Diurnal cycles of salivary cortisol in older adults

Examining Reactivity and Recovery Patterns of Pain-Evoked Cortisol and Alpha-Amylase Trajectories: Relations Between Psychological Markers of Risk and Resilience

Chronic low back pain (cLBP) is one of the leading causes of disability globally and represents an enormous burden to aging adults. While numerous factors contribute to cLBP, dysregulation in the hypothalamic-pituitary-adrenal axis and autonomic nervous system functioning have been implicated in its pathogenesis. It is well documented that negative psychological states can modulate biological stress responsivity in chronic pain; however, little is known regarding the influence of positive psychological factors in this relationship. The aim of this study was to examine the association between psychological risk and resilience factors with patterns of physiological stress reactivity and recovery in 60 older adults with cLBP. Participants completed measures of hope, optimism, pain catastrophizing, and perceived stress, and underwent psychophysical pain testing assessing responses to painful pressure, heat, and cold stimuli. Salivary samples were obtained prior to pain induction and at 7 time points spanning 90 minutes after pain testing terminated. To examine reactivity and recovery profiles in hypothalamic-pituitary-adrenal axis and autonomic nervous system function, samples were assayed for cortisol and alpha-amylase, respectively. Results revealed higher levels of hope and optimism were associated with increased cortisol reactivity (p's < .003) and more rapid recovery (p's = .001). Further, pain catastrophizing and perceived stress were associated with cortisol reactivity, with lower levels of these factors predicting larger increases in cortisol from baseline to peak levels (p's < .04). No significant differences in reactivity or recovery patterns emerged for alpha-amylase. Overall, findings highlight the role of psychological risk and resilience factors in modulating physiological stress reactivity. PERSPECTIVE: This article investigated whether psychosocial risk and resilience factors were associated with stress reactivity and recovery in response to laboratory-based pain testing in older adults with chronic low back pain. Results indicate that high resilience factors may be protective by modulating adrenocortical reactivity and recovery profiles.

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.

Clinical efficacy and metabolomics study of Wendan Decoction in the treatment of phlegm-dampness obstructive sleep apnea-hypopnea syndrome with type 2 diabetes mellitus

ETHNOPHARMACOLOGICAL RELEVANCE

Wendan Decoction (WDD) is one of the classic traditional Chinese prescriptions that has been used in the treatment of type 2 diabetes mellitus (T2DM), metabolic syndrome, obstructive sleep apnea-hypopnea syndrome (OSAHS) and so on. The therapeutic effects and mechanism of WDD remain to be explored, especially from the perspective of metabolomics, oxidative stress and inflammation.

AIM OF THE STUDY

To investigate the therapeutic and metabolic regulatory effects and the underlying mechanism of WDD in OSAHS with T2DM patients.

MATERIALS AND METHODS

All included patients were from Rudong Hospital of Traditional Chinese Medicine, Nantong, Jiangsu Province, China. Both groups received lifestyle interventions; at the same time, all of them were administered metformin (1500 mg/day) and dapagliflozin (10 mg/day), and the treatment group was administered WDD orally. All patients were treated for two months. Before and after treatment, the changes in clinical symptoms and signs of the two groups of patients were evaluated, and the detection indicators such as body mass index (BMI), apnea-hypopnea index (AHI), lowest arterial oxygen saturation (LSaO2), Epworth sleepiness scale (ESS), percentage of total sleep time with oxygen saturation <90% (TST90), fasting plasma glucose (FPG), 2-h post-load glucose(2h-PG), fasting insulin (FINS), homeostasis model assessment of insulin resistance (HOMA-IR)，hemoglobin A1c (HbA1c), blood lipid levels, as well as the adverse reactions and compliance of the patients were observed and detection of serum metabolites in patients to screen out specific biomarkers. The serum metabolic profile of WDD in OSAHS with T2DM patients was explored using ultra-high-performance liquid chromatography-quadrupole/electrostatic field orbitrap high-resolution mass spectrometry (UPLC-Q Orbitrap HRMS).

RESULTS

After treatment with WDD for 8 weeks, biochemical indicators, including BMI, FPG, 2h-PG, blood lipid, FINS, HbA1c, AHI, ESS, LSaO2, TST90, and HOMA-IR, were significantly improved. Serum metabolomic analysis showed that metabolites were differentially expressed before and after WDD-treated patients. Metabolomics results revealed that WDD regulated the biomarkers, such as DL-arginine, guaiacol sulfate, azelaic acid, phloroglucinol, uracil, L-tyrosine, cascarillin, Cortisol and L-alpha-lysophosphatidylcholine. Pathway enrichment analysis showed that the metabolites were associated with oxidative stress and inflammation.

CONCLUSION

The study based on clinical research and metabolomics indicated that WDD can improve OSAHS with T2DM through multiple targets and pathways, and it may be a useful alternative therapy for the treatment of OSAHS with T2DM patients.

Effects of Linpan nature therapy on health benefits in older women with and without hypertension

Background

Nature therapy can significantly benefit the physiology and psychology of middle-aged and older people, but previous studies have focused on forest environments. The restoration potential of rural environments in urban fringe areas, which are more accessible to older people on a daily basis, has not been fully studied. This study assessed the effects of nature therapy on the physical and mental health of older women in a rural setting (locally known as Linpan) in the urban fringe area of Chengdu, China.

Methods

We recruited a total of 60 older women (65.3 ± 5.5 years old) living in cities for 3 days of nature therapy in the winter (30 subjects) and spring (30 subjects), including 20 hypertensive patients.

Results

The results showed that the overall blood pressure, pulse and sleep dysfunction rating scores of the participants were significantly lower than the pretest levels, and the finger blood oxygen saturation, mid-day salivary alpha-amylase and cortisol were increased post-treatment. Increases in these biomarker indicates and increase in stress. There were significant differences in the changes in systolic blood pressure between the hypertension group (HTN) and the normal group (normal) (HTN decreased by 8.8%, normal decreased by 5.4%), salivary alpha-amylase content (HTN decreased by 0.3%, normal increased by 16.9%), and sleep dysfunction rating scores (HTN decreased by 59.6%, normal decreased by 54%). The decreases in systolic blood pressure and pulse in the winter group were higher than those in the spring group by 1.8 and 4.4%, respectively, while the increases in salivary alpha-amylase content and salivary cortisol content were lower than those in the spring group by 11.7 and 11.2%, respectively, and the decrease in sleep dysfunction rating scores was lower than that in the spring group by 7.1%.

Conclusion

Our study concluded that nature therapy based on various health activities in the Linpan has significant health effects on older women. It can regulate blood pressure and pulse in older women, relieve cardiovascular disease, improve sleep quality. Meanwhile, older women with high blood pressure experienced a more significant effect than the healthy group.

Electrochemical sensors for cortisol detection: Principles, designs, fabrication, and characterisation

Psychological stress is a major factor contributing to health discrepancies among individuals. Sustained exposure to stress triggers signalling pathways in the brain, which leading to the release of stress hormones in the body. Cortisol, a steroid hormone, is a significant biomarker for stress management due to its responsibility in the body's reply to stress. The release of cortisol in bloodstream prepares the body for a "fight or flight" response by increasing heart rate, blood pressure, metabolism, and suppressing the immune system. Detecting cortisol in biological samples is crucial for understanding its role in stress and personalized healthcare. Traditional techniques for cortisol detection have limitations, prompting researchers to explore alternative strategies. Electrochemical sensing has emerged as a reliable method for point-of-care (POC) cortisol detection. This review focuses on the progress made in electrochemical sensors for cortisol detection, covering their design, principle, and electroanalytical methodologies. The analytical performance of these sensors is also analysed and summarized. Despite significant advancements, the development of electrochemical cortisol sensors faces challenges such as biofouling, sample preparation, sensitivity, flexibility, stability, and recognition layer performance. Therefore, the need to develop more sensitive electrodes and materials is emphasized. Finally, we discussed the potential strategies for electrode design and provides examples of sensing approaches. Moreover, the encounters of translating research into real world applications are addressed.

Salivary Cortisol Dynamics After Mild Traumatic Brain Injury

OBJECTIVE

To assess mild traumatic brain injury (mTBI)-related alterations in baseline (resting) salivary cortisol and cortisol reactivity to cognitive and exercise stressors, which are frequently encountered during mTBI rehabilitation and recovery.

SETTING

Persons with mTBI were recruited from a level 1 trauma center emergency department. Uninjured controls (UCs) were recruited from the community.

PARTICIPANTS

Participants were 37 individuals with mTBI and 24 UCs. All patients with mTBI were enrolled at 7 ± 3 days post-injury, met the American Congress of Rehabilitation Medicine definition of mTBI, and had no acute intracranial findings on clinical neuroimaging (if performed).

DESIGN

A prospective cohort study design was used. All participants provided saliva samples 10 times during each of 2 visits spaced 3 weeks apart (1 week and 1 month post-injury for the mTBI group). Each visit included baseline saliva sampling and sampling to evaluate reactivity to a cognitive stressor (Paced Auditory Serial Addition Test) and physical stressor (Buffalo Concussion Treadmill Test [BCTT]).

MAIN OUTCOME MEASURE

Natural log-transformed salivary cortisol was measured by enzyme immunoassay. Cortisol was predicted using a linear mixed-effects model by group (mTBI and UC), visit (1 week and 1 month), and saliva sample.

RESULTS

Mean salivary cortisol was higher in the mTBI group (1.67 nmol/L [95% CI 1.42-1.72]) than in controls (1.30 nmol/L [1.12-1.47]), without an mTBI × time interaction. At 1 week, the mTBI group had greater cortisol reactivity in response to the BCTT.

CONCLUSIONS

Higher cortisol in individuals with mTBI at 1 week and 1 month post-injury extends previous findings into the subacute recovery period. Furthermore, the mTBI group demonstrated a greater cortisol response to mild-to-moderate aerobic exercise (BCTT) at 1 week post-injury. Given the increasing role of exercise in mTBI rehabilitation, further research is warranted to replicate these findings and identify the clinical implications, if any, of enhanced hypothalamic-pituitary-adrenal axis responses to exercise in civilians with recent mTBI.

Physical Activity and Cortisol Regulation: A Meta-Analysis

Physical activity participation is associated with effective stress coping, indicated by decreases in both physiological stress reactivity and perceived stress. Quantifying the effect of physical activity on the diurnal regulation of one key physiological stress indicator, the stress hormone, cortisol, across studies may demonstrate the extent to which physical activity participation is associated with diurnal HPA axis regulation. We meta-analyzed studies examining relations between physical activity participation and indices of HPA axis regulation: the diurnal cortisol slope and the cortisol awakening response. We also examined moderators of the relation. The analysis revealed a small, non-zero negative averaged correlation between physical activity and the diurnal cortisol slope (r = -0.043, 95% CI [-0.080, -0.004]). Examination of sample sociodemographic differences, study design characteristics, cortisol measurement methods, and physical activity variables as moderators revealed few effects on the relation between physical activity and diurnal cortisol slope. We did not observe lower levels of variability in the mean cortisol awakening response at higher levels of physical activity participation, and moderator analyses showed little evidence of reductions in heterogeneity for this effect. We found some evidence of systematic publication bias. Findings suggest higher physical activity is associated with a steeper diurnal cortisol slope. However, the cortisol awakening response did not differ by physical activity level. Future studies testing the physical activity and cortisol regulation association should use standardized physical activity measures, follow guidelines for better quality cortisol sampling collection and analysis, and test relations in large-scale empirical studies to confirm the direction and causality of the effect.

Physical Activity Influences Cortisol and Dehydroepiandrosterone (Sulfate) Levels in Older Adults: A Systematic Review and Meta-Analysis

Age-related changes affect the ratio between two steroid hormones of the hypothalamic-pituitary-adrenal axis, cortisol and dehydroepiandrosterone (sulfate) (DHEA[S]). Physical activity (PA) may buffer the effects of chronic stress and counteract the aging decline of DHEA(S). Therefore, a systematic review was conducted to understand how PA influences physiological markers of cortisol and/or DHEA(S) and whether there is a difference in observational associations or experimental effects in older adults aged 65 years and older. A narrative synthesis was performed on nine observational studies, and meta-analyses were performed on 22 randomized controlled trials. There was low- to moderate-quality evidence that regular PA beneficially reduces cortisol and increases DHEA(S) levels. Subgroup analyses showed no clinically important differences between men and women, different exercise modalities, or health states. The findings cautiously suggest that regular PA of older adults' own choice that they find enjoyable could be recommended to improve cortisol and/or DHEA(S) levels.

Study protocol for measuring the impact of (quasi-)monochromatic light on post-awakening cortisol secretion under controlled laboratory conditions

Cortisol secretion has a fundamental role in human circadian regulation. The cortisol awakening response (CAR) can be observed as a daily recurring sharp increase in cortisol concentration within the first hour after awakening and is influenced by environmental light conditions. The current work provides the study protocol for an ongoing research project that is intended to explore the spectral dependencies and to discuss measures of emotional state and cognitive functioning potentially related to the CAR. Based on a controlled within-subjects sleep laboratory study, the impact of a two-hour, (quasi-)monochromatic, post-awakening light exposure of different peak wavelength (applied from 6:00 to 8:00 am) on resulting CAR levels should be investigated in a systematic manner to eventually derive a corresponding spectral sensitivity model. As a secondary outcome, it should be explored whether a potentially light-enhanced cortisol secretion might also impact different measures of sleepiness, mood, and vigilance for certain wavelengths. The study protocol described in the present work discusses the various protocol steps using pilot data collected for two different wavelength settings (i.e., short-wavelength blue-light at λmax = 476 nm and long-wavelength red-light at λmax = 649 nm) experienced by a group of four healthy male adults at an average ± SD age of 25.25 ± 3.59 years.

Salivary Cortisol Reaction Norms in Zoo-Housed Great Apes: Diurnal Slopes and Intercepts as Indicators of Stress Response Quality

Simple Summary

Changes in cortisol fluctuations are used for stress monitoring. Methodologically, this is straight forward, because sample collection is simple and analytical methods advanced, but since cortisol is primarily a hormone that facilitates energy allocation, the interpretation of these measures is often complex. Acute elevations in cortisol levels are not per se bad, but may constitute an adaptive coping mechanism. Likewise, low cortisol levels do not always indicate the absence of a stressor. To distinguish between stress response qualities, a more fine-grained analyses of cortisol fluctuations is warranted. Cortisol excretion follows a diurnal pattern with high levels in the morning, decreasing throughout the day. Two regression coefficients describe this curve: the intercept (the constant with which levels change throughout the day) and the slope (curve steepness and direction). We assessed salivary cortisol intercepts and slopes in zoo-housed apes on routine days, enrichment days, and in the new ape house. While cortisol excretion increased on enrichment days, the daily decline of cortisol levels was not affected. The move to the new house seemingly was a major stressor as cortisol levels increased slightly and the circadian cortisol decrease was impaired. The combination of intercept and slope measures can differentiate between stress responses, thereby constituting a useful tool for stress monitoring.

Abstract

Monitoring changes in cortisol levels is a widespread tool for measuring individuals’ stress responses. However, an acute increase in cortisol levels does not necessarily denote an individual in distress, as increases in cortisol can be elicited by all factors that signal the need to mobilize energy. Nor are low levels of cortisol indicative for a relaxed, healthy individual. Therefore, a more fine-grained description of cortisol patterns is warranted in order to distinguish between cortisol fluctuations associated with different stress response qualities. In most species, cortisol shows a distinct diurnal pattern. Using a reaction norm approach, cortisol levels across the day can be described by the two regression coefficients: the intercept and the slope of the curve. We measured immunoreactive salivary cortisol in three zoo-housed ape species under three conditions (routine days, enrichment days, and after the move to a new house). We examined salivary cortisol intercepts (SCI) and salivary cortisol slopes (SCS) of the diurnal curves. SCI and SCS were independent from each other. SCI was highest on enrichment days and lowest on routine days. SCS was steep on routine days and blunted after the move. Only SCI was species-specific. Our study provides evidence that combining SCI and SCS measures allows us to differentiate between types of stress responses, thereby constituting a useful tool for welfare assessment.

Cortisol on Circadian Rhythm and Its Effect on Cardiovascular System

The synthesis and secretion of cortisol are controlled by the hypothalamic–pituitary–adrenal axis. Cortisol exhibits a proper 24-h circadian rhythm that affects the brain, the autonomic nervous system, the heart, and the vasculature that prepares the cardiovascular system for optimal function during these anticipated behavioral cycles. A literature search was conducted using databases such as Google Scholar, PubMed, and Scopus. Relevant search terms included “circadian rhythm and cardiovascular”, “cortisol”, “cortisol and acute coronary syndrome”, “cortisol and arrhythmias”, “cortisol and sudden cardiac death”, “cortisol and stroke”, and “cardioprotective agents”. A total of 120 articles were obtained on the basis of the above search. Lower levels of cortisol were seen at the beginning of sleep, while there was a rise towards the end of sleep, with the highest level reached at the moment the individual wakes up. In the present review, we discuss the role of 11β-hydroxysteroid dehydrogenase (11β-HSD1), which is a novel molecular target of interest for treating metabolic syndrome and type-2 diabetes mellitus. 11β-HSD1 is the major determinant of cortisol excess, and its inhibition alleviates metabolic abnormalities. The present review highlights the role of cortisol, which controls the circadian rhythm, and describes its effect on the cardiovascular system. The review provides a platform for future potential cardioprotective therapeutic agents.

"It made me feel brighter in myself"- The health and well-being impacts of a residential front garden horticultural intervention

Residential gardens make up 30% of urban space in the UK, yet unlike many other green space typologies, their role in the health and well-being agenda has largely been overlooked. A horticultural intervention introduced ornamental plants to 38 previously bare front gardens (≈ 10 m²) within an economically deprived region of North England, UK. Measures of perceived stress and diurnal cortisol profiles (as an indicator of health status) were taken pre- and post-intervention (over 3 months). Residents reported significant decreases in perceived stress post-intervention. This finding was aligned with a higher proportion of 'healthy' diurnal cortisol patterns post-intervention, suggesting better health status in those individuals. All residents derived one or more reported socio-cultural benefits as a result of the front garden plantings, although overall scores for subjective well-being did not increase to a significant level. Further qualitative data suggested that the gardens were valued for enhancing relaxation, increasing positive emotions, motivation, and pride of place. The results indicate that adding even small quantities of ornamental plants to front gardens within deprived urban communities had a positive effect on an individual's stress regulation and some, but not all, aspects of subjective well-being. The research highlights the importance of residential front gardens to human health and well-being, and thus their contribution to the wider debates around city densification, natural capital and urban planning.

Biocultural approaches to transgender and gender diverse experience and health: Integrating biomarkers and advancing gender/sex research

Transgender and gender diverse (TGD) people are increasingly visible in U.S. communities and in national media. With this increased visibility, access to gender affirming healthcare is also on the rise, particularly for urban youth. Political backlash and entrenchment in a gender binary, however, continue to marginalize TGD people, increasing risk for health disparities. The 2016 National Institute of Health recognition of sexual and gender minority people as a health disparities population increases available funding for much-needed research. In this article, we speak to the need for a biocultural human biology of gender/sex diversity by delineating factors that influence physiological functioning, mental health, and physical health of TGD people. We propose that many of these factors can best be investigated with minimally invasively collected biomarker samples (MICBS) and discuss how to integrate MICBS into research inclusive of TGD people. Research use of MICBS among TGD people remains limited, and wider use could enable essential biological and health data to be collected from a population often excluded from research. We provide a broad overview of terminology and current literature, point to key research questions, and address potential challenges researchers might face when aiming to integrate MCIBS in research inclusive of transgender and gender diverse people. We argue that, when used effectively, MICBS can enhance human biologists' ability to empirically measure physiology and health-related outcomes and enable more accurate identification of pathways linking human experience, embodiment, and health.

Stress-Related Trajectories of Diurnal Cortisol in Older Adulthood Over 12 Years

OBJECTIVE

Although evidence shows that stress experiences can predict both hyper- and hypo-cortisol regulation, there is a lack of research examining these associations longitudinally. Our study assessed whether levels and increases in psychological stress experiences predicted 12-year changes in circadian cortisol levels (area under the curve; AUC) and cortisol slopes in a sample of community-dwelling older adults.

METHODS

In 2004, 190 community dwelling older adults (57 to 94 years) started providing three days of diurnal cortisol and stress experience data every two years for a total of seven waves of data. All analyses controlled for relevant covariates including: SES, BMI, age, sex, cortisol-related medication, chronic illness, and smoking status.

RESULTS

Growth-curve modeling documented that compared to participants who reported generally lower stress experiences (T-ratio = -5.57, p < .01), their counterparts with higher stress experiences showed significantly steeper declines in cortisol AUC over time (T-ratio = -9.23, p < .01). Higher stress experience was associated with generally flatter cortisol slopes. In addition, among participants with high and increasing stress experience over 12 years, cortisol slopes became increasingly flatter over time (T-ratio = 2.78, p < .01).

CONCLUSIONS

Among individuals with high, as compared to low, levels of chronic stress experience, cortisol levels displayed steeper declines across the study period. Moreover, cortisol slopes became increasingly flatter as a function of high and increasing stress experience. Implications for theory and research on the associations between stress experience and cortisol in the context of longitudinal observations are discussed.

Digitalization and the Social Lives of Older Adults: Protocol for a Microlongitudinal Study

BACKGROUND

Digital technologies are increasingly pervading our daily lives. Although older adults started using digital technologies later than other age groups, they are increasingly adopting these technologies, especially with the goal of communicating with others. However, less is known about how online social activities are embedded in older adults' daily lives, how they complement other (offline) social activities, and how they contribute to social connectedness and well-being.

OBJECTIVE

Data generated by this project will allow us to understand how older adults use digital communication in their daily lives to communicate with others, how this relates to well-being and social connectedness, and how communication using digital technologies differs from other types of communication depending on situational and individual characteristics.

METHODS

Microlongitudinal data were collected from 120 older adults from German-speaking regions of Switzerland to examine these questions. Data collection took place from April 2019 to October 2019. Data collection took place over different time scales, including event-based (reporting all social interactions for 21 days), daily (well-being, loneliness, and technology use every evening for 21 days), hourly (cortisol assessments 6 times per day for 3 days), and baseline (relevant interindividual characteristics, including sociodemographics, health, technology use, personality, and cognitive performance) assessments.

RESULTS

Data collection for this study was completed in November 2019. Participants reported an average of 96.35 interactions across the 21 days. Among the total 11,453 interactions, 5494 (47.97%) were face-to-face, and around 16% each were interactions by phone (1858, 16.16%), email (1858, 16.22%), and text message (1853, 16.18%). Otherwise, 246 (2.15%) of the interactions took place on social media, 96 (0.84)% were letters, and 54 (0.47%) of the interactions took place on videochat.

CONCLUSIONS

Participants used a variety of modalities in their daily communication, including digital means such as text messages, email, and video calls. Further analysis will provide more detail as to the role that communication via digital media plays in older adults' daily lives.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR1-10.2196/20306.

Changes in Continuous, Long-Term Heart Rate Variability and Individualized Physiological Responses to Wellness and Vacation Interventions Using a Wearable Sensor

There are many approaches to maintaining wellness, including taking a simple vacation to attending highly structured wellness retreats, which typically regulate the attendee's personal time and activities. In a healthy English-speaking cohort of 112 women and men (aged 30–80 years), this study examined the effects of participating in either a 6-days intensive wellness retreat based on Ayurvedic medicine principles or unstructured 6-days vacation at the same wellness center setting. Heart rate variability (HRV) was monitored continuously using a wearable ECG sensor patch for up to 7 days prior to, during, and 1-month following participation in the interventions. Additionally, salivary cortisol levels were assessed for all participants at multiple times during the day. Continual HRV monitoring data in the real-world setting was seen to be associated with demographic [HRV_ALF: β_Age = 0.98 (95% CI = 0.96–0.98), false discovery rate (FDR) < 0.001] and physiological characteristics [HRV_PLF: β = 0.98 (95% CI = 0.98–1), FDR =0.005] of participants. HRV features were also able to quantify known diurnal variations [HRV_LF/HF: β_{ACT:night vs. early−morning} = 2.69 (SE = 1.26), FDR < 0.001] along with notable inter- and intraperson heterogeneity in response to intervention. A statistically significant increase in HRV_ALF [β = 1.48 (SE = 1.1), FDR < 0.001] was observed for all participants during the resort visit. Personalized HRV analysis at an individual level showed a distinct individualized response to intervention, further supporting the utility of using continuous real-world tracking of HRV at an individual level to objectively measure responses to potentially stressful or relaxing settings.

Diurnal trajectories of salivary cortisol and α-amylase and psychological profiles in patients with central serous chorioretinopathy

It has been hypothesized that the occurrence of central serous chorioretinopathy (CSC) might be associated with stress. Therefore, our purpose was to investigate the diurnal trajectories of salivary cortisol and α-amylase (α-Amy) - markers of hypothalamic-pituitary-adrenal (HPA) axis and sympathetic-adrenal-medullary (SAM) system activity, respectively - and psychological profiles in idiopathic acute CSC. This cross-sectional observational case-control study, which included self-reported psychometric questionnaires, was formally approved by the Ethics Committee. Written informed consent was obtained from all participants. Home diurnal saliva collection was scheduled at several timepoints: at awakening, 30 and 60 min later, and at approximately 13:00 h and 20:00 h. Twenty consecutive male subjects with first-episode CSC attending the outpatient clinic of the Retina Medical Service at the Bietti Foundation were enrolled in the study. Twenty age-matched subjects were recruited as controls. After their initial enrollment, 3 subjects per group were excluded. The production of cortisol and α-Amy and the scores on the negative subscale of the Positive/Negative Affect Schedule, the Daily Hassles and Stress Scale and the Beck Depression Inventory were higher in the CSC group than in the control group. To estimate the diurnal trends in the production of salivary cortisol and α-Amy, an equation was derived for each group of the study population. The equations describing the interpolated regression lines gave salivary cortisol and salivary α-Amy slopes that were determined to be significantly different by Student's t-test (cortisol: t = 3.533, p < .001; α-Amy: t = 2.382, p = .018). Furthermore, the area under the curve with respect to the ground (AUC_G) was calculated to summarize repeated salivary biomarker measurements from 07:00 h to 08:00 h for assessment of the cortisol awakening response (CAR) and the α-Amy awakening response (AR). The diurnal cortisol AUC_G and diurnal α-Amy AUC_G were calculated from 07:00 h to 20:00 h. The CAR AUC_G values of the CSC patients were significantly higher than those of the controls. No differences between the two groups were detected for the α-Amy AR AUC_G. The present study adds novel information to the growing body of data suggesting that abnormal diurnal activity of the HPA axis and the SAM system is associated with CSC in susceptible individuals, providing ophthalmologists with a new chronobiological approach for these patients.

Classroom social experiences in early elementary school relate to diurnal cortisol levels

Social stress has been linked to altered hypothalamic-pituitary-adrenocorticol (HPA) axis activation. During elementary school, children can become exposed to negative peer relations, such as poor appraisal among classroom peers, which is considered a social stressor. However, little is known about the association between classroom peer appraisal and the physiological stress system in children. The goal of this study was to examine the association of peer acceptance and peer non-acceptance with diurnal cortisol concentrations in 222 children from 20 mainstream elementary schools (Mage=6.97years, SD=0.99, 55% boys) in the Netherlands. Saliva samples were collected at awakening, 30min post-awakening, at noon and at 8 pm during a weekend day. From these assessments, the Cortisol Awakening Response (CAR), diurnal cortisol concentration (AUC_g) and diurnal cortisol slope were calculated. Peer nominations of peer acceptance (being liked), and peer non-acceptance (being disliked) were collected across a one year interval. Associations were controlled for peer victimization, age, sex and SES and children's levels of emotional problems and behavioural problems. Results showed that low peer acceptance was associated with heightened diurnal cortisol concentration (i.e., heightened AUG_g), lower cortisol reductions across the day (i.e., less decreasing cortisol slope) and heightened cortisol awakening response (i.e., heightened CAR). Peer non-acceptance and the interaction between peer acceptance and peer non-acceptance (known as peer rejection) were not associated with AUCg, cortisol slope or the CAR. The findings emphasize the association between poor appraisal among classroom peers and children's heightened HPA-axis activation. This underscores the importance of the physiological stress system in studying the consequences of negative peer relations in children.

The effect of an adverse psychological environment on salivary cortisol levels in the elderly differs by 5-HTTLPR genotype

BACKGROUND

An adverse psychological environment (e.g. stressful events or depression) has been shown to influence basal cortisol levels and cortisol response to stress. This differs depending on the adverse stimuli, but also varies across individuals and may be influenced by genetic predisposition. An insertion/deletion polymorphism in the serotonin transporter gene (5-HTTLPR) is a strong candidate in this regard.

OBJECTIVE

To investigate how stressful life events and depression are associated with diurnal cortisol levels in community-dwelling elderly and determine whether this varies according to genetic variability in the 5-HTTLPR.

METHODS

This population-based study included 334 subjects aged 65 and older (mean (SD) = 76.5 (6.3)). Diurnal cortisol was measured on two separate days, under quiet (basal) and stressful conditions. The number of recent major stressful events experienced during the past year was assessed from a 12-item validated questionnaire as an index of cumulative recent stressful events. Lifetime trauma was evaluated using the validated Watson's PTSD inventory, which evaluates the most severe traumatic or frightening experience according to DSM criteria. Depression was defined as having a Mini-International Neuropsychiatric Interview (MINI) diagnosis of current major depressive disorder or high levels of depressive symptoms (Center for Epidemiologic Studies-Depression Scale ≥16). 5-HTTLPR genotyping was performed on blood samples.

RESULTS

Exposure to stressful life events was associated with lower basal evening cortisol levels overall, and in the participants with the 5-HTTLPR L allele but not the SS genotype. The greatest effects (over 50% decrease, p < 0.001) were observed for the LL participants having experienced multiple recent stressful events or severe lifetime traumas. Participants with the L allele also had higher evening cortisol stress response. Conversely, depression tended to be associated with a 42% higher basal morning cortisol in the SS participants specifically, but did not modify the association between stressful events and cortisol levels.

CONCLUSION

An adverse psychological environment is associated with basal cortisol levels and cortisol stress response, but this differs according to 5-HTTLPR genotype.

Stigma and diurnal cortisol among transitioning transgender men

This study assessed diurnal cortisol functioning in relation to stigma-based transition-specific stressors experienced by transgender men during their transition from female to male. Sixty-five healthy transgender men undergoing testosterone therapy participated in in-person interviews through which transition-specific stressors were identified. Interviews were coded according to participant reported (1) Transitioning-identity stress; (2) Coming Out stress; (3) Gender-specific Public Bathroom stress; and (4) levels of general Perceived Stress. Participants provided fifteen salivary samples assessing cortisol diurnal rhythm over three days. Hierarchical linear models, adjusted for duration of time on testosterone therapy, body mass index, steroid-related medication use, mean awakening time, and CAR, confirmed that elevated diurnal cortisol levels at awakening were associated with transition-specific social stressors including experiencing Transitioning-identity stress, frequent Coming Out stress, and Gender-specific Public Bathroom stress. Transitioning-identity stress and Gender-specific Public Bathroom stress also predicted a steeper negative slope at awakening. General Perceived Stress was not associated with elevated cortisol or slope. These results clarify the relation of increased cortisol at awakening with a negative linear slope to perceived stigma and transition-related stress experience among transgender men.

Salivary diurnal cortisol profiles in patients suffering from chronic breathlessness receiving supportive and palliative care services: A cross-sectional study

Chronic breathlessness is a common source of psychological and physical stress in patients with advanced or progressive disease, suggesting that hypothalamic-pituitary-adrenal (HPA) axis dysregulation may be prevalent. The aim of this study was to measure the salivary diurnal cortisol profile in patients receiving supportive and palliative care for a range of malignant and non-malignant conditions and to compare the profile of those experiencing moderate-to-severe disability due to breathlessness against that of patients with mild/no breathlessness and that of healthy controls. Saliva samples were collected over two consecutive weekdays at 3, 6, and 12h after awakening in 49 patients with moderate-to-severe breathlessness [Medical Research Council (MRC) dyspnoea grade ≥3], 11 patients with mild/no breathlessness (MRC dyspnoea grade ≤2), and 50 healthy controls. Measures of breathlessness, stress, anxiety, depression, wellbeing and sleep were examined concomitantly. The diurnal cortisol slope (DCS) was calculated for each participant by regressing log-transformed cortisol values against collection time. Mean DCS was compared across groups using ANCOVA. Individual slopes were categorised into one of four categories: consistent declining, consistent flat, consistent ascending and inconsistent. Controlling for age, gender and socioeconomic status, the mean DCS was significantly flatter in patients with moderate-to-severe breathlessness compared to patients with mild/no breathlessness and healthy controls [F (2, 103)=45.64, p<0.001]. Furthermore, there was a higher prevalence of flat and ascending cortisol profiles in patients with moderate-to-severe breathlessness (23.4%) compared to healthy controls (0%). The only variable which correlated significantly with DCS was MRC dyspnoea grade (rs=0.29, p<0.05). These findings suggest that patients with moderate-to-severe breathlessness have evidence of HPA axis dysregulation and that this dysregulation may be related to the functional disability imposed by breathlessness.

Intra-individual cortisol variability and low-grade inflammation over 10 years in older adults

OBJECTIVE

This study examined the associations between intra-individual variability in, and inter-individual levels of, diurnal cortisol secretion with a marker of low-grade inflammation (i.e., C-Reactive Protein; CRP). Reasoning that greater day-to-day cortisol variability could reflect a dysregulation of the HPA axis, we hypothesized that it would predict higher levels of CRP, above and beyond inter-individual differences in cortisol levels.

METHODS

A 10-year longitudinal study of 130 older adults examined diurnal cortisol secretion on three different days across each of the 6 waves of data collection and levels of CRP during the last 3 waves. Indicators of mean cortisol levels, short-term cortisol variability, and long-term cortisol variability were analyzed.

RESULTS

Hierarchical linear modeling showed significant main effects, linking baseline mean cortisol levels, T-ratio=2.25, p=0.03, and long-term cortisol variability, T-ratio=2.63, p=0.01, with higher CRP values six to ten years after study entry. In addition, a two-way interaction demonstrated that short-term variability in cortisol were associated with higher levels of CRP among individuals who secreted relatively high, T-ratio=2.68, p=0.01, but not low, T-ratio=-1.09, p=0.28, baseline levels of cortisol. Finally, a three-way interaction, T-ratio=2.24, p=0.03, suggested that the effect of long-term cortisol variability on CRP became stronger over time among participants who secreted high average levels of cortisol, whereas it became weaker among their counterparts who secreted low average levels of cortisol.

CONCLUSION

Variability in cortisol secretion across days forecasts low-grade inflammation, and this association is paramount among older adults who secrete high levels of diurnal cortisol.

Salivary cortisol and α-amylase: subclinical indicators of stress as cardiometabolic risk

Currently, the potential for cardiovascular (CV) stress-induced risk is primarily based on the theoretical (obvious) side effects of stress on the CV system. Salivary cortisol and α-amylase, produced respectively by the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic-adrenomedullary (SAM) system during stress response, are still not included in the routine evaluation of CV risk and require additional and definitive validation. Therefore, this article overviews studies published between 2010 and 2015, in which salivary cortisol and α-amylase were measured as stress biomarkers to examine their associations with CV/CMR (cardiometabolic risk) clinical and subclinical indicators. A comprehensive search of PubMed, Web of Science and Scopus electronic databases was performed, and 54 key articles related to the use of salivary cortisol and α-amylase as subclinical indicators of stress and CV/CMR factors, including studies that emphasized methodological biases that could influence the accuracy of study outcomes, were ultimately identified. Overall, the biological impact of stress measured by salivary cortisol and α-amylase was associated with CV/CMR factors. Results supported the use of salivary cortisol and α-amylase as potential diagnostic tools for detecting stress-induced cardiac diseases and especially to describe the mechanisms by which stress potentially contributes to the pathogenesis and outcomes of CV diseases.

Use of Salivary Diurnal Cortisol as an Outcome Measure in Randomised Controlled Trials: a Systematic Review

Background

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is associated with diverse adverse health outcomes, making it an important therapeutic target. Measurement of the diurnal rhythm of cortisol secretion provides a window into this system. At present, no guidelines exist for the optimal use of this biomarker within randomised controlled trials (RCTs).

Purpose

The aim of this study is to describe the ways in which salivary diurnal cortisol has been measured within RCTs of health or behavioural interventions in adults.

Methods

Six electronic databases (up to May 21, 2015) were systematically searched for RCTs which used salivary diurnal cortisol as an outcome measure to evaluate health or behavioural interventions in adults. A narrative synthesis was undertaken of the findings in relation to salivary cortisol methodology and outcomes.

Results

From 78 studies that fulfilled the inclusion criteria, 30 included healthy participants (38.5 %), 27 included patients with physical disease (34.6 %) and 21 included patients with psychiatric disease (26.9 %). Psychological therapies were most commonly evaluated (n = 33, 42.3 %). There was substantial heterogeneity across studies in relation to saliva collection protocols and reported cortisol parameters. Only 39 studies (50 %) calculated a rhythm parameter such as the diurnal slope or the cortisol awakening response (CAR). Patterns of change in cortisol parameters were inconsistent both within and across studies and there was low agreement with clinical findings.

Conclusions

Salivary diurnal cortisol is measured inconsistently across RCTs, which is limiting the interpretation of findings within and across studies. This indicates a need for more validation work, along with consensus guidelines.

Electronic supplementary material

The online version of this article (doi:10.1007/s12160-015-9753-9) contains supplementary material, which is available to authorized users.

The interplay of subjective social status and essentialist beliefs about cognitive aging on cortisol reactivity to challenge in older adults

Older adults are more likely than younger adults to experience stress when confronted with cognitive challenges. However, little is known about individual differences that might explain why some older adults exhibit stronger stress responses than others. We examined the interplay of two social-cognitive factors to explain older adults' cortisol reactivity: (1) subjective social status, and (2) essentialist beliefs about cognitive aging. We hypothesized that, depending on whether older adults believe that aging-related cognitive decline is inevitable versus modifiable, low subjective social status should lead to stronger or weaker cortisol reactivity. Using longitudinal data, we assessed the impact of cognitive challenges on stress reactivity in a sample of older adults (N = 389; 61-86 years). As predicted, regression analyses confirmed that 44 min after cognitively challenging tasks, older adults exhibited a significantly different cortisol reactivity depending on their subjective social status and their essentialist beliefs about cognitive aging. Specifically, older adults with low subjective social status and high essentialist beliefs showed a significantly elevated cortisol reactivity. We discuss the role of essentialist beliefs about cognitive aging to predict when and why high versus low subjective social status leads to stress responses in older adults.

Atypical secretion of cortisol in Nursing professionals

Objective To describe the frequency with which nursing staff in hospitals presents an altered diurnal pattern of cortisol secretion. Method These findings were based on results obtained from 56 randomly selected professional nursing staff working in outpatient clinics, medical clinics, surgical clinics, operating theaters, pediatric and adult emergency units, adult and pediatric intensive care units of a university hospital. The analysis of the diurnal cortisol pattern was based on saliva samples collected over two consecutive working days. Results 42.5% of these nursing staff members presented an atypical pattern of cortisol secretion. Furthermore, the longer the period of exercising this profession, the higher the cortisol concentration (r=0.346; p=0.020). Conclusion Over one-third of nursing staff samples displayed atypical cortisol secretion patterns. This suggests that these professionals are exposed, not only to a mental, but also to a biological, overload and thus, to a risk of contracting stress-related illnesses.

Twenty-four-hour profiles of metabolic and stress hormones in sheep selected for a calm or nervous temperament

Even in the absence of stressors, temperament is associated with changes in the concentration of stress-responsive hormones and, possibly because of such changes, temperament can affect metabolism. We tested whether, in sheep bred for temperament for 14 generations, "nervous" females have greater concentrations of stress-responsive hormones in the absence of stressors than "calm" females, and whether these differences are associated with changes in the concentrations of metabolic hormones. In resting "calm" (n = 8) and "nervous" (n = 8) sheep, concentrations of cortisol, prolactin, leptin, and insulin were measured in blood plasma sampled via jugular catheter every 20 min for 24 h. The animals were individually penned, habituated to their housing and human handling over 7 wk, and fed before sampling began. Diurnal variation was evident for all hormones, but a 24-h cortisol pattern was detected in only 7 individuals. There was no effect of temperament on any aspect of concentrations of cortisol or prolactin, but "calm" animals had greater concentrations of insulin in the early afternoon than "nervous" animals (14.5 ± 1.1 vs 10.0 ± 1.6 μU/mL; P = 0.038), and a similar tendency was seen for leptin (P = 0.092). We conclude that selection for temperament affects the concentration of metabolic hormones in the absence of stressors, but this effect is independent of stress-responsive hormones.

Salivary biomarkers of oxidative stress: A critical review

Human saliva is an increasingly attractive medium for biomarker discovery due to its amenability to noninvasive and repeated sampling, ease of collection and processing, and suitability for single analyte or metabolomic measurements. Salivary biomarkers of oxidative stress reflect local and systemic pathologies and may inform on the diagnosis, prognosis, and therapeutic responsiveness of numerous human diseases. However, for many of the disorders investigated, data reporting on alterations in salivary redox homeostasis are often highly conflicted across studies. We surveyed the available biomedical literature on this topic and noted significant discrepancies in the study designs, target populations, and operating procedures which likely contribute to the discordant data sets reported. Based on these observations, guidelines are provided to minimize interlaboratory variability in redox biomarker discovery based on human saliva.

Hormones as "difference makers" in cognitive and socioemotional aging processes

Aging is associated with well-recognized alterations in brain function, some of which are reflected in cognitive decline. While less appreciated, there is also considerable evidence of socioemotional changes later in life, some of which are beneficial. In this review, we examine age-related changes and individual differences in four neuroendocrine systems-cortisol, estrogen, testosterone, and oxytocin-as "difference makers" in these processes. This suite of interrelated hormonal systems actively coordinates regulatory processes in brain and behavior throughout development, and their level and function fluctuate during the aging process. Despite these facts, their specific impact in cognitive and socioemotional aging has received relatively limited study. It is known that chronically elevated levels of the stress hormone cortisol exert neurotoxic effects on the aging brain with negative impacts on cognition and socioemotional functioning. In contrast, the sex hormones estrogen and testosterone appear to have neuroprotective effects in cognitive aging, but may decrease prosociality. Higher levels of the neuropeptide oxytocin benefit socioemotional functioning, but little is known about the effects of oxytocin on cognition or about age-related changes in the oxytocin system. In this paper, we will review the role of these hormones in the context of cognitive and socioemotional aging. In particular, we address the aforementioned gap in the literature by: (1) examining both singular actions and interrelations of these four hormonal systems; (2) exploring their correlations and causal relationships with aspects of cognitive and socioemotional aging; and (3) considering multilevel internal and external influences on these hormone systems within the framework of explanatory pluralism. We conclude with a discussion of promising future research directions.

Altered circadian patterns of salivary cortisol in low-functioning children and adolescents with autism

BACKGROUND

Reports of higher stress responsivity, altered sleep-wake cycle and a melatonin deficit in autism have stimulated interest in the cortisol circadian rhythm in individuals with autism.

METHODS

The study was conducted on 55 low-functioning children and adolescents with autism (11.3 ± 4.1 years-old) and 32 typically developing controls (11.7 ± 4.9 years-old) matched for age, sex and puberty. Behavioral assessment was performed using the Autism Diagnostic Observation Schedule (ADOS). Salivary samples for measurement of cortisol were collected during a 24-h period (at least 0800 h-Day 1, 1600 h, 0800 h-Day 2 for 46 individuals with autism and 27 controls, and 0800 h-Day 1, 1100 h, 1600 h, 2400 h, 0800 h-Day 2 for 13 individuals with autism and 20 controls). Overnight (2000 h-0800 h) urinary cortisol excretion was also measured.

RESULTS

The autism group displayed significantly higher levels of salivary cortisol at all time-points, flatter daytime and nighttime slopes, higher 0800 h cortisol levels on Day 2 compared to Day 1, and greater variances of salivary and urinary cortisol. There was a significant relationship between salivary cortisol levels and impairments in social interaction and verbal language. Overnight urinary cortisol excretion was similar in the autism and control groups.

CONCLUSION

Anticipation of the stressful collection procedure appears to contribute to the higher 0800 h-Day 2 versus 0800 h-Day 1 salivary cortisol levels in autism. This sensitization to stressors might be as, or even more, important clinically than exposure to novelty in autism. The similar group means for overnight urinary cortisol excretion indicate that basal HPA axis functioning is unaltered in low-functioning autism. The elevated salivary cortisol levels observed in autism over the 24-h period in a repeated stressful condition, flattened diurnal cortisol patterns and the apparent effect of anticipation are consistent with prior findings in high trait anxiety.

Salivary biomarkers of obstructive sleep apnea syndrome in children

OBJECTIVES

The present pilot study was performed to evaluate the HPA axis and ANS activity by measuring salivary cortisol and α-amylase diurnal trajectory and production, respectively, in mild or moderate-to-severe (MS) OSA-affected, but otherwise healthy, children. Moreover, a correlative analysis was performed between the salivary biomarker concentrations and the PSG variables characterizing the OSA severity.

METHODS

We studied 27 consecutive OSA patients (13 mild OSA; 14 MS OSA) and seven healthy children who were enrolled as controls by collecting salivary samples and measuring cortisol and α-amylase levels using enzyme-linked bioassays.

RESULTS

Compared with controls, both mild and MS OSA children showed: (1) increased salivary cortisol diurnal production, (2) maintenance of the physiological circadian activity of the HPA axis, and (3) no changes in α-amylase diurnal trajectory and production. In addition, morning salivary cortisol concentrations was negatively associated with the disease severity in the MS OSA group.

CONCLUSIONS

OSA is associated with dysregulation of the HPA axis activity in children, the latter potentially underlying some of the adverse consequences of the disease.

Variability and reliability of diurnal cortisol in younger and older adults: implications for design decisions

The extant research is inconclusive regarding the best sampling methods to construct reliable measures of between-person differences in derived parameters of diurnal cortisol, and no study provides such recommendations for detecting within-person changes. These studies determined how many days of sampling are necessary to assess between-person differences and within-person changes over multiple occasions in diurnal mean, diurnal slope, and area under the curve (AUC). Generalizability and decision analyses were conducted on diurnal salivary cortisol data from two separate longitudinal studies, one with younger adults (N=124) and one with older adults (N=148). In both studies, results indicated that 3 days of data collection provided the minimal level of reliability in mean cortisol to detect between-person differences; 4-8 days were necessary to reliably assess AUC, and 10 days for cortisol slope. Similarly, in order to reliably characterize within-person changes across occasions, at least 3 days of data collection were needed for mean cortisol and AUC and 5-8 days for slope. Results also indicated that only two samples per day, taken morning and evening, could faithfully reproduce the diurnal slope calculated from 3 or 4 samples (r=.97-.99). Instead of having participants provide many samples per day over the course of a few days, we recommend collecting fewer samples per day over more days.

DOES LOWER SUBJECTIVE SOCIAL STATUS YIELD RISKIER BIOMARKER PROFILES?

Both objective and, more recently, subjective measures of low social status have been linked to poor health outcomes. It is unclear, however, through which precise physiological mechanisms such standing may influence health, although it has been proposed that those of lower status may have biomarker profiles that are more dysregulated (and hence pose a greater risk for poorer health). The main objective of this study was to investigate whether lower subjective social standing is associated with riskier neuroendocrine biomarker profiles. Data were from the Social Environment and Biomarkers of Aging Study (SEBAS), a nationally representative survey of Taiwanese men and women (ages 54-91) conducted in Taiwan in 2000. Five neuroendocrine markers (cortisol, dehydroepiandrosterone sulphate (DHEAS), adrenaline, noradrenaline and dopamine) were analysed both separately and collectively in an index termed neuroendocrine allostatic load (NAL) in relation to status - both self-reported and as measured through objective socioeconomic status (SES) indicators. For the biomarker DHEAS, some connection was found between its levels and the measures of status, but for the other markers and the NAL index almost no connection was found. The overall negative finding of this paper would be further supported with more and different measures of neuroendocrine system function and a reordering of the subjective social status questions in the survey such that the one probing about status in the community (that has no prompt) was asked before the one probing about status in all of Taiwan (which has a SES prompt).

Developmental and contextual considerations for adrenal and gonadal hormone functioning during adolescence: Implications for adolescent mental health

Substantial research has implicated the hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes independently in adolescent mental health problems, though this literature remains largely inconclusive. Given the cross-talk between the HPA and HPG axes and their increased activation in adolescence, a dual-axis approach that examines both axes simultaneously is proposed to predict the emergence and persistence of adolescent mental health problems. After briefly orienting readers to HPA and HPG axis functioning, we review the literature examining associations between hormone levels and changes with behavior during adolescence. Then, we provide a review of the literature supporting examination of both axes simultaneously and present the limited research that has taken a dual-axis approach. We propose future directions including consideration of between-person and within-person approaches to address questions of correlated changes in HPA and HPG hormones. Potential moderators are considered to increase understanding of the nuanced hormone-behavior associations during key developmental transitions.

Diurnal patterns and associations among salivary cortisol, DHEA and alpha-amylase in older adults

BACKGROUND

Cortisol and dehydroepiandrosterone (DHEA) are considered to be valuable markers of the hypothalamus-pituitary-adrenal (HPA) axis, while salivary alpha-amylase (sAA) reflects the autonomic nervous system. Past studies have found certain diurnal patterns among these biomarkers, with some studies reporting results that differ from others. Also, some past studies have found an association among these three biomarkers while other studies have not. This study investigates these patterns and associations in older adults by taking advantage of modern statistical methods for dealing with non-normality, outliers and curvature. Basic characteristics of the data are reported as well, which are relevant to understanding the nature of any patterns and associations.

METHODS

Boxplots were used to check on the skewness and presence of outliers, including the impact of using simple transformations for dealing with non-normality. Diurnal patterns were investigated using recent advances aimed at comparing medians. When studying associations, the initial step was to check for curvature using a non-parametric regression estimator. Based on the resulting fit, a robust regression estimator was used that is designed to deal with skewed distributions and outliers.

RESULTS

Boxplots indicated highly skewed distributions with outliers. Simple transformations (such as taking logs) did not deal with this issue in an effective manner. Consequently, diurnal patterns were investigated using medians and found to be consistent with some previous studies but not others. A positive association between awakening cortisol levels and DHEA was found when DHEA is relatively low; otherwise no association was found. The nature of the association between cortisol and DHEA was found to change during the course of the day. Upon awakening, cortisol was found to have no association with sAA when DHEA levels are relatively low, but otherwise there is a negative association. DHEA was found to have a positive association with sAA upon awakening. Shortly after awakening and for the remainder of the day, no association was found between DHEA and sAA ignoring cortisol. For DHEA and cortisol (taken as the independent variables) versus sAA (the dependent variable), again an association is found only upon awakening.

Angiotensin-converting enzyme gene variants are associated with both cortisol secretion and late-life depression

Angiotensin-converting enzyme (ACE) is assumed to influence the activity of the hypothalamic-pituitary-adrenocortical (HPA) axis, which shows hyperactivity in depressed patients. ACE could thus be a promising candidate gene for late-life depression but this has not been examined previously. Depression was assessed in 1005 persons aged at least 65 years, at baseline and over the 10-year follow-up. A clinical level of depression (DEP) was defined as having a score of > or =16 on the Centre for Epidemiology Studies-Depression scale or a diagnosis of current major depression based on the Mini International Neuropsychiatric Interview and according to DSM-IV criteria. Seven single-nucleotide polymorphisms (SNPs) in the ACE gene were genotyped and diurnal cortisol secretion, as an index of HPA axis activity, was measured. Multivariable analyses were adjusted for socio-demographic and vascular factors, cognitive impairment, and apolipoprotein E. Strong significant associations were found between all seven SNPs and DEP and, in particular, first-onset DEP in persons without a past history of depression (P-values ranging from 0.005 to 0.0004). These associations remained significant after correction for multiple testing. The genotypes that were associated with an increased risk of DEP were also significantly associated with an increase in cortisol secretion under stress conditions. Variants of the ACE gene influence cortisol secretion and appear as susceptibility factors for late-life depression in the elderly population. Whether this could represent a common pathophysiological mechanism linking HPA axis and late-life depression remains to be explored.

Within-person coupling of changes in cortisol, testosterone, and DHEA across the day in adolescents

We comprehensively examined within-person and between-person associations between cortisol and DHEA and cortisol and testosterone across the day. Data are from a sample of 213 adolescents aged 11-16 (M = 13.7, SD = 1.5 years) from the Northeastern US who were oversampled for psychopathology symptoms. Six repeated measures of hormone levels across 3 days were used to test three specific questions of cortisol-DHEA and cortisol-testosterone associations within individuals (coupling) across the day, and one question of cortisol-DHEA and cortisol-testosterone diurnal slopes were associated between adolescents. Results consistently revealed positive cortisol-DHEA and cortisol-testosterone coupling across the day, often more pronounced in girls relative to boys. Cortisol and DHEA slopes were positively associated, whereas cortisol and testosterone were negatively associated between-adolescents. Findings suggest multiple mechanisms and highlight the multifaceted nature of associations of hormone changes during adolescence and importance of considering both axes for between- and within-person aspects of neuroendocrine development.

A day-centered approach to modeling cortisol: diurnal cortisol profiles and their associations among U.S. adults

Diurnal cortisol is a marker of HPA-axis activity that may be one of the biological mechanisms linking stressors to age-related health declines. The current study identified day-centered profiles of diurnal cortisol among 1101 adults living in the United States. Participants took part in up to four consecutive days of salivary cortisol collection, assessed at waking, 30min post-waking, before lunch, and before bedtime. Growth mixture modeling with latent time basis was used to estimate common within-day trajectories of diurnal cortisol among 2894 cortisol days. The 3-class solution provided the best model fit, showing that the majority of study days (73%) were characterized by a Normative cortisol pattern, with a robust cortisol awakening response (CAR), a steep negative diurnal slope, coupled with low awakening and bedtime levels. Relative to this profile, diurnal cortisol on the remainder of days appeared either elevated throughout the day (20% of days) or flattened (7% of days). Relative to the normative trajectory, the elevated trajectory was distinguished by a higher morning cortisol level, whereas the flattened trajectory was characterized by a high bedtime level, with weaker CAR and diurnal slope parameters. Relative to the normative profile, elevated profile membership was associated with older age and cigarette smoking. Greater likelihood of the flattened cortisol pattern was observed among participants who were older, male, smoked cigarettes, used medications that are known to affect cortisol output, and reported poorer health. The current study demonstrates the value of a day-centered growth mixture modeling approach to the study of diurnal cortisol, showing that deviations from the classic robust rhythm of diurnal cortisol are associated with older age, male sex, use of medications previously shown to affect cortisol levels, poorer health behaviors, and poorer self-reported health.

Restoring the salivary cortisol awakening response through nasal continuous positive airway pressure therapy in obstructive sleep apnea

Partial and largely conflicting data are currently available on the interplay between obstructive sleep apnea (OSA) and hypothalamus-pituitary-adrenal axis (HPA) activity in adult obese men. This study was performed to evaluate the daily trajectories of salivary cortisol, specifically with respect to the salivary cortisol awakening response (CAR), a common method used to assess HPA axis activity. The main findings of this study were that adult male obese subjects who were newly diagnosed with severe OSA showed the following: (1) a flattening of the CAR; (2) levels of cortisol at awakening that were lower than those of the controls; and (3) maintenance of the physiological circadian activity of the HPA axis, with the highest hormone concentrations produced in the morning and the lowest in the evening. This study was also designed to investigate the effects of 3 and 6 mos of treatment with continuous airways positive pressure (CPAP). CPAP use resulted in a significant recovery of the sleep patterns disrupted by OSA; moreover, mild neuropsychological signs of depression and anxiety in severe OSA patients were concomitantly progressively improved by CPAP treatment. Furthermore, this study reports that 3 and 6 mos of CPAP therapy restored the presence of CAR and was able to significantly reduce the difference in the morning cortisol levels between the OSA and control groups. In conclusion, we report here that compared with obese nonapneic matched controls, OSA patients present a dysregulation of HPA axis activity, as shown by the flattening of the diurnal pattern of cortisol production in response to repeated challenge due to hypoxia and sleep fragmentation. This dysregulation was especially detectable in the first hour after awakening and restored after 3 and 6 mos of treatment with CPAP.

Post-traumatic disorder symptoms and blunted diurnal cortisol production in partners of prostate cancer patients

Prostate cancer (PC) is the most common cancer diagnosed in men, and research suggests that coping with this illness can cause significant distress in patients as well as their partners. This study examined the relationship of caregiving for a partner with PC with diurnal cortisol output in women between the ages of 42 and 75 years old. Participants were women whose partners had PC (n = 19) and women who were in relationships with men with no diagnosed medical illness (n = 26). Women provided saliva samples (4 times per day over 3 days) in their natural environment. The Structured Clinical Interview for DSM-IV Axis-I Disorders was also conducted to assess for the presence of post-traumatic stress disorder (PTSD) and major depression. Partners of men with PC had lower daily cortisol output across the three days than controls, F(1,444.08) = 20.72, p<.001). They were also more likely to report PTSD symptoms with 68.4% of PC partners fulfilling criteria for sub-threshold PTSD as compared to 23.1% of controls (χ(2) = 11.30, p = .01). Mixed model analyses revealed that the presence of sub-threshold PTSD symptoms significantly predicted cortisol production, F(1,419.64) = 5.10, p<.01). Regardless of caregiver status, women who reported at least sub-threshold PTSD symptoms had lower cortisol production than those with no PTSD symptoms. Major depression did not explain differences in cortisol production between partners of PC patients and controls. Although these findings are preliminary, they highlight the importance of developing interventions aimed at reducing risk of psychopathology in partners of men with PC.

I do…do you? Dependence and biological sex moderate daters' cortisol responses when accommodating a partner's thoughts about marriage

We examined how daters' levels of relationship dependence interact with men's and women's degree of accommodation during a likelihood of marriage discussion to predict cortisol levels at the conclusion of the discussion. Upon arriving at the laboratory, couple members were separated and asked to graph their perceived likelihood of one day marrying each other. Couples were reunited and instructed to create a joint graph depicting their agreed-upon chance of marriage. For the majority of couples, negotiating their likelihood of marriage required one or both partners to accommodate each other's presumed likelihood of marriage. Multilevel analyses revealed a significant Dependence×Accommodation×Sex interaction. For women who increased their likelihood of marriage, feelings of dependence predicted heightened levels of cortisol relative to baseline; we suggest such a response is indicative of eustress. Among men, those who accommodated by decreasing their likelihood of marriage experienced significantly lower levels of cortisol to the extent that they were less dependent on their partners. Discussion focuses on why men and women show different physiological reactions in response to seemingly favorable outcomes from a relationship discussion.

Does physical activity reduce risk for Alzheimer's disease through interaction with the stress neuroendocrine system?

Lack of physical activity (PA) is a risk factor for Alzheimer's disease (AD), and PA interventions are believed to provide an effective non-pharmacological approach for attenuating the symptoms of this disease. However, the mechanism of action of these positive effects is currently unknown. It is possible that the benefits may be at least partially mediated by the effects on the neuroendocrine stress system. Chronic stress can lead to dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis, leading to aberrant basal and circadian patterns of cortisol secretion and a cascade of negative downstream events. These factors have been linked not only to reduced cognitive function but also increased levels of amyloid-β plaques and protein tau "tangles" (the neuropathological hallmarks of AD) in the non-demented mouse models of this disease. However, there is evidence that PA can have restorative effects on the stress neuroendocrine system and related risk factors relevant to AD. We explore the possibility that PA can positively impact upon AD by restoring normative HPA axis function, with consequent downstream effects upon underlying neuropathology and associated cognitive function. We conclude with suggestions for future research to test this hypothesis in patients with AD.

Depressive symptoms, cortisol, and cognition during human aging: the role of negative aging perceptions

Depressive symptoms and memory impairments are associated with heightened stress hormone levels during aging. A factor that is related to memory deficits during aging is internalized negative aging stereotypes; the idea people have about the process of aging. In this study, we assessed the associations between internalized negative aging stereotypes, depressive symptoms, subjective and objective memory assessments, and cortisol concentration among older adults. Forty older adults aged between 58 and 85 years (18 females and 22 males; mean age ± SD: 71.25 ± 8.80 years) were assessed in this study. Measures of internalized negative aging stereotypes, depressive symptoms, and both subjective and objective memory performance were assessed. Salivary samples were obtained for measurement of cortisol concentration. Stepwise linear regressions were executed in our main analyses. Internalized negative aging stereotypes were associated with increased depressive symptoms and subjective memory complaints. No significant differences were observed for objective memory performance, or cortisol concentration. Internalized negative aging stereotypes are associated with increased depressive symptomatology and subjective complaints of memory; however, they do not predict increased cortisol concentration nor objective memory performance during aging. These results indicate that the mechanism underlying the association between internalized negative aging stereotypes and cognitive impairments may not be related to dysregulations of cortisol secretion among older adults.

Aphasia severity and salivary cortisol over time

The current study explored the complicated interplay between aphasia and the stress biomarker, cortisol, in left-hemisphere (LH) and right-hemisphere (RH) stroke patients. Nineteen LH patients and 12 RH patients began the study between one to six months post stroke and were followed for three months. During this time, language skills were assessed monthly while afternoon salivary cortisol samples were collected biweekly. The LH and RH groups showed improvements in language test scores over the course of three months; however, only naming skills in the RH group appeared to be associated with afternoon salivary cortisol levels. Furthermore, contradicting previous reports regarding laterality and cortisol regulation in humans, the current study found that both LH patients and RH patients exhibited similar afternoon salivary cortisol levels across all time points.

High perceived stress is linked to afternoon cortisol levels and greater symptom distress in patients with localized prostate cancer

BACKGROUND

Patients treated with radical prostatectomy (RP) or radiation therapy (RT) for prostate cancer can experience stress and symptoms that impact quality of life.

OBJECTIVE

The objectives of this study were to describe cortisol levels, perceived stress, symptoms, and symptom distress; compare differences in variables measured between RP and RT; and identify associations among cortisol levels, perceived stress, symptoms, and symptom distress in patients treated for localized prostate cancer.

METHODS

A descriptive, cross-sectional study was conducted with 53 patients (RP n = 24, RT n = 29). Data from saliva, questionnaires, and interviews were collected within 3 months of treatment. Saliva samples were collected at 4 times over 2 consecutive days. Data were analyzed using descriptive statistics, correlations, and regressions.

RESULTS

A robust diurnal rhythm of cortisol secretion with heightened levels in the early morning and lowered levels late in the day was found. On average, the entire sample had moderate symptoms and symptom distress for urinary, bowel, and sexual dysfunction. The RP group reported significantly more urinary and sexual dysfunction symptoms and fewer bowel symptoms than did the RT group. Perceived stress was positively correlated with higher afternoon cortisol levels and greater symptom distress.

CONCLUSION

Moderate symptoms and symptom distress found in our sample indicate the need for interventions to address these outcomes in men treated for prostate cancer. Self-reported perceived stress can be used to assess the stress level and symptom distress in clinic setting.

IMPLICATIONS FOR PRACTICE

Patients treated for prostate cancer with RP or RT should be assessed for symptoms and symptom distress and targeted for early symptom management interventions.

Patterns of salivary cortisol levels can manifest work stress in emergency care providers

To develop objective assessments of work fatigue, we investigated the patterns of changes in salivary cortisol levels in emergency care providers working extended work shifts. Fourteen subjects, comprising seven physicians and seven physician assistants, provided unstimulated saliva samples at regular intervals over the course of a 24-h work shift and over their subsequent free day. There was a significant time effect, with early morning cortisol levels being significantly attenuated following the work shift. Native diurnal variations varied by gender, with the female subjects manifesting greater cortisol levels. Physicians also had higher cortisol profiles even though their wake-rest cycles were similar to those of the physician assistants. Our results suggest that temporal changes, as well as diurnal similarities, in the salivary cortisol patterns can reflect work-related stress and recovery. In particular, early morning cortisol levels may manifest individual reactivity to work stressors as well as sleep deprivation.

Diurnal cortisol rhythms in Tsimane' Amazonian foragers: new insights into ecological HPA axis research

Although a growing body of research has documented important pathways by which the HPA axis mediates the interface between the psychosocial world and individual health, there is a paucity of data from nonwestern populations, particularly from those populations with distinct nutritional and infectious disease ecologies. The specific objectives of this study are: (1) to document variation in diurnal cortisol rhythms among the Tsimane', a remote population in the Bolivian Amazon, (2) to explore this variation by age and by gender, and (3) to compare diurnal rhythms from this study to other population based studies of cortisol conducted in industrialized nations. Salivary cortisol samples were collected twice daily, immediately upon waking and before bed, for three consecutive days from 303 participants (age 1.6-82 years, 1564 samples) in conjunction with the Tsimane' Amazonian Panel Study (TAPS). Cortisol rhythms showed strong age effects across the developmental span, with basal levels and slopes increasing into adulthood, although individuals older than 60 years demonstrated a precipitous flattening of the diurnal slope. Cortisol profiles were elevated in adult females compared to their age-matched male counterparts, and diurnal slopes, as well as mean cortisol concentrations among the Tsimane' were the lowest reported in any population based study of HPA axis function. Although the within-population variation in cortisol profiles was consistent with the established correlates of time of day, age, and sex, the between-population comparisons revealed dramatically lower levels of HPA activity among the Tsimane'. This study provides a benchmark against which to reference cortisol levels from industrialized populations, and expands the range of documented variation in HPA axis function in a nonwestern context.

Aging, health behaviors, and the diurnal rhythm and awakening response of salivary cortisol

BACKGROUND/STUDY CONTEXT: The cortisol diurnal rhythm has previously been examined in relation to age and health behaviors. However, less is known about the relationship between multiple health behaviors and diurnal cortisol in the context of aging, where it is possible that the impact of health behaviors on cortisol varies as a function of age. This study compared the awakening response and diurnal rhythm of cortisol in young versus older adults in relation to health behaviors.

METHODS

Twenty-four young students (aged 18-22) and 48 community-dwelling older adults (aged 65-88) completed an assessment of health behaviors (exercise, smoking, sleep, diet, alcohol) over the past year. Salivary cortisol was measured over the course of 1 day: immediately upon awakening, 30 min later, and then 3, 6, 9, and 12 h post awakening. Repeated measures/univariate analysis of variance (ANOVA) was used to test main effects of age and health behaviors, and any interaction effects in relation to diurnal cortisol.

RESULTS

Older adults displayed significantly reduced cortisol upon awakening, a lower cortisol awakening response, and a flatter diurnal profile represented by a reduced area under the curve and cortisol slope. There was also a significant interaction of age, cortisol, and diet; younger adults with a higher fat and lower fruit and vegetable intake exhibited the flattened diurnal cortisol phenotype of the older adults.

CONCLUSION

These findings suggest that the diurnal rhythm and awakening response of salivary cortisol is significantly reduced in older adults and that variations in the cortisol diurnal rhythm of younger adults are associated with dietary factors. Younger adults with a poor quality of food intake may be vulnerable to a reduction in the amplitude of the cortisol diurnal profile and this may have implications for other aspects of health.

Changes in diurnal salivary cortisol levels in response to an acute stressor in healthy young adults

BACKGROUND

Knowledge of the diurnal cortisol response to acute stress in healthy individuals can help us better understand the physiological and health effects of chronic stress.

OBJECTIVE

To compare the diurnal patterns of cortisol secretion of 15 medical students 2 weeks before a major written examination (control phase) and 2 weeks later at the time of the examination (acute stress phase).

DESIGN

Interrupted time series within-subjects.

RESULTS

During the acute stress phase, less cortisol was secreted over the course of the day, as demonstrated by a more prolonged and steeper decline in cortisol levels. In addition, higher cortisol levels were present in the evening. Despite these changes in the usual diurnal pattern, overall exposure to cortisol remained the same for both phases.

CONCLUSIONS

The results of this study suggest that specific adaptations to the diurnal pattern of cortisol are made in the face of acute stress, important information for understanding cortisol regulation in health and illness.