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Prior research has established that testosterone is an important modulator of social decision-making. However, evidence on the relationship between basal testosterone levels, commonly measured in saliva or blood, and social behavior has been inconsistent due to methodological shortcomings. Additionally, it has been suggested that cortisol might moderate the association between basal testosterone and social behavior. The present study examined how individual differences in cumulative hair testosterone map onto social decision-making under consideration of a potential modulating role of hair cortisol in a large community sample of young adults (N = 1002). We observed a negative association between hair testosterone and trust behavior (odds ratio = 0.84) and a positive association with self-reported aggressive behavior (β = 0.08). The effects were small and became nonsignificant after controlling for key covariates of steroid hormones in hair (e.g. hair color, contraceptives, and use of psychoactive substances). Hair testosterone levels were not significantly associated with any other social behavior examined, and no modulating effects of hair cortisol were found. Overall, these findings provide no evidence for a role of basal testosterone hair concentrations in human social decision-making and do not indicate that hair cortisol moderates hair testosterone's effects on social behavior., (© The Author(s) 2024. Published by Oxford University Press.)

Objectives: To explore the potential role of oral bacteria in the pathogenesis of burning mouth syndrome (BMS)., Materials and Methods: Fifteen patients with BMS and 15 healthy controls were enrolled in this study. The relative abundance and diversity of salivary bacterial strains were analyzed using metagenomic DNA sequencing. The functionality of non-redundant genes was obtained by comparing the mmseqs2 with the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. BMS relating salivary protein markers were detected using enzyme-linked immunosorbent assay (ELISA)., Results: Partial least-squares discriminant analysis (PLS-DA) revealed that the salivary bacterial profiles of the BMS group (mean age: 38.9 ± 2.2 years) differed significantly from those of the control group (mean age: 34.1 ± 2.3 years) in terms of the abundance of dominant phyla, classes, orders, families, genera and species. Functional analysis revealed distinct endocrine and immune functions in the BMS group. The salivary cortisol and α-amylase levels were significantly higher, and salivary interleukn-6 levels were significantly lower in the BMS group than in the control group. Species contribution analysis of endocrine and immune functions revealed that Streptococcus mitis was an important contributor to endocrine and immune functions in the BMS group., Conclusions: Salivary dysbiosis related to endocrine and immune functions may be a possible cause of BMS., Clinical Relevance: These findings could assist in the diagnosis and therapy of BMS., Clinical Trial Number: Not applicable., Competing Interests: Declarations. Ethical approval: All procedures involving human participants adhered to the ethical standards of the institutional research committee and the 1964 Declaration of Helsinki and its later amendments, or comparable ethical standards. The study protocol was approved by the Institutional Review Board of Shenzhen University General Hospital (protocol number KYLL-20221222 A). Informed consent: Written informed consent was obtained from all participants prior to the procedures. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: The frequent presence of hunters in hunting areas may have a negative impact on wild animals, which may disturb their welfare. Stressors may long affect individual animal species in different ways. Therefore, the study aimed to compare cortisol level in the hair of male mouflons, red deer, and wild boars harvested at the end of the stalking hunting season depending on the age and carcass mass. The cortisol level was determined using the DetectX ® Cortisol ELISA Kits., Results: The concentration of cortisol in the hair of mouflons was almost six times lower than that of red deer and wild boars. Carcass mass and age researched animals did not affect cortisol levels., Conclusions: Stalking hunts most likely do not impact the welfare of big game. There is probably habituation to long-term stress in the animals studied. Mouflons have the ability to respond effectively to specific stressors and are more resistant to long-term stress., Competing Interests: Declarations. Ethics approval and consent to participate: Ethical review and approval does not apply for this study. Holder of a certificate of competence for designing experiments and experimental projects under Act No. 246/1992 Coll., issued by the Ministry of Agriculture (licence number CZ02471) and an employee ofthe Czech University ofLife Science in Pague, Czech Republicconsiders that this type of project does not fall under the legislation for the protection of animals used for scientific purposes, national decree-law 246/1992 Sb. (2010-63- EU directive ). It considers that this type of project has no impact on animal welfare because all procedures are carried out after the animal has been sacrificed, and the legislation for slaughter in accodance with the Czechia Hunting Law (Journal ofLaws 2001 No. 43, item 488) during the hunting season (between December 15 and January 15, 2023) while stalking hunts (without the use dogs, cars, without drive animals ), by qualified hunters - employees of the Židlochovice forest district and no research procedures detrimental to animal welfare were performer, according to the applicable legislation (Act of 15 January 2015 on the protection of animals used for scientific or educational purposes; Directive 20 I 0/63/EU of the European Parliament and of the Council of 22 September 2010 on the protection of animals used for scientific purposes). Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Cortisol, known as the "stress hormone", is secreted by the adrenal cortex. Measuring cortisol levels in body fluids is essential for evaluating stress levels, adrenal function, hormone imbalance, and psychological well-being. Early diagnosis and management of related conditions depend on this measurement. A rapid detection method that combines immunoassay and surface-enhanced Raman scattering (SERS) technology has become widely used in bioanalysis, offering benefits such as fast detection, high throughput, integrated microsystems, and high specificity. This study introduces a pump-free microfluidic chip integrating a solid-state SERS substrate to detect trace amounts of cortisol in bodily fluids through immunoassay. The method relies on a competitive reaction between cortisol and SERS tags with cortisol antigens immobilized on gold nanostructured substrates in a microfluidic environment. Two detection channels are used to provide controls and enhance measurement efficiency and accuracy. Solid-state gold nanostructured substrates offer a larger surface area for antibody capture and act as SERS-active substrates, which significantly enhance the Raman signal and improve the microsystem's sensitivity and applicability. Driven by a capillary pump, the sample can be loaded within 60 seconds, with the entire detection process taking less than 10 min, significantly reducing the detection time. Results indicate that the detection limit for cortisol is 10 pg mL -1 , meeting clinical biomarker thresholds. The integrated SERS microfluidic chip shows great promise as an analytical tool for the rapid and sensitive diagnosis of cortisol in bodily fluids.

This study investigated the effects of music therapy (MT), a nonpharmacological therapy, on cognitive, behavioral, and physiological outcomes in older adults with mild-to-moderate cognitive decline residing in care home settings. A randomized controlled trial design was employed, with 42 care home residents (Mage = 86.25 years) randomly assigned to either a one-to-one 16-week MT intervention or an active control group receiving storytelling. Experimental and control activities were matched on key aspects, and groups were equivalent at baseline concerning demographic factors, general health, cognitive-behavioral characteristics, and cognitive reserve levels. Pre/postintervention neuropsychological and behavioral measures were collected, alongside saliva samples for cortisol/dehydroepiandrosterone ratio and respiratory sinus arrhythmia analysis as indicators of overall stress and autonomic regulation. The MT group exhibited benefits in cognitive, behavioral, and physiological domains, suggesting potential advantages in maintaining cognitive functioning and reducing neuropsychiatric symptoms. Biomarkers indicated possible mechanisms underlying the effectiveness of MT. The 16 one-to-one interactive MT sessions-delivered over 5 months-had a positive impact on older adults with mild-to-moderate cognitive decline living in care home settings. The implications of these findings for healthy aging and suggestions for future research are discussed. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is one mechanism through which chronic stress during pregnancy and parenthood may affect parental, child, and family health. Hair cortisol concentration (HCC) may be well-suited to elucidate associations between chronic stress and HPA axis regulation because HCC reflects cortisol output over several months. However, most previous studies that examine chronic stress in conjunction with cortisol in pregnant individuals or mothers use measures that reflect HPA axis output over a relatively limited time. We report findings from two longitudinal studies that tested associations between chronic stress and HCC in women during the perinatal period (Study 1; n = 144) and mothers of young children (Study 2; n = 102). Both studies measured chronic stress with a measure developed to comprehensively assess chronic stressors in community samples. Hair samples were collected three times in Study 1 (mid-pregnancy, one month postpartum, and 12 months postpartum) and twice in Study 2, approximately one year apart. Chronic stress was associated with higher HCC in both studies. Exploratory analyses indicated that the strength of associations between chronic stress and HCC differed as a function of the life domain of chronic stress. Chronic work and family demands were associated with higher postpartum HCC in Study 1 whereas neighbourhood/housing and discrimination chronic stress were associated with higher HCC in Study 2. These findings provide evidence of a biological pathway through which chronic stress may influence health in mothers and support the utility of hair cortisol as a neuroendocrine measure of chronic stress during pregnancy and parenthood., (© 2024 The Author(s). Stress and Health published by John Wiley & Sons Ltd.)

Introduction: Stress is one of the most common trigger factors for epileptic seizures and is strongly related to clinical and emotional variables. Despite its influence in the course of the disease, there is an absence of instruments for measuring perceived stress in people with drug-resistant epilepsy. Therefore, this study develops and validates the Epilepsy Perceived Stress Inventory for Adults (EPSI-A), a self-report inventory in Spanish designed to quantify perceived chronic stress in this population., Method: The sample consisted of 236 patients with drug-resistant epilepsy who underwent a neuropsychological assessment in which anxiety, depression, and quality of life were explored. In addition, from 125 patients in the sample, 9 measures of salivary cortisol were collected during the evaluation., Results: The EPSI-A consisted of 15 items, with higher scores indicating higher perceived stress. The exploratory factor analysis showed a four-factor solution: epilepsy concerns (5 items); impact on daily performance (4 items); social consequences (3 items); and epilepsy severity (3 items). These factors explained 63.3 % of the total variance. Internal consistency reliability measured with McDonald's omega and Cronbach's alpha coefficients was satisfactory, with values ≥ 0.78 (except for epilepsy severity with values of 0.59 and 0.58, respectively). Construct validity was demonstrated by its correlation with several psychological scales and clinical variables., Conclusions: The results showed that the EPSI-A is a reliable and valid tool for assessing perceived chronic stress in people with epilepsy. Its conciseness, rapid administration time, and specificity make it an appropriate instrument for this population., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

We examined the feasibility of using the neofunctional deep breathing (NDB) technique to reduce the allostatic load following the Trier Social Stress Test (TSST). Forty-four healthy subjects were randomised into experimental and control groups. Following the TSST procedure, participants underwent either a single session of NDB or an attention control intervention. The Procomp Infinity Biofeedback system measured breath per minute (BPM), respiratory amplitude, HRV linear domains, skin conductance, and trapezius muscle electromyographic activity. Cortisol and cytokine salivary concentrations, perceived stress, and anxiety levels were also assessed. These parameters were combined into an allostatic load index (ALI) to measure the intervention's effect. This pilot RCT demonstrated the feasibility of the study design and practicality of the intervention. The NDB group showed reduced ALI, increased respiratory abdominal amplitude, decreased BPM, increased HRV indicating parasympathetic activation, and decreased cortisol and inflammatory cytokines. This study highlighted the feasibility of testing the NDB technique in reducing allostatic load through a neurobiological and anti-inflammatory response after exposure to psychosocial stress. This protocol can represent a non-invasive therapeutic adjutant in disorders related to a dysregulation of the HPA axis or to an inflammatory state. Trial Registration: NCT04102813., (© 2024 The Author(s). Stress and Health published by John Wiley & Sons Ltd.)

Psychotherapy incorporating equine interaction (PIE) is emerging as an effective supplemental substance use disorder (SUD) treatment. Benefits are attributed to decreased stress levels associated with the presence of the horse, however, research concerning stress parameters related to short-term equine interaction during SUD treatment is limited. Therefore, the purpose of this preliminary study was to investigate cortisol concentrations in SUD patients participating in PIE for two weeks compared with those in traditional cognitive behavioral therapy (CBT). Salivary cortisol samples were collected from two populations of SUD patients: 1) PIE participants (n = 18) and 2) CBT participants (n = 5). The impacts of the therapy type and the week of sampling were analyzed using a mixed linear model in SAS. Significance level was set at P ≤ 0.05. When comparing PIE to CBT, no impact associated with therapy type was determined (P = 0.74). Cortisol concentrations lacked significant changes during the two-week period for both therapeutic interventions. While short-term intervention lacked improvement in cortisol levels for both therapy types, further research is warranted to determine the most effective approach and duration of therapy., Competing Interests: Declaration of competing interest None., (Copyright © 2024. Published by Elsevier Inc.)

Stress may contribute to the development of obesity through its effects on dysregulated eating, although this has not yet been examined among low-income, rural adolescents. We examined adolescents' stress-induced changes in eating an ad libitum meal, and after, in the absence of hunger (EAH), and the extent to which these varied by sex, race, and weight status. Participants included 260 adolescents, drawn from a sample of rural households experiencing poverty. Adolescents completed two home visits while salivary cortisol was measured; during the control (low stress) visit, they completed questionnaires and procedures thought to elicit low levels of stress and had BMI assessed. During the stress visit, adolescents completed a 20-min set of psychosocial stress challenges before eating. At each visit, adolescents consumed an ad-libitum meal after which they were additionally given large portions of snacks (EAH task). Results revealed that indeed cortisol was higher during the stress visit, across the sample. Boys showed stress-induced increases during ad-libitum meal intake (for calories, fat, and carbohydrates) whereas girls exhibited decreased intake. Further, adolescents with obesity showed stress-induced increases in fat intake, but only when hunger was satiated (EAH). There were no differences by race. These findings provide the first evidence of stress-induced alterations in food intake in a rural, low-income sample of adolescents and point to a strong vulnerability for stress-induced increases in eating in rural boys as well as stress-induced increases in fat intake when satiated as a possible contributor to obesity in youth., Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this manuscript to disclose., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Recently, stress has been recognized as a key factor in the emergence of individual and social issues. Numerous attempts have been made to develop sensor-augmented psychological stress detection techniques, although existing methods are often impractical or overly subjective. To overcome these limitations, we acquired a dataset utilizing both wireless wearable multimodal sensors and salivary cortisol tests for supervised learning. We also developed a novel deep neural network (DNN) model that maximizes the benefits of sensor fusion., Method: We devised a DNN involving a shuffled efficient channel attention (ECA) module called a shuffled ECA-Net, which achieves advanced feature-level sensor fusion by considering inter-modality relationships. Through an experiment involving salivary cortisol tests on 26 participants, we acquired multiple bio-signals including electrocardiograms, respiratory waveforms, and electrogastrograms in both relaxed and stressed mental states. A training dataset was generated from the obtained data. Using the dataset, our proposed model was optimized and evaluated ten times through five-fold cross-validation, while varying a random seed., Results: Our proposed model achieved acceptable performance in stress detection, showing 0.916 accuracy, 0.917 sensitivity, 0.916 specificity, 0.914 F1-score, and 0.964 area under the receiver operating characteristic curve (AUROC). Furthermore, we demonstrated that combining multiple bio-signals with a shuffled ECA module can more accurately detect psychological stress., Conclusions: We believe that our proposed model, coupled with the evidence for the viability of multimodal sensor fusion and a shuffled ECA-Net, would significantly contribute to the resolution of stress-related issues., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Autoimmune Addison's disease (AAD) is treated with daily oral hormone replacements for cortisol and aldosterone. The current treatment is sub-optimal, and frequently results in supra- and infra-physiological cortisol levels that might negatively affect the brain and cognitive functioning. It is currently unclear if the brains of these patients need to be better protected. The present study investigates brain function during working memory in young adults with AAD compared to healthy controls. All participants (56 AAD (33 females), 62 controls (39 females), 19-43 years), underwent MRI brain scanning while performing a visuo-spatial and verbal working memory task. No main group differences in accuracy, reaction time or brain activity during the tasks were found. These findings suggest that patients perform equal to controls, and achieve similar levels of brain activity during working memory. However, variations in the patient population may have confounded this outcome. Controlled studies on larger cohorts are therefore needed to confirm these findings and test if having AAD affects the brain on the long term., Competing Interests: Declaration of Competing Interest None., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

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., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The associations of suicidality with stress are poorly studied in schizophrenia. The study aimed to determine whether suicidality was correlated with perceived chronic stress and the cortisol fluctuations under stress tasks in schizophrenia. High suicidality was defined as a lifetime history of suicide attempts or suicidal ideation in the past 2 weeks. Individuals with schizophrenia and high suicidality (SZ-HS, n = 59), with low suicidality (SZ-LS, n = 207), and healthy controls (HC, n = 196) finished the Perceived Stress Scale. Then, they participated in an experiment that induced stress using the Paced Auditory Serial Addition Task and the Mirror Tracing Persistence Task. Negative affect was measured at baseline and after finishing each task. The salivary cortisol was collected before-, after 20 min, and after 40 min of the tasks. SZ-HS had elevated perceived stress than SZ-LS and HC. Mixed effect models showed that stress tasks induced cortisol changes in all groups; cortisol of SZ-LS was reduced more than HC, but SZ-HS and SZ-LS did not differ in cortisol fluctuations. SZ-HS and SZ-LS experienced similar negative affect changes during tasks and the difference in withdrawal rates was nonsignificant. SZ-HS had an increased error rate than SZ-LS. In conclusion, suicidality was correlated with high-level perceived stress but did not result in differences in cortisol reactivities under stress tasks. It suggests the inconsistency between appraisal of stress and biological stress system disturbance among SZ-HS compared to SZ-LS., (© 2024 John Wiley & Sons Ltd.)

Background: The current work aimed to describe and compare the cortisol and insulin concentrations behavior and rate of perceived exertion (RPE) during a 115 km ultramarathon race., Methods: Nine ultrarunners (eight males) were evaluated six times (0, 37, 60, 76, 89 and 115 km). At each moment, saliva samples (for cortisol and insulin assessment) and RPE (CR10 scale) were collected. Statistical analysis included correlation, one-way repeated measure ANOVA, and Statistical Parametric Mapping to define discrete and continues changes and compare cortisol, insulin and RPE profiles., Results: Our main findings revealed an early peak in cortisol and RPE, accompanied by a decline in insulin responses (402±49 min of the race, P<0.05). Cortisol and insulin only showed magnitude differences with inverse behaviors until ~6% (7 km) of the ultramarathon duration. Cortisol and RPE presented similar behaviors, rising from the beginning of the race and remaining elevated throughout the race (η 2 =0.91 and η 2 =1.0, P<0.001). Insulin levels decreased when the race started, remaining below 60% of baseline values from the midpoint to the end of the race (P=0.04)., Conclusions: The study showed an imbalance in the catabolic/anabolic hormone profile during an ultramarathon race, with a prominence in catabolic state. It should be considered in the ultramarathon races preparation and participation due to its possible detrimental effect on the athlete's health.

Introduction: Exposure to moderate levels of simulated hypoxia has subtle cognitive effects relative to ground level, in healthy individuals. However, there are few data on the cognitive consequences of the combination of hypoxia and partial sleep deprivation, which is a classic military or civilian operational context. In this study, we tested the hypothesis that exposure to moderate hypoxia while sleep-restricted impairs several domains of cognition, and we also assessed physiological parameters and salivary concentrations of cortisol and alpha-amylase., Method: Seventeen healthy males completed two sessions of cognitive tests (sustained attention using the PVT psychomotor vigilance task and executive functions using the Go-NoGo inhibition task and N-Back working memory task) after 30 min (T + 30') and 4 h (T + 240') of exposure in a normobaric hypoxic tent (F I O 2 = 13.6 %, ≃ 3,500 m) (HY). This was completed after one night of sleep restriction (3 a.m. to 6 a.m. bedtime, SRHY) and one night of habitual sleep (10 p.m. to 6 a.m. bedtime, HSHY) (with cross-over randomization). The two nights sleep architecture and physiological parameters (oxygen saturation (SpO 2 ) and heart rate (HR) during T + 30' and T + 240'sessions were analyzed. Salivary cortisol and alpha-amylase (sAA) concentrations were analyzed before hypoxia, after the T + 30' and T + 240' cognitive sessions, and after leaving the hypoxic tent., Results: Sustained attention (RT and number of lapses in the PVT) and executive functions (Go-NoGo and 1-Back and 2-Back parameters, as inhibition and working memory signatures) were impaired in the SRHY condition compared to HSHY. SpO 2 and HR were higher after 4 h compared with 30 min of hypoxia in the HSHY condition, while only HR was statistically higher in the SRHY condition. In SRHY, salivary AA concentration was lower and cortisol was higher than in HSHY. A significant increase in sAA concentration is observed after the cognitive session at 4 h of hypoxia exposure compared to that at 30 min, only in the SRHY condition. There are significant positive correlations between reaction time and the corresponding heart rate (a non-invasive marker of physiological stress) for the executive tasks in the two sleep conditions. This was not observed for salivary levels of sAA and cortisol, respective reliable indicators of the sympathoadrenomedullary system and the hypothalamic-pituitary adrenocortical system., Conclusion: Exposure to moderate normobaric hypoxia (≃ 3500 m / ≃ 11,500 ft simulated) after a single night of 3-hour sleep impairs cognitive performance after 30 min and 4 h of exposure. The key determinants and/or mechanism(s) responsible for cognitive impairment when exposed to moderate hypoxia with sleep restriction, particularly on the executive function, have yet to be elucidated., Competing Interests: Declaration of competing interest We declare we have no competing interests., (Copyright © 2024. Published by Elsevier Inc.)

Cortisol is a well-known stress biomarker; this study focuses on using electrochemical immuno-sensing to measure the concentration of cortisol selectively and sensitively in artificial samples. Anti-cortisol antibodies have been immobilised on polycrystalline Au electrodes via strong covalent thiol bonds, fabricating an electrochemical bio-immunosensor for cortisol detection. IrO x was then anodically electrodeposited as a reference electrode on a commercial screen-printed electrode and electrochemical impedance spectrometry (EIS) studies were used to correlate the electrochemical response to cortisol concentration and the induced changes in charge transfer resistance (R ct ). A linear relationship between the R ct and the logarithm of cortisol concentration was found in concentrations ranging from 1 ng/mL to 1 mg/mL with limit of detection at 11.85 pg/mL (32.69 pM). The modification of the reference electrode with iridium oxide has greatly improved the reproducibility of the screen-printed electrode. The sensing system can provide a reliable and sensitive detection approach for cortisol measurements., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article., (Crown Copyright © 2024. Published by Elsevier B.V. All rights reserved.)

Introduction: Hair cortisol concentration (HCC) is a biomarker of long-term stress. Higher HCC is associated with higher adiposity in adults; however, associations are not well characterized in adolescents., Objective: To examine cross-sectional associations of HCC with adiposity in late adolescence., Methods: Amongst 336 non-Hispanic White participants (48.5% female, mean 17.7 years) in Project Viva, we used multivariable linear regression models, overall and sex-stratified, to estimate associations of HCC with body mass index (BMI), bioelectric impedance (BIA) percent body fat, waist circumference (WC) and dual X-ray absorptiometry-measured percent and total fat or trunk fat mass. We adjusted models for age and known predictors of adiposity., Results: Median (interquartile range) HCC was 2.1 pm/mg (1.0-4.5) and mean (SD) BMI was 23.1 kg/m 2 (3.9), BIA %body fat 20.2% (9.9) and WC 80.6 cm (10.9). In adjusted models, higher HCC (per doubling) was associated with higher BMI (β = 0.19 kg/m 2 ; 95%CI 0.00, 0.37) and BIA percent body fat (β = 0.41%; 95%CI 0.04, 0.77). We observed no evidence of effect modification by sex., Conclusions: Higher HCC was associated with greater adiposity in late adolescence. Further research is needed to disentangle the relationship between HCC and adolescent adiposity, including the temporal direction of the relationship and sex-specific associations., (© 2024 World Obesity Federation.)

Purpose: Chronic physical stress in female athletes can reduce mental health and athletic performance. Therefore, a chronic physical stress assessment method is required., Methods: This study examined whether hair cortisol concentration (HCC) predicted chronic physical stress changes in female university football players. We took measurements in August and December, just before the Japan college national tournament., Results: Self-reported training load was significantly positively correlated with HCC. Self-reported training load had no significant relationship with fatigue as measured by the Profile of Mood States 2nd Edition or with the stressors from the Stressor Scale for College Students. HCC was negatively correlated with reaction time in the spatial Stroop task, although the repeated correlation analysis showed no significant relationship., Conclusion: These results suggest that the chronic physical stress experienced by female footballers cannot be predicted by psychological indicators; however, they can be predicted by HCC, which could be used to prevent overtraining in these athletes., Competing Interests: Declarations Conflict of interest The authors have no competing interests to declare that are relevant to the content of this article. The authors declare that they have no conflicts of interest. Ethical considerations We provided participants with information regarding the purpose, content, and safety of the study, and they provided written consent for participating in the study. We conducted this study in accordance with the principles of the Declaration of Helsinki. The Ethics Committee of Niigata University of Health and Welfare (anonymized for review) approved the study (approval number 18881–220831)., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Nonsuicidal selfinjury (NSSI) is an important problem in adolescence, which is thought to serve several reinforcement functions (positive vs. negative, automatic vs. social). While the psychological mechanisms involved in NSSI are relatively well known, there is an important gap in the knowledge regarding the underlying biological mechanisms. This study examined the role of testosterone (T) and cortisol (C) in the frequency and reinforcement functions of NSSI., Methods: A total of 423 adolescents (age range = 13-17; 54.4% girls) from Basque Country (Spain) provided saliva samples to determine T and C levels and completed measures of NSSI 6 months later in 2017-2018., Results: The results showed that T but not C was significantly associated with higher NSSI frequency and the four types of NSSI functions. In addition, C moderated the predictive association between T and NSSI for automatic negative reinforcement, such that this association was significant only when C was high. Participant sex did not moderate any association between hormones and NSSI., Conclusions: These preliminary results suggest that testosterone levels can affect NSSI behaviors in adolescence, thus helping to explain the increase in NSSI during this stage. Moreover, in situations in which NSSI serves to alleviate negative internal states, high levels of cortisol can be involved., (© 2024 The Author(s). Journal of Adolescence published by John Wiley & Sons Ltd on behalf of Foundation for Professionals in Services to Adolescents.)

Introduction: Emerging evidence has been explored to determine the factors affecting the development of infant circadian rhythm. While fetal programming happens during the pregnancy period, external environmental cues and infant nutritional programming can have substantial effects on the infant circadian rhythm. Understanding prenatal and postnatal factors determining infant circadian rhythm can improve future interventions in optimizing maternal and infant health. Methods: This is a prospective observational cohort study, targeting 216 pregnant women from government maternity clinics in Kuala Lumpur, Malaysia. Pregnant women will be recruited at third trimester (baseline), and follow up at 3 months, and 6 months. A subsample will be collected for salivary cortisol analysis to determine circadian rhythm of the mother and infant at third trimester and 3 months. Data of eating misalignment, light exposure, chronotype, infant temperament, sleep quality, and mood will be collected via validated questionnaires. Anthropometric data and birth outcomes will be collected from antenatal and postnatal health records. Summary: Studies on infant circadian rhythm development have yet to be explored and established, hence this study presents a novel approach to identify the factors from prenatal to postnatal periods on infant circadian rhythm and its influence on growth and temperament. Findings from this study will provide insights in the critical timing which has larger effects on infant circadian rhythm development for future interventions to be conducted., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Mental stress, a human's common emotion that is difficult to recognize and describe, can give rise to serious psychological disorders. Skin and sweat are easily accessible sources of biomarkers and bio-signals that contain information about mental stress. It is challenging for current wearable devices to monitor psychological stress in real-time with a non-invasive manner. Therefore, we have developed a smartwatch integrated with a sweat cortisol sensor and a heart rate variation (HRV) sensor. This smartwatch can simultaneously record the cortisol levels in sweat and HRV index in real time over a long period. The cortisol sensors based on organic electrochemical transistor (OECT) are fabricated by utilizing the Prussian-blue (PB) doped molecular imprinting polymer (MIP) modified gate electrode. The sensor signal current will decrease following the combination of sweat cortisol, due to the blocking of the PBMIP conductive path, demonstrating good sensitivity, selectivity, and stability. The HRV sensor is manufactured by a photoplethysmography method. We have integrated the two sensors into a wearable smartwatch that can match well with the mobile phone APP and the upper computer software. Through the use of this smartwatch, we have observed a negative correlation between cortisol levels in sweat and the HRV index in short-term stressful environments. Our research presents a great progress in real-time and non-invasive monitoring human's stress levels, which promotes not only the stress management, but also better psychological research., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Background: Ballet, epitomized by iconic seasonal performances such as "The Nutcracker," combines artistic expression with considerable physical demands. This study investigated the physiological and psychological responses of ballet dancers to the demands of intensive training and performance, with a specific focus on "The Nutcracker." Methods: Thirty- eight dancers volunteered for the study, including 6 youths (10.5 + 1.8 years, n = 6 female), 7 adolescents (15.4 + 1.1 years, n = 5 female), and 25 adults (21.1 + 2.1 years, n = 20 female). Employing an uncontrolled observational design, this pilot study tracked key biomarkers such as CK-MM for muscle damage and B-ALP for bone health, alongside psychological measures via PANAS-C/PANAS and DASS-21. Results: Significant findings included a post-performance reduction in cortisol and depression levels. Conclusion: These insights advocate for tailored strategies that address the multifaceted needs of dancers, acknowledging the intricate balance required to maintain peak performance and overall health within the demanding realm of professional ballet., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Sports competitions present a highly stressful environment for the athletes. The stress that is produced because of physiological or psychological demands could influence athletes' performance. This study aimed to understand the dynamics of stress biomarkers during official national bouldering climbing competition., Methods: Twelve sport climbers ([6 females] average age: 20.3±5.21 years, body height: 174.0±10.27 cm, body mass: 64.7±10.80 kg, training age: 10.3±2.40 years) took part in this study. Their saliva cortisol (C) and alpha-amylase (AA) were sampled during the official climbing competition (qualification and final)., Results: The results showed that C had higher values post- (qualification, 1.02±0.43 µg/dL; final, 0.46±0.27 µg/dL) than precompetition (0.45±0.24 µg/dL; 0.29±0.68 µg/dL, respectively). A similar trend can be observed in AA, with higher values post- (qualification, 156.07±133.24 U/dL; final, 199.09±51.24 U/dL) than precompetition (88.18±80.24 U/dL; 88.72±51.24 U/dL, respectively). Furthermore, C had a significantly higher response prequalification (0.45±0.24 µg/dL) than prefinal (0.29±0.19 µg/dL), with the same response post both competition rounds (qualification, 1.02±0.43 µg/dL; final, 0.46±0.27 µg/dL)., Conclusions: Overall, the results showed a strong endocrine and nervous system response. These findings lead to the conclusion that sports climbing competitions present a highly stressful environment for athletes, both physically and psychologically.

In previous studies, various steroids have been associated with stress and have therefore been quantified to investigate stress-related questions. Since the main stress-related steroid cortisol follows a circadian rhythm, often hair is analysed to quantify this steroid. Further, hair analysis gives the unique possibility of long-time monitoring by analysing a certain segment of hair, since hair grows on average 1 cm per month. Hair is a difficult matrix due to the complex sample preparation with many steps including washing and grinding, followed by various extraction steps. Additionally, steroids are endogenous and are therefore present in the hair matrix. Hence, no analyte free matrix is available, which is needed for the quantification via external calibrators. To overcome this problem, the so-called surrogate methods can be used, for which a 13 C 3 labelled or deuterated reference compound of the steroid of interest is used for quantification. In the present study, a surrogate method was developed and fully validated for the quantitative analysis of seven steroids in human hair. Validation experiments showed that the method is further suitable for semi-quantitative analysis of estradiol. However, it is not suitable for the analysis of androsterone and DHEAS. The method was successfully used to analyse steroids in a comprehensive study of 360 adolescent hair samples, enabling research into stress markers., (© 2024 The Authors. Drug Testing and Analysis published by John Wiley & Sons Ltd.)

Background: The lack of association between serum testosterone levels and symptoms suggestive of hypogonadism is a significant barrier in the determination of late-onset hypogonadism (LOH) in men. This study explored whether testosterone levels increase after morning awakening, likewise the cortisol awakening response (CAR) in the hypothalamic-pituitary-adrenal (HPA) axis, and whether testosterone levels during the post-awakening period are associated with age and symptoms suggestive of late-onset hypogonadism (LOH) in men., Methods: Testosterone and cortisol levels were determined in saliva samples collected immediately upon awakening and 30 and 60 min after awakening, and scores of the Aging Males' Symptoms (AMS) questionnaire were obtained from 225 healthy adult men., Results: A typical CAR (an increase in cortisol level ≥ 2.5 nmol/L above individual baseline) was observed in 155 participants (the subgroup exhibiting typical CAR). In the subgroup exhibiting CAR, testosterone levels sharply increased during the post-awakening period, showing a significant negative correlation with age, total AMS score, and the scores of 11 items on the somatic, psychological, and sexual AMS subscales. Of these items, three sexual items (AMS items #15-17) were correlated with age. Meanwhile, there was no notable increase in testosterone levels and no significant correlation of testosterone levels with age and AMS score in the subgroup exhibiting no typical CAR ( n  = 70)., Conclusions: The results indicate that the hypothalamus-pituitary-gonad (HPG) axis responds to morning awakening, and determining testosterone levels during the post-awakening period in men with typical CAR may be useful for assessing HPG axis function and LOH.

Hair cortisol concentration (HCC) and a questionnaire were used as indicators of chronic stress status and quality of life (QoL), respectively, in cats. To date, there has been limited research on the simultaneous application of both indicators in unwell cats. Our aim was to evaluate HCC and questionnaire data obtained from a healthy cat cohort ( n  = 61) and cat cohorts with either chronic kidney disease (CKD) ( n  = 78) or suspected feline infectious peritonitis (FIP) ( n  = 24). Furthermore, we also investigated the correlation between HCC and clinical pathological data. For this study, hair from the abdomen of cats was collected and analyzed for HCC using a commercial ELISA kit. Owners also completed a questionnaire, from which average-item-weighted-impact-scores (AWISs) were calculated. Cats with late-stage-CKD (median, HCC = 330.15 pg/mg, AWIS = -0.43) presented with a significantly higher HCC ( p  < 0.01) and a significantly lower AWIS ( p  < 0.01) than cats with early-stage-CKD (HCC = 183.56 pg/mg, AWIS = 1.08). Similarly, there were significant differences in both HCC ( p  < 0.001) and AWIS ( p  < 0.001) between cats with suspected FIP (HCC = 896.27 pg/mg, AWIS = -1.97) and healthy cats (HCC = 181.24 pg/mg, AWIS = 1.24). The degree of consistency between the HCC results and the questionnaire results reminds us that the severity of a chronic disease or the presence of a life-threatening disease can significantly increase stress and thus can affect the QoL of cats.

Chanting, an ancient ritual practiced in diverse cultures and traditions worldwide, has typically been employed for meditation, healing, self-awareness, and psychological growth. However, there is little understanding of the physiological and psychological benefits of chanting, and how vocalization might contribute to such effects. This study aimed to determine whether 12-minutes of group chanting, through vocal or silent repetition of the sound "om," would reduce stress and anxiety, while increasing feelings of social connection, and whether vocal chanting would yield stronger effects. Thirty-four participants were randomly assigned to vocal or silent group chanting conditions. Saliva samples were collected before and after chanting to assess cortisol levels, while self-report measures included the State Trait Anxiety Inventory and the Adapted Self-Report Altruism Scale (including additional items on cross-cultural altruism). Following chanting, participants also provided a written description of their experiences. Both vocal and silent chanting resulted in significant decreases in cortisol levels and self-reported anxiety. The reduction in cortisol was similar for vocal and silent chanting, but self-reported anxiety decreased more following vocal chanting. Altruism scores increased following both vocal and silent chanting. However, there was no evidence of altruistic tendencies extending toward people from a culture other than one's own. Results are discussed in relation to the phenomenology of chanting, and to current theory and evidence on the physiological and psychological effects of chanting and singing., Competing Interests: Declarations Competing Interests The authors declare that they have no conflict of interest. Ethics Approval This study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Ethics Committee of Macquarie University (protocol code: 5201823832756). Informed Consent Informed consent was obtained from all subjects involved in the study., (© 2023. Crown.)

Background: Inflammatory bowel disease (IBD) is a chronic gastrointestinal condition. While inflammatory biomarkers are valuable for diagnosing and monitoring the disease, their correlation with patients' quality of life (QoL) is not well-established., Purpose: This study aims to investigate the correlations between inflammatory biomarkers and the quality of life (QoL) variables of individuals diagnosed with IBD in clinical remission., Methods: The sample of this cross-sectional study included 74 patients (80% women; 45 ± 11 years old) diagnosed with IBD. Outcome variables included faecal calprotectin (FC), C-reactive protein (CRP), cortisol levels from hair samples, and anxiety and depression assessed using the Hospital Anxiety and Depression Scale (HADS-A and HADS-D, respectively), alongside QoL evaluated with the Inflammatory Bowel Disease Questionnaire 32 (IBDQ-32). Bivariate correlations were calculated using the Pearson correlation coefficient, and stepwise linear regression analyses were conducted to identify independent factors contributing to IBDQ-32 scores., Results: The IBDQ-32 did not significantly correlate with any biomarkers. However, it exhibited a large and statistically significant negative correlation with HADS-A (r = -0.651) and HADS-D (r = -0.611) scores ( p  < 0.001). Stepwise linear regression analyses indicated that HADS-A was a significant and independent predictor for IBDQ-32 scores (Adjusted R 2 = 0.41, β = -0.65, p  < 0.001)., Conclusions: Inflammatory markers such as CRP, FC, or cortisol in hair do not play a decisive role in assessing the QoL of IBD patients. These findings emphasize the significance of considering psychological factors in evaluating and managing QoL in IBD patients in order to identify severity, suggesting that instruments like HADS should be integral to comprehensive patient assessments.

Purpose: Gendered domestic violence and coercive control are prevalent public heath concerns in Canada with dire consequences for survivors. Peer support groups may address and reduce negative impacts of domestic violence and coercive control on women's stress, coping, safety, and alliances with social support network members, the focus of this study., Methods: A one-group, pre-test/post-test quasi-experimental study was undertaken to evaluate the effectiveness of Growth Circle, a 14-week peer support program offered at an agency serving women affected by domestic violence in a major western Canadian city. Through convenience sampling, women 18 years and older who experienced domestic violence were recruited and provided data on stress, coping, safety-related empowerment, and social support/alliances. Thirty-five participants provided all pre-test and post-test data, with a subsample of 14 providing repeated hair samples. Hair was employed to determine stress hormone (cortisol) levels., Results: A significant reduction in self-reported levels of perceived stress and stress hormone levels following completion of the Growth Circle program was revealed. Participants also reported a significant increase in safety-related empowerment, and supportive alliances with group members., Conclusions: The Growth Circle peer support program was demonstrated to be effective. Further implementation and research into the Growth Circle program across Canada is recommended., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose: Screening of Cushing Syndrome (CS) and Mild Autonomous Cortisol Secretion (MACS) in hypertensive patients is crucial for proper treatment. The aim of the study was to investigate screening and management of hypercortisolism among patients with hypertension in Italy., Methods: A 10 item-questionnaire was delivered to referral centres of European and Italian Society of Hypertension (ESH and SIIA) in a nationwide survey. Data were analyzed according to type of centre (excellence vs non-excellence), geographical area, and medical specialty., Results: Within 14 Italian regions, 82 centres (30% excellence, 78.790 patients during the last year, average 600 patients/year) participated to the survey. Internal medicine (44%) and cardiology (31%) were the most prevalent medical specialty. CS and MACS were diagnosed in 313 and 490 patients during the previous 5 years. The highest number of diagnoses was reported by internal medicine and excellence centres. Screening for hypercortisolism was reported by 77% in the presence of specific features of CS, 61% in resistant hypertension, and 38% in patients with adrenal mass. Among screening tests, the 24 h urinary free cortisol was the most used (66%), followed by morning cortisol and ACTH (54%), 1 mg-dexamethasone suppression test (49%), adrenal CT or MRI scans (12%), and late night salivary cortisol (11%). Awareness of referral centres with expertise in management of CS was reported by 67% of the participants, which reduced to 44% among non-excellence centres., Conclusions: Current screening of hypercortisolism among hypertensive patients is unsatisfactory. Strategies tailored to different medical specialties and type of centres should be conceived., (© 2024. The Author(s).)

This study introduces StressFit, a novel hybrid wearable sensor system designed to simultaneously monitor electromyogram (EMG) signals and sweat cortisol levels. Our approach involves the development of a noninvasive skin patch capable of monitoring skin temperature, sweat pH, cortisol levels, and corresponding EMG signals using a combination of physical and electrochemical sensors integrated with EMG electrodes. StressFit was optimized by enhancing sensor output and mechanical resilience for practical application on curved body surfaces, ensuring accurate acquisition of cortisol, pH, body temperature, and EMG data without sensor interference. In addition, we integrated an onboard data processing unit with Internet of Things (IoT) capabilities for real-time acquisition, processing, and wireless transmission of sensor measurements. Sweat cortisol and EMG signals were measured during cycling exercises to evaluate the sensor suite's performance. Our results demonstrate an increase in sweat cortisol levels and decrease in the EMG signal's power spectral density following exercise. These findings suggest that combining sweat cortisol levels with EMG signals in real-time could serve as valuable indicators for stress assessment and early detection of abnormal physiological changes., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: Biopsychosocial changes during adolescence are thought to confer risk for emotion dysregulation, and in particular, anxiety disorders. However, there are substantial gaps in our knowledge about the biological mechanisms underlying anxiety during adolescence, and whether this contributes to the higher prevalence in females. The Puberty and NeuroDevelopment in Adolescents (PANDA) study aims to examine links between biological (sex hormones, cortisol) and social environmental factors and brain function during adolescence, with a focus on key processes (emotion regulation, fear learning) identified as relevant for the development of anxiety disorders., Methods: PANDA is a cross-sectional study with an observational design that aims to recruit a total of 175 adolescents aged 11-16 (majority female) and their parents/guardians, from the community. Brain function will be examined using magnetic resonance imaging (MRI), including functional MRI tasks of emotion regulation and fear learning. Hormones will be measured from hair (i.e., cortisol) and weekly saliva samples (i.e., oestradiol, progesterone, five across a month in females). Questionnaires and semi-structured interviews will be used to assess mental health and social environmental factors such as parenting and adverse childhood experiences. An online study of 113 adolescents was also incorporated during the COVID-19 pandemic as a questionnaire-only sub-study., Discussion: Strengths of this study include the collection of multiple saliva samples to assess variability in hormone levels, examination of the timing of adverse childhood experiences, inclusion of both maternal and paternal parental factors, exploration of mechanisms through the examination of brain structure and function, and multi-method, multi-informant collection of mental health symptoms. This study addresses important gaps in the literature and will enhance knowledge of the biological and environmental contributors to emotion dysregulation and anxiety in adolescents., Competing Interests: Declarations. Ethics approval and consent to participate: Ethics approval was granted through the Royal Children’s Hospital Human Ethics Research Office (#1955580). Informed assent is provided by the adolescent for their participation and informed consent is provided by a parent/caregiver for their own and their child’s participation. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

The purpose of this study was to investigate the effects of elevated core temperature by exposure to heat stress vs. heat exposure without elevated core temperature (mean skin temperature only) in addition to mental fatigue on aerobic exercise capacity in the heat. Seven highly trained athletes completed two experimental conditions: elevation in core and skin temperatures (hyperthermia: HYP), and skin temperatures (SKIN). Participants performed the AX-Continuous Performance Task and Stroop Task to induce mental fatigue during a warm water immersion at 40 °C (HYP) and a passive seated heat exposure in a climatic chamber at 35 °C and 60% relative humidity (SKIN) for 45 min before exercise. Thereafter, participants performed running trial at 80% maximal oxygen uptake until voluntary exhaustion in the same chamber as the SKIN. Exercise time to exhaustion was significantly shorter in the HYP trial (538 ± 200 s) than in the SKIN trial (757 ± 324 s). Rectal temperature at the end of tasks in the HYP trial increased by 0.86 ± 0.26℃ and was significantly higher (37.69 ± 0.18℃) than that of the SKIN trial (36.96 ± 0.13℃), albeit no significant differences in mean skin temperature. Self-reported mental fatigue using visual analog scale was significantly higher after tasks in both trials, but no significant difference between trials was found. Throughout the trial, salivary cortisol concentration and perceptual responses were not affected by hyperthermia. This study demonstrated that a combination of high core temperature and mean skin temperature, and mental fatigue limit aerobic exercise capacity in highly trained athletes in hot environments compared with heat exposure without an elevation of core temperature., Competing Interests: Declarations. Ethics approval and consent to participate: The study protocol was approved by the ethical committee of the National Institute of Fitness and Sports in Kanoya (approval no.22–1-14). Each participant in the study was given detailed information about the research objectives, data collection procedures, benefits, risk, and confidentiality before written informed consent was obtained. The study complied with the latest version of the Declaration of Helsinki and was conducted according to international standards. Consent for publication: Not applicable. Competing interests: No potential conflicts of interest were reported by the authors., (© 2024. The Author(s).)

Objective: Salivary alpha-amylase (sAA) has been recently proposed as biomarker of stress responsiveness within the sympathetic nervous system, preferable to cortisol, since limitations related to cortisol measurement (e.g. diurnal and seasonal rhythms, drugs interferences). Several factors, as age, collection device and analytical methods, also influence sAA levels and interpretation. This study aims to assess whether sAA could be useful to evaluate the stress response, also verifying some sources of variability., Methods: To identify any sources of sAA variability, saliva samples were collected from eight healthy subjects at five different times (8:00, 10:00, 12:00, 14:00 and 16:00) over five consecutive days using two different collection devices. Saliva was then collected from 35 obstetric residents before and after a simulated shoulder dystocia scenario, one of the most traumatic birth events in the professional life of gynecologists, to assess the stress levels. Samples were analysed throughout two different assays. Heart rate (HR) of residents was also measured before and after simulation scenario. Residents self-collected two saliva samples 10 min apart on a typical day., Results: Overall, sAA levels increased significantly from morning to afternoon. Levels varied between subjects, but no differences were found between days or sampling devices. sAA activity levels in samples from 35 residents were significantly higher than those obtained before the scenario took place (about ten minutes later). These results were confirmed by two different assays. Moreover, a similar trend was observed when HR was considered. No differences were observed between samples collected 10 minutes apart on a typical day., Conclusions: Salivary alpha-amylase activity is a reliable, quick, and efficient marker for stress response, then its measurement will be of potential interest in the field of stress-related disorders. However, it is important to consider the timing of sample collection before introducing sAA in a clinical setting., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Aita et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

This study evaluates the impact of the COVID-19 pandemic on healthcare workers in Argentina, during the second wave in 2021. The aim is to assess stress and burnout, incorporating the assessment of hair cortisol levels as a biomarker of chronic stress. A total of 496 healthcare workers from three different hospitals were included in this study. Two of these hospitals depend on the Buenos Aires City Ministry of Health and the third hospital belongs to Buenos Aires University. Hair samples were obtained using scissors from the posterior vertex, as close to the scalp as possible. Each sample was weighed, and cortisol was extracted and then measured using an automated chemiluminescent method. Notably, 10% of the population exhibited hair cortisol levels above 128 pg/mg. Associations were found between high hair cortisol levels and age, workload, emotional exhaustion, and depersonalization. In addition, burnout, identified in 11% of participants, correlated with higher perceived stress and lower social support. Binary logistic regression revealed associations between burnout and perceived stress, and age. Finally, mediation analysis showed depersonalization as a mediating variable in the relationship between hair cortisol concentration and emotional exhaustion. In conclusion, this study highlights the complex relationships between stress, cortisol levels, and burnout. Prioritizing interventions and research is essential to support the well-being of frontline healthcare professionals, ensuring their resilience during challenging times., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Stress carries diverse implications for perceptual, cognitive, and affective functions. One population particularly susceptible to acute stress-induced cognitive changes are individuals with high-stress jobs (e.g., military personnel). These individuals are often tasked with maintaining peak cognitive performance, including memory, spatial navigation, and decision-making under threatening and uncertain conditions. Previous research has separately examined decision-making under conditions of stress or uncertainty (i.e., ambiguous discrimination between friends and foes). However, questions remain about how operationally relevant stress impacts memory encoding and recall, or spatial learning, as well as how uncertainty may impact decision-making during stress. To address this gap, we examined the influence of a military-relevant emotional stressor on a series of cognitive tasks including recognition memory task (RMT), spatial orienting task (SOT), and shoot/don't shoot decision making (DMT). To examine the effects of uncertainty and stress we varied the stimulus clarity in the DMT. We utilized threat of shock (TOS) as a high-stakes outcome for decision errors. TOS increased sympathetic arousal but did not affect subjective emotional or HPA responses. TOS influenced decision times and confidence ratings in the DMT, but not response sensitivity or response bias. DMT performance varied by stimulus clarity (uncertainty) but did not differ between stress conditions. TOS did not influence recognition memory or spatial orienting. In sum, high levels of stress and uncertainty characterize military operations, yet stress experienced in military contexts can be difficult to induce in laboratory settings. We discuss several avenues for future research, including methodological considerations to better assess the magnitude and specificity of emotional stress-induction techniques in Soldiers., Competing Interests: The authors have declared that no competing interests exist., (Copyright: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.)

Background and Objectives: Patients with primary Sjögren's disease (pSjD) show contradictory results regarding the activity of the hypothalamic-pituitary-adrenal (HPA) axis. The aim of this study was to determine the salivary cortisol concentration to evaluate the function of the HPA axis (hypoactive/hyperactive) between patients with pSjD and control subjects. Materials and Methods: A total of 34 subjects participated in the cross-sectional study: 17 patients with pSjD and 17 control subjects. Stimulated whole saliva (SWS) was used to determine salivary cortisol concentration using an enzyme-linked immunosorbent assay (ELISA). Results: The salivary cortisol concentration showed a statistically significant difference between patients with pSjD and control subjects (4.69 ± 2.88 vs. 0.49 ± 0.37; p < 0.001; Student t -test). The area under the curve (AUC) was 100.0% in patients with pSjD ( p < 0.001). The cut-off point was set to >1.454. The patients with pSjD had four times higher scores for depression and stress and six times higher scores for anxiety compared to the control subjects ( p = 0.048, p < 0.001, p = 0.038; Mann-Whitney U test). The patients with pSjD had a statistically significantly higher total Oral Health Impact Profile (OHIP) score compared to the control subjects ( p < 0.001, Mann-Whitney U test). Conclusions: The patients with pSjD showed short-term hyperactivity of the HPA axis compared to the control subjects.

Psychosocial stress affects the relationship between prolactin (PRL) and cortisol (CORT). The dynamics of PRL and CORT changes under stress in human milk (HM) are largely unknown. We investigated how maternal stress related to recent life changes affects milk CORT and PRL concentrations. The study involved 116 mothers exclusively breastfeeding 5-month-old infants. Maternal psychological stress was evaluated using the Recent Life Changes Questionnaire (RLCQ). Stress response was determined by administering the cold pressor test and measuring CORT in saliva taken during and in milk collected after the test. Hormones concentrations were assayed using the ELISA method. The hierarchical regression models were run to test the association between maternal RLCQ, salivary CORT, and PRL, and CORT in milk. Maternal RLCQ correlated positively with the CORT in saliva, however, no direct association was found between RLCQ and PRL. After controlling for covariates, a positive association was found between salivary and milk CORT. A negative relationship was observed between salivary CORT and milk PRL. The results of the present study indicate that maternal psychological stress may affect the relationship between CORT and PRL in HM. In response to psychological stress, both hormones transported via milk can program infant development in the early postnatal period., Competing Interests: Declarations Competing interests The authors declare no competing interests. Acknowledgments and statement of financial support The study was funded by a Polish National Science Center grant (project ID 2015/17/B/NZ8/02436) to Anna Ziomkiewicz. The study was approved by the Ethics Committee of Lower Silesian Medical Chamber in Wroclaw (protocol code 1/NT/2016 from 10.02.2016)., (© 2024. The Author(s).)

Background: Clowning has been used in many hospitals, particularly for children. Studies suggest the effectiveness of this methodology, but more evidence is needed. The aim of this study was to evaluate the impact of a humour therapy intervention on biological markers, pain and anxiety levels in paediatric patients., Methods: Three different clinical contexts were chosen to assess the effect of clowning interventions: patients who were subjected to venepuncture (group 1), patients undergoing general anesthesia for any cause (group 2)and patients hospitalized in the pediatric ward without distinction of their disease (group 3). Groups 1 and 2 were divided into control (C) and intervention (I) subgroups. A saliva sample was taken from all the children to measure oxytocin and cortisol levels by ELISAs. Validated scales and crying time were used to determine pain, stress, and anxiety levels. Children in group 3 were assessed before and after the intervention, employing the same methods., Results: A total of 272 patients were included. The children in group 1 (n = 125) were 7.7 ± 3.2 years old, and 53.6% were females. 48% were in the I group, which showed decreased cortisol levels and increased oxytocin levels. The I group exhibited a decrease in perceived pain and crying time. The children in group 2 (n = 69) were aged 7.1 ± 3.5 years, and 36% were females. 51% were in the I group, which showed increased oxytocin levels and decreased cortisol levels, acute stress levels, perceived pain, and crying time. The children in group 3 (n = 78) were 8.6 ± 3.3 years old, and 54% of the children were females. There was an increase in oxytocin levels and a decrease in cortisol levels, stress levels and perceived pain following the intervention., Conclusions: This study suggested that an intervention based on clowning is an effective strategy for decreasing pain, stress, and anxiety levels in paediatric patients in different clinical contexts. These findings support the implementation of humour therapy programs in paediatric units., Competing Interests: Declarations Ethics approval and consent to participate This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of Universidad Tecnológica de Pereira (Code 32–160421). Written informed consent was obtained from the parents or proxies. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Background: The etiology of temporomandibular disorders (TMD) is multifactorial, involving a complex interplay of psychological and physiological factors. While salivary biomarkers, particularly cortisol, play an important role in TMD pathophysiology, evidence in the literature is still scarce and inconsistent. Hence, this study aims to evaluate the applicability of salivary cortisol as a potential biomarker for TMD in adults., Methods: The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) were used to accurately diagnose TMD patients. The study included adults, both male and female, aged 18-40 in the TMD group (n = 66) and non TMD participants (n = 66) matched for age and gender. Salivary samples were collected from participants at two time points: early and late morning. Cortisol levels in the samples were quantified using enzyme-linked immunosorbent assay (ELISA). Statistical analysis was performed using a one-way ANOVA to evaluate the correlations between cortisol levels and the study variables. Tukey's post-hoc tests were applied to adjust for multiple comparisons., Results: Salivary cortisol levels were significantly higher in the TMD group than in the corresponding controls (p = 0.034). In the TMD group, the mean cortisol levels early in the morning were 29.95 ± 75.05 (0-398.64), while the late morning levels were recorded as 4.87 ± 3.96 (0-17.13). In the control group, the mean cortisol levels early in the morning were 10.98 ± 16.83 (2.16-92.90), and late morning mean cortisol levels were 6.15 ± 6.13 (0-20.42). This indicates that the early morning levels of cortisol are higher in TMD patients (p = 0.046). In the subgroup analysis of the TMD, the mean salivary cortisol levels recorded were highest at 82.49 ± 124.34 (8.32-398.64) in patients having disc displacement without reduction with limited mouth opening. Furthermore, the mean salivary cortisol levels in the early morning were statistically higher (84.83 ± 132.80) in males compared to females (9.36 ± 9.01) (p = 0.008) with TMD., Conclusion: The result of this study suggests that salivary cortisol could be a potential biomarker for a specific TMD subtype (disc displacement without reduction with limited mouth opening). However, further studies are needed to better understand the role of cortisol biomarker in the underlying pathogenesis of TMD., Competing Interests: Declarations Ethics approval and consent to participate Obtained from the Institutional Review Board (IRB),King Saud University under project number (E-23-7619). All participants provided written informed consent prior to their inclusion in the study. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

The physiological impact of walking in nature was quantified via continuous heart rate variability (HRV), pre- and post-walk saliva cortisol measures, and self-reported mood and mindfulness scores for N = 17 participants who walked "The Green Road" at Walter Reed National Military Medical Center in Bethesda, Maryland. For N = 15 of the participants, HRV analysis revealed two main groups: group one individuals had a 104% increase (mean) in the root mean square standard deviation (RMSSD) and a 47% increase (mean) in the standard deviation of NN values (SDNN), indicating an overall reduction in physiological stress from walking the Green Road, and group two individuals had a decrease (mean) of 42% and 31% in these respective HRV metrics, signaling an increase in physiological stresses. Post-walk self-reported scores for vigor and mood disturbance were more robust for the Green Road than for a comparable urban road corridor and showed that a higher HRV during the walk was associated with improved overall mood. Saliva cortisol was lower after taking a walk for all participants, and it showed that walking the Green Road elicited a significantly larger reduction in cortisol of 53%, on average, when compared with 37% of walking along an urban road. It was also observed that the order in which individuals walked the Green Road and urban road also impacted their cortisol responses, with those walking the urban road before the Green Road showing a substantial reduction in cortisol, suggesting a possible attenuation effect of walking the Green Road first. These findings provide quantitative data demonstrating the stress-reducing effects of being in nature, thus supporting the health benefit value of providing access to nature more broadly in many settings.

Attention deficit hyperactivity disorder (ADHD) is a common neuropsychiatric condition often persisting into adulthood, characterized by inattention, impulsivity, and hyperactivity. Emerging research suggests a connection between ADHD and gut microbiota, highlighting probiotics as potential therapeutic agents. This study involved a double-blind, randomized controlled trial where college students with ADHD received either a multi-strain probiotic supplement or a placebo daily for three months. ADHD symptoms were evaluated using a computerized performance test (MOXO) and the MATAL questionnaire. Academic records provided performance data. Additionally, eating and sleeping habits, gastrointestinal symptoms, and anthropometrics were assessed through questionnaires before and after the intervention. Fingernail cortisol concentrations (FCC) measured the long-term activity of the hypothalamic-pituitary-adrenal axis. The findings indicated that the probiotic significantly decreased hyperactivity, improved gastrointestinal symptoms, and enhanced academic performance. A multivariate analysis identified age as a significant predictor, with younger participants experiencing greater overall benefits from the intervention. There was also a negative correlation between FCC and symptoms of attention and impulsivity. Furthermore, higher academic grades were associated with lower levels of hyperactivity and impulsivity. These results suggest a beneficial impact of probiotics on ADHD symptoms and lay the groundwork for further studies to evaluate the effects of various probiotic strains on clinical outcomes in ADHD., (© 2024. The Author(s).)

Introduction: The ability to objectively measure chronic stress has important implications for research, prevention, and treatment. Cortisol is currently the most used biological marker in the investigation of stress and can be measured via blood, saliva, and urine; however, these methods have disadvantages. The measurement of cortisol in hair is a more recently developed method that quantifies the cumulative production of cortisol over longer periods of time. Given the potential benefits of hair as a chronic stress biometric, research with this novel method is burgeoning, yet rarely involves transgender ("trans") populations, despite high levels of reported stress among trans people due to experiences of stigma and discrimination. Since hair is a key part of gender presentation, trans people might be less likely than cisgender people to donate hair for research. To explore the feasibility and acceptability of hair collection for use as a stress biometric with trans women, we nested a study into an ongoing clinical trial in São Paulo, Brazil, "Manas por Manas" (Sisters for Sisters). Here, we describe the hair biometric substudy protocol, as well as the feasibility and acceptability of collecting hair in the study cohort., Methods: We randomly selected a subsample (n = 180) from the Manas por Manas cohort (n = 392), all of whom are trans women, age 18 or older. We messaged participants via phone, WhatsApp, or social media for at least three attempted contacts. Study visits included four components: (1) video introduction, including a demonstration of hair sampling; (2) informed consent; (3) a brief survey with the validated Short Stress Overload Scale (translated to Portuguese) and questions on hair care that could moderate stress hormone results; and (4) hair sample collection. Hair samples were collected and stored using validated protocols. Participants were reimbursed for travel costs., Results: Between April and December 2022, we messaged with 143 individuals out of the 180 sampled (79%) and invited them to participate in the study. Of those invited to participate, we scheduled study visits with 102 people (71.3% of those invited to participate), of whom 100 attended their study visits and completed all activities. Two people did not attend their study visits and stopped communication. Of those who were invited to participate and declined a study visit, four individuals declined due to the hair sample collection procedures (2.8% of those invited to participate). Other reasons for declining to participate included having moved (n = 7), lack of time (n = 11), not interested in research participation (n = 8), or unknown/stopped responding to messages (n = 11). Most participants reported that they chemically treated their hair to bleach, color, or straighten it, which could impact laboratory assays., Conclusion: We found hair sampling for stress measurement to be feasible and acceptable to our participants. We successfully completed all study activities for our desired sample size, and most recruited individuals volunteered to participate. Reasons provided for declining study participation reflected general barriers to research participation, with only four people declining due to hair sample collection procedures., (© 2024 The Author(s). Brain and Behavior published by Wiley Periodicals LLC.)

Cortisol and testosterone are important biomarkers for diagnosing complex disorders, including polycystic ovary syndrome and Cushing's syndrome, where symptomatology usually overlaps with other prevalent disorders. This work proposes, for the first time, an analytical method based on a switchable hydrophilicity solvent as an extraction phase for the determination of cortisol and testosterone in oral fluid (OF) by high-performance liquid chromatography with diode-array detection. The optimized extraction conditions consisted of 1000 µL of OF, 100 µL of decanoic acid solution (65 mg/mL), 170 µL of Na 2 CO 3 , 900 µL of H 2 SO 4 and 150 µL of acetonitrile for dilution. The method was validated, and coefficients of determination higher than 0.9926, the limit of detection of 4.55 ng/mL and the limit of quantification of 15.00 ng/mL were obtained. Intra-day precision varied from 5.6% to 11.9%, inter-day precision ranged from 6.1% to 13.5%, and relative recoveries ranged from 98.9% to 104.6% for cortisol, and 89.1% to 103.9% for testosterone. This methodology was successfully applied to five OF samples from volunteers. Moreover, the greenness of this methodology was evaluated based on the sample preparation metric of sustainability achieving a global score of 7.37 which can be considered sustainable., (© 2024 Wiley‐VCH GmbH.)

Numerous studies have associated interdependent self-construal (InterSC) with heightened acute salivary cortisol stress responses in collectivist cultures. Hair cortisol concentration (HCC) is an important biomarker of chronic stress and is associated with acute salivary cortisol stress response. However, few studies have explored the association between InterSC and HCC. This study aimed to investigate the role of InterSC in the acute salivary cortisol stress response, HCC, and their associations. Seventy-seven healthy Chinese participants underwent assessments of InterSC, social anxiety, and HCC. The ScanSTRESS paradigm was used to induce an acute stress response and saliva samples were collected. These results replicated earlier findings showing that InterSC was associated with rapid salivary cortisol reactivity and recovery during acute stress. Additionally, InterSC was positively correlated with HCC, and social anxiety mediated this association. Importantly, InterSC moderated the HCC-acute salivary cortisol stress response association. Specifically, high HCC predicted a blunted acute salivary cortisol stress response in participants with low InterSC, including a slow salivary cortisol response during the acute stress reactivity phase and a small overall acute salivary cortisol response. However, this blunting effect was not observed with high InterSC participants, indicating that high InterSC buffered the blunting effect of HCC on the acute salivary cortisol stress response. In conclusion, this study provided new insights into how InterSC is associated with the hypothalamus-pituitary-adrenal axis stress system and revealed the dual-faceted role of InterSC for acute salivary cortisol stress and HCC., Competing Interests: Declaration of competing interest The authors have no conflict of interest relevant to this article., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Higher serum cortisol levels appear to be associated with stress that can overlap or manifest anxiety, fatigue, depression, and sleep dysfunction. These are common and intrusive non-motor symptoms of Parkinson's disease (PD). Thus, stress has been proposed to mediate Parkinson's disease development, and cortisol has been suggested as a biomarker for the generation of stress-related symptoms in Parkinson's disease. This study describes sensitive and robust disposable pipette extraction (DPX) and ultra-efficient liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method to determine cortisol and cortisone (as potential endocrine biomarkers for Parkinson's disease) in 24-h urine and saliva samples obtained from Parkinson's disease patients. Important parameters on DPX extraction were optimized to achieve the best extraction recovery and cleanup efficiency. The proposed method was linear from 0.5 (lower limit of quantification) to 500 ng mL -1 for cortisol and from 3.0 (lower limit of quantification) to 500 ng mL -1 for cortisone. To determine whether urinary cortisol and urinary cortisone are adequate as biomarkers to evaluate the level of anxiety in patients suffering from Parkinson's disease, twenty-nine Parkinson's disease patients (18 with anxiety and 11 without anxiety) were selected for urine analysis. Based on the obtained results, 24-h urine samples obtained from Parkinson's disease patients with anxiety had higher cortisone levels than samples obtained from healthy controls. Receiving operating curves (ROC) analysis, which presented the area under the ROC curve (AUC = 0.733), showed that urinary cortisone levels (µg/24-h urine) were sensitive (56.3%) and specific (93.3%) for distinguishing Parkinson's disease patients with anxiety from healthy controls. In terms of salivary results, PD patients' samples taken 30 min after waking up had higher cortisol and cortisone levels than healthy controls, while their samples taken at night had lower cortisol and cortisone levels., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

Objectives: The impacts of stress on inflammation, although hypothesized, have not been thoroughly examined, especially in relation to social and environmental factors and particularly within Black populations. This study aims to explore the biological mechanisms of embodiment linking stress and health to understand physiological changes in the body's response to psychological stress in a Nigerian population. Through a multidisciplinary approach, this study queries the relationship between stress, cortisol, and salivary C-reactive protein (sCRP), a biomarker of inflammation, while also validating the use of sCRP as a potential and accurate stress indicator in the field., Methods: In this cross-sectional study, 138 passive drool saliva samples (n female  = 89 n male  = 49) were collected and assessed for sCRP and cortisol levels in adults. Participants also completed a short demographic survey and, to measure psychological stress, the General Health Questionnaire 12 (GHQ-12). Relationships between sCRP and stress-related variables (i.e., cortisol, GHQ-12, and demographic data) were assessed using Spearman's correlations, simple regression, multivariable linear regression, and exploratory factor analysis., Results: sCRP levels ranged from 20.57 to 6879.41 pg/mL across all samples, with significant differences between female and male participants. The GHQ-12 was not a significant predictor of sCRP variability. However, socio-demographic factors such as body mass index (BMI), age, self-reported sex, ethnic identity, and cortisol were significant predictors, collectively explaining 24%-27% of the variation in sCRP., Conclusion: Socio-demographic predictors like BMI, age, sex, and particularly ethnic group experience in Nigeria encapsulate aspects of embodied stress, that significantly affect sCRP variability., (© 2024 The Author(s). American Journal of Human Biology published by Wiley Periodicals LLC.)

Study Question: Is the degree of maternal vulnerability positively associated with stress biomarkers (stress hormones, C-reactive protein, tryptophan metabolites, and one-carbon metabolites), and does long-term exposure to stress hormones reduce first-trimester growth?, Summary Answer: The maternal vulnerability risk score is positively associated with concentrations of hair cortisol and cortisone and negatively with tryptophan, while higher hair cortisol concentrations are associated with reduced first-trimester growth without mediation of tryptophan., What Is Known Already: A high degree of maternal vulnerability during the periconception period is associated with impaired first-trimester growth and pregnancy complications, with consequences for long-term health of the child and future life course. However, due to the challenges of early identification of vulnerable women, the uptake of periconception care is low in this target group., Study Design, Size, Duration: Between June 2022 and June 2023, this study was conducted in a sub-cohort of 160 pregnant women participating in the Rotterdam Periconceptional Cohort (Predict Study), an ongoing prospective tertiary hospital-based cohort., Participants/materials, Setting, Methods: One hundred and thirty-two women with ongoing pregnancies and available stress biomarker data were included in the analysis. Data on periconceptional social, lifestyle, and medical risk factors were collected via self-administered questionnaires, and these factors were used for the development of a composite maternal vulnerability risk score. Stress biomarkers, including stress hormones (hair cortisol and cortisone) and inflammatory and oxidative stress biomarkers (C-reactive protein, total homocysteine, and tryptophan metabolites) were determined in the first trimester of pregnancy. First-trimester growth was assessed by crown-rump length (CRL) and embryonic volume (EV) measurements at 7, 9, and 11 weeks gestation by making use of an artificial intelligence algorithm and virtual reality techniques using 3D ultrasound data sets. The associations between the maternal vulnerability risk score and stress biomarkers were identified using linear regression models, and between stress hormones and CRL- and EV-trajectories using mixed models. A mediation analysis was performed to assess the contribution of tryptophan. All associations were adjusted for potential confounders, which were identified using a data-driven approach. Several sensitivity analyses were performed to check the robustness of the findings., Main Results and the Role of Chance: The maternal vulnerability risk score was positively associated with concentrations of hair cortisol and cortisone (pg/mg) (β = 0.366, 95% CI = 0.010-0.722; β = 0.897, 95% CI = 0.102-1.691, respectively), and negatively with tryptophan concentrations (µmol/L) (β = -1.637, 95% CI = -2.693 to -0.582). No associations revealed for C-reactive protein and total homocysteine. Higher hair cortisol concentrations were associated with reduced EV-trajectories (3√EV: β = -0.010, 95% CI = -0.017 to -0.002), while no associations were found with CRL-trajectories. Mediation by tryptophan was not shown., Limitations, Reasons for Caution: Residual confounding cannot be ruled out, and the external validity may be limited due to the study's single-center observational design in a tertiary hospital., Wider Implications of the Findings: There is mounting evidence that a high degree of maternal vulnerability negatively affects maternal and perinatal health, and that of the future life course. The results of our study emphasize the need to identify highly vulnerable women as early as possible, at least before conception. Our findings suggest that the chronic stress response and alterations of the maternal tryptophan metabolism are involved in maternal vulnerability, affecting first-trimester growth, with potential impact on the long-term health of the offspring., Study Funding/competing Interest(s): This study was funded by the Departments of Obstetrics and Gynecology and Clinical Chemistry of the Erasmus MC, University Medical Center, Rotterdam, the Netherlands, and the Junior Award granted by the De Snoo-van 't Hoogerhuijs Foundation in March 2022. There are no conflicts of interest., Trial Registration Number: N/A., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology.)

Previous studies have suggested that maternal childhood trauma (MCT) may influence infant temperament, but the underlying physiological mechanisms remain unclear. This study sought to confirm the involvement of breast milk cortisol in the link between MCT and infant temperament. The study sample included 90 mother-infant dyads recruited from the urban Polish population. MCT was assessed based on the Early Life Stress Questionnaire (ELSQ) and infant temperamental factors (surgency/extraversion, negative affectivity, and orienting/regulation) using the Infant Behavior Questionnaire-Revised at 12 months of life. Cortisol was assayed in milk samples collected at 5 months of life using the ELISA method. Based on the ELSQ median, the sample was divided into low and high MCT groups. The ANCOVA models with milk cortisol as a covariant were run to check the effect of low versus high MCT on infant temperament. We found a positive association between milk cortisol and orienting/regulation. Surprisingly, the low and high MCT groups did not significantly differ in milk cortisol. Furthermore, we found that MCT was unrelated to any infant temperamental factor. While recent literature on the association between milk cortisol and infant temperament is inconsistent, our results suggest that high orienting/regulation might be an adaptation to adverse environments such as stress. Moreover, the infant's temperament appears to be more responsive to the current exposition to maternal stress than her experience of traumatic stress., (© 2024 Wiley Periodicals LLC.)