Assessment of the cortisol awakening response: Expert consensus guidelines

Cortisol awakening response in pregnant women with depressive disorders: a potential marker of recovery status from pregnancy to postpartum

Introduction

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been linked to peripartum depression, potentially contributing to symptom persistence. This study examines the relationship between the cortisol awakening response (CAR) during pregnancy and depressive symptom reduction postpartum.

Methods

Pregnant women with a current depressive episode were included in this study, part of a larger RCT on bright light therapy. At baseline (12-32 weeks of pregnancy), participants provided saliva samples at awakening, +30, and +60 min post-awakening. The CAR was assessed using three measures: area under the curve relative to ground (AUCg), area under the curve relative to increase (AUCi), and peak reactivity (difference between awakening and +30 min cortisol levels). Depressive symptoms were measured using the Hamilton Depression Rating Scale (HAM-D) at baseline and two months postpartum. Linear regression models assessed associations between CAR measures and depressive symptom change, adjusting for relevant covariates.

Results

The study included 55 pregnant women (mean age: 32.3 years, SD 4.8; mean gestational age: 19.7 weeks). Mean HAM-D scores decreased from 16.7 (SD 5.3) at baseline to 5.7 (SD 5.6) postpartum. Higher AUCi during pregnancy was associated with less symptom reduction postpartum (unadjusted β = 0.36, p = .02; adjusted β = 0.36, p = .02), as was peak cortisol reactivity (unadjusted β = 0.33, p = .03; adjusted β = 0.32, p = .03), while AUCg showed no significant association with symptom change (unadjusted p = .19; adjusted p = .28).

Conclusion

Higher AUCi and peak cortisol reactivity of the cortisol awakening response during pregnancy were linked to persistence of depressive symptoms postpartum, suggesting that heightened cortisol reactivity to awakening may indicate persistent stress vulnerability in peripartum depression. Total cortisol output (AUCg) was not predictive of recovery. These findings underscore the potential relevance of stress reactivity over basal cortisol levels in peripartum depression and highlight the need for further research in larger samples to elucidate the usefulness in clinical practice.

Effects of Exposure to Life Stressors, Perceived Stress, and Psychopathological Symptoms on Cortisol Awakening Response: Individual Differences in Resilience

Cortisol awakening response (CAR) has been proposed as a viable biomarker for assessing the function of the hypothalamic-pituitary-adrenal axis. However, there are inconsistencies within the literature on the relationship between CAR and psychopathology. This study examined the unique effects of psychopathological symptoms on hypothalamic-pituitary-adrenal axis functioning (indexed through CAR) while considering the effects of exposure to major life stressors and self-reported perceived stress. The sample consisted of 71 participants, aged 25-37 years old. The Life Stress Index, Perceived Stress Scale, and Symptom Checklist-90 were administered. Salivary cortisol samples were collected across five time points (1 pre-bedtime and 4 upon awakening). A generalised additive model revealed a non-linear effect of time on cortisol concentration upon awakening, characterising CAR's prototypical inverted U-shaped pattern. The analysis also revealed a unique linear relationship between major life stressors and cortisol concentration. That is, greater exposure to major life stressors over the past 5 years was associated with elevated CAR. By contrast, there was also a unique linear relationship between psychopathological symptoms and cortisol concentration in the opposite direction. Contrary to expectations, our findings suggest that exposure to major life stressors, but not perceived stress, may increase cortisol awakening response, which may have implications for negative mental health outcomes (i.e., potential protective factor). These results highlight the importance of considering the complex interplay between stressors and psychopathological symptoms in understanding resilience.

How intersectional identity and discrimination contribute to depressive symptoms and hair cortisol concentrations among low-income, racially and sexual diverse adults

Significant gaps remain in our understanding of how minority stress patterns health outcomes for adults at the intersection of ethnicity/ race and sexual orientation. In particular, little is known about how cumulative cortisol (measured via hair cortisol concentration as an indicator of chronic stress; HCC) and depressive symptoms are related to holding an intersectional minoritized identity (e.g., sexual minority people of color; SM-POC) and experiencing intersectional discrimination (e.g., heterosexism and racism). The current study examined the relationship between intersectional identity or discrimination and HCC or depressive symptoms. Participants were (N = 69) low-income, predominantly sexual minority and people of color in the Greater Los Angeles area. Participants completed self-report measures and provided a hair sample for cortisol assay. Intersectional identity was not associated with greater HCC or depressive symptoms. However, differences in HCC emerged based on discrimination type (F (2, 66) = 3.74, p = .03, η2= .10). Participants who reported intersectional heterosexism and racism had greater HCC concentrations (M = 30.71, SD = 29.71) than did participants who reported only a single type of discrimination (i.e., racism only or heterosexism only; M = 15.35, SD = 2.60, p = .03, 95 % CI = [2.01, 28.71]), or than participants who reported neither types (M = 12.40, SD = 16.11, p = .01, 95 % CI [4.85, 31.76]). There were no differences in depressive symptoms by discrimination type. These results provide initial empirical support to largely theoretical arguments about how to investigate mechanisms underlying disparities to understand why and how minority stress is patterned. Findings showing associations between intersectional discrimination and HCC, but not depressive symptoms, provide potential support for theories about examining allostatic load markers to identify stress-related etiological mechanisms linked to health disparities among minoritized populations.

Exploring the role of negative expectations and emotions in primary dysmenorrhea: insights from a case-control study

BACKGROUND

Primary dysmenorrhea, characterized by painful menstruation, significantly impacts the quality of life for women worldwide. Negative expectations and associated emotions are known to trigger nocebo effects and may also influence cyclic menstrual pain. In this study, we investigated the role of pain expectations and negative anticipatory emotions as potential contributing factors to hyperalgesia in women with severe menstrual pain, compared to women with absent or mild menstrual pain.

METHODS

We conducted a prospective case-control study in women with severe menstrual pain due to primary dysmenorrhea, comparing them with age-matched women with absent or mild menstrual pain. Data collection included the Depression, Anxiety, and Stress Scale (DASS-21) at baseline, as well as daily numeric rating scales (NRS) to evaluate pain expectations, anticipatory negative emotions, and daily stress during the 10 days preceding menstruation. Saliva samples were collected to evaluate the Cortisol Awakening Response (CAR) before menstruation, and pain was assessed during the first 3 days of menstruation.

RESULTS

Women with high menstrual pain reported significantly higher DASS-21 anxiety levels compared to low-pain controls, although still within the normal range (median [IQR], 3 [2; 5] vs. 1 [1; 3], p <.05). In the 10 days preceding menstruation, the high-pain group expected significantly higher maximum pain levels than controls (median [IQR], 8 [7.3; 8.5] vs. 2.1 [1; 3.3], p <.001), which aligned with their actual experiences of maximum pain during menstruation (6.5 [4.8; 7.7] vs. 1.2 [0.7; 2.3], p <.001). Anticipatory stress (2.1 [0.9; 4.2] vs. 0.2 [0; 0.9], p <.001), anticipatory anxiety (0.7 [0.0; 2.3] vs. 0 [0; 0], p <.001), anticipatory worry (1.3 [0.4; 2.6] vs. 0.1 [0; 0.3], p <.001), and anticipatory anger (0.7 [0; 1.5] vs. 0 [0; 0.2], p <.01) were also significantly higher in the high-pain group in the 10 days before menstruation. The CAR showed no significant differences between groups in the days before menstruation. Correlational analyses revealed multiple positive associations between expected pain levels, anticipatory negative emotions, and subsequently perceived levels of menstrual pain in both groups (all p-values < 0.05).

CONCLUSIONS

This pioneering study supports the hypothesis that cognitive-emotional factors such as heightened pain anticipation and negative emotions intensify menstrual pain severity in primary dysmenorrhea, although causal conclusions cannot be drawn from this observational study. Strategies aimed at optimizing expectations could play a significant role in managing primary dysmenorrhea.

Diurnal cortisol profiles and subjective well-being: Longitudinal associations among children and adolescents

There has been evidence suggesting that cortisol is related to subjective well-being. (i.e., positive affect, negative affect, life satisfaction). However, longitudinal associations between diurnal cortisol and subjective well-being remain inadequately explored, and less is known about how combinations of multiple diurnal cortisol indicators may impact subjective well-being. To address these gaps, the current study revealed heterogeneity in diurnal cortisol patterns and examined whether these diurnal cortisol patterns were prospectively associated with subjective well-being six months and one year later among 304 Chinese children and adolescents aged 9-13 (Mage = 10.80, SD = 0.84; 67.1 % boys). Latent profile analysis, a person-centered approach, was conducted using multiple diurnal cortisol indicators (i.e., waking cortisol level, cortisol awakening response, diurnal cortisol slope, area under the curve, and bedtime cortisol level), and identified four distinct diurnal cortisol patterns: steep/medium (57.6 %), moderate/high (25.7 %), flat/high (10.5 %), and steep/low (6.2 %). The flat/high pattern, characterized by sustained elevated cortisol levels throughout the day, was associated with impaired subjective well-being six months and one year later. The moderate/high pattern, which had the same waking cortisol level as the flat/high pattern but demonstrated lower cortisol awakening response and steeper diurnal cortisol slope, was associated with more negative affect six months later. These findings facilitate understanding the heterogeneity in diurnal cortisol rhythm and their implications to subjective well-being over time, which may support targeted psychosocial interventions for promoting subjective well-being among children and adolescents.

Prepartal Stress, Prepartal and Postpartal Hair Glucocorticoid Concentrations, and Symptoms of Postpartum Depression 3 Days and 12 Weeks After Delivery

Background

Postpartum depression (PPD) is a serious mental health problem that affects about 17% of mothers. The aims of the current study were to observe the associations between prenatal stress, self- and expert-rated PPD, and prepartal and postpartal hair cortisol and cortisone concentrations as proxies for altered hypothalamic-pituitary-adrenal axis activity (HPA-AA).

Methods

A total of 129 mothers (mean age 33.1 years) completed the Edinburgh Postnatal Depression Scale 3 days (baseline) and 12 weeks (study end) postpartum. At the end of the study, participants reported on prepartum stressful life events, experts rated participants' symptoms of depression, and participants provided 6 cm of hair strands for analysis of hair glucosteroid levels 12 weeks before and 12 weeks after delivery.

Results

Prepartal stress was associated with higher scores for self- and expert-rated PPD and with lower hair cortisone concentrations as a proxy for less adaptive HPA-AA. Higher prepartal and postpartal hair cortisol/cortisone ratios (i.e., higher cortisol/lower cortisone concentrations) were associated with higher PPD symptom scores.

Conclusions

Women with prepartal stress were at increased risk of experiencing PPD 12 weeks after delivery. Altered hair steroid levels (lower cortisone concentrations) as a proxy for altered HPA-AA further substantiated this association. Results suggest that 1) both prepartal stress and the suppression of HPA-AA appear to be involved in the development of PPD; 2) hair steroid analysis can be used to predict PPD; and 3) women with prepartal stressful life events may benefit from timely support and relief to decrease their risk of developing PPD.

Do not exclude your observations: Negative cortisol awakening responses (CAR) may be biologically relevant

The Cortisol Awakening Response (CAR) is the change in cortisol concentrations within 30-40 minutes after waking from sleep and is frequently used in stress research. Since a positive CAR is expected, we hypothesized that negative values could be associated to an underlying health condition (reflected in hematological parameters) or to environmental exposures such as lead (Pb), which has neuroendocrine effects including altered cortisol diurnal rhythms. Our aim was to analyze the prevalence of negative CAR values and their association with hematological parameters and blood Pb (BPb) levels in pregnant women (n = 900). Cortisol was measured by luminescence immunoassay in two-day saliva samples. CAR was estimated as the difference between the first (time of awakening) and second (45 min after) cortisol concentrations for each collection day and was operationalized as: both days positive (CAR-PP, 23 %), either day with a negative (CAR-NP/PN, 40 %), and both negative (CAR-NN, 37 %). A complete blood count was done using a coulter hematology analyzer. BPb was analyzed by inductively coupled plasma-mass spectrometry. Associations between hematological variables and CAR groups were analyzed using adjusted multinomial logistic regression models. Probabilities were estimated to assess the influence of BPb and hematological variables between CAR groups. The median (25th, 75th) CAR for the first collection day was -2.76 nmol/L (-16.55, 14.62) and -4.14 nmol/L (-17.66, 13.24) for the second day. Women with higher concentrations of leukocytes, eosinophils, basophils, and BPb were more likely to belong to CAR-NN or CAR-NP/PN groups. Compared to women with CAR-PP, those with CAR-NP/PN and CAR-NN had inverse associations for leukocyte levels and higher BPb concentrations. We conclude that negative CAR values could be an indicator of an underlying health condition or associated with environmental exposures such as Pb. Research should consider a thorough assessment of negative CAR values before excluding them from analyses.

Modulation Effect of Physical Activity on Sleep Quality and Mental Hyperactivity in Higher-Education Students

Objectives: The present study seeks to analyze the relationships between the intensity of physical activity, mental hyperactivity and sleep quality. A comparative, descriptive and exploratory study was carried out. Methods: A sample of 1907 university students belonging to the degree of Physiotherapy and Physical Activity and Sport Sciences was used. The International Physical Activity and Mental Hyperactivity Questionnaires were used. The scale used was the Pittsburgh sleep quality index. The proposed model analyzes the relationships of physical activity with mental hyperactivity and various sleep-related factors. Results: The following fit indices were evaluated: Chi-Square = 80.242; Degrees of Freedom = 3; Incremental Fit Index = 0.951, Comparative Fit Index = 0.977; Normed Fit Index = 0.946; Root Mean Square Error of Approximation = 0.071. The values obtained show the good fit of the theoretical model. Statistically significant differences are observed (p < 0.05) in the causal relationship of mental hyperactivity with the personal assessment of sleep as a function of the intensity of physical activity. A greater effect of light (β = 0.671) compared to moderate- (β = 0.428) or vigorous-intensity (β = 0.343) physical activity in personal sleep assessment is evident. Statistically significant differences were also observed in the causal relationship of mental hyperactivity with the time to fall asleep (p < 0.05). Light physical activity (β = 0.479) has a greater causal relationship with time to fall asleep than moderate- (β = 0.302) or vigorous-intensity (β = 0.413) physical activity. Conclusions: Based on the results obtained, it is concluded that the intensity with which physical activity is performed has a modulating effect on sleep quality and mental hyperactivity.

Salivary cortisol trajectories among inpatients undergoing substance use disorder treatment: A prospective repeated-measures study

BACKGROUND

A growing body of research among inpatients with substance use disorders (SUD) suggests a link between cortisol levels and treatment outcomes. However, there is limited insight into the pattern of cortisol level during an inpatient SUD treatment stay.

AIM

The aim was to investigate changes in salivary cortisol levels during 8 weeks of an inpatient SUD treatment stay, and to determine whether the primary SUD diagnosis exerted a distinct effect on cortisol level trajectories.

METHODS

We employed a prospective repeated-measures design and followed a cohort of patients with various SUD diagnoses. Salivary cortisol samples were collected at four time points during the first 8 weeks of the treatment stay (t1: week 2 (baseline); t2: week 4; t3: week 6; and t4: week 8). We assessed basal cortisol concentration by calculating the area under the curve with respect to ground (AUCG), which represents total daily cortisol output. Associations were determined using Linear mixed model analyses (LMMs).

RESULTS

The analytic sample comprised 173 patients. The full LMM model, including covariates (i.e. polysubstance disorder, age, gender, treatment history, treatment unit, mental distress) revealed that cortisol levels decreased from t1 to t2 (β = -7.218; 95 % CI: -11.126 to -3.310; p < 0.001) and stabilized thereafter. Patients with opioid use disorders (OUD) had lower cortisol level trajectories than patients with stimulant use disorders (β=-20.357; 95 % CI: -29.394 to -11.319; p < 0.001), while patients treated in the long-term unit showed elevated cortisol trajectories relative to those in the short-term unit (β=6.650; 95 % CI: 0.072-13.229; p = 0.048).

CONCLUSION

This study showed a decline in cortisol levels during the first 4 weeks of SUD inpatient treatment, followed by stabilization. Patients with stimulant use disorders had higher cortisol levels over time than those with OUD. Further research should explore the clinical implications of the current findings. In particular, greater insight into the moderating effects of polysubstance disorders on cortisol levels may contribute to the development of individual tailored treatment approaches.

Stress can be detected during emotion-evoking smartphone use: a pilot study using machine learning

Introduction

The detrimental consequences of stress highlight the need for precise stress detection, as this offers a window for timely intervention. However, both objective and subjective measurements suffer from validity limitations. Contactless sensing technologies using machine learning methods present a potential alternative and could be used to estimate stress from externally visible physiological changes, such as emotional facial expressions. Although previous studies were able to classify stress from emotional expressions with accuracies of up to 88.32%, most works employed a classification approach and relied on data from contexts where stress was induced. Therefore, the primary aim of the present study was to clarify whether stress can be detected from facial expressions of six basic emotions (anxiety, anger, disgust, sadness, joy, love) and relaxation using a prediction approach.

Method

To attain this goal, we analyzed video recordings of facial emotional expressions collected from n = 69 participants in a secondary analysis of a dataset from an interventional study. We aimed to explore associations with stress (assessed by the PSS-10 and a one-item stress measure).

Results

Comparing two regression machine learning models [Random Forest (RF) and XGBoost], we found that facial emotional expressions were promising indicators of stress scores, with model fit being best when data from all six emotional facial expressions was used to train the model (one-item stress measure: MSE (XGB) = 2.31, MAE (XGB) = 1.32, MSE (RF) = 3.86, MAE (RF) = 1.69; PSS-10: MSE (XGB) = 25.65, MAE (XGB) = 4.16, MSE (RF) = 26.32, MAE (RF) = 4.14). XGBoost showed to be more reliable for prediction, with lower error for both training and test data.

Discussion

The findings provide further evidence that non-invasive video recordings can complement standard objective and subjective markers of stress.

Effects of acute psychological stress on blood cell-free mitochondrial DNA (cf-mtDNA): A crossover experimental study

In response to acute stress, prior studies have found an increase in circulating cell-free mitochondrial DNA (cf-mtDNA) and pro-inflammatory cytokines, highlighting two potential inter-related mechanisms by which stressors can get under the skin. However, prior studies lacked a resting control condition to isolate the effect of psychological stress from other aspects related to laboratory procedures. Here, we conducted a crossover experimental trial examining responses to a socio-evaluative stressor under laboratory conditions. 72 volunteers (age 20-50, 48% women) were tested on two occasions, counterbalanced, separated by at least a month. On one occasion, they were exposed to a 5-min socio-evaluative stressor (speech task), and on the other occasion, rested for the same period. Blood samples were obtained at 10 timepoints from pre- to 2 hours post-exposure to assess neuroendocrine (cortisol, catecholamines), pro-inflammatory cytokine (IL-6, IL-10, TNF-ɑ), and both plasma and serum cf-mtDNA responses. Compared to the control visit, the stressor significantly increased anxiety, heart rate, blood pressure, cortisol, and norepinephrine ( p 's<0.05-0.0001), confirming the psychobiological impact of the stressor. Unexpectedly, IL-6 and plasma cf-mtDNA increased (time effect p <0.0001) in both the stress and control conditions. While no significant effect of time was found for serum cf-mtDNA, plasma cf-mtDNA showed a bi-phasic response with an initial 22-24% increase at 5-10 min (g=0.07, stress-control visits), followed by a decrease and another 70-81% increase from 45 to 75 min (g=0.59 (stress visit), g=0.41 (control visit)). There were no significant associations between the pro-inflammatory and cf-mtDNA responses, pointing to their independent regulation. While mood, cardiovascular, and neuroendocrine reactivity were selectively induced by socio-evaluative stress, IL-6 and blood cf-mtDNA increased across both the stress and control conditions, suggesting that these biomarkers may reflect non-specific responses to the laboratory protocols (e.g., blood draw) rather than to socio-evaluative stress itself.

Do biological alterations precede the onset of psychosis? A systematic review and meta-analysis of immune, cardiometabolic, prolactin and HPA axis alterations in clinical high-risk for psychosis

First episode psychosis (FEP) individuals show biological abnormalities preceding antipsychotic treatment. However, it remains unclear whether such alterations are also present before the onset of psychosis. We aim to provide estimates of standardized mean differences for immune, cardiometabolic, prolactin, and HPA axis parameters in individuals at clinical high-risk for psychosis (CHR-P) compared to healthy controls (HC) and FEP individuals, and between CHR-P transitioning to psychosis (CHR-T) compared non-transitioning (CHR-NT). A multistep literature search was performed from database inception until September 25, 2023. PRISMA/MOOSE-compliant and pre-registered (PROSPERO: CRD42024507670) systematic review identified studies reporting on immune, cardiovascular or endocrine parameters in CHR-P samples compared with HC or FEP samples or comparing CHR-T vs CHR-NT. Inter-group differences in magnitude of effect were estimated using Hedges g and estimates were pooled using random-effects meta-analysis. Heterogeneity was high for most outcomes. 37 studies were included, total sample 2509 CHR-P, 710 FEP, and 1444 HC individuals. A statistically significant elevation of pro-inflammatory proteins was found among CHR-P compared with HC (k = 12; N = 1710; g = 0.16; p < 0.01) and FEP (k = 7; g = 0.15; p = 0.04) subjects. Interleukin-6 (IL-6) was increased in CHR-P compared to HC (k = 9; N = 1243; g = 0.54; p < 0.01), and interleukin-4 (IL-4) was increased in CHR-T compared with CHR-NT (k = 2; N = 318; g = 0.36; p < 0.01). CHR-P exhibited stronger cortisol awakening response than FEP subjects (k = 3; N = 173; g = 0.51; p = 0.01). CHR-P and FEP individuals did not show statistically significant differences in terms of prolactin levels. An inflammatory state (particularly marked by elevated IL-6 and IL-4 levels) and HPA axis alterations are present in CHR-P individuals.

Associations between perceived stress and cortisol biomarkers in predominantly Latino adolescents

The relationship between cortisol and perceived stress is poorly understood. We sought to determine whether perceived stress is associated with cortisol biomarkers in adolescents. In a sample of 229 adolescents (mean age = 15.8 years) we measured perceived stress with the 14-item Perceived Stress Scale (PSS) questionnaire, serum cortisol (sCOR), salivary Cortisol Awakening Response (CAR: 30-minute post-awakening - awakening), salivary Diurnal Cortisol Slope (DCS: evening-awakening), and total daily salivary cortisol (TDC). Multivariable linear regression was used to estimate baseline associations between PSS, TDC, and sCOR Mixed effects linear regression was used to estimate baseline associations between PSS and CAR and DCS. A twelve-week longitudinal association between PSS and cortisol biomarkers using random effects regression was tested. Analyses were adjusted for age, gender, and BMI. There were statistically significant associations between PSS and TDC (beta= -104.36 ± 34.3; p = 0.002) at baseline and between PSS and DCS at 12 weeks (beta= -0.058 ± 0.02; p = 0.01), but no association between PSS and sCOR or CAR (p > 0.26 for all) at baseline or 12-weeks. There were no associations between change in PSS and change in cortisol biomarkers longitudinally. In adolescents, perceived stress, measured by the PSS, was inconsistently associated with TDC and DCS, and consistently unassociated with CAR and sCOR. Studies reporting on PSS outcomes should exercise caution when making conclusions about cortisol biomarkers. There is a need for greater specificity of psychological stress to understand their relationship with biomarkers of stress.

What factors influence thriving in adolescent and young adult cancer patients? A focus on psychological health, biological markers, and quality of life

PURPOSE

This study explores the role of psychological health, biological markers, and quality of life (QoL) in influencing thriving - defined as resilience and enhanced well-being - among adolescent and young adult (AYA) cancer patients.

METHODS

A total of 148 AYA cancer patients were assessed for psychological health indicators (anxiety, depression, character strengths), physiological markers (cortisol awakening response [CAR], melatonin), and QoL. Thriving levels were evaluated using ordinary least squares regression and quantile regression to identify predictors across different thriving percentiles.

RESULTS

Psychological health was the strongest predictor of thriving. Depression negatively impacted thriving at lower levels, while inquisitiveness consistently enhanced it. CAR and melatonin played roles at higher and median thriving levels, respectively, and QoL was most influential at lower levels. These factors collectively explained 23.0% of the variance in thriving scores.

CONCLUSIONS

This study highlights depression, inquisitiveness, CAR, and QoL as key factors influencing thriving in AYA cancer patients. Depression affects thriving at lower levels, inquisitiveness enhances thriving consistently, CAR is significant at higher levels, and QoL is crucial at lower levels. These findings underscore the need for tailored interventions to support thriving across varying levels of adaptation.

Sleep Quality and Evening Salivary Cortisol Levels in Association with the Psychological Resources of Parents of Children with Developmental Disorders and Type 1 Diabetes

BACKGROUND

Sleep deprivation can decrease parental well-being and degrade mental and physical health in parents of children with chronic illness. The aim of this study was to explore the associations of sleep quality, psychological stress perception, and evening salivary cortisol concentration with self-esteem, optimism and happiness in parents of children with type 1 diabetes and developmental disorders compared to parents of healthy, typically developing children.

METHODS

We studied 196 parents of children with chronic conditions, including autistic spectrum disorder (N = 33), cerebral palsy (N = 18), Down syndrome (N = 33), and diabetes mellitus type 1 (N = 40) and parents of healthy children (N = 72). We evaluated parental sleep quality, evening salivary cortisol levels, self-esteem, optimism and happiness. Multiple linear regression models were used to assess associations between variables.

RESULTS

Compared with those of the control group, the parents of children with autistic spectrum disorders had higher evening cortisol concentrations (β = 0.17; p = 0.038) and lower perceptions of happiness (β=-0.17; p = 0.017), while parents of children with type 1 diabetes had disrupted sleep quality (β = 0.25; p = 0.003). Optimism was negatively associated with the evening cortisol concentration (β=-0.18; p = 0.023) and sleep quality index (β=-0.20; p = 0.012).

CONCLUSIONS

Public health programs aimed at lifestyle habit improvement, respite care, and relaxation for parents of children with chronic conditions would be useful for improving parental sleep quality, self-esteem, optimism and happiness.

Hypothalamic-pituitary-adrenal axis functioning in offspring of parents with a major affective disorder: a meta-analytic review

Because the offspring of parents with an affective disorder (OAD) are at high risk for developing mental disorders, and persons with an affective disorder (AD) show dysfunctional hypothalamic-pituitary-adrenal (HPA) axis activity, changes in HPA functioning in OAD might be an etiological risk factor that precedes the development of ADs. The primary aim of the meta-analysis was to quantitatively summarize the existing data on different indices of diurnal cortisol in the OAD. The secondary aim was to explore potential moderators of this relation. Following PRISMA guidelines, we included 26 studies (3052 offspring) on diurnal cortisol in our meta-analysis after an initial screening of 3408 articles. Intercept-only and meta-regression models were computed using the robust variance estimation method. Analyses examining mean cortisol levels at discrete timepoints, total cortisol output, and the cortisol rise in response to awakening (CAR) were conducted separately. The results demonstrated that the OAD had higher mean levels of cortisol at different timepoints throughout the day compared to controls (Hedge's g = 0.21). There was evidence of publication bias in studies examining CAR, such that effect sizes were positively biased. The present findings are consistent with a meta-analysis showing elevated cortisol in youth having an AD. Notable limitations across studies include the method of cortisol measurement and assessment of ADs. Altogether, these results highlight the fact that increased cortisol levels may act as a potential neuroendocrine antecedent and/or risk factor for the development of ADs among high risk youth.

The Ecology of Human Sleep (EcoSleep) Cohort Study: Protocol for a longitudinal repeated measurement burst design study to assess the relationship between sleep determinants and outcomes under real-world conditions across time of year

The interplay of daily life factors, including mood, physical activity, or light exposure, influences sleep architecture and quality. Laboratory-based studies often isolate these determinants to establish causality, thereby sacrificing ecological validity. Furthermore, little is known about time-of-year changes in sleep and circadian-related variables at high resolution, including the magnitude of individual change across time of year under real-world conditions. The Ecology of Human Sleep (EcoSleep) cohort study will investigate the combined impact of sleep determinants on individuals' daily sleep episodes to elucidate which waking events modify sleep patterns. A second goal is to describe high-resolution individual sleep and circadian-related changes across the year to understand intra- and inter-individual variability. This study is a prospective cohort study with a measurement-burst design. Healthy adults aged 18-35 years (N = 12) will be enrolled for 12 months. Participants will continuously wear actimeters and pendant-attached light loggers. A subgroup will also measure interstitial fluid glucose levels (six paticipants). Every 4 weeks, all participants will undergo three consecutive measurement days of four ecological momentary assessments each day ('bursts') to sample sleep determinants during wake. Participants will also continuously wear temperature loggers (iButtons) during the bursts. Body weight will be captured before and after the bursts in the laboratory. The bursts will be separated by two at-home electroencephalogram recordings each night. Circadian phase and amplitude will be estimated during the bursts from hair follicles, and habitual melatonin onset will be derived through saliva sampling. Environmental parameters (bedroom temperature, humidity, and air pressure) will be recorded continuously.

The cortisol awakening response in very preterm born adults compared to term born adults

Very preterm infants are at higher risk of long-term neurodevelopmental and psychiatric impairments, including anxiety. Prematurity is also linked to altered programming of the hypothalamus-pituitary-adrenal (HPA) axis, associated with stress-related diseases. The cortisol awakening response (CAR), marked by a rapid cortisol increase after waking, is a biomarker of HPA reactivity and is linked to psychiatric disorders. This study aimed to evaluate for the first time the CAR in adults born very preterm and to explore its association with anxiety and stress. Twenty-five young adults born very preterm and 24 age- and sex-matched term-born controls collected saliva samples on two consecutive mornings at 0, 30, 45, and 60 min after awakening. Anxiety was measured using the State-Trait Anxiety Inventory, and stress was assessed with the Perceived Stress Scale. The CAR was analyzed using the sample at 0 min (S1), total cortisol output (AUCg), and actual CAR (AUCi). There were no significant differences in AUCi. The preterm group exhibited lower S1 levels and a reduced AUCg. Preterm-born participants reported higher trait anxiety and stress, though no consistent link with the CAR was identified. Findings suggest long-term neuroendocrine changes in adults born very preterm, warranting further research. Clinical Trial Registration: Duetsche Register Klinischer Studien (DRKS): 00020235.

Psychobiological Stress Regulation in Depressive Women Achieved Through Group Music Therapy: Results From the Randomised-Controlled Music Therapy for Depression Study

Major depressive disorder (MDD) is a stress-related disease that affects women more often than men. Music therapy (MT) has been shown to be effective in the treatment of MDD. However, clinical trials investigating the effects of MT on psychological and psychobiological stress-related outcomes in women suffering from MDD are still scarce. This study was conducted as a randomised controlled trial, with participants assigned to either an intervention group (IG), which received group MT (GMT), or a waitlist control group (CG), which received GMT 6 months later. The primary objective was to assess the impact of GMT on psychological stress outcomes (chronic stress, stress coping, and stress experienced in daily life) and psychobiological stress markers (diurnal salivary cortisol levels and circadian heart rate variability), considering the effects of both group allocation and time. Outcome measurements were taken before, immediately after, and-for some variables-10 weeks following the intervention period. A total of 102 women 18-65 years old and diagnosed with current MDD took part in the study. Overall, the IG demonstrated significantly stronger stress-reducing effects than the CG. Significant improvements were observed in general stress coping, positive thinking, daily life stress, and cortisol levels. GMT is a cost-effective and non-invasive approach to effectively address the stress-related psychological and psychobiological burden associated with MDD. To demonstrate long-term effects and gain a better understanding of the underlying mechanisms, further methodologically robust studies are needed. TRAIL REGISTRATION: The MUSED study was pre-registered at the German Clinical Trials Registry (DRKS00016616). All study-related procedures were published in detail in a study protocol.

Research prospect of human salivary cortisol: a bibliometric analysis

Background

Salivary cortisol has garnered increasing attention; the aim of this study was to employ bibliometric analysis to identify key papers in this research field and to explore its current status and trends.

Methods

Data were sourced from Clarivate Analytics' Web of Science core database, utilizing the search terms 'TS = ('Salivary cortisol') AND (Human) NOT (animal)'. All articles published from January 1, 2004, to September 30, 2024, were included.

Results

A total of 876 articles were identified. The United States has made a significant contribution to this field, with the highest number of publications at 291. The University of California system leads this research area, having published 40 articles. Professor Clemens Kirschbaum has authored 21 articles in this domain. The journal Psychoneuroendocrinology published the largest number of articles, totaling 99, which accounts for 11.3% of the overall articles. Additionally, Psychoneur-oendocrinology was the most cited journal, with 3,681 citations. High-frequency keywords reveal the developmental status and future trends of human salivary cortisol. As a biomarker and signaling molecule, salivary cortisol is closely linked to human gender, personality, psychology, and physiology. We identified that "mental health," "circadian rhythm," and "assay" may become focal points of interest in the coming years.

Conclusion

Global publications related to human salivary cortisol were systematically reviewed. CiteSpace and VOSviewer were utilized to analyze their bibliometric characteristics, identify the most cited articles in the field, and determine the leading countries, authors, and institutions, along with the interconnections among them. This analysis aims to elucidate the current status, hotspots, and trends in global research, while providing future development directions for scientific inquiry and medical practitioners.

Salivary cortisol measures across the clinical stages of psychosis: An individual participant data (IPD) meta-analysis

BACKGROUND

Studies of salivary cortisol levels in psychosis have yielded inconsistent findings, which may be attributable to heterogeneity in cortisol measurement, illness stage, and approaches to dealing with sampling factors and potential confounders. To address these issues, we performed an individual participant data (IPD) meta-analysis comparing individuals at different stages of psychosis to controls using five different salivary cortisol measures and explored potential effect modifiers.

METHODS

Salivary cortisol data from five London-based cohorts were used to derive the cortisol awakening response, total daytime cortisol output, basal cortisol, and diurnal slope measures (wake-to-evening and peak-to-evening). Linear regression models were first performed to obtain standardised beta coefficients (β), representing the difference in each cortisol metric between each clinical stage group (cases) and healthy individuals (controls) after accounting for relevant sampling factors; we then used random-effects meta-analyses and meta-regression models to investigate the effect of psychosis stage and sample characteristics on effect sizes.

RESULTS

Data were available for 352 individuals distributed across psychosis clinical stages (1a - distress disorder: N = 35; 1b - clinical high-risk for psychosis: N = 90; 2a - first-episode psychosis: N = 197; 2b - single episode remitted: N = 5; 3 - relapsing/remitting illness: N = 18; 4 - severe and persistent illness: N = 7) and 292 controls. A significant overall main effect of clinical stage on peak-to-evening diurnal slope was observed (χ2=12.83, p = 0.025), with both the clinical high-risk (β=0.21, 95 % CI: 0.06, 0.36) and first-episode psychosis (β=0.20, 95 % CI: 0.10, 0.31) groups characterised by flatter slopes than controls. The clinical stage groups and controls did not differ on any other cortisol measure. Several sample characteristics were significantly associated with diurnal slope effect sizes, but after accounting for clinical stage, only the association between mean age in cases and wake-to-evening diurnal slope retained significance.

CONCLUSION

Clinical high-risk and first-episode psychosis participants differed from healthy controls in the peak-to-evening diurnal cortisol slope. This measure has not been examined in these populations before, and its potential predictive and prognostic utility for psychotic disorders merits further investigation.

Immune-neuroendocrine crosstalk in mood and psychotic disorders: A meta-analysis and systematic review

Background

Bidirectional interactions between immune and neuroendocrine mechanisms are involved in mood and psychotic disorders, although individual studies report inconsistent and even contradictory findings on the nature of this crosstalk. Our objective was to perform an up to date systematic review and meta-analysis of the association between hypothalamic-pituitary-adrenal (HPA) axis and immune system functioning in mood and psychotic disorders.

Methods

We searched the Pubmed, Web of Science and Embase databases for studies reporting correlations between one or more HPA- and immune markers (IM) in patients with mood or psychotic disorders. We analyzed unchallenged correlations as well as challenge studies investigating the HPA-immune interaction through dexamethasone (DEX) and/or CRH suppression, HPA-mediated challenge of immune cell proliferation, immune challenges, or psychological stressors. Finally, genetic studies focusing on HPA x immune interrelation were evaluated. For meta-analyzable data, three primary outcome measures were defined for immune functioning, namely the pro-inflammatory index (PII) and anti-inflammatory index (AII) for the molecular IM and a composite cellular immune marker score (CCIM) for the cellular IM. Secondary analyses were performed for the individual molecular and cellular IM. Heterogeneity was evaluated with the I2 statistic. Meta-regression analyses were performed to evaluate the impact of potential covariates (publication year, gender, age, symptom severity) on the primary outcome analyses.

Results

93 studies (n = 8226) were included, of which 50 (n = 5649) contained meta-analyzable data. The majority of the included studies (k = 72) investigated major depressive disorder (MDD) patients, nineteen schizophrenia spectrum disorders (SSD) and six bipolar disorder (BD). Under physiological conditions, a poor association was found between cortisol and the PII only in the unmedicated subsample of MDD (k = 8; n = 425; r = .205; z = 2.151; p = .031) and the medicated subsample of SSD (k = 4; n = 152; r = .0.237; z = 2.314; p = .021). No significant correlation was found in MDD between the AII and cortisol (k = 3; n = 1243; r = .005; z = .188; p = .851). Similar results were found for the association between immune cell numbers and cortisol in both MDD (k = 10; n = 773; r = -.005; z = -.113; p = .894) and SSD (k = 4; n = 99; r = .167; z = 1.356; p = .175). A total of 42 studies discussed post-challenge associations between immune alterations and HPA disturbances, of which 12 (n = 389; all MDD) contained meta-analyzable data and 37 entered the systematic review (n = 1783). No post-DEX correlations were found between cortisol and PII (k = 3; n = 105; r = .074; z = .355; p = .722) or CCIM (k = 5; n = 259; r = -.153; z = -1.294; p = .196). However, a significant association was found between post-DEX cortisol/ACTH and PII produced by stimulated blood cells in vitro (k = 3; n = 61; r = .508; z = 4.042; p < .001) as well as for cortisol and CCIM score in MDD after in vitro mitogen stimulation (k = 4; n = 90; r = -.309; z = -2498; p = .012). Following a psychological stressor (k = 6; n = 121), cortisol responses tended to be blunted in all included pathologies, while immune activation was comparable to healthy controls. Genetic studies (k = 7; n = 464) demonstrate altered gene expression of glucocorticoid receptors (GR) in peripheral immune cells in MDD. Heterogeneity over studies tended to be moderate to high.

Discussion

The main limitations are the heterogeneity of outcome measures (both HPA and IM) and small sample sizes of the included studies. We conclude that, in physiological conditions, associations between HPA-axis and molecular or cellular IM are absent or poor in both MDD and SSD and psychotropic medication may influence this crosstalk differently in both patient groups. Studies using challenge paradigms in MDD populations did reveal differences in the HPA-immune crosstalk. The normally expected decrease in lymphocytes after DEX distribution tended to be less pronounced in MDD, especially in glucocorticoid-insensitive non-suppressors. It is recommended that future studies should be properly powered and assess HPA functioning using multiple cortisol assessments. Challenge studies are probably more useful than baseline biomarker studies and cellular IM are more informative than molecular IM. It is recommended to broadly assess leucocyte function and, when possible, perform subgroup analyses based on HPA- and/or immune function.

Parenting Behavior and Early Childhood Mental Health: Cortisol Awakening Response as a Moderator of Child Internalizing and Externalizing

Certain observable parenting behaviors contribute to the risk of children developing internalizing and externalizing problems. Yet parenting behaviors do not affect all children uniformly and effects may depend on identifiable child characteristics. One factor is a child's biological sensitivity to the caregiving environment, an indicator of which is a stress hormone, cortisol. This longitudinal study examines two dimensions of observable parenting behaviors, responsive and rejecting/harsh. These parenting behaviors and child cortisol awakening response (CAR) were measured during home visits in a sample of 100 mostly low-income White and Latina/Hispanic mothers and their children at ages 4-6. Children's internalizing and externalizing behaviors were assessed one year later. We tested the effects of responsive and harsh/rejecting parenting on child internalizing and externalizing and examined child CAR as a moderator. Results indicated that responsive parenting predicted better child mental health as indexed by fewer internalizing and externalizing behaviors, whereas harsh/rejecting parenting predicted more internalizing behaviors. Harsh/rejecting parenting interacted with child CAR such that harsh/rejecting parenting predicted more externalizing only among children with low CAR; there was no interaction of responsive parenting with child CAR. These results elucidate how child CAR may shape mental health outcomes associated with harsh/rejecting parenting.

Resting Hypothalamic-Pituitary-Adrenal Axis Activity in Childhood Following Maltreatment: A Meta-Analysis

The experience of maltreatment in childhood is associated with poorer developmental and health outcomes. This may be explained by the capacity for maltreatment to dysregulate stress-responsive neurophysiological systems, including the hypothalamic-pituitary-adrenal (HPA) axis. This study presents the results of the first meta-analysis that examines the association between maltreatment and resting HPA-axis activity in children and the role of "third variables" in accounting for observed heterogeneity in this association. Analyses of 18 studies, including N = 2216 children, indicated that although there was no difference in resting HPA-axis activity between children who had been maltreated and those who had not (standardized mean difference [SMD] = 0.04), there was substantial heterogeneity in the association between maltreatment and HPA-axis activity across studies (I2 = 58.60%, p = 0.001). Further analyses revealed that the association between maltreatment and resting HPA-axis activity was contingent upon the source of information regarding maltreatment (B = 0.33, p = 0.002) and the degree to which maltreated and comparison groups differed in their socioeconomic status (B = 0.39, p = 0.037).

Increasing student well-being through a positive psychology intervention: changes in salivary cortisol, depression, psychological well-being, and hope

The significant prevalence of mental health problems among children and adolescents is a major concern worldwide. The current study evaluates the impact of a year-long, school-based intervention, Flourishing Students, on adolescents' salivary cortisol levels, depressive symptoms, psychological well-being, and hope. Utilizing a cluster randomized design with intervention and control classes, 72 students engaged in 32 well-being lessons during academic year 2016-2017, whereas 68 students followed their standard curriculum. Depressive symptoms and psychological well-being were assessed at three time points, while the stress hormone cortisol and hope were measured at two. The results showed a slight increase in cortisol levels from baseline to post-intervention during school hours in the control group, whereas no change occurred in the intervention group. Additionally, total cortisol levels at post-intervention were slightly lower among intervention-group students compared with control group students. Questionnaire data revealed significant interaction effects on psychological well-being and hope from baseline to post-intervention, and on depression and psychological well-being from baseline to the 5-month follow-up. The intervention group scored lower in depressive symptoms and higher in psychological well-being and hope compared with the control group. These findings underscore the essential role of comprehensive assessment methods in evaluating intervention efficacy in well-being programs.

Identity change and the transition to university: Implications for cortisol awakening response, psychological well-being and academic performance

The social identity model of identity change (SIMIC) posits that social group memberships protect well-being during transitional periods, such as the transition to university, via two pathways - maintaining previously held social group memberships (social identity continuity) and gaining new social group memberships (social identity gain). Breaking new ground, this study investigates how these processes can influence an important biomarker of stress - cortisol awakening response (CAR). A total of 153 first year undergraduate students (69.3% female) completed measures (group memberships, depression, life satisfaction) at the beginning of the academic year (October, time 1; T1), of which 67 provided a saliva sample for CAR assessment. Seventy-nine students completed the time 2 (February, T2) measures 4 months later (41 provided saliva). Academic performance was assessed objectively through end-of-academic year university grade data (June, T3). At T1, students who maintained and gained social group memberships reported lower depressive symptoms and greater life satisfaction. Across the academic year, social identity gain was associated with a larger post-awakening cortisol response at T2, indicative of a better ability to cope with stress. Thus, gaining new social group memberships during the transition to university was associated with a better ability to cope with stress.

Maternal stress in the early postpartum period is associated with alterations in human milk microbiome composition

BACKGROUND

Maternal stress is associated with negative early-life development and (mental)health outcomes. There is recent evidence that maternal stress in the postpartum period impacts the nutrient composition of human milk (HM). However, it is currently not known whether maternal stress is associated with changes in the HM microbiome during the critical early postpartum period.

METHODS

In this prospective observational cohort study, lactating women were recruited into a high-stress (HS, n = 23) and control (CTL, n = 69) group. The HS group included mothers with infants hospitalized for at least two days. Maternal stress was assessed using validated questionnaires and cortisol concentrations in hair, saliva and HM. HM was collected at days 10 and 24 and its microbiome was analyzed using 16 s rRNA sequencing. HM bacterial composition was compared between study groups and their correlation with maternal stress levels, maternal characteristics and infant outcomes was determined.

RESULTS

HM microbiome β-diversity differed significantly between study groups, with HS mothers displaying decreased abundance of Streptococcus, Gemella, and Veillonella, and increased levels of Staphylococcus, Corynebacterium and Acinetobacter compared to the control group. While the strongest correlation of β-diversity was with stress, HM microbiome β-diversity also correlated significantly with maternal education level and infant sex. No correlation between HM microbiome composition and HM cortisol concentrations was found.

CONCLUSIONS

This study demonstrates stress-associated alterations in the early HM microbiome that could potentially contribute to early gut colonization and subsequent (mental)health outcomes. Future research is needed to elucidate the physiological significance of these changes for infant development and health.

Psychophysiological markers of athlete burnout: a call to arms

Burnout is a growing problem in high-performance sport and has negative consequences for athletes (e.g., mental ill-health). It is therefore important to effectively monitor athlete burnout to aid intervention efforts. While self-report measures are available (e.g., athlete burnout questionnaire), the limitations associated with these measures (e.g., social desirability bias) means that objective physiological markers may also be useful. Thus, this article critically discusses potential biomarkers of athlete burnout, drawing on research inside and outside of sport to offer an overview of the current state-of-the-art in this research area. First, it outlines what athlete burnout is, its deleterious consequences, and discusses existing psychological assessments. The article then critically discusses literature on hypothalamic-pituitary-adrenal axis (e.g., salivary cortisol) and autonomic nervous system (e.g., heart rate variability) indices of burnout, highlighting some promising biomarkers for future research (e.g., salivary cortisol at bedtime, vagally-mediated heart rate variability at rest). Finally, the article concludes by highlighting key considerations and offering recommendations for future research (e.g., use of more homogenous methods in assessing burnout and physiological parameters). As a result, the intention of this article is to spark more higher quality research on the psychophysiology of athlete burnout, thereby helping tackle this prominent issue in high-performance sport.

Measuring salivary cortisol in biobehavioral research: A systematic review and methodological considerations

The assessment of salivary cortisol in community settings has gained popularity in biobehavioral research due to its noninvasive sampling, ease of handling and storage, and suitability for repeated sampling in short intervals. Ensuring consistent methodological practices for salivary cortisol is essential. This systematic review critically examines salivary cortisol collection procedures, data cleaning, and analysis to better understand its role in biobehavioral research within community populations. Fifty-eight articles met the inclusion criteria. Results indicated significant variability in study designs and cortisol measurement procedures, particularly regarding the biobehavioral role of cortisol, sampling periods, covariate considerations, cortisol analysis parameters, and data analysis plans. The review highlights commonly used and promising study designs while identifying methodological issues in cortisol measurement and analysis that should be addressed to improve comparability in future research.

Early-life adversity as a predictor of fibromyalgia syndrome: the central role of perceived stress over endocrine stress indicators

ABSTRACT

This study investigates the associations between early childhood adversities, stress perception, and fibromyalgia syndrome (FMS). Although the interconnection between dysregulated stress systems and FMS is well documented, the interconnection between early adversities and FMS remains less understood. This study explores the relationship of early-life stress and FMS by examining its mediation through perceived stress, and acute and chronic endocrine stress indicators. Stress was assessed using the perceived stress scale, as well as using salivary and hair cortisol as endocrine indicators of acute and chronic stress, respectively. The sample consisted of 99 individuals with FMS and 50 pain-free controls. A structural equation model was used to assess the mediating effects of stress indicators between early adversities and the severity of FMS. Compared with controls, individuals with FMS had notably higher early adversity scores (d = 0.63) and greater occurrence of exposure to adversity (78.8% vs 66%). Structural equation modeling indicated that the influence of early adversities on FMS symptoms is mediated by perceived stress levels, with no direct effect observed. Our findings indicate that early-life adversity is a significant determinant of the development of FMS, with the relationship between these factors mediated by perceived stress rather than by endocrine stress indicators. These results underscore the critical role of stress perception in the development and management of FMS, suggesting that perceived stress may serve as a valuable therapeutic target. Incorporating trauma-informed and stress-targeted care into treatment strategies could significantly improve outcomes for individuals with FMS, emphasizing the importance of addressing psychological factors alongside physical symptoms.

Longitudinal investigation of neurobiological changes across pregnancy

Pregnancy is a period of profound biological transformation. However, we know remarkably little about pregnancy-related brain changes. To address this gap, we chart longitudinal changes in brain structure during pregnancy and explore potential mechanisms driving these changes. Ten participants (Mean age = 28.97 years) are assessed 1-6 times (median = 3) during their pregnancy. Each visit includes anatomical and diffusion-weighted MRI, and assessments of waking salivary hormones, hair hormones, and inflammatory cytokines. Here we observe a reduction in gray matter volume and an increase in neurite density index (NDI), a proxy of axon density, in white matter tracts across pregnancy. Progesterone levels are associated with reductions in brain volumetric measurements, and both progesterone and estradiol levels are linked to increases in NDI in white matter tracts. This study highlights the profound neurobiological changes experienced by pregnant individuals and provides insights into neuroplasticity in adulthood.

The Cortisol Awakening Response: Regulation and Functional Significance

In healthy individuals, the majority of cortisol secretion occurs within several hours surrounding morning awakening. A highly studied component of this secretory period is the cortisol awakening response (CAR), the rapid increase in cortisol levels across the first 30 to 45 minutes after morning awakening. This strong cortisol burst at the start of the active phase has been proposed to be functional in preparing the organism for the challenges of the upcoming day. Here, we review evidence on key regulatory and functional processes of the CAR and develop an integrative model of its functional role. Specifically, we propose that, in healthy individuals, the CAR is closely regulated by an intricate dual-control system, which draws upon key circadian, environmental, and neurocognitive processes to best predict the daily need for cortisol-related action. Fine-tuned CAR expression, in turn, is then assumed to induce potent glucocorticoid action via rapid nongenomic and slower genomic pathways (eg, affecting circadian clock gene expression) to support and modulate daily activity through relevant metabolic, immunological, and neurocognitive systems. We propose that this concerted action is adaptive in mediating two main functions: a primary process to mobilize resources to meet activity-related demands and a secondary process to help the organism counterregulate adverse prior-day emotional experiences.

Increasing stress resilience in older adults through a 6-week prevention program: effects on coping strategies, anxiety symptoms, and cortisol levels

Introduction

As people age, chronic stress, resulting in prolonged or repeated activation of the hypothalamic-pituitary-adrenal (HPA) axis, has been associated with long-term adverse health outcomes. Coping strategies and social support have been recognized as contributing to resilience to stress in older adults. Few studies have evaluated stress management training (SMT) interventions based on psychoneuroendocrinology that were designed to be delivered to healthy older adults in community settings.

Methods

In this study, a total of 170 older adults (mean age = 76.07, SD = 7.67) participated in a cluster-randomized trial designed to compare the delivery of an SMT intervention with a waitlist condition.

Results

The effect of SMT on coping strategies, stress, anxiety, and depression was measured 3 weeks and 3 months after the intervention. In addition, we tested the effect on basal cortisol secretion over 2 days from saliva samples upon awakening and the total diurnal cortisol output [area under the curve with respect to ground (AUCg)]. Results from repeated measures analyses of variance showed that participants who received the intervention demonstrated a significant increase in problem-solving coping strategies and a decrease in anxiety scores 3 weeks after the intervention compared to the waitlist group. STM participants also demonstrated lower cortisol levels on the AUCg index. At the 3-month follow-up, gains were maintained only on the AUCg index.

Discussion

This type of brief preventive program could reduce basal cortisol levels in older adults, which may be an important protective factor against health outcomes associated with chronic HPA activation. Our results provide sufficient evidence to warrant further research to improve the effectiveness of O'stress in different settings.

Hypothalamic-pituitary-adrenal axis function in the offspring of parents with bipolar disorder and the impact of the family environment: A pilot study of the Reducing Unwanted Stress in the Home (RUSH) prevention program

BACKGROUND

The home environment of offspring of parents with bipolar disorder (OBD) has been characterized by high levels of stress and disorganization, which may impact development of the hypothalamic-pituitary-adrenal (HPA) axis and their subsequent risk for affective disorders. The present study examined the effects of a family-based preventative intervention on the OBD's HPA axis functioning and whether intervention-related changes in the home environment might have driven change in the HPA axis.

METHODS

Fifty-five children (6-11 years) were recruited from families having a parent with bipolar disorder (n=26) or families having two parents with no current mental disorders (n=29). Only those families with a parent having bipolar disorder participated in the preventative intervention. Both groups completed assessments at baseline, post-prevention, 3-, and 6-months post-prevention. At each assessment, family organization, control, cohesion, conflict, and expressiveness, in addition to childhood internalizing problems, were measured, and offspring saliva samples were collected across two consecutive days.

RESULTS

Hierarchical Linear Modelling found no significant differences in HPA axis functioning between groups at baseline or across time. Improvements in family organization, however, were associated with elevations in participants' cortisol awakening response (CAR; p =.004) and total daily output (p =.023), and a steepening of their diurnal slope (p =.003) across time. Similar findings were obtained for family cohesion with respect to CAR (p <.001) and, to a lesser degree, diurnal slope (p =.064).

DISCUSSION

HPA axis functioning did not differ between the OBD and healthy controls at baseline or in response to the preventative intervention. However, intervention-related improvements in family organization and, to a lesser degree, cohesion, were associated with adaptive changes in HPA functioning over time.

Exposure to diesel-related particulate matter, cortisol stress responsivity, and depressive symptoms in adolescents

Exposure to air pollution is associated with higher risk for psychopathology; however, the mechanisms underlying this association are not clear. Dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis in response to stress has been implicated in depression. Here, we estimated annual exposure to particulate matter (PM) from diesel emissions in 170 9- to 15-year-old adolescents (56 % female) using their residential addresses and data from nearby monitoring sites. We obtained salivary cortisol samples from participants while they completed a social stress task and calculated area under the curve with respect to ground (AUCg) and with respect to increase (AUCi) in order to assess cortisol responsivity during stress. Participants also reported on their depressive symptoms and sleep disturbances. Greater exposure to diesel PM was associated with lower cortisol output (AUCg) during stress, which was associated with higher depressive symptoms, particularly for adolescents with more sleep disturbances. Importantly, these effects were independent of household and neighborhood socioeconomic disadvantage and exposure to early adversity. Thus, HPA-axis dysfunction may be one mechanism through which environmental pollutants affect adolescents' mental health.

Attention to social threat predicts diurnal cortisol dynamics during the high school transition

Adolescence is a developmental period marked by significant social shifts accompanied by concurrent changes across biological, cognitive, and emotional domains. Within adolescence, the high school transition is a pivotal time for youth that is ripe with opportunities yet has the potential to disrupt functioning. An increasingly sophisticated understanding of health and developmental biology indicates that the hypothalamic-pituitary-adrenal (HPA) axis plays an important role in transducing social experiences into physiological changes that have long-term impacts on health and wellbeing. There is reason to believe that attentional biases to social threat could impact cortisol, a steroid hormone indexing activity of the HPA axis, during the high school transition. The present study examined associations between attentional biases to socially threatening stimuli, measured using the Affective Posner paradigm, and components of the diurnal cortisol rhythm among youth across the first two days of high school. Participants included 67 youth (N = 504 saliva samples) with a mean age of 12.86 years and a relatively equal split with regard to both sex assigned at birth and gender identity (54 % male; 54 % boys). Findings build upon and extend previous work by demonstrating that greater attentional engagement bias to socially threatening stimuli is associated with a pattern of greater diurnal HPA axis reactivity across the first two days of the high school transition, as evidenced by a steeper cortisol awakening response and a steeper diurnal cortisol slope. This work extends our understanding of the mechanisms through which stress relates to wellbeing in youth by embedding biological development in the life course. Clinically, this work has the potential to inform interventions to protect youth against the biological embedding of stress by identifying a theoretically driven, socio-contextually relevant risk factor to be attenuated - namely, attentional bias to threat.

Variation in diurnal cortisol patterns among the Indigenous Shuar of Amazonian Ecuador

OBJECTIVES

The hypothalamic-pituitary-adrenal (HPA) axis and its primary end product, the glucocorticoid cortisol, are major components of the evolved human stress response. However, most studies have examined these systems among populations in high-income settings, which differ from the high pathogen and limited resource contexts in which the HPA axis functioned for most of human evolution.

METHODS

We investigated variability in diurnal salivary cortisol patterns among 298 Indigenous Shuar from Amazonian Ecuador (147 males, 151 females; age 2-86 years), focusing on the effects of age, biological sex, and body mass index (BMI) in shaping differences in diurnal cortisol production. Saliva samples were collected three times daily (waking, 30 minutes post-waking, evening) for three consecutive days to measure key cortisol parameters: levels at waking, the cortisol awakening response, the diurnal slope, and total daily output.

RESULTS

Age was positively associated with waking levels and total daily output, with Shuar juveniles and adolescents displaying significantly lower levels than adults (p < .05). Sex was not a significant predictor of cortisol levels (p > .05), as Shuar males and females displayed similar patterns of diurnal cortisol production across the life course. Moreover, age, sex, and BMI significantly interacted to moderate the rate of diurnal cortisol decline (p = .027). Overall, Shuar demonstrated relatively lower cortisol concentrations than high-income populations.

CONCLUSIONS

This study expands the documented range of global variation in HPA axis activity and diurnal cortisol production and provides important insights into the plasticity of human stress physiology across diverse developmental and socioecological settings.

Stress reactivity moderates the association between early experiences of unpredictability and emotional problems in adolescents

Researchers have documented that exposure to different kinds of psychosocial stressors can lead to emotional difficulties and, further, that heightened reactivity to stress can moderate these associations. Recently, investigators have distinguished among threat, deprivation, and unpredictability as different dimensions of early life stress (ELS). It is not clear, however, whether reactivity in specific stress response systems functions as a diathesis to lead to emotional difficulties following exposure to these dimensions of ELS. In this study (N = 154) we examined whether stress reactivity, assessed across different psychobiological systems during the Trier Social Stress Test, is a unitary or multidimensional construct, and if reactivity differentially moderates the associations between ELS dimensions and adolescents' susceptibility to emotional and behavioral problems two years later. A factor analysis conducted on stress reactivity measures yielded two factors: one composed of reactivity in heart rate, heart rate variability, and cortisol, and one composed of reactivity in skin conductance and self-reported mood. These two factors independently moderated the associations between early unpredictability and subsequent emotional problems. For each factor, the combination of higher unpredictability and higher stress reactivity predicted higher emotional problems; stress reactivity factors were not significant moderators of the effects of threat and deprivation. Our findings suggest that increased stress reactivity, assessed across several domains of functioning, functions as a diathesis that interacts with ELS characterized by unpredictability to predict subsequent mental health difficulties in adolescents and, further, that low stress reactivity buffers against mental health difficulties in adolescents who have experienced unpredictability early in life.

Growth Differentiation Factor 15 during pregnancy and postpartum as captured in blood, cerebrospinal fluid and placenta: A cohort study on associations with maternal mental health

INTRODUCTION

Growth Differentiation Factor 15 (GDF15) increases substantially during pregnancy and is primarily produced by the placenta. Elevated levels of GDF15 have been associated with mental health problems in non-perinatal populations, higher corticosterone levels, and decreased estrogen receptor activity. However, the role of GDF15 in mental health during the perinatal transition remains unknown. This longitudinal study is the first to evaluate pregnancy levels of GDF15 in cerebrospinal fluid (cGDF15), plasma (pGDF15) and placenta GDF15 mRNA, along with mapping plasma GDF15 (pGDF15) level changes from late pregnancy to early postpartum. Moreover, we aimed to evaluate the association between pregnancy cGDF15 levels and cortisol early postpartum, evaluate the association between pregnancy cGDF15 levels and mental health in pregnancy and postpartum, and evaluate the association between pGDF15 and estrogens and high-sensitivity C-reactive protein (CRP).

METHODS

We included data from 95 women scheduled for a planned cesarean section and obtained cerebrospinal fluid (CSF) and plasma levels of GDF15. We quantified GDF15 mRNA levels in placenta biopsies. Estrogens, high-sensitivity CRP, and mental health measures were further collected on the day or one day before the cesarean section. At five weeks postpartum, mental health measures and saliva samples for cortisol analyses were collected. Correlation analyses for GDF15 in CSF, plasma, and placenta mRNA were performed, along with association analyses for pregnancy cGDF15, Cortisol Awakening Response, and mental health outcomes.

RESULTS

We demonstrated a strong correlation between cGDF15 and pGDF15 (r=0.52; p<0.001) and found that both cGDF15 and pGDF15 correlated with placenta GDF15 mRNA*placental weight (r=0.62, p<0.001 and r=0.44, p=0.008, respectively). During late pregnancy, both estradiol (E2) and estriol (E3) were significantly associated with pGDF15 levels (E2: p=0.002; E3: p(corrected)<0.001). Finally, we found that cGDF15 levels were not associated with self-reported mental well-being or the Cortisol Awakening Response or absolute cortisol at awakening postpartum.

CONCLUSION

This novel study points to the unique hormonal landscape during the perinatal transition and the specific role of GDF15 in pregnancy, which appears uncoupled with perinatal mental health and cortisol outcomes. Our data also strongly imply that the overall amount of circulating GDF15 in late pregnancy is closely related to placenta size.

Cortisol awakening response prompts dynamic reconfiguration of brain networks in emotional and executive functioning

Emotion and cognition involve an intricate crosstalk of neural and endocrine systems that support dynamic reallocation of neural resources and optimal adaptation for upcoming challenges, an active process analogous to allostasis. As a hallmark of human endocrine activity, the cortisol awakening response (CAR) is recognized to play a critical role in proactively modulating emotional and executive functions. Yet, the underlying mechanisms of such proactive effects remain elusive. By leveraging pharmacological neuroimaging and hidden Markov modeling of brain state dynamics, we show that the CAR proactively modulates rapid spatiotemporal reconfigurations (state) of large-scale brain networks involved in emotional and executive functions. Behaviorally, suppression of CAR proactively impaired performance of emotional discrimination but not working memory (WM), while individuals with higher CAR exhibited better performance for both emotional and WM tasks. Neuronally, suppression of CAR led to a decrease in fractional occupancy and mean lifetime of task-related brain states dominant to emotional and WM processing. Further information-theoretic analyses on sequence complexity of state transitions revealed that a suppressed or lower CAR led to higher transition complexity among states primarily anchored in visual-sensory and salience networks during emotional task. Conversely, an opposite pattern of transition complexity was observed among states anchored in executive control and visuospatial networks during WM, indicating that CAR distinctly modulates neural resources allocated to emotional and WM processing. Our findings establish a causal link of CAR with brain network dynamics across emotional and executive functions, suggesting a neuroendocrine account for CAR proactive effects on human emotion and cognition.

Longitudinal analysis of academic stress and its effects on salivary cortisol, alpha-amylase, and academic outcomes: Study protocol

INTRODUCTION

Academic stress is a prevalent problem among university students, affecting both their psychological well-being and academic performance. This study aims to investigate the mediating roles of biological and psycho-behavioural variables in the relationship between academic stress and academic performance over the course of a semester. Through a longitudinal approach and using accessible data collection technologies, the results will enable the design of effective interventions to mitigate the impact of academic stress.

HYPOTHESES

(i) Biological variables related to academic performance will mediate the relationship between academic stress and students' academic performance. (ii) Psycho-behavioural variables will also act as mediators in this relationship, impacting academic performance differently.

GENERAL OBJECTIVE

To explore the mediating roles of biological and psycho-behavioural variables in the relationship between academic stress and academic performance over the course of a university semester.

DESIGN

A longitudinal non-experimental observational design will be applied. Data will be collected in three assessment cycles, each consisting of three consecutive weeks during the academic semester.

PARTICIPANTS

A sample of 160 undergraduate students from the Faculty of Medicine of the University of Concepción will be included. Students will be recruited on a voluntary basis through social networks and student associations. Students under psychological or pharmacological treatment will also be included to more representatively reflect the student reality and to ensure the ecological validity of the study.

BIOLOGICAL AND PSYCHO-BEHAVIOURAL DATA COLLECTION

Participants will answer electronic questionnaires on academic stress and psycho-behavioural variables three times a week via the REDCap platform. In addition, smart devices will be used to continuously collect biological data such as heart rate, oxygen saturation, and sleep patterns. Students will also collect saliva samples three times a week to measure cortisol levels, and alpha-amylase enzyme activity.

STATISTICAL ANALYSIS

(i) Descriptive analysis of variables will be performed using measures of central tendency and dispersion for continuous variables and frequencies and percentages for categorical variables. (ii) Bivariate and multivariate analyses will be conducted to compare groups. (iii) Random intercept cross-lagged models will be used to assess the direction and reciprocal effects between variables over time. To analyze mediations, structural models (SEM) will be applied, considering biological and psycho-behavioural variables as mediators.

EXPECTED RESULTS

It is anticipated that (i) biological variables, such as cortisol and salivary alpha-amylase, will play a significant mediating role in the relationship between academic stress and academic performance, particularly towards the end of the semester. (ii) psycho-behavioural variables will also have a mediating effect, with different impacts on academic performance depending on the level of stress experienced. The use of accessible technologies and non-invasive methods such as saliva sample collection will provide a replicable model for future research.

Longitudinal Investigation of Neurobiological Changes Across Pregnancy

Pregnancy is a period of profound biological transformation. However, we know remarkably little about pregnancy-related brain changes. To address this gap, we chart longitudinal changes in brain structure during pregnancy and explore potential mechanisms driving these changes. Ten participants (Mean age = 28.97 years) are assessed 1-6 times (median = 3) during their pregnancy. Each visit includes anatomical and diffusion-weighted MRI, and assessments of waking salivary hormones, hair hormones, and inflammatory cytokines. Here we observe a reduction in gray matter volume gestational week, while neurite density index (NDI), a proxy of axon density, in white matter tracts increase across pregnancy. Progesterone levels are associated with reductions in brain volumetric measurements, and both progesterone and estradiol levels are linked to increases in NDI in white matter tracts. This study highlights the profound neurobiological changes experienced by pregnant individuals and provides insights into neuroplasticity in adulthood.

Perceived and endocrine acute and chronic stress indicators in fibromyalgia syndrome

Fibromyalgia syndrome (FMS) is a chronic disorder characterized by widespread musculoskeletal pain, fatigue and tenderness and closely associated with high levels of stress. FMS is therefore often considered a stress-related disease. A comparative study was conducted with 99 individuals diagnosed with FMS and a control group of 50 pain-free individuals. Stress indicators were classified into three categories: perceived stress assessed using the Perceived Stress Scale, and daily average salivary cortisol and hair cortisol concentrations as indicators of acute and chronic stress levels related to the hypothalamic-pituitary-adrenal axis. Analysis of variance and covariance were used to identify group differences and the influence of covariates age, sex, and body mass index. Correlational analyses further elucidated the relationship between stress indicators and clinical symptoms. Participants with FMS reported significantly higher perceived stress levels than controls (p < .001, ηp2 = 0.3), which were positively correlated with symptom burden (r = .41, p < .001). In contrast, there were no significant differences in the endocrinological stress indicators salivary and hair cortisol between the groups (p > .05), nor were these indicators associated with clinical symptoms. The study highlights the central role of perceived stress in FMS, whereas endocrinological indicators did not differentiate FMS from controls. This finding calls for a nuanced approach to clinical assessment and therapeutic interventions tailored to patients with FMS, emphasizing the management of perceived stressors.

Autonomic nervous system and endocrine system response to upper or lower cervical spine mobilization in males with persistent post-concussion symptoms: a proof-of-concept trial

INTRODUCTION

The peripheral stress response, consisting of the autonomic nervous system (ANS) and hypothalamic pituitary adrenal-axis (HPA-axis), functions to maintain homeostasis in response to stressors. Cervical spine manual therapy has been shown to differentially modulate the stress response in healthy populations. No study has investigated whether cervical spine mobilizations can differentially modulate the stress response in individuals with persistent post-concussion symptoms (PPCS), a population characterized by a dysfunctional stress response.

METHODS

A randomized, controlled, parallel design trial was performed to investigate whether upper or lower cervical spine mobilization can differentially modulate components of the stress response in individuals with PPCS. The outcomes were salivary cortisol (sCOR) concentration (primary) and the HRV metric, rMSSD, measured with a smartphone application (secondary). Nineteen males diagnosed with PPCS, aged 19-35, were included. Participants were randomly assigned into either intervention group, upper (n = 10) or lower (n = 9) cervical spine mobilization. Each outcome was collected at different time points, pre- and post-intervention. Statistical analyses were performed using the Friedman's Two-Way ANOVA, Mann-Whitney U test, and Wilcoxon Signed Rank Test.

RESULTS

There was a statistically significant within-group reduction in sCOR concentration 30 minutes following lower cervical spine mobilizations and statistically significant within-group increase in rMSSD 30 minutes following upper cervical spine mobilizations.

CONCLUSION

The results of this trial provide preliminary evidence for cervical spine mobilizations to differentially modulate components of the stress response at specific time points. Understanding the mechanisms of the effect of cervical spine mobilizations on the stress response provides a novel rationale for selecting cervical spine mobilizations to rehabilitate individuals with PPCS.

Association of salivary testosterone levels during the post-awakening period with age and symptoms suggestive of late-onset hypogonadism in men

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.

Can consumption of finger millet diet improve mental health status in athletes: a possible link with modulation of cortisol levels

PURPOSE

Despite the promising health benefits of finger millet, there is a notable lack of research specifically examining its effects on athletes' mental health. Therefore, the present narrative review aimed to explore the potential of finger millet (Eleusine coracana) in enhancing the mental health status of athletes.

METHODS

For this narrative review databases like "PubMed," "SPORTDiscus," "Scopus," "ProQuest" and "Google Scholar" were referred to identify and analyze the studies to determine their relevance and findings.

RESULTS

Studies have shown that nutritional intervention has a significant impact on mental health through improved mood, cognitive function, and overall well-being. Finger millet is a valuable reservoir of vital nutrients , including amino acids, vitamins, minerals, and antioxidants, which play crucial roles in reducing oxidative stress and cortisol levels, which are key factors in mental health disorders. Furthermore, low glycemic index and high dietary fiber content of finger millet contribute to stable blood sugar levels, which are crucial for maintaining mental stability and preventing stress-induced cortisol spikes. Dietary fiber in finger millet also helps in boosting the gut microbiota, which helps in stimulating mental and cognitive health through the gut-brain axis.

CONCLUSION

Given the physical and psychological demands on athletes, incorporating finger millet into their diets could offer a holistic approach for improving both performance and mental well-being. Despite these promising findings, the specific effect of finger millet on athletes' mental health remains unclear. This review highlights the need for more focused research on this topic, emphasizing the potential of finger millet as a na-t ural dietary intervention to enhance mental health and stress management in athletes. We conclude by calling for more comprehensive studies to fully understand the mechanisms and benefits of finger millet in athletic populations, aiming to bridge the current gap in the literature and pave the way for evidence-based dietary recommendations.

The burdens and benefits of managing and engaging: a diary study approach to person-centred risk assessment of top executives and works council members

The present diary study investigates the impact of daily effort-reward imbalance (ERI), subjective stress and the cortisol awakening response (CAR) as an objective measure on work engagement of top managers and high-level works council members (N = 45) on three consecutive working days. In the scope of psychosocial risk assessment, we argue that focusing on ERI as a generalized work characteristic might be more suitable for work re-design of higher leadership positions because of their highly dynamic and unpredictable psychosocial work characteristics, while at the same time having more access to job resources. The analyses reveal that both baseline and daily ERI, as well as subjective stress, influence work engagement. Our results suggest that interventions to reduce daily levels of ERI may improve the work environment of top managers and works councils by promoting work engagement and related positive health outcomes in the scope of person-centred risk assessment.

The influence of light on Interleukin-10: A preliminary study

Light influences circadian rhythms, including that of the stress hormone cortisol. Cortisol, in turn, has been observed to promote expression of the anti-inflammatory cytokine IL-10. It is thus of interest whether the cytokine IL-10 is also influenced by light, perhaps in accord with the diurnal variations in cortisol. Hence, this highly standardized preliminary sleep laboratory study in healthy adult men investigated a potential influence of different light exposure on IL-10 and cortisol concentrations in blood. In a between-subject design, N = 42 participants were exposed to either bright, dim, blue or red light after wake-up. Two mixed-model analyses with the factors of light condition and time (across eight IL-10 and cortisol sampling points) were conducted. Additionally, area under the curve measurements (AUCg and AUCi) were calculated for both cortisol and IL-10. Across all conditions, IL-10 and cortisol concentrations significantly changed over time. However, none of the light conditions exerted a greater influence on IL-10 or cortisol levels than others. For cortisol, there was greater total output (AUCg) in the blue-light condition in particular. Further research is needed to gain insight into whether or not types of light or cortisol levels have a hand in influencing natural IL-10 concentrations.

Sex Differences in Basal Cortisol Levels Across Body Fluid Compartments in a Cross-sectional Study of Healthy Adults

Context

Many studies have moved toward saliva and peripheral blood sampling for studying cortisol, even in relation to disorders of the brain. However, the degree to which peripheral cortisol reflects central cortisol levels has yet to be comprehensively described. Data describing the effect that biological characteristics such as age and sex have on cortisol levels across compartments is also limited.

Objective

To assess the relationships of cortisol levels across cerebrospinal fluid (CSF), saliva, and plasma (total and free) compartments and describe the effects of age and sex on these relationships.

Design

Multisite cross-sectional observation study.

Setting

Samples collected in academic outpatient settings in 2001-2004.

Patients or Other Participants

Healthy community volunteers (n = 157) of both sexes, aged 20-85 years.

Interventions

None.

Main Outcome Measures

This study was a secondary analysis of data collected from a previously published study.

Results

CSF cortisol correlated more strongly with plasma (r = 0.49, P < .0001) than with saliva cortisol levels. Sex but not age was a significant modifier of these relationships. CSF cortisol levels trended higher with older age in men (R2 = 0.31, P < .001) but not women. Age-related cortisol binding globulin trends differed by sex but did not correlate with sex differences in cortisol levels in any compartment.

Conclusion

Variability in the correlations between central and peripheral cortisol discourages the use of peripheral cortisol as a direct surrogate for central cortisol measures. Further investigation of how mechanistic drivers interact with biological factors such as sex will be necessary to fully understand the dynamics of cortisol regulation across fluid compartments.

Mindfulness-Based Interventions and the Hypothalamic-Pituitary-Adrenal Axis: A Systematic Review

BACKGROUND

Numerous studies have evaluated the effect that mindfulness-based interventions (MBIs) have on multiple health outcomes. For its part, stress is a natural response to environmental disturbances and within the associated metabolic responses, alterations in cortisol levels and their measurement in different tissues are a way to determine the stress state of an individual. Therefore, it has been proposed that MBIs can modify cortisol levels.

METHODS AND RESULTS

The objective of this systematic review was to analyze and summarize the different studies that have evaluated the effect of MBIs on cortisol levels. The following databases were consulted: MEDLINE, AMED, CINAHL, Web of Science, Science Direct, PsycINFO, SocINDEX, PubMed, the Cochrane Library and Scopus. The search terms "mindfulness", "mindfulness-based interventions" and "cortisol" were used (and the search was limited to studies from January 1990 to May 2024). In order to reduce selection bias, each article was scrutinized using the JBI Critical Appraisal Checklist independently by two authors. We included those studies with specified intervention groups with at least one control group and excluded duplicate studies or those in which the intervention or control group was not adequately specified. Significant changes in cortisol following MBIs were found in 25 studies, while 10 found no changes. The small sample size, lack of randomization, blinding, and probable confounding and interaction variables stand out in these studies.

CONCLUSION

MBIs have biological plausibility as a means of explaining a positive effect on cortisol levels; however, the weakness of the studies and the absence of robust designs makes it difficult to establish a causal association between both variables.

REGISTRATION NUMBER

INPLASY2024110017.