lifecourse, can affect the health of her children. This study examines the associations between maternal lifetime interpersonal trauma (IPT) and children's asthma by age 6 years (n = 857).

METHODS

Pregnant women completed the Revised Conflict Tactics Scale; IPT exposure was categorized as unexposed (55%), early (childhood and/or teen years only, 25%), late (adulthood and/or index pregnancy, 7%), and chronic (early and late, 13%). Clinician-diagnosed asthma in children was reported by mothers at each follow-up visit until the child reached age 6 years. We examined the effects of maternal IPT categories and child's asthma using logistic regression. Using structural equation models, we also examined indirect relationships between maternal chronic IPT and child asthma operating through active asthma in pregnancy, prepregnancy BMI, prenatal smoking, and/or increased exposure to other adverse life events or environmental toxins prenatally. Effect modification by the child's sex was examined.

RESULTS

Mothers were primarily Hispanic (55%) or black (30%) with less than high school education (62%). In logistic regression models, chronic maternal IPT (compared with unexposed) was associated with asthma in boys (odds ratio = 2.87, 95% confidence interval = 1.48-5.57) but not girls (odds ratio = 0.69, 95% confidence interval = 0.23-2.12; pinteraction = .042). In structural equation models, chronic IPT was associated with maternal active asthma in pregnancy (β = 0.59, p < .001), maternal active asthma was associated with children's asthma (β = 0.20, p = .009), and the total indirect effect for this path was significant (β = 0.12, p = .031). Associations were most evident among boys.

CONCLUSIONS

Mothers' history of chronic IPT was associated with asthma in boys. This association was mediated through active maternal asthma in pregnancy.

Marital Disruption and Allostatic Load in Late Life

OBJECTIVE

This study examines the link between marital disruption and biological risk, and asks whether the association of this precarious life event with health is contingent on marital loss duration and history.

METHOD

Data are drawn from the National Social Life, Health, and Aging Project ( N = 1,414), and Poisson regressions are presented for allostatic load and logistic regressions for individual biomarkers.

RESULTS

The currently unmarried with more distant marital disruptions exhibit higher levels of allostatic load than the currently married, which is primarily driven by dysregulation of cardiovascular and metabolic indicators. Results also reveal the differing ways marital disruption "gets under the skin" with widowhood associated with compromised inflammatory, metabolic, and cardiovascular functioning, and divorce with cardiovascular and neuroendocrine markers.

DISCUSSION

Findings lend support for both the crisis and chronic strain models, and likely reflect normative expectations of the timing of life events, decrements in marital resources, and selection processes.

Early Detection of Physical Activity for People With Type 1 Diabetes Mellitus

BACKGROUND

Early detection of exercise in individuals with type 1 diabetes mellitus (T1DM) may allow changes in therapy to prevent hypoglycemia. Currently there is limited experience with automated methods that detect the onset and end of exercise in this population. We sought to develop a novel method to quickly and reliably detect the onset and end of exercise in these individuals before significant changes in blood glucose (BG) occur.

METHODS

Sixteen adults with T1DM were studied as outpatients using a diary, accelerometer, heart rate monitor, and continuous glucose monitor for 2 days. These data were used to develop a principal component analysis based exercise detection method. Subjects also performed 60 and 30 minute exercise sessions at 30% and 50% predicted heart rate reserve (HRR), respectively. The detection method was applied to the exercise sessions to determine how quickly the detection of start and end of exercise occurred relative to change in BG.

RESULTS

Mild 30% HRR and moderate 50% HRR exercise onset was identified in 6 ± 3 and 5 ± 2 (mean ± SD) minutes, while completion was detected in 3 ± 8 and 6 ± 5 minutes, respectively. BG change from start of exercise to detection time was 1 ± 6 and -1 ± 3 mg/dL, and, from the end of exercise to detection time was 6 ± 4 and -17 ± 13 mg/dL, respectively, for the 2 exercise sessions. False positive and negative ratios were 4 ± 2% and 21 ± 22%.

CONCLUSIONS

The novel method for exercise detection identified the onset and end of exercise in approximately 5 minutes, with an average BG change of only -6 mg/dL.

Violence and cardiovascular health: a systematic review

CONTEXT

Violence, experienced in either childhood or adulthood, has been associated with physical health outcomes, including cardiovascular disease. However, the consistency of the existing literature has not been evaluated.

EVIDENCE ACQUISITION

In 2013, the authors conducted a PubMed and Web of Science review of peer-reviewed articles published prior to August 2013 on the relation between violence exposure, experienced in either childhood or adulthood, and cardiovascular outcomes. To meet inclusion criteria, articles had to present estimates for the relation between violence exposure and cardiovascular outcomes (e.g., hypertension, blood pressure, stroke, coronary disease, or myocardial infarction) adjusted for demographic factors. Articles focusing on violence from television, video games, natural disasters, terrorism, or war were excluded.

EVIDENCE SYNTHESIS

The initial search yielded 2,273 articles; after removing duplicates and applying inclusion and exclusion criteria, 30 articles were selected for review. A consistent positive relation was noted on the association between violence experienced during childhood and cardiovascular outcomes in adulthood (i.e., hypertension, coronary heart disease, and myocardial infarction). Associations across genders with varying types of violence exposure were also noted. By contrast, findings were mixed on the relation between adult violence exposure and cardiovascular outcome.

CONCLUSIONS

Despite varying definitions of violence exposure and cardiovascular endpoints, a consistent relation exists between childhood violence exposure, largely assessed retrospectively, and cardiovascular endpoints. Findings are mixed for the adult violence-cardiovascular health relation. The cross-sectional nature of most adult studies and the reliance of self-reported outcomes can potentially be attributed to the lack of findings among adult violence exposure studies.