Evaluation and update of the expert consensus guidelines for the assessment of the cortisol awakening response (CAR)

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.

Infant colic and HPA axis development across childhood

This study examines the long-term impact of infant colic on Hypothalamic-Pituitary-Adrenal (HPA) axis development and the moderating role of attachment security, in a low-risk Dutch sample of 193 children. We assessed infant colic at 6 weeks, circadian cortisol concentrations at ages 1, 2.5, 6, and 10 years, and attachment security at 1 year. Findings indicated that infant colic was associated with steeper diurnal cortisol slopes and slightly higher cortisol concentrations throughout childhood. Attachment security did not moderate these associations. This is the first study to reveal a link between infant colic and the development of the HPA axis in healthy children beyond infancy. These findings have important implications for understanding early risk and protective factors in the stress system's development.

The cortisol awakening response is blunted in healthy women early postpartum

INTRODUCTION

The dynamic capacity of the hypothalamic-pituitary-adrenal (HPA) axis supports healthy adaptions to stress and play a key role in maintaining mental health. Perinatal adaptations in the HPA-axis dynamics in terms of the Cortisol Awakening Response (CAR), may be involved in dysregulation of perinatal mental health. We aimed to determine if CAR and absolute evening cortisol early postpartum differed from non-perinatal women and evaluate the association between the CAR and maternal mental well-being.

METHODS

The CAR was computed as the area under the curve with respect to increase from baseline from serial home-sampling of saliva across 0-60 minutes from awakening. We evaluated differences in CAR and absolute evening cortisol between postpartum women (N=50, mean postpartum days: 38, SD: ±11) and non-perinatal women (N=91) in a multiple linear regression model. We also evaluated the association between CAR and maternal mental well-being in a multiple linear regression model.

RESULTS

We found that healthy postpartum women had a blunted CAR (p<0.001) corresponding to 84% reduction and 80% lower absolute evening cortisol (p<0.001) relative to non-perinatal healthy women. In the postpartum group, there was a trend-level association between lower CAR and higher scores on the WHO Well-Being Index (WHO-5) (p=0.048) and lower Edinburgh Postnatal Depression Scale (EPDS) scores (p=0.04).

CONCLUSION

Our data emphasize the unique hormonal landscape during the postpartum period in terms of blunted CAR and lower absolute evening cortisol in healthy women early postpartum compared to non-perinatal. Our findings show a potential association between a reduced CAR and improved mental well-being during early motherhood, which suggests that reduced CAR might reflect healthy adjustment to early motherhood.

Relationship of sleep with diurnal cortisol rhythm considering sleep measurement and cortisol sampling schemes

Information on the relationships between the previous night's sleep and the next-day diurnal cortisol rhythm is inconsistent due to confounding factors such as sleep measurements (trait/state sleep and objective/subjective sleep) and cortisol sampling schemes. Therefore, this study aimed to investigate these relationships, considering the confounding factors. College students (n = 79) wore actigraphy for 3 days to undergo an evaluation of previous night-time sleep objectively and reported their subjective sleep parameters in a sleep diary. In addition, participants provided six salivary cortisol samples daily. Furthermore, six cortisol sampling schemes were created to reflect diurnal cortisol rhythms, and two different methods were used to calculate the index of diurnal cortisol slope (DCS). A multilevel model was created to examine the impact of both trait and state sleep on next-day diurnal cortisol rhythm. The results revealed that higher objective state sleep efficiency and longer objective state total sleep time were associated with a higher cortisol awakening response (CAR). Moreover, higher objective trait sleep efficiency and longer objective trait total sleep time were associated with higher waking cortisol levels and steeper DCS. In addition, a minimum of four saliva samples were required at different time points, including upon waking, 30 min after waking, 1 h after waking, and at bedtime, to explore the relationship of sleep efficiency/total sleep time with waking cortisol, CAR, and DCS. Furthermore, the index of the peak-to-bed slope was appropriately employed to examine the relationship between sleep efficiency and DCS, whereas the wake-to-bed slope was effective for examining the relationship between total sleep time and DCS. In summary, this study clarified the relationship between sleep and next-day diurnal cortisol rhythm and suggested a cost-effective cortisol sampling schedule and calculation methods.

Association Between EEG Microarousal During Nocturnal Sleep and Next-Day Selective Attention in Mild Sleep-Restricted Healthy Undergraduates

Purpose

To explore whether sleep electroencephalogram (EEG) microarousals of different standard durations predict daytime mood and attention performance in healthy individuals after mild sleep restriction.

Participants and Methods

Sixteen (nine female) healthy college students were recruited to examine the correlations between nocturnal EEG microarousals of different standard durations (≥3 s, ≥5 s, ≥7 s, ≥9 s) under mild sleep restriction (1.5 h) and the following morning's subjective alertness, mood, sustained attention, and selective attention task performance.

Results

Results revealed that mild sleep restriction significantly reduced subjective alertness and positive mood, while having no significant effect on negative mood, sustained attention and selective attention performance. The number of microarousals (≥5 s) was negatively associated with positive mood at 6:30. The number of microarousals was significantly and positively correlated with the response time difference value of disengagement component of the selective attention task at around 7:30 (≥5 s and ≥7 s) and 9:00 (≥5 s). The number of microarousals (≥7 s) was significantly and positively correlated with the inaccuracy difference value of orientation component of the selective attention task at around 9:00.

Conclusion

The number of EEG microarousals during sleep in healthy adults with mild sleep restriction was significantly and negatively related to their daytime positive affect while positively associated with the deterioration of disengagement and orientation of selective attention performance, but this link is dependent on the standard duration of microarousals, test time and the type of task.

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.

Sex differences in sleep, circadian rhythms, and metabolism: Implications for precision medicine

The number of individuals experiencing sleep loss has exponentially risen over the past decades. Extrapolation of laboratory findings to the real world suggests that females are more affected by extended wakefulness and circadian misalignment than males are. Therefore, long-term effects such as sleep and metabolic disorders are likely to be more prevalent in females than in males. Despite emerging evidence for sex differences in key aspects of sleep-wake and circadian regulation, much remains unknown, as females are often underrepresented in sleep and circadian research. This narrative review aims at highlighting 1) how sex differences systematically impinge on the sleep-wake and circadian regulation in humans, 2) how sex differences in sleep and circadian factors modulate metabolic control, and 3) the relevance of these differences for precision medicine. Ultimately, the findings justify factoring in sex differences when optimizing individually targeted sleep and circadian interventions in humans.

Does stress response axis activation differ between patients with autoimmune disease and healthy people?

Many studies have shown that patients with autoimmune disease present a hypoactive hypothalamic-pituitary-adrenal (HPA) axis, but the results are controversial. Our objective was to study differences in stress response axis activity between patients with autoimmune disease and healthy people. The study sample consisted of 97 women divided into four groups: 37 healthy women (HW), 21 with systemic lupus erythematosus (SLE), 21 with Sjögren's syndrome (SS), and 18 with systemic sclerosis (SSc). After being exposed to a stress task, participants' skin conductance and salivary cortisol levels were measured in order to assess their response to psychological stress. Diurnal cortisol concentrations were assessed by measuring salivary cortisol in samples collected five times over one day. In addition, self-administered questionnaires were used to assess psychological variables. A time × group interaction effect was found (p = 0.003) in salivary cortisol secretion in response to stressful challenge. The healthy group presented normal activation, the SS and SLE groups showed no activation, and the SSc group presented a similar activation pattern to the HW group, except at the time of recovery. Total cortisol production (AUCg) was higher in the SSc group than in the HW group (p = 0.001). Differences were also observed in the cortisol AUCg collected over one day between healthy women and patients with SLE (p = 0.004) as well as with SSc (p = 0.001): women with SLE and SSc presented higher total hormone production than healthy women. Patients with autoimmune disease present a different HPA axis response, which may contribute to the harmful effects of stress in these diseases.

Concurrent and prospective associations between family socioeconomic status, social support and salivary diurnal and hair cortisol in adolescence

BACKGROUND

Exposure to socioeconomic adversity is hypothesized to impact hypothalamic-pituitary-adrenal (HPA) axis activity and cortisol secretion, but existing evidence is inconsistent. Yet, few studies have investigated this association using a developmental approach that considers potential protective contextual factors. This study examined the role of stability and changes in family socioeconomic status (SES) in the prediction of multiple cortisol indicators and tested whether social support moderated these associations.

METHODS

Participants were part of a population-based sample of twin pairs recruited at birth. Family SES was assessed in early childhood (ages 0-5) and mid-adolescence (age 14). Social support was assessed at ages 14 and 19. Diurnal cortisol (n = 569) was measured at age 14 at awakening, 30 min later, in the afternoon and evening over four non-consecutive days. Hair cortisol concentration (HCC, n = 704) was measured at age 19. All data were collected before the pandemic and multilevel regression models were conducted to account for the nested data structure.

RESULTS

Youth exposed to lower family SES levels in childhood and mid-adolescence had a flatter diurnal slope and higher HCC compared with those who experienced upward socioeconomic mobility in mid-adolescence. Contrastingly, mid-adolescence SES showed no association with the diurnal slope or HCC for youth from higher-SES households in early childhood. Moreover, youth raised in higher-SES families in early childhood had a higher CAR in mid-adolescence if they reported greater social support in mid-adolescence. Social support also moderated the SES-cortisol association in mid-adolescence, with higher-SES youth showing higher awakening cortisol secretion when reporting more social support.

CONCLUSIONS

Our findings support the hypothesis that early socioeconomic adversity sensitizes HPA axis activity to later socioeconomic disadvantage, which may bear consequences for socioemotional and behavioral functioning.

Early childhood multiple or persistent regulatory problems and diurnal salivary cortisol in young adulthood

BACKGROUND

Early childhood multiple or persistent regulatory problems (RPs; crying, sleeping, or feeding problems) have been associated with a risk of behavioural problems in young adulthood. It has been suggested that this may be due to the possible influence of early RPs on the functioning of the hypothalamic-pituitary-adrenal (HPA) axis. However, associations between early RPs and HPA-axis activity in young adulthood remain unexplored. Thus, the aim of the current study was to investigate whether early childhood multiple or persistent RPs are associated with diurnal salivary cortisol in young adulthood.

METHODS

At the ages of 5, 20 and 56 months, RPs of 308 children from the Arvo Ylppö Longitudinal Study were assessed via standardized parental interviews and neurological assessments. Multiple RPs were defined as two or three RPs at the age of 5 months and persistent RPs as at least one RP at 5, 20 and 56 months. At the mean age of 25.4 years (SD= 0.6), the participants donated saliva samples for cortisol at awakening, 15 and 30 min thereafter, 10:30 am, at noon, 5:30 pm, and at bedtime during one day. We used mixed model regressions, and generalized linear models for testing the associations, controlling for important covariates.

RESULTS

Of the 308 children, 61 (19.8%) had multiple or persistent RPs in early childhood: 38 had multiple, and 27 had persistent RPs. Persistent RPs were associated with significantly higher cortisol peak and output in the waking period, and cortisol awakening response. On the other hand, multiple RPs were not associated with salivary cortisol.

CONCLUSION

Children displaying persistent RPs throughout early childhood show, over two decades later, increased HPA axis activity in response to awakening stress. This may be one physiological mechanism linking early childhood RPs to adulthood behavioural outcomes.

Gender minority stress and diurnal cortisol profiles among transgender and gender diverse people in the United States

The field of behavioral neuroendocrinology has only begun to explore the lived experiences of transgender and gender diverse (TGD) people exposed to stigma. In light of escalating attacks and legislation targeting TGD people in the United States, it is crucial to examine the physiological pathways through which gender minority stressors become embodied, impact health, and contribute to health inequities. The Trans Resilience and Health Study included baseline data collection from fall 2019 to spring 2020 from a sample of 124 TGD people, reflecting a diversity of gender identities (e.g., trans masculine, trans feminine, and nonbinary) and ages (range = 19-70 years old; M = 34.10), living in Michigan, Nebraska, Oregon, and Tennessee. These analyses examine experiences of gender-related enacted stigma in association with hypothalamic-pituitary-adrenal (HPA)-axis functioning. Among those experiencing the highest levels of enacted stigma, findings show a blunted cortisol awakening response and sluggish daily decline that resulted in elevated concentrations at bedtime compared to those experiencing less enacted stigma. These results of flattened diurnal activity are consistent with an emergent literature on discrimination as a social determinant of potential stress pathophysiology. In contrast, community connectedness was associated with a larger, more dynamic cortisol awakening response. These findings emphasize the importance of incorporating gender-minority stress and resilience measures when studying HPA-axis functioning among TGD people.

Effects of menstrual cycle phase and ovulation on the salivary cortisol awakening response

The cortisol awakening response (CAR) is influenced by several state and trait variables, one of which might be the menstrual cycle in women. Previous results suggested that the CAR is enhanced around ovulation, which is why it has been recommended to avoid sampling during the ovulatory phase. In two separate studies, we aimed to replicate previous findings that reported the CAR's modulation across the menstrual cycle, especially during ovulation. In Study 1, a group of 27 healthy naturally cycling women collected saliva at 0, 30, 45, and 60 min post-awakening on two days during their follicular, ovulatory, and luteal phases in a repeated measures design. In Study 2, CAR samples were collected from 30 healthy naturally cycling women on seven consecutive days around the expected ovulation. To increase reliability of CAR measurements, participants' compliance of saliva sampling times was monitored, ovarian steroids (estradiol and progesterone) were collected, and ovulation was confirmed with specific test kits. Contrary to our expectations, we detected no differences in the CAR over the menstrual cycle, and no significant association with variations in estradiol and progesterone. In addition, we excluded confounding effects such as compliance and validated the cycle phase. These results suggest that the CAR is largely robust against hormonal variations across the menstrual cycle, including the mid-cycle phase around ovulation. However, further research is needed to understand the potential ovarian steroid-induced modulation of HPA axis functioning and the menstrual cycle's effects on salivary cortisol levels in psychobiological studies.

The association between depression and the cortisol awakening response is moderated by loneliness in men from a non-clinical sample

Previous studies investigating cortisol levels in people with depression or depressive symptoms have provided mixed findings. It has been suggested that the difficulty to generalize findings across studies in this field might be related to interindividual variability in experiencing depressive symptoms in terms of clinical and social contexts. Therefore, in the present study we aimed to test the association of morning cortisol levels and depressive symptoms in a non-clinical sample of young men taking into consideration the level of perceived loneliness. We hypothesized that the level of loneliness might moderate the association between morning cortisol levels and depressive symptoms. A total of 102 participants (aged 29.9 ± 5.0 years) completed questionnaires measuring the levels of depressive and anxiety symptoms, perceived stress, and loneliness. Cortisol levels were determined in four morning samples of saliva. There were significant positive correlations of the cortisol awakening response (CAR) and the mean increase in cortisol levels during the measurement period (MnInc) with the levels of depressive symptoms and loneliness. Moreover, a significant association of the depressive symptoms by loneliness interaction with the CAR and the MnInc was found. Specifically, the correlation of depressive symptoms with the CAR and the MnInc appeared to be significant and negative at high levels of loneliness. No significant association between depressive symptoms and the CAR was observed in men with low levels of loneliness. There were no significant associations of depressive symptoms, loneliness and the depressive symptoms by loneliness interaction with cortisol levels at awakening. In conclusion, findings from the present study indicate the importance of social contexts in understanding the association between altered activity of the hypothalamic-pituitary-adrenal axis and depressive symptoms in men.

The cortisol awakening response in a 3 month clinical trial of service dogs for veterans with posttraumatic stress disorder

Recent literature suggests that service dogs may be a valuable complementary intervention option for posttraumatic stress disorder (PTSD) among military veterans due to the potential influence on stress response dysregulation. The aim of this short-term longitudinal study was to quantify the impact of service dogs in US military veterans with PTSD with particular attention to the cortisol awakening response. A sub aim of the study was to empirically evaluate the physiological effects of PTSD service dogs on veteran partners. We conducted a clinical trial (ID: NCT03245814) that assessed the cortisol awakening response for 245 participants at baseline and 3 months follow-up across an intervention group (service dog: veterans n = 88, partners n = 46) and control group (usual care: n = 73, partners n = 38). A total of N = 161 veterans and N = 84 partners collected whole saliva samples via a passive drool collection immediately upon waking, 30 min after waking, and 45 min after waking on three consecutive weekdays at baseline and again at follow-up. Mixed model repeated measures (MMRM) with a fixed effect of the intervention group (service dog or control) were utilized. Covariates considered for the model included time of awakening, sleep duration, sleep efficiency, prior day experiences (measured via ecological momentary assessment), traumatic brain injury, age, gender, race, ethnicity, socioeconomic status, smoking status, alcohol use, physical health, and body mass index. A total of 3951 salivary samples were collected (veterans: 2613, partners: 1338). MMRM results demonstrated that veterans with a service dog had a statistically significant higher cortisol awakening response, including the area under the curve with respect to both increase (AUCi, β = 1.46, p = 0.046) and absolute increase (AINC, β = 0.05, p = 0.035). Results were not statistically significant for partners. Findings suggest that veterans with service dogs have a higher, less blunted CAR in comparison to veterans receiving usual care alone. In veterans with a blunted morning cortisol response, service dog placement could help boost their morning cortisol response.

Prenatal maternal cortisol, stress and anxiety, and childhood obesity at 5 years: a nested case-control study

BACKGROUND

Paediatric obesity is a global public health issue. Prenatal maternal mental health is potentially implicated in the development of childhood obesity. This study examined associations between prenatal maternal cortisol, self-reported stress, anxiety and depression in the second trimester, and childhood overweight and obesity at 5 years of age.

METHODS

A nested case-control study was conducted using data from the Irish prospective longitudinal birth cohort SCOPE BASELINE. Cases were children with overweight or obesity, operationalised as having a BMI z-score above +2 standard deviations. Controls were children with a BMI z-score between -0.5 and 0.5 standard deviations at 5 years of age. Two to one matching by sex was conducted. Thirty-eight cases and 83 sex-matched controls were included. Maternal serum cortisol concentration and self-reported stress, anxiety and depression were measured at 15 ± 1 and 20 ± 1 weeks gestation. Conditional logistic regression analyses were conducted to examine associations between prenatal maternal cortisol and self-reported stress, anxiety and depression, and childhood overweight and obesity.

RESULTS

Despite some evidence for associations between anxiety and depression, and child BMI z-scores in univariate analyses, adjusted models indicated no associations between prenatal maternal stress (OR: 1.02, 95% CI: 0.94-1.12), anxiety (OR: 1.03, 95% CI: 0.97-1.09), depression (OR: 1.04, 95% CI: 0.91-1.19), or cortisol concentration (OR: 0.99, 95% CI: 0.99-1.00) and child BMI z-score.

CONCLUSION

Our findings do not provide support for associations between foetal exposure during the second trimester of pregnancy and maternal cortisol, stress and anxiety, and childhood overweight or obesity at 5 years of age.

Biological sensitivity to adolescent-parent discrepancies in perceived parental warmth

Introduction

Parenting behaviors are formative to the psychological development of young people; however, parent and adolescent perceptions of parenting are only moderately correlated with each other. Whereas discrepant perceptions may represent a normative process of deindividuation from caregivers in some adolescents, in others a discrepancy might predict psychological maladjustment. The biological sensitivity to context model provides a framework from which individual differences in development can be estimated in adolescents whose perceptions of parenting diverge from those of their parents.

Methods

At baseline we obtained diurnal cortisol samples from US adolescents (M = 13.37 years of age, SD = 1.06) as well as parents' and adolescents' ratings of parental warmth; we obtained adolescent-reported symptoms of psychopathology at baseline and again at follow-up two years later (N = 108, 57.5% female). We estimated waking cortisol, cortisol awakening response, and daytime cortisol slopes using piecewise regression models.

Results

Lower adolescent than parent ratings of parental warmth predicted increased externalizing symptoms at follow-up. Higher waking cortisol and steeper cortisol awakening response and daytime slopes predicted increased internalizing symptoms at follow-up. Further, discrepant ratings of parental warmth interacted with cortisol awakening response and daytime slopes such that greater discrepancies predicted greater increases in externalizing symptoms in adolescents with steeper cortisol slopes.

Conclusions

These findings indicate that steeper changes in cortisol production throughout the day index a greater sensitivity to perceived parental warmth. Lower adolescent than parent ratings of parental warmth may represent dysfunction in the parental relationship rather than a normative process of deindividuation in adolescents with steeper diurnal cortisol slopes.

Short-term cortisol adaption to discrimination and Mexican-origin adolescents' mental and sleep health

Discrimination experiences are a salient contributor to the health disparities facing Latina/x/o youth. The biopsychosocial model of minority health posits that discrimination influences health through wear and tear on the biological stress responses, including the hypothalamic-pituitary-adrenal (HPA) axis, which is a primary stress response system in the body. Emerging evidence suggests that discrimination alters the secretion of cortisol, the end product of the HPA axis, yet, whether the daily processes between discrimination and diurnal cortisol response influence mental and sleep health remains unanswered. This study integrated daily diary and post-diary survey data to examine whether daily diurnal cortisol responses to discrimination influence adolescents' mental (depressive symptoms, anxiety) and sleep (sleep quality, duration) health in a sample of Mexican-origin youth (N = 282; M age = 17.10; 55% female). Results showed that adolescents who experienced more discrimination across the four-day diary period exhibited steeper diurnal cortisol slopes and lower evening cortisol; however, such physiological responses tended to be associated with poorer adolescents' mental and sleep health. The current study underscores the potential adaptation cost associated with short-term cortisol adaptation in the face of discrimination.

Longitudinal association between saliva and hair cortisol concentration: A systematic comparison

Cortisol assays from hair have become increasingly common in psychoneuroendocrinological research as indicators of long-term output relevant to stress and health outcomes. Comparisons of hair cortisol concentration (HCC) with salivary samples have produced mixed findings, and it remains unclear which aspects of the diurnal salivary profile correspond most closely to HCC, and what time intervals between saliva and hair sampling are most relevant, taking the rate of hair growth into account. This longitudinal study aimed to evaluate the correspondence between HCC and parameters of total salivary cortisol output in the morning (CARauc and CARi) and during the rest of the day excluding the early morning period (DAYauc), by systematically studying three time periods - two weeks, four weeks, and six weeks - before hair sampling. At each time period, 54 female university students (mean age: 20.85 ± 1.16 years) provided three saliva cortisol samples on day 1 at 11 am, 3 pm, at bedtime, then two samples the following day on waking and 30 min after awakening. Hair strand collection (1 cm nearest the scalp) took place two weeks after the last saliva sample. Results of multivariable regressions indicate that HCC was consistently associated with DAYauc for all three time periods and with the aggregate DAYauc across days after adjusting for age, body mass index, smoking, oral contraceptive use, hair washing frequency and hair treatments. The strongest associations were found for DAYauc two weeks before hair sampling (β = 0.578, p < 0.001) and the aggregated DAYauc across all three time periods (β = 0.596, p < 0.001), although the confidence intervals overlapped those for four and six week analyses. There was no significant association between HCC and either CARauc or CARi. Our study confirms that hair cortisol could be a reliable retrospective biomarker of basal and long-term cortisol output secretion at least up to six weeks earlier. The results contribute to a better understanding of the different associations between HCC and salivary cortisol in the morning and the rest of the day, while also having implications for the use of HCC as an outcome measure in intervention and treatment research.

Dimensions of child maltreatment and longitudinal diurnal cortisol patterns: The roles of resilience and child sex

Informed by the dimensional approach to adversity, this study disaggregated child maltreatment effects to examine how abuse versus neglect influenced cortisol at the baseline assessment and longitudinal changes in diurnal cortisol among a sample of Chinese children and adolescents (N = 312; aged 9-13 years; M age = 10.80, SD = 0.84; 67% boys). The moderating roles of resilience and sex differences in these associations were also explored. Results revealed distinct effects of abuse versus neglect on diurnal cortisol in girls, but not boys, which varied by the time scale of assessment and type of cortisol measure. Specifically, abuse was associated with girls' longitudinal changes in awakening cortisol, cortisol awakening response, and diurnal cortisol slope over one year, whereas neglect was associated with girls' awakening cortisol and cortisol awakening response at the baseline assessment. Further, resilience moderated the effects of abuse on girls' baseline awakening cortisol and longitudinal changes in diurnal cortisol slope, suggesting both the potential benefits and costs of resilience. Findings support the application of the dimensional approach to research on stress physiology and deepen our understanding of individual differences in the associations between child maltreatment and diurnal cortisol.

Trait and state effects of different modes of thinking on salivary cortisol in daily life in patients with recurrent major depression and healthy individuals

Habitual modes of thinking such as repetitive negative thinking (RNT), but also momentary cognitive processes such as mindwandering could be vulnerability factors for the course of Major Depressive Disorder (MDD). On the physiological level, cortisol represents an important biological stress marker of the hypothalamic-pituitary-adrenal (HPA) axis. Being a dynamic and non-invasive measure, salivary cortisol can be assessed in daily life via Ambulatory Assessment (AA). So far, consensus exists on a dysregulation of the HPA axis in MDD. However, findings are ambiguous and AA-studies examining both trait and state level effects of cognitive processes on cortisol release in daily life in patients with recurrent major depression (rMDD) and healthy controls (HCs) are lacking. A sample of 119 (n_rMDD=57, n_HCs=62) participants underwent a baseline session, including self-rated questionnaires (RNT, mindfulness) followed by a 5-day AA, where participants indicated the occurrence of mindwandering and levels of mentalshift problems ten times per day via smartphone, and collected saliva cortisol samples five times per day. Via multilevel models, we found habitual RNT, but not mindfulness, to predict higher cortisol levels, with the effects being stronger in rMDD patients. State mindwandering and mentalshift problems predicted increased cortisol 20 min later across groups. State cognitions did not mediate the effects of habitual RNT on cortisol release. Our results suggest independent mechanisms of action for trait and state cognitions on cortisol activity in daily life and indicate a greater physiological vulnerability toward trait RNT and the tendency to experience mentalshift problems in patients with recurrent major depression.

Salivary cortisol awakening levels are reduced in human subjects with intermittent explosive disorder compared with controls

BACKGROUND

The role of the hypothalamic-pituitary-adrenal (HPA) axis in human aggressive behavior is poorly characterized, though some studies report that, unlike depression, circulating or salivary levels of cortisol are low compared with controls.

METHODS

In this study, we collected three salivary cortisol levels (two in the morning and one in the evening) on three separate days in 78 adult study participants with (n = 28) and without (n = 52) prominent histories of impulsive aggressive behavior. Plasma C-Reactive Protein (CRP) and Interleukin-6 (IL-6) were also collected in most study participants. Aggressive study participants meet DSM-5 criteria for Intermittent Explosive Disorder (IED) while non-aggressive participants either had a history of a psychiatric disorder or no such history (Controls).

RESULTS

Morning, but not evening, salivary cortisol levels were significantly lower in IED (p < 0.05), compared with control, study participants. In addition, salivary cortisol levels correlated with measures of trait anger (partial r = -0.26, p < 0.05) and aggression (partial r = -0.25, p < 0.05) but not with measures of impulsivity, psychopathy, depression, history of childhood maltreatment, or other tested variables that often differ in individuals with IED. Finally, plasma CRP levels correlated inversely with morning salivary cortisol levels (partial r = -0.28, p < 0.05); plasma IL-6 levels showed a similar, though not statistically significant (rp = -0.20, p = 0.12) relationship with morning salivary cortisol levels.

CONCLUSION

The cortisol awakening response appears to be lower in individuals with IED compared with controls. In all study participants, morning salivary cortisol levels correlated inversely with trait anger, trait aggression, and plasma CRP, a marker of systemic inflammation. This suggests the present of a complex interaction between chronic-low level inflammation, the HPA axis, and IED that warrants further investigation.

Occupational stress is associated with insulin resistance and incident type 2 diabetes: a prospective cohort study of functional community

BACKGROUND

To exploit the association of occupational stress with the development of insulin resistance (IR) and type 2 diabetes (T2D) in a Chinese population-based cohort.

METHODS

A total of 6109 participants from a functional community cohort in Beijing were enrolled in 2015 and followed up until 2021. Copenhagen Psychosocial Questionnaire (COPSOQ) were used to evaluate occupational stress.

RESULTS

At baseline, increase values of all five scales of COPSOQ and total COPSOQ were significantly associated with IR. During an average 5.63 y follow-up, 732 individuals developed T2D. Increasing in values of "Demands at work", "Insecurity at work", "Job satisfaction" and total COPSOQ were significantly associated with incident T2D (P<0.01). Mediation analysis showed that subjectively perceived occupational stress promoted T2D mainly by affecting plasma cortisol and the mediation effects of HOMA-IR, SBP, DBP, TG, Urea and UA were significant on the association between cortisol and incident T2D, with proportion mediated of 37.1%, 8.12%, 2.02%, 2.94%, 2.35% and 2.70%.

CONCLUSION

Occupational stress was independently associated with the development of IR and T2D. IR, BP, TG, Urea and UA all partly mediated the association between occupational stress and incident T2D.

CARWatch - A smartphone application for improving the accuracy of cortisol awakening response sampling

BACKGROUND

Many studies investigating the cortisol awakening response (CAR) suffer from low adherence to the study protocol as well as from the lack of precise and objective methods for assessing the awakening and saliva sampling times which leads to measurement bias on CAR quantification.

METHODS

To address this issue, we have developed "CARWatch", a smartphone application that aims to enable low-cost and objective assessment of saliva sampling times as well as to concurrently increase protocol adherence. As proof-of-concept study, we assessed the CAR of N = 117 healthy participants (24.2 ± 8.7 years, 79.5% female) on two consecutive days. During the study, we recorded awakening times (AW) using self-reports, the CARWatch application, and a wrist-worn sensor, and saliva sampling times (ST) using self-reports and the CARWatch application. Using combinations of different AW and ST modalities, we derived different reporting strategies and compared the reported time information to a Naive sampling strategy assuming an ideal sampling schedule. Additionally, we compared the AUC_I, computed using information from different reporting strategies, against each other to demonstrate the effect of inaccurate sampling on the CAR.

RESULTS

The use of CARWatch led to a more consistent sampling behavior and reduced sampling delay compared to self-reported saliva sampling times. Additionally, we observed that inaccurate saliva sampling times, as resulting from self-reports, were associated with an underestimation of CAR measures. Our findings also revealed potential error sources for inaccuracies in self-reported sampling times and showed that CARWatch can help in better identifying, and possibly excluding, sampling outliers that would remain undiscovered by self-reported sampling.

CONCLUSION

The results from our proof-of-concept study demonstrated that CARWatch can be used to objectively record saliva sampling times. Further, it suggests its potential of increasing protocol adherence and sampling accuracy in CAR studies and might help to reduce inconsistencies in CAR literature resulting from inaccurate saliva sampling. For that reason, we published CARWatch and all necessary tools under an open-source license, making it freely accessible to every researcher.

Revisiting the stress recovery hypothesis: Differential associations of cortisol stress reactivity and recovery after acute psychosocial stress with markers of long-term stress and health

Exposure to excessive and long-term stress may result in dysregulation of the stress system, including the acute stress response. In particular, failure to downregulate stress-related reactivity may lead to prolonged stress responses and the accumulation of allostatic load. However, the contribution of altered acute cortisol recovery to chronic stress and associated health impairments has often been neglected. Addressing this lack of research, we explored whether recovery from - more so than reactivity to - acute stress captures the basal stress load of an individual. Using Piecewise Growth Curve Models with Landmark Registration, we analyzed cortisol reactivity and recovery slopes of 130 healthy participants exposed to a standardized psychosocial laboratory stressor. Reactivity and recovery were predicted by measures indicative of long-term stress and its downstream effects, including self-report questionnaires, diurnal cortisol indices [cortisol awakening response (CAR); diurnal cortisol slope], markers of pro-inflammatory activity (interleukin-6; high-sensitive C-reactive protein), and hippocampal volume (HCV). Among these measures, only an increased CAR was specifically and consistently associated with relatively impaired recovery. Since the CAR represents the physiological enhancement needed to meet the anticipated demands of the forthcoming day, this finding may highlight the contribution of cognitive processes in determining both CAR and acute stress recovery. Furthermore, greater cortisol reactivity covaried with smaller HCV, showing that increased acute reactivity translates to health-relevant downstream effects. The lack of further associations between long-term and acute stress measures may arise from biases in self-reported chronic stress and the rigorously health-screened study sample. Overall, our findings suggest that while cortisol stress recovery might not supersede reactivity as an indicator of the long-term stress load or associated health effects, recovery and reactivity have differential utility in describing individuals' allostatic states.