Cortisol in hair measured in young adults - a biomarker of major life stressors?

Hair cortisol levels, perceived stress and body mass index in women and children living in socioeconomically disadvantaged neighborhoods: the READI study

Disadvantaged communities provide adverse psychosocial exposures that have been linked to high levels of stress, and this may provide one explanatory pathway linking socioeconomic disadvantage to obesity. This study used hair cortisol analysis to quantify associations between stress and body mass index (BMI), and between hair cortisol and perceived psychological stress levels, in women and children living in socioeconomically disadvantaged neighborhoods. Participants were a volunteer sample of 70 women from the Resilience for Eating and Activity Despite Inequality study, including 30 maternal-child pairs. Women self-reported body weight, height and perceived psychological stress using the Perceived Stress Scale (PSS), and provided hair samples for themselves and their child. Children's body weight and height were measured. Following extraction, hair cortisol levels were measured using enzyme-linked immunosorbent assay. Multiple linear regression models examined associations between stress and BMI, and between hair cortisol and perceived stress levels in women and children. Women's hair cortisol levels were not associated with their BMI or PSS scores. Women's PSS scores were positively associated with their BMI (p = 0.015). Within maternal-child pairs, mothers and children's hair cortisol levels were strongly positively associated (p = 0.006). Maternal hair cortisol levels and PSS scores were unrelated to their child's zBMI. Children's hair cortisol levels were not associated with their zBMI or with their mother's PSS score. Findings suggest that cortisol-based and perceived psychological measures of stress may be distinct among women and children living in disadvantaged neighborhoods. Perceived psychological measures may be more important predictors of weight-related risk.

The relationship between cortisol, stress and psychiatric illness: New insights using hair analysis

BACKGROUND

Stress is an established important contributor to the development of mental illness and stress related disorders. The biology implicated in the homeostasis of pathological stress mechanisms is not fully established. One of the difficulties with current techniques is the limitation in capturing chronic levels of cortisol as an expression of stress levels in humans. Hair samples can be used to evaluate cortisol levels averaged over relatively long periods of time, therefore providing a more valid measure of chronic levels of this hormone. A highly replicable technique to measure long-term cortisol could prove pivotal in improving our understanding of the role of stress in psychiatric disorders.

METHODS

This review synthesises all the published studies relating hair cortisol concentration (HCC) to stress and to psychiatric disorders. It describes and summarises their findings with the aim of providing a summary picture of the current state of this line of research.

RESULTS

The strongest finding to date is the replicable increases in hair cortisol associated with stressful life events. Findings in psychiatric disorders are more sparse and inconsistent. There is some support for the presence of raised HCC in major depressive disorders, and for lowered HCC in posttraumatic stress disorder, suggesting chronic hypercortisolaemia and hypocortisolaemia respectively.

CONCLUSIONS

HCC is a promising methodology to study chronic cortisol levels with the potential to help characterise psychiatric and stress related disorders. The combination of chronic and acute cortisol measurements has the potential for more accurately determining different aspects of the stress response, and ultimately for the development of a biological marker to aid diagnosis and response to treatment.

Clinical applications of cortisol measurements in hair

Cortisol measurements in blood, saliva and urine are frequently used to examine the hypothalamus-pituitary-adrenal (HPA) axis in clinical practice and in research. However, cortisol levels are subject to variations due to acute stress, the diurnal rhythm and pulsatile secretion. Cortisol measurements in body fluids are not always a reflection of long-term cortisol exposure. The analysis of cortisol in scalp hair is a relatively novel method to measure cumulative cortisol exposure over months up to years. Over the past years, hair cortisol concentrations (HCC) have been examined in association with a large number of somatic and mental health conditions. HCC can be used to evaluate disturbances of the HPA axis, including Cushing's syndrome, and to evaluate hydrocortisone treatment. Using HCC, retrospective timelines of cortisol exposure can be created which can be of value in diagnosing cyclic hypercortisolism. HCC have also been shown to increase with psychological stressors, including major life events, as well as physical stressors, such as endurance exercise and shift work. Initial studies show that HCC may be increased in depression, but decreased in general anxiety disorder. In posttraumatic stress disorder, changes in HCC seem to be dependent on the type of traumatic experience and the time since traumatization. Increased hair cortisol is consistently linked to obesity, metabolic syndrome and cardiovascular disease. Potentially, HCC could form a future marker for cardiovascular risk stratification, as well as serve as a treatment target.

Mehr Stress durch G8?

Zusammenfassung. Ziel der vorliegenden Studie war es die Auswirkungen der Schulzeitverkürzung von der neunjährigen (G9) zur achtjährigen (G8) Gymnasialzeit auf die Stressbelastung von Schülern zu untersuchen. An der Studie nahmen insgesamt 69 Abiturienten des doppelten Abiturjahrganges 2013 in NRW teil. Von diesen wurde mit Hilfe der Cortisolkonzentration im Speichel und der subjektiven Stresseinschätzung die Stressbelastung im Schulalltag erfasst. Des Weiteren wurde auch die langfristige Stressbelastung vor und während der Abiturprüfungen betrachtet, indem die Cortisolkonzentration im Haar analysiert wurde. Hierbei zeigte sich, dass die Cortisolkonzentration der beiden untersuchten Schülergruppen im Tagesverlauf sehr ähnlich ist, wobei die G8-Schülerinnen in der Tendenz eine leicht höhere Cortisolkonzentration aufweisen. Auf das subjektive Stressempfinden hat die Schulbiographie jedoch keinen Einfluss. Des Weiteren steigt die Cortisolkonzentration im Haar beider Schülergruppen zwischen der Vorprüfungs- und Prüfungsphase signifikant an, was darauf hindeutet, dass die Prüfungsphase einen langfristigen Stressor darstellt.

High cortisol in 5-year-old children causes loss of DNA methylation in SINE retrotransposons: a possible role for ZNF263 in stress-related diseases

Background

Childhood stress leads to increased risk of many adult diseases, such as major depression and cardiovascular disease. Studies show that adults with experienced childhood stress have specific epigenetic changes, but to understand the pathways that lead to disease, we also need to study the epigenetic link prospectively in children.

Results

Here, we studied a homogenous group of 48 5-year-old children. By combining hair cortisol measurements (a well-documented biomarker for chronic stress), with whole-genome DNA-methylation sequencing, we show that high cortisol associates with a genome-wide decrease in DNA methylation and targets short interspersed nuclear elements (SINEs; a type of retrotransposon) and genes important for calcium transport: phenomena commonly affected in stress-related diseases and in biological aging. More importantly, we identify a zinc-finger transcription factor, ZNF263, whose binding sites where highly overrepresented in regions experiencing methylation loss. This type of zinc-finger protein has previously shown to be involved in the defense against retrotransposons.

Conclusions

Our results show that stress in preschool children leads to changes in DNA methylation similar to those seen in biological aging. We suggest that this may affect future disease susceptibility by alterations in the epigenetic mechanisms that keep retrotransposons dormant. Future treatments for stress- and age-related diseases may therefore seek to target zinc-finger proteins that epigenetically control retrotransposon reactivation, such as ZNF263.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-015-0123-z) contains supplementary material, which is available to authorized users.

LC-MS/MS-based method for long-term steroid profiling in human scalp hair

BACKGROUND

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is the method of choice for quantification of steroids. Human scalp hair provides the possibility to measure long-term retrospective steroid concentrations, which is especially useful for steroids with large time-dependent fluctuations in concentration, such as the glucocorticoid cortisol.

AIM

We set up and validated a LC-MS/MS-based method for long-term steroid profiling, quantifying cortisol, cortisone, testosterone, androstenedione, dehydroepiandrosterone sulphate (DHEAS) and 17-α-hydroxyprogesterone (17OHP).

METHOD

Hair locks were cut from the posterior vertex of healthy male and female volunteers and washed in isopropanol. Steroids were extracted using methanol, and extract was cleaned up by solid-phase extraction and measured on a Waters XEVO-TQ-S LC-MS/MS. Lower limit of quantification, precision, matrix interference and intra-individual variation were determined.

RESULTS

The functional sensitivity of our steroid analysis was <1·3, <9·3, 2·3, <1·3, <15·9, 1·87 pg/mg hair for cortisol, cortisone, testosterone, androstenedione, dehydroepiandrosterone sulphate (DHEAS), and 17OHP, respectively. Measured over a 9-month period, the inter-run CVs were below 16% for all steroids. Intra-individual coefficients of variation were below 15% for all steroids, except 17OHP (19·7%).

CONCLUSION

The authors present a LC-MS/MS-based method for long-term steroid profiling in human scalp hair, potentially providing novel insights by a multitude of clinical and research applications in the field of endocrinology.

Analyzing pathways from childhood maltreatment to internalizing symptoms and disorders in children and adolescents (AMIS): a study protocol

BACKGROUND

Effective interventions for maltreated children are impeded by gaps in our knowledge of the etiopathogenic mechanisms leading from maltreatment to mental disorders. Although some studies have already identified individual risk factors, there is a lack of large-scale multilevel research on how psychosocial, neurobiological, and genetic factors act in concert to modulate risk of internalizing psychopathology in childhood following maltreatment. To help close this gap, we aim to delineate gender-specific pathways from maltreatment to psychological disorder/resilience. To this end, we examine the interplay of specific maltreatment characteristics and psychological, endocrine, metabolomic, and (epi-)genomic stress response patterns as well as cognitive-emotional/social processes as determinants of developmental outcome. Specifically, we will explore endocrine, metabolomic, and epigenetic mechanisms leading from maltreatment to a higher risk of depression and anxiety disorders.

METHODS/DESIGN

Four large samples amounting to a total of N = 920 children aged 4-16 years will be assessed: Two cohorts with prior internalizing psychopathology and controls will be checked for maltreatment and two cohorts with substantiated maltreatment will be checked for internalizing (and externalizing) psychopathology. We will apply a multi-source (interview, questionnaires, official records), multi-informant strategy (parents, children, teachers) to assess maltreatment characteristics (e.g., subtypes, developmental timing, chronicity) and psychopathological symptoms, supplemented with multiple measurements of risk and protective factors and cutting-edge laboratory analyses of endocrine, steroid metabolomic and epigenetic factors. As previous assessments in the two largest samples are already available, longitudinal data will be generated within the three year study period.

DISCUSSION

Our results will lay the empirical foundation for (a) detection of early biopsychosocial markers, (b) development of screening measures, and

Early psychosocial exposures, hair cortisol levels, and disease risk

BACKGROUND

Early psychosocial exposures are increasingly recognized as being crucial to health throughout life. A possible mechanism could be physiologic dysregulation due to stress. Cortisol in hair is a new biomarker assessing long-term hypothalamic-pituitary-adrenal axis activity. The objective was to investigate whether early-life adverse psychosocial circumstances influence infant cortisol levels in hair and health outcomes in children prospectively until age 10.

METHODS

A cohort study in the general community using a questionnaire covering 11 psychosocial items in the family during pregnancy and the cumulative incidence of diagnoses until age 10 years in 1876 children. Cortisol levels in hair were measured by using a radioimmunoassay in those with sufficient hair samples at age 1, yielding a subsample of n = 209.

RESULTS

Children with added psychosocial exposures had higher infant cortisol levels in hair (B = 0.40, P < .0001, adjusted for gender and size for gestational age) in a cumulative manner and were significantly more often affected by 12 of the 14 most common childhood diseases, with a general pattern of increasing odds ratios.

CONCLUSIONS

The findings support the model of physiologic dysregulation as a plausible mechanism by which the duration and number of early detrimental psychosocial exposures determine health outcomes. The model indicates that the multiplicity of adversities should be targeted in future interventions and could help to identify children who are at high risk of poor health. Furthermore, given the prolonged nature of exposure to a stressful social environment, the novel biomarker of cortisol in hair could be of major importance.

Recent negative life events increase hair cortisol concentrations in patients with bipolar disorder

Life events induce stress, which is considered to negatively impact the course of disease in patients with bipolar disorder (BD), its effects being predominantly mediated by cortisol. Cortisol in scalp hair has been identified as a biomarker for assessing long-term cortisol levels, and allows clarifying the relation between life events, hair cortisol concentrations (HCC), and clinical course over time. In 71 BD patients, we analyzed the proximal 3 cm of hair, reflecting 3 months of cortisol production, and investigated the association between HCC, the number of life events, the amount of social support, and mood in the 3 months prior to the hair assessment and between HCC and mood in the subsequent 3 months. Although the total number of life events was not associated with HCC (p > 0.05), the number of negative life events was associated with increased HCC (r(2)( )= 0.04, p = 0.02). Social support showed an inverse association with HCC in patients reporting negative life events (r(2)( )= 0.07, p = 0.03). HCC and mood were not associated in the 3 months prior to hair sampling or in the subsequent 3 months. This study indicates that patients who experienced recent negative life events have increased hair cortisol levels, which seem to be attenuated by social support.

Life events trajectories, allostatic load, and the moderating role of age at arrival from Puerto Rico to the US mainland

Our aim was to examine the effects of trajectories of stressful life events on allostatic load, measured over a two year time period, and to investigate the roles of language acculturation and age at migration in this association, in a sample of Puerto Rican migrants. We used data from the Boston Puerto Rican Health Study; a population-based prospective cohort of older Puerto Ricans recruited between the ages of 45 and 75 years. The Institutional Review Boards at Tufts Medical Center and Northeastern University approved the study. We used latent growth mixture modeling (LGMM) to identify different classes of two-year trajectories of stressful life events; analysis of variance to examine group differences by stress trajectory; and linear regression to test for the modifying effects of age at arrival on the association of stress trajectory with allostatic load at follow-up. In LGMM analysis, we identified three distinct stress trajectories; low, moderate ascending, and high. Unexpectedly, participants in the low stress group had the highest allostatic load at follow-up (F=4.4, p=0.01) relative to the other two groups. Age at arrival had a statistically significant moderating effect on the association. A reported two year period of moderate but repetitive and increasingly bad life events was associated with increases in allostatic load for participants who arrived to the U.S. mainland after the age of 5 years, and was particularly strong for those arriving between 6 and 11 years, but not for those arriving earlier or later. Results from this study highlight the complex effects of stress during the life course, and point to certain vulnerable periods for immigrant children that could modify long term effects of stress.

Both hair cortisol levels and perceived stress predict increased symptoms of depression: an exploratory study in young adults

OBJECTIVE

Depressive symptoms are a common mental health problem among young adults, but the physiological mechanisms that mediate between stress and depressive symptoms remain unclear. Accordingly, this exploratory study (1) examined how hair cortisol concentrations were associated with self-perceived stress and depressive symptoms in a sample of young adults and (2) tested whether hair cortisol could explain variance in depressive symptoms beyond perceived stress before and after controlling for levels of vigorous physical activity (VPA).

METHODS

The sample consisted of 42 exercise and health science university students (20 males, 22 females; mean age = 21.2 years). Cortisol concentrations were extracted from hair strands close to the scalp. Participants completed self-rating questionnaires about depressive symptoms and perceived stress.

RESULTS

Students with elevated hair cortisol levels tended to report lower depressive symptoms and lower perceived stress. Increased perceived stress was associated with higher depressive symptoms, and both hair cortisol and perceived stress predicted depressive symptoms after controlling for VPA.

CONCLUSIONS

The present data suggest that elevated hair cortisol levels do not necessarily constitute a health risk. Hair cortisol measurement can serve as a noninvasive and painless biomarker of chronic stress and mental disorders; however, additional research is needed.

Cultural and socio-economic conditions as factors contributing to chronic stress in sub-Saharan African communities

Stress is known to contribute to overall health status. Many individuals in sub-Saharan Africa are believed to be stressed about their employment, income, and health. This study aimed to investigate hair cortisol as a biomarker of chronic stress in settlement communities in Kenya. Hair samples were collected from 108 volunteers from settlement communities in Kenya. An enzyme-linked immunosorbent assay technique was used to measure hair cortisol concentrations. In parallel, a health survey was completed. The mean ± SD for the cortisol concentration in the hair of volunteers from the settlement communities in Naivasha was 639 ± 300 ng/g, which was higher than found for a Caucasian reference group (299 ± 110 ng/g; one-way ANOVA, P = 0.0003). There were no differences in hair cortisol concentrations between members of slum settlements adjacent to large floriculture farms in Naivasha (Karagita, Kamere/Kwa Muhia/DCK, and Kasarani) compared with those well-removed from all floriculture in Mogotio (Mogotio and Westlands/Katorongot). However, hair cortisol concentrations were significantly higher in females, divorced volunteers, those who made below minimum wage, and those who reported feeling unsafe collecting water or using sanitation facilities within these 2 settlement groups. We found no evidence for increased chronic stress (measured by hair cortisol content) between members of slum settlements adjacent to versus distant to large floriculture farms. Cultural and socio-economic conditions that prevail in much of sub-Saharan Africa were found to be factors contributing to chronic stress.

Associations of hair cortisol concentration with self-reported measures of stress and mental health-related factors in a pooled database of diverse community samples

A pooled database from diverse community samples was used to examine the associations of hair cortisol concentration (HCC) with self-reported stress and stress-linked mental health measures, including depression, anxiety, alcohol and drug use, disability and experiences with aggression. As part of innovative research using a mobile laboratory to study community mental health, data were pooled from five sub-studies: a random sample of the general population (n = 70), people who had received treatment for a mental health and/or substance use problem (n = 78), family members of people treated for mental health and/or substance use problems (n = 49), community volunteers who sometimes felt sad or blue or thought they drank too much (n = 83) and young adults in intimate partner relationships (n = 44). All participants completed a computerized questionnaire including standard measures of perceived stress, chronic stress, depression, anxiety, hazardous drinking, tobacco use, prescription drug use, illicit drug use, disability and intimate partner aggression. HCC was significantly associated with use of antidepressants, hazardous drinking, smoking and disability after adjusting for sub-study and potential confounders (sex, body-mass index, use of glucocorticoids and hair dyed). In addition, preliminary analyses suggest a significant curvilinear relationship between HCC and perceived stress; specifically, HCC increased with higher perceived stress but decreased at the highest level of stress. Overall, HCC was associated with mental health-related variables mainly reflecting substance use or experiencing a disability. The relationship between HCC and self-reported stress is unclear and needs further research.

Relationship between effort-reward imbalance and hair cortisol concentration in female kindergarten teachers

OBJECTIVE

The present study aims to investigate the relationship between effort-reward imbalance and hair cortisol concentration among teachers to examine whether hair cortisol can be a biomarker of chronic work stress.

METHODS

Hair samples were collected from 39 female teachers from three kindergartens. Cortisol was extracted from the hair samples with methanol, and cortisol concentrations were measured with high performance liquid chromatography-tandem mass spectrometry. Work stress was measured using the effort-reward imbalance scale.

RESULTS

The ratio of effort to reward showed significantly positive association with hair cortisol concentration.

CONCLUSION

The cortisol concentration in the system increases with the effort-reward imbalance. Measurement of hair cortisol can become a useful biomarker of chronic work stress.

A Life Course Model of Self-Reported Violence Exposure and Ill-health with A Public Health Problem Perspective

Violence has probably always been part of the human experience. Its impact can be seen, in various forms, in all parts of the world. In 1996, WHO:s Forty-Ninth World Health Assembly adopted a resolution, declaring violence a major and growing public health problem around the world. Public health work centers around health promotion and disease prevention activities in the population and public health is an expression of the health status of the population taking into account both the level and the distribution of health. Exposure to violence can have many aspects, differing throughout the life course ― deprivation of autonomy, financial exploitation, psychological and physical neglect or abuse — but all types share common characteristics: the use of destructive force to control others by depriving them of safety, freedom, health and, in too many instances, life; the epidemic proportions of the problem, particularly among vulnerable groups; a devastating impact on individuals, families, neighborhoods, communities, and society. There is considerable evidence that stressful early life events influence a variety of physical and/or psychological health problems later in life. Childhood adversity has been linked to elevated rates of morbidity and mortality from number of chronic diseases. A model outlining potential biobehavioural pathways is put forward that may be a potential explanation of how exposure to violence among both men and women work as an important risk factor for ill health and should receive greater attention in public health work.

Chronic HPA axis response to stress in temporomandibular disorder

PURPOSE

Perceived stress is associated with temporomandibular disorder (TMD), but whether cortisol levels are elevated in individuals with TMD is unknown. We hypothesized that cortisol concentration, a biomarker of hypothalamic-pituitary-adrenal (HPA) axis function, was elevated in TMD cases relative to controls, and that perceived stress was positively correlated with cortisol concentration.

METHODS

In this case control study, TMD case status was determined by examiners using TMD Research Diagnostic Criteria. Participants (n=116) aged 18 to 59 years were recruited from within a 50 mile radius of the University of North Carolina at Chapel Hill. Following examination, cases (n=45) and controls (n=71) completed the 14-item Perceived Stress Scale using a reference interval of the past 3 months. Approximately 100 strands of hair were cut from the posterior vertex segment of their scalp. The 3 centimeters of hair most proximal to the scalp was analyzed with a commercially available salivary cortisol enzyme immunoassay adapted for hair cortisol. This length corresponds to the last 3 months of systemic HPA axis activity.

RESULTS

TMD cases perceived higher stress than controls (p=0.001). However, hair cortisol concentration was lower in TMD cases than controls (p<0.001). The correlation coefficient revealed a weak negative relationship (r=-0.188) between perceived stress and hair cortisol concentration (p=0.044). In analysis stratified by case status, the relationship of perceived stress and hair cortisol concentration was non-significant for cases (p=0.169) and controls (p=0.498).

CONCLUSION

Despite greater perceived stress, TMD cases had lower hair cortisol concentrations than controls and the 2 measures of stress were weakly and negatively correlated.

Correlates of cortisol in human hair: implications for epidemiologic studies on health effects of chronic stress

Assessment of cortisol concentrations in hair is one of the latest innovations for measuring long-term cortisol exposure. We performed a systematic review of correlates of cortisol in human hair to inform the design, analysis, and interpretation of future epidemiologic studies. Relevant publications were identified through electronic searches on PubMed, WorldCat, and Web of Science using keywords, "cortisol," "hair," "confounders," "chronic," "stress," and "correlates." Thirty-nine studies were included in this review. Notwithstanding scarce data and some inconsistencies, investigators have found hair cortisol concentrations to be associated with stress-related psychiatric symptoms and disorders (e.g., post-traumatic stress disorder), medical conditions indicating chronic activation of the hypothalamic-pituitary-adrenal axis (e.g., Cushing's syndrome), and other life situations associated with elevated risk of chronic stress (e.g., shiftwork). Results from some studies suggest that physical activity, adiposity, and substance abuse may be correlates of hair cortisol concentrations. In contrast to measures of short-term cortisol release (saliva, blood, and urine), cigarette smoking and use of oral contraceptives appear not to be associated with hair cortisol concentrations. Studies of pregnant women indicate increased hair cortisol concentrations across successive trimesters. The study of hair cortisol presents a unique opportunity to assess chronic alterations in cortisol concentrations in epidemiologic studies.

Maternal influence on child HPA axis: a prospective study of cortisol levels in hair

OBJECTIVE

To investigate cortisol concentrations in hair as biomarker of prolonged stress in young children and their mothers and the relation to perinatal and sociodemographic factors.

METHODS

Prospective cohort study of 100 All Babies In Southeast Sweden study participants with repeated measures at 1, 3, 5, and 8 years and their mothers during pregnancy. Prolonged stress levels were assessed through cortisol in hair. A questionnaire covered perinatal and sociodemographic factors during the child's first year of life.

RESULTS

Maternal hair cortisol during the second and third trimester and child hair cortisol at year 1 and 3 correlated. Child cortisol in hair levels decreased over time and correlated to each succeeding age, between years 1 and 3 (r = 0.30, P = .002), 3 and 5 (r = 0.39, P < .001), and 5 and 8 (r = 0.44, P < .001). Repeated measures gave a significant linear association over time (P < .001). There was an association between high levels of hair cortisol and birth weight (β = .224, P = .020), nonappropriate size for gestational age (β = .231, P = .017), and living in an apartment compared with a house (β = .200, P = .049). In addition, we found high levels of cortisol in hair related to other factors associated with psychosocial stress exposure.

CONCLUSIONS

Correlation between hair cortisol levels in mothers and their children suggests a heritable trait or maternal calibration of the child's hypothalamic-pituitary-adrenocortical axis. Cortisol output gradually stabilizes and seems to have a stable trait. Cortisol concentration in hair has the potential to become a biomarker of prolonged stress, especially applicable as a noninvasive method when studying how stress influences children's health.

Psychological and physiological responses following repeated peer death

Objective

Undergraduates at a university in the United States were exposed – directly and indirectly – to 14 peer deaths during one academic year. We examined how individual and social factors were associated with psychological (e.g., anxiety, depression, somatization) and physiological (i.e., cortisol) distress responses following this unexpected and repeated experience with loss.

Method

Two to three months after the final peer death, respondents (N = 122, 61% female, 18–23 years, M = 20.13, SD = 1.14) reported prior adverse experiences, degree of closeness with the deceased, acute responses to the peer deaths, ongoing distress responses, social support, support seeking, and media viewing. A subset (n = 24) returned hair samples for evaluation of cortisol responses during the previous 3 months.

Results

Ongoing psychological distress was associated with a) prior interpersonal trauma, b) fewer social supports, and c) media exposure to news of the deaths (p's<.05). Participants who had no prior bereavements showed, on average, high cortisol (>25 p/mg) compared to individuals with one or two prior bereavement experiences (who were, on average, within the normal range, 10 to 25 p/mg) (p<.05). Only 8% of the sample utilized available university psychological or physical health resources and support groups.

Conclusions

Limited research has examined the psychological and physiological impact of exposure to chronic, repeated peer loss, despite the fact that there are groups of individuals (e.g., police, military soldiers) that routinely face such exposures. Prior adversity appears to play a role in shaping psychological and physiological responses to repeated loss. This topic warrants further research given the health implications of repeated loss for individuals in high-risk occupations and university settings.

Higher perceived stress but lower cortisol levels found among young Greek adults living in a stressful social environment in comparison with Swedish young adults

The worldwide financial crisis during recent years has raised concerns of negative public health effects. This is notably evident in southern Europe. In Greece, where the financial austerity has been especially pronounced, the prevalence of mental health problems including depression and suicide has increased, and outbreaks of infectious diseases have risen. The main objective in this study was to investigate whether different indicators of health and stress levels measured by a new biomarker based on cortisol in human hair were different amongst comparable Greek and Swedish young adults, considering that Sweden has been much less affected by the recent economic crises. In this cross-sectional comparative study, young adults from the city of Athens in Greece (n = 124) and from the city of Linkoping in Sweden (n = 112) participated. The data collection comprised answering a questionnaire with different health indicators and hair samples being analyzed for the stress hormone cortisol, a biomarker with the ability to retrospectively measure long-term cortisol exposure. The Greek young adults reported significantly higher perceived stress (p<0.0001), had experienced more serious life events (p = 0.002), had lower hope for the future (p<0.0001), and had significantly more widespread symptoms of depression (p<0.0001) and anxiety (p<0.0001) than the Swedes. But, the Greeks were found to have significantly lower cortisol levels (p<0.0001) than the Swedes, and this difference was still significant in a multivariate regression (p<0.0001), after adjustments for potential intervening variables. A variety of factors related to differences in the physical or socio-cultural environment between the two sites, might possibly explain this finding. However, a potential biological mechanism is that long-term stress exposure could lead to a lowering of the cortisol levels. This study points out a possible hypothesis that the cortisol levels of the Greek young adults might have been suppressed and their HPA-axis down-regulated after living in a stressful environment with economic and social pressure.

Hair cortisol, stress exposure, and mental health in humans: a systematic review

The deleterious effects of chronic stress on health and its contribution to the development of mental illness attract broad attention worldwide. An important development in the last few years has been the employment of hair cortisol analysis with its unique possibility to assess the long-term systematic levels of cortisol retrospectively. This review makes a first attempt to systematically synthesize the body of published research on hair cortisol, chronic stress, and mental health. The results of hair cortisol studies are contrasted and integrated with literature on acutely circulating cortisol as measured in bodily fluids, thereby combining cortisol baseline concentration and cortisol reactivity in an attempt to understand the cortisol dynamics in the development and/or maintenance of mental illnesses. The studies on hair cortisol and chronic stress show increased hair cortisol levels in a wide range of contexts/situations (e.g. endurance athletes, shift work, unemployment, chronic pain, stress in neonates, major life events). With respect to mental illnesses, the results differed between diagnoses. In major depression, the hair cortisol concentrations appear to be increased, whereas for bipolar disorder, cortisol concentrations were only increased in patients with a late age-of-onset. In patients with anxiety (generalized anxiety disorder, panic disorder), hair cortisol levels were reported to be decreased. The same holds true for patients with posttraumatic stress disorder, in whom - after an initial increase in cortisol release - the cortisol output decreases below baseline. The effect sizes are calculated when descriptive statistics are provided, to enable preliminary comparisons across the different laboratories. For exposure to chronic stressors, the effect sizes on hair cortisol levels were medium to large, whereas for psychopathology, the effect sizes were small to medium. This is a first implication that the dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis in the development and/or maintenance of psychopathology may be more subtle than it is in healthy but chronically stressed populations. Future research possibilities regarding the application of hair cortisol research in mental health and the need for multidisciplinary approaches are discussed.

High long-term cortisol levels, measured in scalp hair, are associated with a history of cardiovascular disease

BACKGROUND

Stress is associated with an increased incidence of cardiovascular disease. The impact of chronic stress on cardiovascular risk has been studied by measuring cortisol in serum and saliva, which are measurements of only 1 time point. These studies yielded inconclusive results. The measurement of cortisol in scalp hair is a novel method that provides the opportunity to measure long-term cortisol exposure. Our aim was to study whether long-term cortisol levels, measured in scalp hair, are associated with cardiovascular diseases.

METHODS

A group of 283 community-dwelling elderly participants were randomly selected from a large population-based cohort study (median age, 75 y; range, 65-85 y). Cortisol was measured in 3-cm hair segments, corresponding roughly with a period of 3 months. Self-reported data concerning coronary heart disease, stroke, peripheral arterial disease, diabetes mellitus, and other chronic noncardiovascular diseases were collected.

RESULTS

Hair cortisol levels were significantly lower in women than in men (21.0 vs 26.3 pg/mg hair; P < .001). High hair cortisol levels were associated with an increased cardiovascular risk (odds ratio, 2.7; P = .01) and an increased risk of type 2 diabetes mellitus (odds ratio, 3.2; P = .04). There were no associations between hair cortisol levels and noncardiovascular diseases.

CONCLUSIONS

Elevated long-term cortisol levels are associated with a history of cardiovascular disease. The increased cardiovascular risk we found is equivalent to the effect of traditional cardiovascular risk factors, suggesting that long-term elevated cortisol may be an important cardiovascular risk factor.

Chronic HPA axis response to stress in temporomandibular disorder

PURPOSE

Perceived stress is associated with temporomandibular disorder (TMD), but whether cortisol levels are elevated in individuals with TMD is unknown. We hypothesized that cortisol concentration, a biomarker of hypothalamic-pituitary-adrenal (HPA) axis function, was elevated in TMD cases relative to controls, and that perceived stress was positively correlated with cortisol concentration.

METHODS

In this case control study, TMD case status was determined by examiners using TMD Research Diagnostic Criteria. Participants (n=116) aged 18 to 59 years were recruited from within a 50 mile radius of the University of North Carolina at Chapel Hill. Following examination, cases (n=45) and controls (n=71) completed the 14-item Perceived Stress Scale using a reference interval of the past 3 months. Approximately 100 strands of hair were cut from the posterior vertex segment of their scalp. The 3 centimeters of hair most proximal to the scalp was analyzed with a commercially available salivary cortisol enzyme immunoassay adapted for hair cortisol. This length corresponds to the last 3 months of systemic HPA axis activity.

RESULTS

TMD cases perceived higher stress than controls (p=0.001). However, hair cortisol concentration was lower in TMD cases than controls (p<0.001). The correlation coefficient revealed a weak negative relationship (r=-0.188) between perceived stress and hair cortisol concentration (p=0.044). In analysis stratified by case status, the relationship of perceived stress and hair cortisol concentration was non-significant for cases (p=0.169) and controls (p=0.498).

CONCLUSION

Despite greater perceived stress, TMD cases had lower hair cortisol concentrations than controls and the 2 measures of stress were weakly and negatively correlated.

Concerns regarding hair cortisol as a biomarker of chronic stress in exercise and sport science

Hair cortisol has the potential to fill the methodological void of long-term cortisol assessment while becoming a widely accepted measure in biopsychology. This review critically examines the applicability and relevance of hair cortisol measurement specifically within the field of exercise and sport science. Current measures of the HPA axis only cover a brief time period, whereas hair cortisol is a unique, non-invasive means to capture long- term cortisol secretion. Studies have shown that individuals who have elevated cortisol secretion (e.g. due to diseases associated with a disturbed activation of the HPA axis or exposure to stressful life events) reveal increased hair cortisol. By contrast, only weak correlations exist between hair cortisol and perceived stress, and the direction of the relationship between hair cortisol levels and mental disorders is unclear. Acute exercise, however, results in increased levels of cortisol that eventually is reflected in higher levels of cortisol in hair samples and studies have shown that exercise intensity is related to hair cortisol level. Thus, elevated hair cortisol levels found among regular exercisers are not necessarily pathological. Thus, one should practice caution when associating athletes' elevated hair cortisol with poor mental health or disease. Hair cortisol analysis can contribute to a more complete understanding of how long-term cortisol elevation mediates stress-related effects on the health and performance of recreational exercisers and elite athletes. Nevertheless, it is crucial for exercise and sport scientists to consider whether their research questions can be adequately addressed, given that regular intense exercise results in substantially augmented hair cortisol levels.

Analysis of cortisol in hair--state of the art and future directions

Changes to long-term secretion of the glucocorticoid cortisol are considered to play a crucial role in mediating the link between chronic stress and the development of numerous immune system related diseases. However, obtaining valid assessments of long-term cortisol levels is difficult due to limitations of previous measurement strategies in blood, saliva or urine. This review discusses evidence on a recent methodological development assumed to provide a considerable advancement in this respect: the analysis of cortisol in hair. Being incorporated into the growing hair, hair cortisol concentrations (HCC) are assumed to provide a retrospective reflection of integrated cortisol secretion over periods of several months. Over the past years, supportive evidence has accumulated regarding several fundamental characteristics of HCC, including its validity as an index of long-term systemic cortisol levels, its reliability across repeated assessments and its relative robustness to a range of potential confounding influences. Based on this groundwork, research has now also commenced to utilise HCC for answering more specific questions regarding the role of long-term cortisol secretion in different stress and health-related conditions. The possibility of extending hair analysis to also capture long-term secretion of other steroid hormones (e.g., androgens or estrogens) provides a further intriguing prospect for future research. Given its unique characteristics, the use of hair analysis holds great promise to significantly enhance current understanding on the role of steroid hormones in psychoimmunological research.

Minireview: Hair cortisol: a novel biomarker of hypothalamic-pituitary-adrenocortical activity

Activity of the hypothalamic-pituitary-adrenocortical (HPA) axis is commonly assessed by measuring glucocorticoids such as cortisol (CORT). For many years, CORT was obtained primarily from blood plasma or urine, whereas later approaches added saliva and feces for noninvasive monitoring of HPA functioning. Despite the value of all these sample matrices for answering many research questions, they remain limited in the temporal range of assessment. Plasma and saliva are point samples that vary as a function of circadian rhythmicity and are susceptible to confounding by environmental disturbances. Even urine and feces generally assess HPA activity over a period of only 24 h or less. We and others have recently developed and validated methods for measuring the concentration of CORT in the body hair of animals (e.g. rhesus monkeys) and scalp hair of humans. CORT is constantly deposited in the growing hair shaft, as a consequence of which such deposition can serve as a biomarker of integrated HPA activity over weeks and months instead of minutes or hours. Since the advent of this methodological advance, hair CORT has already been used as an index of chronic HPA activity and stress in human clinical and nonclinical populations, in a variety of laboratory-housed and wild-living animal species, and in archival specimens that are many decades or even centuries old. Moreover, because human hair is known to grow at an average rate of about 1 cm/month, several studies suggest that CORT levels in hair segments that differ in proximity to the scalp can, under certain conditions, be used as a retrospective calendar of HPA activity during specific time periods preceding sample collection.

Intercorrelations between serum, salivary, and hair cortisol and child-reported estimates of stress in elementary school girls

To evaluate the impact of stress on children's well-being, it is important to have valid and reliable stress assessment methods. Nevertheless, selection of an appropriate method for a particular research question may not be straightforward, as there is currently no consensus on a reference method to measure stress in children. This article examined to what extent childhood stress can be estimated accurately by stressor questionnaires (i.e., Coddington life events scale) and biological markers (serum, salivary, and hair cortisol) using the Triads (a triangulation) method in 272 elementary school girls. Salivary cortisol was shown to most accurately indicate true childhood stress for short periods in the past (i.e., last 3 months), whereas hair cortisol may be preferred above salivary measurements for periods more distant and thus for chronic stress assessment. However, applicability should be confirmed in larger and more heterogeneous populations.

Cortisol levels in hair reflect behavioural reactivity of dogs to acoustic stimuli

Cortisol levels in hair samples were examined in fourteen domestic dogs and related to the dogs' responses to different acoustic stimuli. Stimuli were playbacks of species-typical vocalizations recorded during three different situations ("disturbance", "isolation" and "play" barks) and the sounds of a thunderstorm. Hair samples were collected at 9:00 h and 17:00 h two weeks after the behavioural tests. Results showed that behavioural reactivity to playback of the various stimuli correlates with cortisol levels in hair samples collected at 9:00 h, and the same was the case for the separate measures of behaviour (i.e. hiding, running away, seeking attention from the tester, panting and lowering of the body posture). Hence, levels of cortisol in hair appear to reflect the dog's chronic state of emotional reactivity, or temperament.