Splitting hair for cortisol? Associations of socio-economic status, ethnicity, hair color, gender and other child characteristics with hair cortisol and cortisone

Hair steroid before and after COVID-19 in preschoolers: the moderation of family characteristics

BACKGROUND

Frequent or prolonged exposure to stressors may jeopardize young children's health. The onset of the COVID-19 pandemic, coupled with disruptions in daily routines and social isolation resulting from public health preventive measures, have raised concerns about its potential impact on children' experienced stress, particularly for young children and vulnerable families. However, whether the pandemic was accompanied by changes in physiological stress remains unknown as perceived stress is not a good proxy of physiological stress. This study examined if preschoolers showed increasing hair steroid concentrations following the onset of the COVID-19 pandemic and whether family characteristics may have exacerbated or buffered these changes.

METHODS

136 preschoolers (2-4 years) provided hair for steroid measurement (cortisol, dehydroepiandrosterone (DHEA), cortisone, cortisol-to-DHEA ratio, cortisol-to-cortisone ratio) in October-November 2019 (T0) and in July-August 2020 (T1). A 2-centimeter hair segment was analyzed, reflecting steroid production over the two months leading up to collection. Family income, conflict resolution and lack of cohesion, as well as parents' COVID-19 stress were reported by parents. Linear mixed models for repeated measures and Bayes factors were used.

RESULTS

No significant changes were noted from before to after the onset of the COVID-19 pandemic for most hair steroids. However, a moderating role of family conflict resolution was noted. Children living with parents with a better ability to resolve conflicts had lower levels of DHEA compared to those who had more difficulty managing conflicts. Additionally, lower levels of family cohesion and income were linked to some steroids, especially DHEA, suggesting that these factors may relate to children's physiological stress. Finally, boys had higher DHEA levels than girls.

CONCLUSION

Our findings suggest that stress biomarkers were comparable from before to during the COVID-19 pandemic. This observation holds true despite the pandemic being perceived by many as a novel, unpredictable, and potentially threatening event. Findings further suggest that family characteristics are associated with hair steroid, especially DHEA, which deserves further investigation.

Associations of schizophrenia with the activities of the HPA and HPG axes and their interactions characterized by hair-based biomarkers

BACKGROUND

Past studies on schizophrenia (SCZ) and the stress-sensitive neuroendocrine systems have mostly focused on a single system and traditionally utilized acute biomarkers (e.g., biomarkers from blood, urine and saliva) that poorly match the chronic course of schizophrenia in time span. Using eight biomarkers in hair, this study aimed to explore the functional characteristics of SCZ patients in the hypothalamic-pituitary-adrenocortical (HPA) and hypothalamic-pituitary-gonadal (HPG) axes and the interaction between the two axes.

METHODS

Hair samples were taken from 137 SCZ patients and 73 controls. The SCZ patients were diagnosed by their attending physician according to the Diagnostic and Statistical Manual of Mental Disorders IV and were clinically stable after treatment. Gender, age, BMI, frequency of hair washing, marital status, education level, family history of mental illness and clozapine dosage were concurrently collected as covariates. The 10-item perceived stress scale (PSS-10) and the social readjustment rating scale were used to assess chronic stress status in SCZ patients. Eight hair biomarkers, cortisol, cortisone, dehydroepiandrosterone (DHEA), testosterone, progesterone, cortisol/cortisone, cortisol/DHEA and cortisol/testosterone, were measured by high performance liquid chromatography tandem mass spectrometer. Among them, cortisol, cortisone, DHEA and cortisol/DHEA reflected the functional activity of the HPA axis, and testosterone and progesterone reflected the functional activity of the HPG axis, and cortisol/cortisone reflected the activity of 11β-hydroxysteroid dehydrogenase types 2 (11β-HSD 2), and cortisol/testosterone reflected the HPA-HPG interaction.

RESULTS

SCZ patients showed significantly higher cortisone and cortisol/testosterone than controls (p<0.001, η²p=0.180 and p=0.015, η²p=0.031), lower testosterone (p=0.009, η²p=0.034), progesterone (p<0.001, η²p=0.069) and cortisol/cortisone (p=0.001, η²p=0.054). There were significant intergroup differences in male and female progesterone (p=0.003, η²p=0.088 and p=0.030, η²p=0.049) and female testosterone (p=0.028, η²p=0.051). In SCZ patients, cortisol, cortisol/cortisone, cortisol/DHEA and cortisol/testosterone were positively associated with PSS-10 score (ps<0.05, 0.212

CONCLUSION

The function of the HPA and HPG axes, the activity of 11β-HSD 2 and the HPA-HPG interaction were abnormal in SCZ patients. The abnormality of neuroendocrine systems was associated with chronic stress status in SCZ patients. This study provided evidence for abnormalities in the neuroendocrine systems in SCZ patients.

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Key Words

• 11β-HSD 2
• HPA axis
• HPG axis
• Hair biomarkers
• Schizophrenia

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Affiliation(s)

Deyi Qi Department of Brain and Learning Science, School of Biological Science & Medical Engineering, Southeast University, Nanjing 211189, China; Key Laboratory of Child Development and Learning Science (Southeast University), Ministry of Education, Nanjing 211189, China; Institute of Child Development and Education, Southeast University, Nanjing 211189, China
Weiliang Wang School of Nursing, Harbin Medical University, Harbin 163319, China.
Liuxi Chu Department of Brain and Learning Science, School of Biological Science & Medical Engineering, Southeast University, Nanjing 211189, China; Key Laboratory of Child Development and Learning Science (Southeast University), Ministry of Education, Nanjing 211189, China; Institute of Child Development and Education, Southeast University, Nanjing 211189, China
Yan Wu Department of Brain and Learning Science, School of Biological Science & Medical Engineering, Southeast University, Nanjing 211189, China; Key Laboratory of Child Development and Learning Science (Southeast University), Ministry of Education, Nanjing 211189, China; Institute of Child Development and Education, Southeast University, Nanjing 211189, China
Wei Wang Department of Brain and Learning Science, School of Biological Science & Medical Engineering, Southeast University, Nanjing 211189, China; Key Laboratory of Child Development and Learning Science (Southeast University), Ministry of Education, Nanjing 211189, China; Institute of Child Development and Education, Southeast University, Nanjing 211189, China
Minhui Zhu Department of Brain and Learning Science, School of Biological Science & Medical Engineering, Southeast University, Nanjing 211189, China; Key Laboratory of Child Development and Learning Science (Southeast University), Ministry of Education, Nanjing 211189, China; Institute of Child Development and Education, Southeast University, Nanjing 211189, China
Lin Yuan Department of Brain and Learning Science, School of Biological Science & Medical Engineering, Southeast University, Nanjing 211189, China; Key Laboratory of Child Development and Learning Science (Southeast University), Ministry of Education, Nanjing 211189, China; Institute of Child Development and Education, Southeast University, Nanjing 211189, China
Wei Gao Institute of Child Development and Education, Southeast University, Nanjing 211189, China; School of Psychology, Nanjing Normal University, Nanjing 210024, China
Huihua Deng Department of Brain and Learning Science, School of Biological Science & Medical Engineering, Southeast University, Nanjing 211189, China; Key Laboratory of Child Development and Learning Science (Southeast University), Ministry of Education, Nanjing 211189, China; Institute of Child Development and Education, Southeast University, Nanjing 211189, China.

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Association between maltreatment, hair cortisol concentration, positive parent-child interaction, and psychosocial outcomes in Chinese preschool children

Children now are facing an increasing risk of early life stress (ELS), which leads to detrimental psychosocial outcomes. Behavior studies suggested that positive parental interactions might moderate the negative impact of ELS, but the related biological alteration remains unclear. This study aims to investigate whether positive parent-child interactions moderate the association between maltreatment (as a severe form of ELS) and hair cortisol concentration (HCC), as well as between HCC and psychosocial outcomes in young children. Participants were 6-year-old Chinese children (N = 257, Mage = 6.2, 121 were male) selected by stratified cluster random sampling from a Shanghai population representative cohort. Proximal 3 cm hair strands were analyzed using liquid chromatography coupled with tandem mass spectrometry for HCC. Children's psychosocial outcome was evaluated using the parental report Strengths and Difficulties Questionnaire (SDQ). Parents also reported the frequency of positive parent-child interactions using the Chinese Parent-Child Interaction Scale (CPCIS) as well as the history of maltreatment. Multi-level logistic regression models adjusting for individual, kindergarten, and district confounders were used to evaluate the associations between maltreatment, HCC, and psychosocial outcomes. Interactions terms tested whether more frequent positive parent-child interactions moderates the association between maltreatment and HCC, as well as between HCC and psychosocial outcomes. Maltreated children exhibited higher levels of HCC (B = 1.20, 95% CI: 0.38,2.02; p = 0.004), and children with higher HCC exhibited poorer psychosocial outcomes (B = 0.34, 95% CI: 0.18,0.51; p < 0.001). Positive parent-child interactions did not have a moderating effect on the association between maltreatment and HCC, but they demonstrated a moderating effect on the association between increased HCC and psychosocial outcomes (interaction term: B = -0.42, 95% CI: -0.75,-0.10; p = 0.01). These findings provide evidence that positive parental interaction may serve as a moderator between chronic cortisol exposure and psychosocial problems. It highlights the importance of frequent parent-child interactions, especially among children under a high risk of ELS.

Socioeconomic Disparities in Hypothalamic-Pituitary-Adrenal Axis Regulation and Prefrontal Cortical Structure

Socioeconomic disadvantage during childhood predicts an increased risk for mental health problems across the life span. Socioeconomic disadvantage shapes multiple aspects of children's proximal environments and increases exposure to chronic stressors. Drawing from multiple literatures, we propose that childhood socioeconomic disadvantage may lead to adaptive changes in the regulation of stress response systems including the hypothalamic-pituitary-adrenal (HPA) axis. These changes, in turn, affect the development of prefrontal cortical (PFC) circuitry responsible for top-down control over cognitive and emotional processes. Translational findings indicate that chronic stress reduces dendritic complexity and spine density in the medial PFC and anterior cingulate cortex, in part through altered HPA axis regulation. Socioeconomic disadvantage has frequently been associated with reduced gray matter in the dorsolateral and ventrolateral PFC and anterior cingulate cortex and lower fractional anisotropy in the superior longitudinal fasciculus, cingulum bundle, and uncinate fasciculus during middle childhood and adolescence. Evidence of socioeconomic disparities in hair cortisol concentrations in children has accumulated, although null findings have been reported. Coupled with links between cortisol levels and reduced gray matter in the PFC and anterior cingulate cortex, these results support mechanistic roles for the HPA axis and these PFC circuits. Future longitudinal studies should simultaneously consider multiple dimensions of proximal factors, including cognitive stimulation, while focusing on epigenetic processes and genetic moderators to elucidate how socioeconomic context may influence the HPA axis and PFC circuitry involved in cognitive and emotional control. These findings, which point to modifiable factors, can be harnessed to inform policy and more effective prevention strategies.

Associations of psychoactive substances and steroid hormones in hair: Findings relevant to stress research from a large cohort of young adults

OBJECTIVE

Epidemiological studies increasingly use hair samples to assess people's cumulative exposure to steroid hormones, but how the use of different psychoactive substances may affect steroid hormone levels in hair is, so far, largely unknown. The current study addresses this gap by establishing the substance exposure correlates of cortisol, cortisone, and testosterone in hair, while also accounting for a number of relevant covariates.

METHOD

Data came from a large urban community-sample of young adults with a high prevalence of substance use (N = 1002, mean age=20.6 years, 50.2% female), who provided 3 cm of hair samples. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) quantified cortisol, cortisone, and testosterone, as well as delta-9-tetrahydrocannabinol (THC), 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy"), cocaine, several opioids, and their respective metabolites. Multiple linear regression models with covariates were used to predict steroid hormone levels from substance exposure in a four-step approach: In the full sample, low and high substance hair concentrations (median split) were first tested against no use for each substance individually (step 1) and for all substances together (step 2). Then, within the participants with any substance in hair only, the continuous hair concentration of each substance in pg/mg (step 3) and finally of all substances together, were regressed (step 4).

RESULTS

Low, high, and continuous levels of THC in hair were robustly associated with higher levels of cortisol (sig. in step 1 low THC: β = 0.29, p = .021; high THC: β = 0.42, p = .001; step 2: low THC: β = 0.27, p = 0.036, and high THC: β = 0.40, p = .004, and step 4: β = 0.12, p = .041). Participants with high MDMA levels had higher levels of cortisone without adjusting for other substances (step 1: β = 0.34, p = .026), but this effect was not significant in the other models. While high THC levels were associated with lower levels of testosterone in step 2 (β = -0.35, p = .018), MDMA concentration was positively related to testosterone concentration with and without adjusting for other substances (step 3: β = 0.24, p = .041; step 4: β = 0.17, 95%, p = .015) in male participants.

CONCLUSION

The use of psychoactive substances, especially of cannabis and ecstasy, should be considered in studies investigating steroid hormones in hair.

Effect of cosmetic hair treatment and natural hair colour on hair testosterone concentrations

PURPOSE

Testosterone analysis in hair allows for retrospective evaluation of endogenous testosterone concentrations, but studies devoted to investigating confounders in hair testosterone analysis have hitherto been scarce. The current study examined the stability of testosterone concentrations between two hair samples collected three months apart and investigated two potential confounding factors: natural hair colour and cosmetic hair treatments.

METHODS

Testosterone was analysed with an in-house radioimmunoassay with a limit of detection adequate for the purpose.

RESULTS

The testosterone concentrations from the two samplings, at baseline and three months later, had an intra-individual correlation of moderate strength (rho = 0.378, p<0.001, n = 146). Hair treatment, such as colouring or bleaching, seemed to increase testosterone concentrations (p = 0.051, n = 191, and in a paired analysis in a subset of the cohort p = 0.005, n = 24), while no effect of natural colour in untreated hair (p = 0.133) could be detected.

CONCLUSION

The current results suggest that cosmetic hair treatments need to be considered in hair testosterone analyses and demonstrate the utility of a radioimmunoassay to reliably measure testosterone concentrations in small hair samples in women.

Measuring hair cortisol concentration, insomnia symptoms and quality of life in preschool children with severe early childhood caries - a case-control pilot study

OBJECTIVE

This study aimed to 1) investigate the relationships between hair cortisol concentration (HCC), insomnia symptoms, Health-Related Quality of Life (HRQoL) and Oral Health-Related Quality of Life (OHRQoL) in preschool children with severe early childhood caries, 2) compare HCC, insomnia symptoms, HRQoL and OHRQoL in preschool children with severe early childhood caries with these factors in children without clinical signs of dental caries, and 3) explore correlations between caries scores and HCC, insomnia symptoms, HRQoL and OHRQoL.

MATERIAL AND METHODS

A case-control pilot study, including 12 children with severe early childhood caries and 28 controls, aged 3-5 years. Dental examination was performed and hair samples for cortisol were taken. Parents filled out questionnaires about their child's insomnia symptoms, HRQoL and OHRQoL. Interpreters were used in families with language difficulties.

RESULTS

The key findings in this pilot study were tendencies that children with severe early childhood caries had more insomnia symptoms, and poorer OHRQoL than the controls. Caries scores was correlated with insomnia symptoms and OHRQoL.

CONCLUSIONS

Dentists should include questions about the child's sleep when they see the child, as insomnia related to dental caries may lead to several physical, mental, and social problems.

Segmental hair analysis as a retrospective testosterone diary: possibilities and pitfalls

Testosterone is thought to be incorporated in growing hair strands so that specific hair segments reflect average free hormone concentrations from the corresponding time period. However, the exact mechanisms of hormone integration in scalp hair have not yet been established and it is not known how testosterone is stored in the hair segments over time. The aim of this study was to investigate the stability of testosterone concentrations in hair as it grows and to determine if segmental hair analysis can be used as a retrospective testosterone diary. Thirty men and 40 women provided two hair samples and 16 saliva samples during a period of three months. Hair growth between the two samplings was measured. Hair samples were cut into 10 mm segments resulting in three segments from the first sampling and six segments from the second sampling. Hair samples were pulverised and extracted with methanol. Hair testosterone concentrations were analysed using an in-house radioimmunoassay. Salivary testosterone was analysed using a commercial enzyme-linked immunosorbent assay (Demeditec). The results demonstrated that there is a degree of segmental hormone conservation over time (rho = 0.405-0.461, p < 0.001, n = 66-67), but also highlighted three potential confounders. Firstly, testosterone concentrations were higher in distal hair segments (mean concentration ratio most distal by most scalp-near was 1.55, SD 0.70), which may be due to continuous hormone integration from sebum and changes in hair matrix composition. Secondly, more frequent hair washing stunted the increase in testosterone concentrations in distal segments (rho = -0.404, p =  < 0.001, n = 66). And lastly, intra- and inter- individual variability in hair growth rate influenced the temporal resolution along the hair, although mean growth rate was indeed 30.0 mm for three months. In a multiple regression model the biological sex, natural hair colour, and relationship status were significant explanatory variables to hair testosterone concentrations. The current results indicate that repeated hair sampling near the hair roots during a study may be preferable to analysing concentration changes between proximal and distal segments within the same hair sample. Also, hair testosterone analysis needs to be adjusted for sex and the natural hair colour.

Longitudinal Examination of Hair Cortisol Concentrations and Weight Changes in Preschool-Aged Children of Latino Farmworkers

Background: Hair cortisol concentrations may serve as a measure of biologically embedded stress. While the cross-sectional association between hair cortisol and obesity in children has been examined, the data examining this relationship over time are limited. Methods: We examined hair cortisol and anthropometrics in 40 children with obesity from Latino families enrolled in a Head Start program serving farmworkers. All participants were enrolled in a clinical trial using parent mentors to encourage healthy lifestyles. We analyzed the proximal 3 cm of hair at the beginning and the end of the trial, a period of about 8 months. Linear mixed models were used to examine if changes in hair cortisol were associated with changes in adiposity. Results: Children had a median BMI percentile of 98% and parents with lower education with 25 of 40 having less than high school diploma and high food insecurity (17 of 40, 43%). Among the 40 children with valid data for both time points, the median hair cortisol concentration at baseline was 4.09 pg/mg (interquartile range [IQR] 2.65-8.68) and 6.05 pg/mg (IQR 3.95-9.33) at the end point. Increases in cortisol from baseline to follow-up had a small but significant association with decreased obesity over time. Hair cortisol did not moderate an association between food security and weight. Conclusion: In children with chronic stressors and obesity, we found that increases in cortisol over time were associated with decreases in adiposity. Further studies following hair cortisol concentrations over time are needed to understand how this biomarker relates to weight status and stressors. Clinicaltrials.gov ID: NCT03330743.

Physical Activity and Chronic Stress in Early Life: Findings From the 2015 Pelotas (Brazil) Birth Cohort

BACKGROUND

The association of physical activity through early childhood on children's chronic stress still is unclear. Therefore, the aim of the present study is to test the association of physical activity through early childhood (1-4 y) with chronic stress, measured by hair cortisol at age 4.

METHODS

Longitudinal study including children from the 2015 Pelotas (Brazil) Birth Cohort. Cortisol at age 4 was measured using a hair sample, which provided cortisol concentration from the past months. Physical activity was measured using accelerometers at 1, 2, and 4 years. Linear regression models were used to assess the association between physical activity and chronic stress. Trajectory models were also applied to examine chronic stress in relation to physical activity patterns throughout early childhood.

RESULTS

Children with valid physical activity and hair cortisol data were included in the analyses (N = 1475). Three groups of physical activity trajectories between 1 and 4 years were identified: low, medium, and high. No association between physical activity at 1, 2, and 4 years and chronic stress at age 4 was observed. However, children in the "high" physical activity trajectory presented low cortisol concentration; the magnitude of the regression coefficient was slightly larger in girls (β = -0.125; 95% confidence interval, -0.326 to 0.074) than boys (β = -0.051; 95% confidence interval, -0.196 to 0.09).

CONCLUSION

There was no clear association between physical activity and chronic stress in early childhood. Trajectories models suggest that higher activity throughout early childhood may positively impact chronic stress; however, more studies are needed to confirm that hypothesis.

Hair cortisol concentration in postpartum dairy cows and its association with parameters of milk production

Hair cortisol concentration (HCC) is considered as an indicator for a minimally invasive assessment of long-term stress. In dairy cows, in addition to stress influences, changing physiological conditions during gestation and lactation (eg, due to varying energy requirements or fluctuating milk yield) may affect HCCs. Thus, the aim of our study was to investigate HCCs of dairy cows during different stages of lactation and to determine the relationship between milk production traits and hair cortisol levels. Samples of natural hair and regrown hair were collected from 41 multiparous Holstein Friesian cows at 100-d intervals from parturition to 300 d postpartum. All samples were analyzed for cortisol concentration and the association of HCC with milk productions traits was evaluated. Our results show that cortisol concentration in natural hair increased after parturition and was highest 200 d postpartum. Cumulative milk yield from parturition to 300 d showed moderate and positive correlation with HCC in natural hair at 300 d. There was a positive correlation between urea concentration in milk and cortisol levels in regrown hair at 200 d, and between somatic cell count in milk and HCC in natural and regrown hairs 200 d postpartum. Together, these findings suggest that physiological loads during lactation, eg, caused by metabolic stress and/or inflammation, may be associated with increased HCC levels. In addition, the results on hair color confirm previous findings in cattle that black hair has higher cortisol concentrations than white hair. Black hair therefore appears to be more suitable for hair cortisol analysis as it provides higher protection against photodegradation.

Associations between chronic stress and hair cortisol in children: A systematic review and meta-analysis

OBJECTIVES

This review systematically examined the associations between chronic stress and hair cortisol concentration (HCC) in children, and the potential modification effects of type, measurement period and scales of chronic stress, child age and sex, hair length and HCC measurement method, characteristics of study site, and congruence between time periods measured for chronic stress and HCC.

METHODS

Pubmed, Wed of Science, and APA PsycINFO were systematically searched for articles examining the association between chronic stress and HCC.

RESULTS

Thirteen studies from five countries with 1,455 participants were included in the systematic review and nine studies were included in the meta-analysis. Meta-analysis revealed that chronic stress was associated with HCC (pooled-r = 0.09, 95 % CI: 0.03, 0.16). Stratified analyses revealed that type, measurement time and scales of chronic stress, hair length and measurement method of HCC, and the congruence between time periods measured for chronic stress and HCC modified such correlations. The positive correlations between chronic stress and HCC were significant for studies measuring chronic stress as stressful life events, assessing chronic stress within the past six months, extracting HCC from 1 cm, 3 cm, or 6 cm of hair, measuring HCC by LC-MS/MS, or having congruence between time periods measured for chronic stress and HCC. The potential modifying effects of sex and country developmental status could not be concluded due to the limited number of studies included.

CONCLUSIONS

Chronic stress was positively correlated with HCC, varying by characteristics and measurements of chronic stress and HCC. HCC could be a biomarker for chronic stress among children.

Preschool-aged children's hair cortisol and parents' behavior, psychopathology, and stress

Parental factors, including parenting behavior, parent mental health, and parent stress, are associated with child stress. More recently, studies have shown that these parental factors may also be associated with children's hair cortisol concentration (HCC). HCC is a novel biomarker for chronic stress. HCC indexes cumulative cortisol exposure thereby reflecting longer-term stress reactivity. Although HCC is associated with a range of problems in adults such as depression, anxiety, appraisal of stressful events, and diabetes, studies investigating HCC in children have been inconsistent, with particularly little information about parental factors and HCC. As chronic stress may have long-term physiological and emotional effects on children, and parent-based interventions can reduce these effects, it is important to identify parental factors that relate to children's HCC. The aim of this study was to examine associations between preschool-aged children's physiological stress measured via HCC and mother- and father-reported parenting behavior, psychopathology, and stress. Participants included N = 140 children ages 3-5-years-old and their mothers (n = 140) and fathers (n = 98). Mothers and fathers completed questionnaire measures on their parenting behavior, depressive and anxiety symptoms, and perceived stress. Children's HCC was assessed by processing small hair samples. HCC levels were higher in boys compared to girls, and higher in children of color compared to white children. There was a significant association between children's HCC and fathers' authoritarian parenting. Children's HCC was positively associated with physical coercion, a specific facet of fathers' authoritarian parenting, even after accounting for sex of the child, race/ethnicity of the child, stressful life events, fathers' depression, fathers' anxiety, and fathers' perceived stress. In addition, there was a significant interaction between higher levels of both mothers' and fathers' authoritarian parenting and children's HCC. Children's HCC was not significantly related to mothers' and fathers' anxiety and depression or mothers' and fathers' perceived stress. These findings contribute to the large literature that links harsh and physical parenting practices with problematic outcomes in children.

Determinants of hair cortisol in preschool children and their mothers: A Brazilian birth cohort study

OBJECTIVE

Few large-scale studies have provided population-based estimates of hair cortisol levels and its determinants. Hair cortisol and potential determinants were measured in children and their mothers in a population-based sample in a Brazilian city with large variations in socioeconomic conditions.

METHODS

We used data from the 4-year follow-up of the 2015 Pelotas (Brazil) Birth Cohort Study. Hair samples were collected by trained fieldworkers to analyze average levels of cortisol over a 3-month period. Four groups of variables were tested as potential determinants: hair characteristics (natural color, treatment, type, and frequency of wash), use of corticosteroids and oral contraceptives, sociodemographic factors (sex, age, skin color, socioeconomic level, maternal relationship, pregnancy, daycare enrollment), maternal perceived stress, and substance exposure (smoking and illicit drug use). Linear regression with log transformation was used to test associations.

RESULTS

3235 children and 3102 mothers were analyzed (80.7% and 77.4% of those interviewed when children were 4 years of age, respectively), for whom sufficient hair was collected for cortisol analysis. The median of hair cortisol concentration was 7.8 pg/mg (IQR = 5.6 - 11.0) for children, and 5.6 pg/mg (IQR = 4.2 - 7.8) for mothers. In adjusted models, sex and socioeconomic level were associated with child cortisol levels. For mothers, hair cortisol levels were associated with socioeconomic level, skin color, age, hair treatment and hair natural color.

CONCLUSION

This study provides estimates of hair cortisol levels in a diverse population in a upper-middle income country. Although just a few predictors were associated with maternal/child cortisol levels, socioeconomic level was the key variable that should be incorporated in studies using hair cortisol to measure biological manifestations of stress, but other variables, such as some hair and sociodemographic characteristics are important to consider when using hair cortisol.

Intergenerational impact of childhood trauma on hair cortisol concentrations in mothers and their young infants

Background

Alterations in stress regulation and function of the hypothalamic-pituitary-adrenal (HPA) axis during infancy may be a risk factor for the development of psychopathology later in life. Maternal childhood trauma, depression, anxiety and stressful life events are individually associated with HPA axis dysregulation. Less is known about their interdependent influence on maternal and infant stress regulation in at risk populations. In a sample of mothers with a history of depressive-, and/or anxiety disorders and their infants we explored if a history of maternal childhood trauma, current depressive and anxiety symptomatology, and recent life events were associated with maternal and infant long-term cortisol levels three months postpartum.

Methods

Data were available of 89 mothers and 49 infants. All mothers fulfilled criteria for a lifetime depressive or anxiety disorder. Diagnosis was established with a diagnostic interview. Current depressive symptomatology was assessed with the Edinburgh Postnatal Depression Scale (EPDS), current anxiety with the State-Trait Anxiety Inventory (STAI), maternal childhood trauma with the Childhood Trauma Questionnaire (CTQ) and recent life events with the Everyday Problem Checklist (EPC). Maternal and infant hair cortisol concentrations (HCC) were quantified with liquid chromatography with tandem mass spectrometry (LC-MS/MS) three months after birth. Total scores of the CTQ and subscales, EPDS, STAI, and EPC were regressed on maternal and infant HCC using regression analyses. Differences in HCC regarding trauma history were tested with t-tests. Potential confounders were identified and adjusted for.

Results

In regression analyses, a positive curvilinear relationship was found between CTQ total score and maternal HCC (n = 83, B = 0.076, SE 0.033, p = .021), but not for current depression (n = 88, B = -0.001, SE 0.011, p = .931), current anxiety (n = 88, B = 0.002, SE 0.004, p = .650) or recent life events (n = 89, B = 0.018, SE 0.032, p = .568). Analyses were adjusted for confounders. A negative linear relationship was found between maternal CTQ score and infant HCC (n = 49, β = -0.264, B = -0.006, SE 0.003, p = .052), but not for current maternal depression (n = 45, β = -0.182, B = -0.011, SE 0.008, p = .164), current maternal anxiety (n = 45, β = -0.209, B = -0.005, SE 0.003, p = .113) or recent life events (n = 46, β = -0.128, B = -0.022, SE 0.023, p = .325). Analyses were adjusted for relevant infant hair characteristics. Specifically, maternal emotional and physical neglect were related to HCC in both mothers and infants.

Conclusions

Results suggest that maternal childhood trauma is more prominent in altering maternal and infant long-term cortisol levels than perinatal depressive and anxiety symptomatology or recent life stressors in mothers with a history of depressive and/or anxiety disorders, and their infants. As infants of mothers with psychopathology are at increased risk for later psychiatric disease, future studies should investigate the interplay of possible risk factors for transgenerational transmission, intra-uterine programming of the HPA axis, including (epi-)genetic phenomena, of the HPA axis, and the influence of parenting impairment.

Maternal distress, DNA methylation, and fetal programing of stress physiology in Brazilian mother-infant pairs

Maternal prenatal psychosocial stress is associated with adverse hypothalamic-pituitary-adrenal axis (HPAA) function among infants. Although the biological mechanisms influencing this process remain unknown, altered DNA methylation is considered to be one potential mechanism. We investigated associations between maternal prenatal psychological distress, infant salivary DNA methylation, and stress physiology at 12 months. Mother's distress was measured via depression and anxiety in early and late pregnancy in a cohort of 80 pregnant adolescents. Maternal hair cortisol was collected during pregnancy. Saliva samples were collected from infants at 12 months to quantify DNA methylation of three stress-related genes (FKBP5, NR3C1, OXTR) (n = 62) and diurnal cortisol (n = 29). Multivariable linear regression was used to test for associations between prenatal psychological distress, and infant DNA methylation and cortisol. Hair cortisol concentrations in late pregnancy were negatively associated with two sites of FKBP5 (site 1: B = -22.33, p = .003; site 2: B = -15.60, p = .012). Infants of mothers with elevated anxiety symptoms in late pregnancy had lower levels of OXTR2 CpG2 methylation (B = -2.17, p = .03) and higher evening salivary cortisol (B = 0.41, p = .03). Furthermore, OXTR2 methylation was inversely associated with evening cortisol (B = -0.14, p-value ≤ .001). Our results are, to our knowledge, the first evidence that the methylation of the oxytocin receptor may contribute to the regulation of HPAA during infancy.

Maternal stress and hair cortisol among pregnant women following hurricane Florence

Natural disasters represent major stressors, resulting in psychological distress and physiological responses such as increased cortisol. During pregnancy, this impacts not only maternal well-being, but also fetal development. In 2018, Hurricane Florence caused extensive damage across the eastern United States. Studies indicated that compared to married pregnant women, unmarried pregnant women had higher risk of distress. Here we assess hair cortisol among a subsample of participants, and variations based on marital status.

METHODS

We analyzed multiple stress measures among 37 participants who were pregnant during Hurricane Florence. We used questionnaires modeled on previous studies to assess hardship associated with the hurricane, psychological distress, sociodemographic characteristics, social support, and food security. We analyzed cortisol concentrations in proximal and distal hair sections, representing stress around the time of the disaster (distal) and 3-4 months following the disaster (proximal). We used linear regression to test relationships between hair cortisol and self-report stress measures, and variations based on marital status.

RESULTS

Self-report measures of distress and hardship were similar among married and unmarried participants. Mean cortisol levels in distal and proximal sections were higher among unmarried participants. Controlling for confounding variables, hardship was not associated with hair cortisol. Distress predicted cortisol in distal sections (β = .482, p = .018), with a trend for proximal sections (β = .368, p = .055). Marital status was a significant predictor of distal (β = .388, p = .027) and proximal (β = .333, p = .047) hair cortisol, explaining 8.6%-11.7% of unique variance.

CONCLUSIONS

Preexisting and intersecting risk factors likely place unmarried pregnant individuals at risk of stress during and following a disaster.

Conduct Problems and Hair Cortisol Concentrations Decrease in School-Aged Children after VIPP-SD: A Randomized Controlled Trial in Two Twin Cohorts

The Video-feedback Intervention to promote Positive Parenting and Sensitive Discipline (VIPP-SD) is effective in increasing parental sensitivity and sensitive discipline, and aims to decrease child behavior problems. Changes in quality of parenting may be accompanied by effects on child stress levels. However, studies of VIPP-SD effects on child behavior problems have shown mixed results and there are no studies to date of the effect of the intervention on children's stress levels, as measured by hair cortisol concentration (HCC). Furthermore, differences in intervention effectiveness may be explained by differential susceptibility factors. We hypothesized that the effects of the VIPP-SD on child behavior problems might be moderated by currently available child polygenic scores of differential susceptibility (PGS-DS). In the current pre-registered trial, we randomly assigned 40% of n = 445 families with school-aged twin children to the intervention group. The VIPP-SD was successful in decreasing both children's conduct problems and HCC. Effects were not moderated by available child PGS-DS. We conclude that a brief, home-based video-feedback parenting intervention can decrease child behavior problems and affect the child's stress-related neuroendocrine system as assessed with hair cortisol. In future studies, more specific PGS-DS for externalizing behaviors should be used as well as parental PGS-DS.

Race/ethnicity and age associations with hair cortisol concentrations among children studied longitudinally from early through middle childhood

A total of 513 children were included in this secondary analysis of data from the NET-Works trial of low income children at risk for obesity. The purpose of the analysis was to examine HCC longitudinally over 5 assessments from early through middle childhood with the goal of i) determining if there were racial/ethnic differences in HCC, and if so, how early in childhood these differences could be observed; and (ii) whether racial/ethnic differences in HCC reflected structural and family-level indicators of disadvantage. The sample consisted of children from diverse racial/ethnic backgrounds: Black, including Hispanic Black (N = 156), non-Hispanic White (N = 67) and Non-Black Hispanic (N = 290) children. As the largest group, the last group was used as the reference group in analyses. Structural and family-level indicators of disadvantage, including the neighborhood child opportunity index (COI), family income, and parent perceived neighborhood safety, were collected at each assessment. The results showed higher HCC among Black children beginning as early as 2-4 years of age than non-Black Hispanic children who did not differ from non-Hispanic White children. Although family income and COI were lower for children from minoritized racial-ethnic backgrounds, entering these measures as covariates did not reduce the difference in HCC between Black children and the other two groups. The results also showed that HCC initially decreased with age and then plateaued, with no evidence that this pattern differed by race/ethnicity. Because of the potential health risks of chronically elevated cortisol concentrations, these data argue for increased attention to the myriad of factors (oppressive structures, systems, and interpersonal experiences) that likely contribute to elevated cortisol levels among Black children.

Association between the timing of family socioeconomic deprivation and adolescence hair cortisol among adolescent twins: A study of the genetic and environmental processes involved

BACKGROUND

While evidence shows that lower socioeconomic status (SES) is related to dysregulated hair cortisol concentration (HCC), the genetic and environmental processes underlying this association remain understudied.

OBJECTIVES

(1) to examine whether childhood and adolescence SES are phenotypically related to late adolescence HCC and to what extent these associations are explained by common underlying genetic factors (2) to estimate whether the genetic and environmental etiology of HCC varies according to SES and the timing of these experiences.

METHODS

Participants were 422 twin pairs for whom SES was measured in childhood (ages 0-5 years) and adolescence (age 14 years). Hair cortisol was assessed at age 19.

RESULTS

Additive genetic factors explained 39% of variability in HCC, whereas nonshared environmental factors accounted for the remaining 61%. A significant negative association emerged between HCC and family SES assessed in adolescence (β=-.11,p = .02), which was entirely explained by common underlying environmental influences. We also found evidence of stronger genetic contributions to HCC among youths who lived in more disadvantaged households during childhood in comparison to those from wealthier backgrounds.

CONCLUSIONS

This study provides first-time evidence that the association between adolescence SES and HCC is environmentally-explained and that genetic influences underlying HCC are not uniformly distributed across the family SES continuum measured during childhood. These findings may pave the way for a fuller understanding of the impact of early adversity on HPA axis activity.

Hair cortisol as a biomarker of chronic stress in preadolescents: influence of school context and bullying

Bullying has been identified as the most common form of aggression and a major source of stress among children and adolescents. The main objective of this study was to analyze the association that school context in general and bullying in particular might have with hair cortisol concentration (HCC), examining the effect of executive function and sex on this association. The study included 659 11-year-old preadolescents from the cohorts of Gipuzkoa and Sabadell of the INMA (INfancia y Medio Ambiente-Children and Environment) project. We gathered information about school-related factors (bullying, school environment, problems with peers and academic performance) and executive function (risky decision-making). Hair samples were collected to measure cortisol concentrations and Structural Equation Modeling was used to examine associations between school-related factors, executive function and HCC. Results showed that being involved as a bully/victim was related to higher HCC and, higher HCC was associated with poorer executive function. This study may contribute to a better understanding of the consequences that chronic exposure to a stressful factors may have on preadolescents' health and developmental outcomes. Besides, our results are relevant for designing programs for prevention and intervention, which could modify individual physiological responses to stress and reduce the effects of stress on the health.

Do subjective and objective measures of stress agree in a clinical sample of youth and their parents?

This study explored agreement and potential relationships among perceived stress (self-reported using the Perceived Stress Scale), hair cortisol concentration (HCC), and mental disorders in a clinical sample of youth and their parents. Data were collected from a cross-sectional sample of 48 youth (38 females; mean age = 15.6 years) with a mental disorder and 72 parents (65 females; mean age = 45.49 years). Agreement was assessed using Bland-Altman plots and intraclass correlation coefficients. Multiple regression was used to model the association between covariates and HCC and perceived stress for youth and parents. Agreement between perceived stress and HCC was low for both youth and parents (ICC = 0.15 to 0.31). Among youth, lower income (β = 0.24) and parent psychopathology (β = 0.42) were associated with higher HCC. Female sex (β = 0.42) and higher parent psychopathology (β = 0.28) were associated with higher perceived stress, whereas chronic physical illness was associated with lower perceived stress (β = −0.24). Among parents, female sex (β = −0.21) was associated with lower HCC and family functioning (β = 0.46) was associated with higher perceived stress. In youth, higher HCC was associated with generalized anxiety (OR = 1.14) and higher perceived stress was associated with major depressive episode (OR = 1.33), generalized anxiety (OR = 1.10), and separation anxiety (OR = 1.14). Among parents, higher HCC was associated with depression (β = 0.27) and perceived stress was associated with depression (β = 0.53) and anxiety (β = 0.45). This exploratory study shows that agreement between psychological and physiological stress is low in a clinical sample of youth and their parents. Sociodemographic and psychosocial factors, and mental health, are differentially associated with psychological and physiological stress.

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Agreement between perceived stress and hair cortisol is low for youth and parents.

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Sex, physical illness, and parent psychopathology are associated with youth stress.

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Sex and family functioning are associated with stress among parents.

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Hair cortisol and perceived stress are differentially associated with mental illness.

Association between hair cortisol concentration and behavioral difficulties in children and adolescents

This study aimed to assess associations between behavioral difficulties and an objectively measurable indicator for long-term stress (hair cortisol) in children and adolescents. We expected increased hair cortisol levels in participants with more externalizing (conduct problems, hyperactivity/inattention) or internalizing (peer relationship problems, emotional problems) behavioral difficulties. Behavioral difficulties were assessed using the parent version of the Strengths and Difficulties Questionnaire (SDQ). Hair cortisol concentration (HCC), measured via liquid chromatography mass spectrometry (LC-MS3), was used as stress marker. A 1 cm strand of hair was cut off from the occipital or parietal cranium closest to the scalp. The study sample comprised 1321 children and adolescents aged between 3 and 17 years participating in the LIFE Child cohort study (Leipzig, Germany). To assess associations, we applied multiple linear regression analyses. Only a few associations met expectations, others contradicted our hypotheses. No association reached statistical significance. The present findings may suggest that behavioral difficulties gathered by SDQ are not associated with stress measured through HCC.

Associations Between Different Cortisol Measures and Adiposity in Children: A Systematic Review and Meta-Analysis

This study examined associations between hair, salivary, serum, and urinary cortisol concentration with adiposity-related indicators in children, and explored their potential effects modification by age, sex, cortisol measurement method, and country developmental context. We systematically searched PubMed, Web of Science, and Embase for studies examining at least one of the four aforementioned cortisol with objectively measured adiposity-related outcomes in children. Meta-analyses of cross-sectional studies revealed that hair cortisol concentration was associated with fat mass index (FMI)-standard deviation score (SDS)/FMI z-score (pooled-β = 0.04, 95% CI: 0.01, 0.08) and BMI/BMI z-score (pooled-β = 0.15, 95% CI: 0.06, 0.25), and these associations were significant among children aged ≤ 12 years (pooled-β = 0.15, 95% CI: 0.05, 0.26) and >12 years (pooled-β = 0.13, 95% CI: 0.04, 0.22), children from developed countries (pooled β = 0.12, 95% CI: 0.03, 0.21) and developing countries (pooled-β = 0.193, 95% CI: 0.188, 0.198), and in studies extracting cortisol via LC-MS/MS (pooled-β = 0.18, 95% CI: 0.06, 0.29) but not ELISA (pooled-β = 0.08, 95% CI: −0.06, 0.22). Meta-analyses of both cohort and cross-sectional studies revealed non-significant associations of morning salivary cortisol concentration and total daily cortisol output with BMI/BMI z-score. Serum cortisol concentration was not associated with BMI or waist circumference. Meta-analysis of urinary cortisol concentration and adiposity was hindered by insufficient data. These findings further corroborate understanding of chronic stress’ physiological contribution to increased pediatric obesity risk.

The relationship of hair glucocorticoid levels to immunological and virological outcomes in a large cohort of combination antiretroviral therapy treated people living with HIV

Background

Existing literature mostly investigated the relationship of acute or short-term glucocorticoid exposure to HIV disease progression using cortisol levels in serum, saliva, or urine. Data are limited on the relationship of long-term glucocorticoid exposure to HIV disease progression. This study examined whether hair glucocorticoid levels, novel retrospective indicators of long-term glucocorticoid exposure, are associated with two common indicators of HIV disease progression (CD4 count and HIV viral load) among a large cohort of combination antiretroviral therapy treated Chinese people living with HIV (PLHIV).

Methods

A total of 1198 treated PLHIV provided hair samples for glucocorticoid (cortisol and cortisone) assay and completed a survey assessing sociodemographic, lifestyle, and HIV-related characteristics. Meanwhile, CD4 count and HIV viral load were retrieved from their medical records. Spearman correlation was used to examine the associations of hair cortisol and cortisone levels to continuous CD4 count and HIV viral load. Multivariate logistic regression was used to predict CD4 count < 500 cells/mm³.

Results

Both hair cortisol and cortisone levels were negatively associated with CD4 count but not with HIV viral load. The odds ratio for CD4 count < 500 cells/mm³ was 1.41 [95% CI 0.99–2.00] and 2.15 [95% CI 1.51–3.05] for those with hair cortisol and cortisone levels in the highest quartile compared to the lowest when controlling for sociodemographic, lifestyle, HIV-related covariates, and HIV viral load.

Conclusion

Hair glucocorticoid levels were associated with CD4 count but not viral load in treated Chinese PLHIV. Our data furtherly supported the hypothesis that elevated glucocorticoid levels are associated with the lower CD4 count.

Determinants of Chronic Biological Stress, Measured as Hair Cortisol Concentration, in a General Population of Adolescents: From Individual and Household Characteristics to Neighborhood Urbanicity

Chronic biological stress may adversely affect adolescents' physical and mental health, but insight in the personal and environmental factors that determine chronic stress is limited. We measured 3-month cumulative hair cortisol concentration (HCC) in 419 adolescents, participating in the Flemish Environment and Health Study. Adolescents' health and lifestyle characteristics, household and neighborhood socio-economic status as well as neighborhood urbanicity were assessed as potential determinants of HCC, using multiple linear regression models. We additionally explored heterogeneity of our results by sex. HCC were significantly higher in boys from densely populated neighborhoods, the association was not significant in girls. Accordingly, boys living outside cities had significantly lower HCC than boys, living in cities. HCC was significantly lower in adolescents with an optimal vitality, a measure of a positive mental health status. In adolescent girls, menarcheal status (pre-/postmenarche) was a significant determinant of HCC. Our findings are the first to suggest that residential urbanicity may have an impact on chronic biological stress in a general population of adolescent boys.

Psychophysiological Regulation and Classroom Climate Influence First and Second Graders' Well-Being: The Role of Body Mass Index

This study examines the associations between physical and emotional well-being and classroom climate, cardiac vagal response, and body mass index (BMI) in a sample of 6- to-8-year-olds. Specifically, we expected a direct link between classroom climate, vagal withdrawal, BMI and children's physical and emotional comfort. Furthermore, we explored whether these individual and environmental characteristics influenced well-being in an interactive fashion. Participants were 142 (63 boys, 44%) first and second graders living in the North of Italy who were interviewed on their emotional and physical comfort. Heart rate and a measure of vagal influence on the heart (cardiac vagal tone) were recorded at rest and during an oral academic test. Height and weight were collected. Classroom climate was positively linked with physical well-being, whereas emotional well-being was negatively related with BMI. In addition, an inverted U-shaped effect of cardiac vagal withdrawal (i.e., cardiac vagal tone during stress minus resting vagal tone) on emotional well-being was found. Two regression models highlighted the role played by BMI when interacting with vagal withdrawal in predicting children's physical and emotional well-being. The interplay between BMI and cardiac vagal withdrawal played an important role in primary school children's well-being. From a clinical perspective, preventive training to improve autonomic regulation in concert with interventions promoting healthy eating attitudes might be critical for supporting primary school children's emotional and physical health.

Emotional Availability as a Moderator of Stress for Young Children and Parents in Two Diverse Early Head Start Samples

Positive parent-child relationship quality is critical for buffering children from the effects of stress on development. It is thus vital to develop interventions that target parent-child relationship quality for families experiencing stress. We examined the moderating role of parent-child relationship quality (as measured by parental emotional availability [EA]) in the intergenerational association between parental adverse childhood experiences (ACEs) and their young children's hair cortisol concentrations (HCCs)-a physiological marker of cumulative hypothalamic pituitary adrenal (HPA)-axis activity. Using data from 127 parent-child dyads collected by two of six ACF-funded Buffering Toxic Stress consortium sites, we tested interaction effects of parental ACEs with parental EA on young children's (Mage = 18.38, SDage = 7.10) HCC. Results revealed curvilinear main effects such that higher parental ACEs were significantly associated with greater HCC and stronger associations occurred at higher levels of parental ACEs. However, this association was moderated by parental EA. Thus, among children with higher parental history of ACEs, children of parents with higher EA had lower HCC compared to children of parents with lower EA. These findings provide support for the risk-buffering and risk-exacerbating role of parent-child relationship quality (e.g., EA) for the transmission of parents' early life adversity on their children's HPA-axis activity, documented here in a racially and ethnically diverse sample of children and parents served by Early Head Start. Findings suggest that intervention and prevention efforts targeting stress response in children of mothers with childhood adversity should also support parents in building an emotionally available relationship with their children.

Association between hair cortisol, hair cortisone, and fatigue in people living with HIV

Cumulative evidence to date largely supports an association between dysregulation of the activity of the hypothalamic-pituitary-adrenal (HPA) axis and fatigue. People living with HIV (PLHIV), in particular, are vulnerable to both HPA axis dysregulation and fatigue. Few investigations have examined the possible role of HPA-axis dysfunction in the occurrence of fatigue in PLHIV. This cross-sectional study aimed to investigate the association between glucocorticoids in hair, retrospective indicators of long-term HPA axis activity and biomarkers of chronic stress, and fatigue in PLHIV. A total of 446 PLHIV from Guangxi China provided hair samples for cortisol and cortisone assay and provided information on fatigue levels, sociodemographic, lifestyle, and HIV-related characteristics. Results showed that before and after controlling sociodemographic, lifestyle, and HIV-related characteristics, hair cortisone levels, but not hair cortisol levels, were associated with fatigue levels in PLHIV. In conclusion, we found that higher cortisone levels are associated with greater fatigue levels in a large cohort of Chinese PLHIV.LAY SUMMARYWe found that hair cortisone levels were significantly associated with fatigue levels in a large cohort of Chinese PLHIV. Hair cortisol levels were, however, not associated with fatigue levels in the PLHIV studied. We thus show that Chinese PLHIV who have higher cortisone levels are associated with higher fatigue levels.

Effects of social tolerance on stress: hair cortisol concentrations in the tolerant Tonkean macaques (Macaca tonkeana) and the despotic long-tailed macaques (Macaca fascicularis)

Group living is a source of stress and an individuals' social environment has been shown to have a significant effect on its health and well-being. However, little is known about how different social organizations affect the stress levels of their members. Is living in a hierarchical society more or less stressful than living in a more tolerant structure? Here, we assess cortisol concentrations in the hair of two macaque species with radically different dominance styles: the egalitarian Tonkean macaque (Macaca Tonkeana) and the despotic long-tailed macaques (Macaca fascicularis). Hair was sampled in winter and again in late spring in two mixed-sex groups of 22 Tonkean macaques and 9 long-tailed macaques; Hair cortisol concentrations were significantly higher in the egalitarian Tonkean macaques than in the despotic long-tailed macaques, ranging from 161.13 to 938.8 pg/mg (mean ± SD 349.67 ± 126.22) and from 134.46 to 339.86 pg/mg (mean ± SD 231.2 ± 44.24), respectively. There was no difference between male and female cortisol concentrations, but hair cortisol increased with age in males. Dominance rank certainty was lower among female Tonkean macaques compared to long-tailed macaques. Our results suggest that species differences in dominance styles may translate into differences in long-term cortisol concentrations. We suggest that the higher cortisol concentrations in Tonkean macaques could be linked to the instability and lack of predictability and control around social relationships.

Children's hair cortisol and hair testosterone concentrations in response to environmental changes: from summer holidays to school

Elevated hair cortisol concentrations in children have been linked to several stress-related conditions, including school-related demands. However, little is known about changes in hair testosterone in children. The present study investigated changes in hair cortisol and hair testosterone concentrations in the time course of four months - from summer holidays until mid of autumn of the following school year - in 60, 10-12-year-old (11.31 ± 0.63) school children (29 girls). Children's mental health was assessed by the strengths and difficulties questionnaire (SDQ) and related to hair cortisol and hair testosterone levels. Body mass index, waist-to-height ratio, and parental education were evaluated as potential confounders. In girls, the expected increase of hair cortisol concentrations was observed during school as compared to summer holidays, partly accounted for by peer- and emotional problems and the increase of HTC. In boys, hair cortisol and testosterone concentrations were significantly higher. Hair cortisol increased only slightly, while hair testosterone decreased significantly during school. The findings suggest a reciprocal influence of the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axis, differentially affecting girls' and boys' hormone production in response to environmental changes.

Child maltreatment affects fathers’ response to infant crying, not mediated by cortisol or testosterone

Parents' ability to appropriately respond to infant crying is essential for parental care and has been found to relate to parents' own childhood experiences. Additionally, childhood experiences can affect endocrine factors, which may subsequently affect behavior. In the current study, preregistered on https://osf.io/hwgtu, we examined in expectant and new fathers (N = 152) associations between experiences of maltreatment in their own childhood, hair cortisol and testosterone concentrations and their ability to modulate handgrip force when exposed to infant crying. Cortisol and testosterone were quantified from the 1 cm of hair most proximal to the scalp using Liquid chromatography-tandem mass spectrometry. Participants were asked to squeeze a handgrip dynamometer at full and half strength while listening to infant cries and control sounds. Results indicated that fathers who experienced more childhood maltreatment used more excessive handgrip force during infant cry sounds. Hair cortisol and testosterone were not related to either experienced childhood maltreatment or handgrip strength modulation. These findings confirm that fathers’ early experiences of maltreatment reduce their ability to modulate their behavioral responses during infant cries, but suggest that hair cortisol and testosterone concentrations do not identify the underlying mechanism of this association.

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Childhood maltreatment relates to fathers' behavioural responses to infant crying.

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Childhood maltreatment is unrelated to fathers' hair cortisol and testosterone.

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Cortisol and testosterone are unrelated to behavioural responses to infant cries.

The embodiment of water insecurity: Injuries and chronic stress in lowland Bolivia

Water is critical to health and wellbeing. Studies have theorized that problems with water can become embodied, yet few studies have quantified this. Therefore, we first sought to understand the lowland Bolivian water environment of Tsimane' forager-horticulturalists. We assessed the water environment holistically, using objective measures of water quality and water services (Joint Monitoring Programme's drinking water services ladder) and subjective measures, including perceived water safety and water insecurity experiences [Household Water Insecurity Experiences Scale (HWISE)]. We tested how water service levels, perceived water safety, and water fetching frequency were associated with HWISE scores using Tobit regression models among 270 households. We then tested if and how water becomes embodied via self-reported water-related injury and a chronic stress biomarker, hair cortisol concentration (HCC). Results demonstrated that, compared with households using surface water, households with basic water services had HWISE scores 1.59-pts lower (SE = 0.29; P < 0.001). Ingestion of water perceived to be "bad" and more daily water-fetching trips were associated with higher HWISE scores. Twenty percent of households reported prior water-related injuries, with women most commonly injured. In logistic regressions, each point higher HWISE score was associated with 28% (95%CI:1.16-1.41; P < 0.001) higher odds of injury. Basic water services compared to surface water was associated with 48% lower odds (OR = 0.52; 95%CI:0.33-0.82; P = 0.005) of injury. Finally, using linear regressions among 332 adults, HWISE scores were not associated with HCC. Past water-related injury was associated with higher HCC (Beta = 0.31; SE = 0.09; P = 0.029) among women, but not men. Relying on unimproved water services compared to surface was associated with 46.2% higher HCC for women (Beta=0.38; SE=0.14; P=0.048) and 55.3% higher HCC for men (Beta=0.44; SE=0.15; P=0.044), respectively. Overall, our findings demonstrate that water insecurity can become embodied through water-related injuries and elevated HCC. Improving water service levels through an equity lens may help ameliorate water insecurity and its accompanying negative health effects.

Long-term cortisol levels in hair of children and adolescents with Prader-Willi Syndrome

CONTEXT

Prader-Willi syndrome (PWS) is characterized by hypothalamic dysfunction. In children with PWS, stress-induced central adrenal insufficiency (CAI) has been described, however, daily life cortisol production may be normal. Hair cortisol concentration (HCC) is a marker of long-term systemic cortisol production. Cortisol awakening response (CAR) is the increase in cortisol level after awakening. A negative CAR might suggest hypothalamic-pituitary-adrenal (HPA)-axis reactivity problems. Little is known about HCC and CAR in children with PWS.

OBJECTIVE

To investigate long-term cortisol levels in hair and CAR in children with PWS.

DESIGN

Cross-sectional study.

PATIENTS

41 children with PWS.

SETTING

Dutch PWS Reference Center.

MAIN OUTCOME MEASURES

HCC and salivary cortisol measured by LCMS.

RESULTS

Median (IQR) HCC was 1.90 (1.02-3.30) pg/mg at a median (IQR) age of 14.5 (8.20-19.0) years, with median HCC in age-matched references being 2.63 pg/mg. Five patients (13.2%) had HCC < 2.5th percentile for age and these patients had a repeatedly negative CAR. Median HCC was significantly lower in patients with negative CAR than in patients with normal CAR (1.00 (0.22-1.59) vs. 2.25 (1.47-3.26) pg/mg, p = 0.007). One patient had both HCC < 2.5th percentile and repeatedly low morning salivary cortisol levels and negative CAR, and was diagnosed with adrenal insufficiency by overnight metyrapone test.

CONCLUSIONS

HCC were normal in the majority of children with PWS. Our data suggest that children with HCC < 2.5th percentile and (repeatedly) negative CAR might possibly have adrenal insufficiency or delayed HPA-axis responsiveness.

Parental cannabis and tobacco use during pregnancy and childhood hair cortisol concentrations

BACKGROUND

Fetal exposure to cannabis and tobacco during pregnancy leads to adverse fetal and childhood outcomes. We hypothesized that fetal exposure to cannabis and tobacco have persistent programming effects on hypothalamic pituitary adrenal (HPA) axis functioning in childhood. Therefore, we examined the associations of parental cannabis and tobacco use during pregnancy with childhood hair cortisol and cortisone concentrations at 6 years, as biomarkers of long-term HPA-axis functioning.

METHOD

In a population-based prospective birth cohort among 2577 mothers and their children, information of parental cannabis and tobacco use was collected by questionnaires, and maternal urine samples were additionally analyzed to detect cannabis metabolite concentrations. Cortisol and cortisone were measured in hair samples at 6 years. Linear regression analysis with adjustment for several confounders was used to test our hypothesis.

RESULTS

As compared to non-exposed children, offspring exposed to cannabis during pregnancy (in combination with tobacco) had higher childhood cortisol concentrations (log-10 transformed difference 0.16, 95 % Confidence Interval 0.04 to 0.28). This association was not mediated by birth weight. No differences in cortisone concentrations among cannabis-exposed children were observed. Maternal tobacco use during pregnancy was not associated with childhood cortisol or cortisone concentrations. Further, paternal cannabis or tobacco use was not associated with childhood cortisol or cortisone concentrations.

CONCLUSIONS

Our findings suggest that maternal cannabis use, combined with tobacco, during pregnancy is associated with alterations in offspring HPA-axis functioning. Further studies need to replicate these findings, and assess the causality and long-term consequences of these associations.

Maternal and neonatal canine cortisol measurement in multiple matrices during the perinatal period: A pilot study

Stress exposure during perinatal period may lead to maternal cortisol increase that negatively affects the offspring development. In recent years, the interest on non-invasive sampling methods to measure cortisol as a marker of stress is increasing in both humans and animals. Indeed, discomfort due to blood collection may compromise the diagnostic outcome, mainly in uncooperative patients. So far, some alternative matrices but not milk have been explored in adult dogs, while no data are available on the neonate and paediatric live pups. This study aimed to measure cortisol concentration in different biological substrates in both dams (blood, saliva, hair and milk) and pups (saliva and hair) at established times from proestrus up to two months after parturition. For this purpose, five female German shepherd bitches and their 22 pups were enrolled. Cortisol concentration was assessed using the enzyme immunoassay kit (Salivary Cortisol ELISA kit, Salimetrics) after matrices appropriate preparation if required. Cortisol was measurable in all the substrates, except some milk samples below the detection limit. Maternal cortisol concentrations differed among the matrices (P <0.0001) with the highest values recorded in plasma (median 0.596 μg/dL) compared to saliva (median 0.159 μg/dL), hair (median 0.083 μg/dL) and milk (median 0.045 μg/dL). Cortisol in dams did not vary within the same matrix over time. In pups, salivary (median 0.295 μg/dL) cortisol was always higher than hair (median 0.049 μg/dL; P <0.0001). At birth (P = 0.01) and two months later (P = 0.05), neonatal salivary cortisol was higher compared to other samplings. The present study demonstrates the suitability of these innovative substrates for cortisol measurement, suggesting them as potential diagnostic support in canine neonatology and welfare.

Father involvement in infancy predicts behavior and response to chronic stress in middle childhood in a low-income Latinx sample

Fathers' involvement in early childhood is important for children's physical, emotional, and cognitive development, particularly in low-income families. However, little is known about the longitudinal relations between early father involvement and children's later physiological responses to chronic stress and behaviors impacted by stress in the context of poverty. These issues are particularly important among Latinx immigrant families who face significant psychosocial and poverty-related risk. In the current study, we examined the relationship between father involvement in infancy and physiological chronic stress in the middle childhood period, as measured through hair cortisol concentration (HCC), and several behavioral measures (attention problems, working memory) in a Latinx immigrant sample with low income. Father involvement in infancy predicted children's later HCC, and working memory in second to third grade. Father involvement also moderated the effect of HCC on working memory, such that increased HCC predicted better working memory when fathers were not involved. These findings suggest that the fathers' involvement in infancy has lasting impacts on health and behavior and that associations between physiological and behavioral measures of stress may be moderated by differences in early father involvement.

Household Food Insecurity, Hair Cortisol, and Adiposity Among Tsimane' Hunter-Forager-Horticulturalists in Bolivia

OBJECTIVES

This study examined how household food insecurity (HFI) and chronic stress relate to adiposity among Tsimane' hunter-forager-horticulturalists in remote Bolivia with limited access to energy-dense processed foods that promote weight gain among industrialized populations.

METHODS

Retrospective cross-sectional data on HFI (via the Household Food Insecurity Access Scale [HFIAS]), hair cortisol concentration (HCC), adiposity (BMI, body fat percentage [%BF]), and sociodemographics were collected from 171 men, 164 women, and 167 children. Linear mixed-effects models tested linear, quadratic, joint, and interactive relationships between adiposity measures and both the HFIAS score and HCC.

RESULTS

Among children, each 3-point HFIAS score increase was associated with a 0.44-point higher %BF (SE = 0.22, P = 0.04). However, each 20% increase in HCC was associated with a -0.29-point difference in %BF (SE = 0.12, P = 0.01). Among men, a slight curvilinear relationship emerged between HFIAS and BMI. HFIAS and HCC were unrelated to adiposity measures among women. HCC did not modify relationships between HFIAS and adiposity in any subgroup.

CONCLUSIONS

These findings from a remote, small-scale population suggest that positive associations between HFI and adiposity are not isolated to contexts of industrialized food environments and heavy reliance on processed foods. However, these dynamics and the role of stress appear to differ by sex and age group.

The dark side of white hair? Artificial light irradiation reduces cortisol concentrations in white but not black hairs of cattle and pigs

Analysing hair cortisol concentrations (HCCs) is a minimally invasive way to retrospectively assess long-term stress, and its application in studies of animal welfare and stress has attracted considerable interest. However, not only stress-related effects but also hair-specific characteristics and external influences can affect HCCs and interfere with the interpretation of results. Thus, it was the aim of this study to investigate the impact of daylight and UV irradiation on cortisol concentrations in the hairs of pigs and cattle. We also examined whether a potential irradiation effect on HCCs depended on the colour of the hair. For this purpose, black and white hair samples from 18 Saddleback pigs and 18 Holstein Friesian cattle were exposed to artificial light (both visible and UV) and compared with control hair samples from the same animals kept in the dark. Exposure to artificial light significantly decreased HCCs in both pigs (P < 0.05) and cattle (P < 0.001), and hair colour had an influence on HCCs, with black hair showing higher cortisol levels than white hair (cattle: P < 0.001, pigs: P = 0.07). The interaction between light exposure and hair colour was significant in both pigs (P < 0.01) and cattle (P < 0.001), so light exposure reduced HCCs in porcine white hair but not black hair. In cattle, light-exposed white hair exhibited lower hair cortisol levels than control white hair or black hair. These results demonstrate that artificial light irradiation degrades hair cortisol or favours its elimination by structural changes of the hair matrix. However, this effect was only detectable in white hair, indicating that the melanin pigments in black hair absorbed radiation, thereby reducing the effects of photodegradation. Compared with other known influencing factors on HCCs, such as age and body region, the influence of light irradiation was relatively low in this in vitro experiment. However, further studies should investigate this influence under real-life animal conditions, such as outdoor and indoor housing.

Messengers of stress: Towards a cortisol sociology

In 2008, Timmermans and Haas called for a 'sociology of disease' to develop and challenge the sociology of health and illness. A sociology of disease, they argued, would take seriously the biological and physiological processes of disease in theorising health and illness. Building on two decades of Science and Technology Studies and feminist work on biological actors such as hormones and genes, we propose a 'cortisol sociology' to push further at this argument. As a 'messenger of stress', cortisol is key to understanding human and non-human health as a biosocial phenomenon. We argue that sociologists should engage with cortisol through critical yet open-minded reading of the relevant science and critical triangulation studies, and by tracking cortisol's movements from science into public worlds of biosensing and self-monitoring.

Associations between social adversity and young children's hair cortisol: A systematic review

Psychosocial and socioeconomic adversity in early childhood (termed 'social adversity') can have lifelong detrimental effects on health and development. Physiological stress is one proposed mechanism by which social adversity 'gets under the skin'. There is substantial research interest in whether hair cortisol, a biomarker proposed to measure the cumulative physiological stress response over time, can illustrate this mechanism. As a result, a growing number of studies have tested for associations between indicators of social adversity and child hair cortisol. The aim of this paper is to conduct a comprehensive, systematic review of the evidence for associations between indicators of social adversity and hair cortisol, specifically in young children (birth to 8 years) published any time up to 31 December 2019. The literature search identified 44 published studies that met inclusion criteria. The studies examined associations between one or more indicators of social adversity and child hair cortisol across 35 independent cohorts comprising 8370 children. Indicators of adversity examined in the identified literature included socioeconomic factors (e.g. low parental education, low income and unemployment), psychosocial factors (e.g. parent stress, poor mental health and family violence), and children's direct exposure to maltreatment, abuse and stressful events. Across all indicators of adversity, a total of 142 associations with hair cortisol were examined. Evidence of associations was limited and inconsistent; 34/142 (24%) showed evidence of a positive association between adversity and higher hair cortisol, 8/142 (6%) showed a negative association, and more than two thirds (100/142, 70%) of all examined associations were null. The collective evidence appears insufficient to conclude that there is a relationship between social adversity and hair cortisol, as a measure of physiological stress response, in young children.

Cumulative exposure to socioeconomic and psychosocial adversity and hair cortisol concentration: A longitudinal study from 5 months to 17 years of age

BACKGROUND

Exposure to early adversity has been associated with long-lasting risks for poor health and functioning. Prior research suggests that the hypothalamic-pituitary-adrenal (HPA) axis, and its main end-product glucocorticoid hormone cortisol, may be at play. This study tested whether an index of cumulative socioeconomic and psychosocial adversity assessed prospectively, from infancy to adolescence, was associated with hair cortisol concentration (HCC), and if this association differed by sex.

METHODS

The sample comprised 556 adolescents (42.0% males) who provided hair for cortisol measurement at 17 years of age. Adversity indicators (young and single motherhood, low socioeconomic status (SES), maternal alcohol use, hostile-reactive parenting, and depressive symptoms, as well as peer victimization and neighborhood dangerousness) were repeatedly reported by mothers or youths between the ages of 5 months and 15 years.

RESULTS

Chronic adversity was non-linearly associated with HCC; youth exposed to lower and higher levels of adversity had moderate-to-higher HCC compared to lower HCC noted in participants with moderate levels of adversity, for both males and females. None of the indicators taken separately, except the perception of neighborhood dangerousness, were significantly associated with HCC.

CONCLUSION

Our findings support the hypothesis that HPA axis activity varies according to cumulative adversity, albeit non-linearly, which may bear consequences for later health and functioning.

Greater Pain Severity is Associated with Higher Glucocorticoid Levels in Hair Among a Cohort of People Living with HIV

Background

Pain is a common occurrence and persistent symptom, which has an adverse impact on individual well-being and quality of life among people living with HIV (PLHIV). Alteration in the activity of the Hypothalamic-Pituitary-Adrenal (HPA) axis resulting in abnormal glucocorticoid levels had been proposed to play important roles in those associations.

Purpose

This study aimed to investigate whether pain severity was associated with hair glucocorticoid levels, a novel method of measuring long-term glucocorticoid exposure, among a large cohort of Chinese PLHIV.

Methods

A measure of pain severity and hair samples were collected from 431 adults PLHIV in Guangxi, China. Glucocorticoid (cortisol and cortisone) in hair were quantified by liquid chromatography-tandem mass spectrometry. The general linear model was used to test the associations of pain severity with hair glucocorticoid levels after adjusting for potential confounding factors.

Results

Of the 431 PLHIV, 273 reported none pain, 87 reported mild pain, and 71 reported moderate-severe pain. Hair cortisone, but not hair cortisol, was found to differ significantly among the three pain severity groups (F=3.90, p=0.021). PLHIV reported moderate-severe pain had higher hair cortisone than those reported mild (p=0.070) or none pain (p=0.014), with no differences between the latter two pain severity groups.

Conclusion

Greater pain severity is associated with higher hair cortisone levels among Chinese PLHIV. In order to reduce the long-term glucocorticoid levels, interventions managing pain should be considered for PLHIV with moderate-severe pain.

Momentary emotions and salivary cortisol: A systematic review and meta-analysis of ecological momentary assessment studies

An integrated view of the stress response requires consideration of both the emotional and hormonal sequelae of stress, which are regulated by the hypothalamic-pituitary-adrenal (HPA) axis. Understanding the extent of the association between emotions and cortisol at the momentary level can shed light on the biopsychological pathways linking stress to health. Research in this area has adopted heterogeneous approaches and produced mixed findings; thus, it is critical to conduct a systematic review and meta-analysis. Systematic searches in major databases identified 22 studies (negative emotions [k = 19; 38,418 momentary observations]; positive emotions [k = 15; 31,721 momentary observations]). Meta-analysis found a significant positive association between momentary negative emotions and cortisol (r = .06, p < .001) and a significant negative association between momentary positive emotions and cortisol (r = -.05, p = .003). No methodological differences moderated these associations. Our findings suggest that emotional states correlate with cortisol levels at the momentary level. We discuss the health implications of our findings and provide recommendations for advancing this area of research.

Associations of Hair Cortisol Concentrations with General and Organ Fat Measures in Childhood

CONTEXT

Stress may lead to an adverse body fat distribution from childhood onwards.

OBJECTIVE

To examine the associations of hair cortisol concentration (HCC) at 6 years with general and organ fat measures, risk of overweight, and nonalcoholic fatty liver disease (NAFLD) at 10 years and to assess whether these were independent of adiposity measures at 6 years.

DESIGN, SETTING AND PARTICIPANTS

HCCs were measured in hair of 6-year-old children (n = 2042) participating in the Generation R Study, a population-based prospective cohort study.

MAIN OUTCOME MEASURES

Body mass index (BMI), fat mass index measured by dual-energy X-ray absorptiometry scan, and visceral fat index, pericardial fat index, liver fat fraction measured by magnetic resonance imaging and risk of overweight and NAFLD were obtained at 10 years.

RESULTS

The associations of higher HCC at 6 years, with higher BMI, fat mass index, and increased risk of overweight at age 10 years are explained by the relationships observed at 6 years. HCCs at 6 years were associated with a higher liver fat fraction (difference 0.11 liver fat fraction standard deviation score; 95% confidence interval [CI] 0.03, 0.18) and a higher risk of NAFLD at 10 years (odds ratio 1.95; 95% CI 1.06, 3.56), independent of fat mass index at 6 years. HCCs were not associated with pericardial or visceral fat indices.

CONCLUSIONS

Higher HCCs at 6 years were associated with higher BMI, fat mass index, liver fat fraction, and higher risks of overweight and NAFLD at 10 years. Only the associations for liver fat fraction and NAFLD were independent of fat mass index at 6 years.

Cortisol and socioeconomic status in early childhood: A multidimensional assessment

The hypothalamic-pituitary-adrenal (HPA) axis is sensitive to early life stress, with enduring consequences for biological stress vulnerability and health (Gunnar & Talge, 2008). Low socioeconomic status (SES) is associated with dysregulation of the stress hormone cortisol in early childhood. However, a mechanistic understanding of this association is lacking. Multidimensional assessment of both SES and cortisol is needed to characterize the intricate relations between SES and cortisol function in early childhood. We assessed parent-reported family income, parent education, occupational prestige, neighborhood risk, food insecurity, and household chaos for 12-month-old infants (N = 90) and 3.5-year-old children (N = 91). Hair cortisol concentration (HCC) was obtained from parent and child, indexing chronic biological stress, and diurnal salivary cortisol was measured in the children. Controlling for parent HCC, parent education uniquely predicted infant and child HCC and, in addition, neighborhood risk uniquely predicted infant HCC. Household chaos predicted bedtime salivary cortisol concentration (SCC) for both infants and children, and infant daily cortisol output. Food insecurity was associated with flattened cortisol slope in 3.5-year-old children. Parental sensitivity did not mediate relations between SES and cortisol. Results highlight the utility of SES measures that index unpredictable and unsafe contexts, such as neighborhood risk, food insecurity, and household chaos.

Addressing educational inequalities and promoting learning through studies of stress physiology in elementary school students

To be ready to learn, children need to be focused, engaged, and able to bounce back from setbacks. However, many children come to school with heightened or diminished physiological arousal due to exposure to poverty-related risks. While stress physiology plays a role in explaining how adversity relates to processes that support students' cognitive development, there is a lack of studies of physiological stress response in educational settings. This review integrates relevant studies and offers future directions for research on the role of stress physiology in the school adaptation of elementary school students, focusing on these important questions: (a) What are the links between physiological stress response and learning-related skills and behaviors, and do they vary as a function of proximal and distal experiences outside of school? (b) How are school experiences associated with students' physiological stress response and related cognitive and behavioral adaptations? (c) How can we leverage measures of students' physiological stress response in evaluations of school-based interventions to better support the school success of every student? We hope to stimulate a new wave of research that will advance the science of developmental stress physiology, as well as improve the application of these findings in educational policy and practice.

An exploratory study of perinatal hair cortisol concentrations in mother-infant dyads with severe psychiatric disorders versus healthy controls

BACKGROUND

Maternal psychopathology during pregnancy is associated with negative outcomes in offspring. Increased placental transfer of maternal cortisol may contribute to mediate this association. Hair cortisol concentrations (HCCs) appear to be a good biomarker of long-term prenatal stress exposure. Little is known about the associations between severe maternal psychopathology and perinatal infant HCCs.

AIMS

We assessed HCCs in the perinatal period in mother-infant dyads with and without severe psychiatric disorders.

METHOD

We examined group differences in HCCs of mother-infant dyads (n = 18) subjected to severe maternal psychiatric disorders versus healthy control dyads (n = 27). We assessed the correlation of HCCs between mother and infant within both groups, and the association between current maternal symptoms and HCCs in patient dyads.

RESULTS

Median (interquartile range) and distribution of HCC differed in patients compared with control mothers (U = 468.5, P = 0.03). HCCs in infants of patients did not differ from control infants (U = 250.0, P = 0.67). Subsequently, we found that HCCs within healthy control dyads were correlated (n = 27, r 0.55 (0.14), P = 0.003), but were not within patient dyads (n = 18, r 0.082 (0.13), P = 0.746). HCCs in infants of patients showed a positive correlation with maternal symptoms (n = 16, r = 0.63 (0.06), P = 0.008).

CONCLUSIONS

These preliminary findings suggest that infant HCC reflect perinatal stress exposure. In infants, these early differences could influence lifetime hypothalamic-pituitary-adrenal axis functioning, which might be associated with increased susceptibility to later disease.

Longitudinal Trajectories of Hair Cortisol: Hypothalamic-Pituitary-Adrenal Axis Dysfunction in Early Childhood

The objective of this study was to examine if longitudinal trajectories of hair cortisol concentrations (HCC) measured at two or three yearly time points can identify 1-3 year old children at risk for altered hypothalamic-pituitary-adrenal (HPA)-axis function due to early life stress (ELS). HCC was measured (N = 575) in 265 children using a validated enzyme-linked immunosorbent assay. Hair was sampled in Clinic Visits (CV) centered at years 1, 2, and 3 (n = 45); 1 and 2 (n = 98); 1 and 3 (n = 27); 2 and 3 (n = 95). Log-transformed HCC values were partitioned using latent class mixed models (LCMM) to minimize the Bayesian Information Criterion. Multivariable linear mixed effects models for ln-HCC as a function of fixed effects for age in months and random effects for participants (to account for repeated measures) were generated to identify the factors associated with class membership. Children in Class 1 (n = 69; 9% Black) evidenced declining ln-HCC across early childhood, whereas Class 2 members (n = 196; 43% Black) showed mixed trajectories. LCMM with only Class 2 members revealed Class 2A (n = 17, 82% Black) with sustained high ln-HCC and Class 2B (n = 179, 40% Blacks) with mixed ln-HCC profiles. Another LCMM limited to only Class 2B members revealed Class 2B1 (n = 65, 57% Black) with declining ln-HCC values (at higher ranges than Class 1), and Class 2B2 (n = 113, 30% Black) with sustained high ln-HCC values. Class 1 may represent hair cortisol trajectories associated with adaptive HPA-axis profiles, whereas 2A, 2B1, and 2B2 may represent allostatic load with dysregulated profiles of HPA-axis function in response to varying exposures to ELS. Sequential longitudinal hair cortisol measurements revealed the allostatic load associated with ELS and the potential for developing maladaptive or dysregulated HPA-axis function in early childhood.

The social ecology of childhood and early life adversity

An increasing prevalence of early childhood adversity has reached epidemic proportions, creating a public health crisis. Rather than focusing only on adverse childhood experiences (ACEs) as the main lens for understanding early childhood experiences, detailed assessments of a child's social ecology are required to assess "early life adversity." These should also include the role of positive experiences, social relationships, and resilience-promoting factors. Comprehensive assessments of a child's physical and social ecology not only require parent/caregiver surveys and clinical observations, but also include measurements of the child's physiology using biomarkers. We identify cortisol as a stress biomarker and posit that hair cortisol concentrations represent a summative and chronological record of children's exposure to adverse experiences and other contextual stressors. Future research should use a social-ecological approach to investigate the robust interactions among adverse conditions, protective factors, genetic and epigenetic influences, environmental exposures, and social policy, within the context of a child's developmental stages. These contribute to their physical health, psychiatric conditions, cognitive/executive, social, and psychological functions, lifestyle choices, and socioeconomic outcomes. Such studies must inform preventive measures, therapeutic interventions, advocacy efforts, social policy changes, and public awareness campaigns to address early life adversities and their enduring effects on human potential. IMPACT: Current research does not support the practice of using ACEs as the main lens for understanding early childhood experiences. The social ecology of early childhood provides a contextual framework for evaluating the long-term health consequences of early life adversity. Comprehensive assessments reinforced with physiological measures and/or selected biomarkers, such as hair cortisol concentrations to assess early life stress, may provide critical insights into the relationships between early adversity, stress axis regulation, and subsequent health outcomes.