Measuring Stress in Young Children Using Hair Cortisol: The State of the Science

Hair cortisol determinants in 11-year-old children: Environmental, social and individual factors

INTRODUCTION

Children's exposure to chronic stress is associated with several health problems. Measuring hair cortisol concentration is particularly useful for studying chronic stress but much is unknown about hair cortisol determinants in children and adolescents, and previous research has often not considered the simultaneous exposure of multiple variables. This research is focused on investigating the relationship between environmental, social and individual factors with hair cortisol concentration in children.

METHODS

The data used in this study are from the INMA prospective epidemiological cohort study. The assessment of chronic stress was made on the basis of hair samples taken at the age of 11 years in the INMA-Gipuzkoa cohort (n = 346). A metamodel summarizing the hypothesized relationships among environmental, social and individual factors and hair cortisol concentration was constructed based on previous literature. Structural Equation Modelling was performed to examine the relationships among the variables.

RESULTS

In the general model higher behavioural problems were associated with higher cortisol levels and an inverse relationship between environmental noise and cortisol levels was observed, explaining 5 % of the variance in HCC. Once stratified by sex these associations were only hold in boys, while no significant effect of any of the study variables was related with cortisol levels in girls. Importantly, maternal stress was positively related to behavioural difficulties in children. Finally, higher traffic-related air pollution and lower exposure to neighborhood greenness were related to higher environmental noise.

DISCUSSION

This study highlights that simultaneous exposure to different environmental, social and individual characteristics may determine the concentration of hair cortisol. More research is needed and future studies should include this complex view to better understanding of hair cortisol determinants in children.

The effect of stress on the antibody response after vaccination in children aged 0-18 years: A systematic review

Stress has been associated with less effective vaccine responses in adults. This review aims to investigate the evidence for a similar association in children. A systematic review search was conducted in January 2021 in three databases: Medline, Embase and PsycInfo. An updated search of the Medline database was systematically conducted until the most recent update on September 25th, 2023, to ensure the inclusion of the most current research available. Keywords related to stress, vaccines and children were used, and a total of 7263 (+1528) studies were screened by two independent investigators. Six studies met the inclusion criteria for data extraction and analysis. For quality assessment of the studies, the risk of bias in non-randomized studies-of interventions (ROBINS-I) tool was applied. Most of the studies suggest a negative role of stress on vaccine responses. However, the scarcity of studies, lack of confirmatory studies, risk of bias and heterogeneity according to age, type of vaccine, measures of stress and vaccine responses prevent a clear conclusion. Future studies should emphasize the use of as strict study designs as possible, including well-defined stress metrics and thorough examination of both pre- and post-vaccination responses. Systematic review registration: Prospero CRD42021230490.

Examining parental stress and its link to hair cortisol and DHEA levels in kindergartners

BACKGROUND

Parental work-family conflict (WFC) and parental household income have been linked to negative outcomes for children. So far, no study has associated these two stressors with the hair concentration of cortisol (HCC) and dehydroepiandrosterone (DHEA) in kindergarteners as a measurement of their objective stress.

METHODS AND MEASURES

44 children (40.91% female) with a mean age of 5.16 years and their parents participated in this cross-sectional study. Children's cortisol and DHEA measurements reflected the hormones produced over the past two months. Parents filled out questionnaires concerning their WFC and parenting behavior.

RESULTS

Higher maternal WFC and a lower parental net household income were negatively associated with the DHEA and positively with HCC/DHEA ratio of their children. No significant associations were found between HCC and any included variables. Paternal WFC had no impact on the stress hormones and negatively affected parenting behavior of both parents. Levels of stress hormones were not correlated with parenting behavior.

CONCLUSION

The present results indicated a higher stress exposure in children of mothers with a higher WFC and lower net household income. Conceivably, this may have led to an accumulation of allostatic load. Potential influences of demographic variables on the children's hormones are discussed.

Longitudinal effects of maternal depressive and anxious symptomatology on child hair cortisol and cortisone from pregnancy to 5-years: The EDEN mother-child cohort

Exposure to maternal depressive and anxious symptomatology in utero and after birth can affect child outcomes. One proposed mechanism is through changes in child stress hormone levels, however current studies present inconsistent findings, and further research is needed to better understand the impact of maternal mental health on child stress response. This study aims to add to the limited literature by analysing longitudinal data ranging from 24 weeks amenorrhea to 5 years postpartum among 281 mother-child pairs from the French EDEN mother-child birth cohort. Hair cortisol and cortisone data were collected from children at four time points: birth, 1, 3, and 5 years. Mothers reported depressive symptomatology via the Center for Epidemiologic Studies Depression Scale (CES-D) (at 24-weeks amenorrhea, 3-, and 5-year follow-up), and the Edinburgh Postnatal Depression Scale (EPDS) (at 4, 8 and 12 months postpartum). Prenatal anxiety symptomatology was measured via the State Anxiety Inventory (STAI) at 24 weeks amenorrhea. Group-based trajectory modelling indicated a 1-cluster classification of longitudinal child hair cortisol, cortisone and cortisol-to-cortisone ratio, as analyses did not reveal a classification by subgroups representing different child profiles. After inverse probability weighting, small effects showed prenatal depressive symptomatology was significantly associated to higher levels of child hair cortisone at one year. Prenatal anxiety symptomatology was significantly linked to higher levels of child cortisol measured at birth and cortisone at birth and at 1 year. Postpartum depressive symptomatology at 8 months was related to higher levels of cortisone among 3-year-olds. These effects were not moderated by child sex or maternal socio-economic status. Further research is needed to understand why there are associations at some time points and not others to determine any potential buffering factors.

Stress Markers, Executive Functioning, and Resilience Among Early Adolescents With Complex Congenital Heart Disease

Importance

Infants with complex congenital heart disease (cCHD) may experience prolonged and severe stress when undergoing open heart surgery. However, little is known about long-term stress and its role in neurodevelopmental impairments in this population.

Objective

To investigate potential differences between early adolescents aged 10 to 15 years with cCHD and healthy controls in physiological stress markers by hair analysis, executive function (EF) performance, and resilience.

Design, Setting, and Participants

This single-center, population-based case-control study was conducted at the University Children's Hospital Zurich, Switzerland. Patients with different types of cCHD who underwent cardiopulmonary bypass surgery during the first year of life and who did not have a genetic disorder were included in a prospective cohort study between 2004 and 2012. A total of 178 patients were eligible for assessment at ages 10 to 15 years. A control group of healthy term-born individuals was cross-sectionally recruited. Data assessment was between 2019 and 2021. Statistical analysis was performed from January to April 2023.

Exposure

Patients with cCHD who underwent infant open heart surgery.

Main Outcomes and Measures

Physiological stress markers were quantified by summing cortisol and cortisone concentrations measured with liquid chromatography with tandem mass spectrometry in a 3-centimeter hair strand. EFs were assessed with a neuropsychological test battery to produce an age-adjusted EF summary score. Resilience was assessed with a standardized self-report questionnaire.

Results

The study included 100 patients with cCHD and 104 controls between 10 and 15 years of age (mean [SD] age, 13.3 [1.3] years); 110 (53.9%) were male and 94 (46.1%) were female. When adjusting for age, sex, and parental education, patients had significantly higher sums of hair cortisol and cortisone concentrations (β, 0.28 [95% CI, 0.12 to 0.43]; P < .001) and lower EF scores (β, -0.36 [95% CI, -0.49 to -0.23]; P < .001) than controls. There was no group difference in self-reported resilience (β, -0.04 [95% CI, -0.23 to 0.12]; P = .63). A significant interaction effect between stress markers and EFs was found, indicating a stronger negative association in patients than controls (β, -0.65 [95% CI, -1.15 to -0.15]; P = .01). The contrast effects were not significant in patients (β, -0.21 [95% CI, -0.43 to -0.00]; P = .06) and controls (β, 0.09 [95% CI, -0.11 to 0.30]; P = .38).

Conclusions and Relevance

This case-control study provides evidence for altered physiological stress levels in adolescents with cCHD and an association with poorer EF. These results suggest that future studies are needed to better understand the neurobiological mechanisms and timing of alterations in the stress system and its role in neurodevelopment.

A systematic review of hair cortisol in healthy adults measured using immunoassays: Methodological considerations and proposed reference values for research

Hair cortisol concentration (HCC) has shown remarkable promise as a stable, non-invasive measure of systemic cortisol; however, despite methodological advances, the value that would typically be seen in healthy adults has not been established. Therefore, we sought to review the relevant literature to determine a reference value for HCC in healthy (i.e., non-clinical) adults. To this end, we conducted a systematic review of the PubMed, Scopus, and CINAHL databases for studies that measured healthy adult HCC using immunoassay methods, given that these are the most widely accessible analytical tools. To be eligible, studies were required to have been published in English, to have provided relevant descriptive statistics (i.e., means and standard deviations), and to have used a healthy adult human sample. We found 17 studies that met our inclusion criteria; the reports involved 1348 participants with a mean age of about 38 years. Since we identified a large amount of between-study heterogeneity, we completed a random-effect meta-regression analysis and found that test kit vendor was the only significant variable of the model. As a result, when using methodologies from traditional finite mixture distributions to determine reference values for mean and elevated HCC in individual healthy adults, we calculated these estimates for each of the major test kit vendors. Future work will need to determine whether our estimated reference values need to be modified, and these efforts will be greatly assisted by studies that account for potential moderating factors, such as age, sex, and ethnicity.

The Role of Cortisol in Chronic Stress, Neurodegenerative Diseases, and Psychological Disorders

Cortisol, a critical glucocorticoid hormone produced by the adrenal glands, plays a pivotal role in various physiological processes. Its release is finely orchestrated by the suprachiasmatic nucleus, governing the circadian rhythm and activating the intricate hypothalamic-pituitary-adrenal (HPA) axis, a vital neuroendocrine system responsible for stress response and maintaining homeostasis. Disruptions in cortisol regulation due to chronic stress, disease, and aging have profound implications for multiple bodily systems. Animal models have been instrumental in elucidating these complex cortisol dynamics during stress, shedding light on the interplay between physiological, neuroendocrine, and immune factors in the stress response. These models have also revealed the impact of various stressors, including social hierarchies, highlighting the role of social factors in cortisol regulation. Moreover, chronic stress is closely linked to the progression of neurodegenerative diseases, like Alzheimer's and Parkinson's, driven by excessive cortisol production and HPA axis dysregulation, along with neuroinflammation in the central nervous system. The relationship between cortisol dysregulation and major depressive disorder is complex, characterized by HPA axis hyperactivity and chronic inflammation. Lastly, chronic pain is associated with abnormal cortisol patterns that heighten pain sensitivity and susceptibility. Understanding these multifaceted mechanisms and their effects is essential, as they offer insights into potential interventions to mitigate the detrimental consequences of chronic stress and cortisol dysregulation in these conditions.

Biomarkers of Stress and Inflammation in Children

Background: Children are increasingly exposed to stressors that can affect their immune function. Given the possible negative effects of stress and inflammation on health, researchers need to use appropriate biomarkers to measure both the effects of stress and subsequent inflammatory responses. Purpose: The purpose of this paper is to briefly review stress and inflammatory pathways, identify biomarkers used to measure chronic stress and chronic inflammation particularly in children in clinical and community settings, and to discuss methodological considerations when measuring stress and inflammation in children. Discussion: Biomarkers of chronic stress can be classified as central, meaning they are made in the brain, or peripheral, meaning they are made in the peripheral tissues in response to central signals. The peripheral biomarker, cortisol, is most frequently used in the community setting. In addition, indirect measures, such as oxytocin, may complement the assessment of stress. Common biomarkers of chronic inflammation in children are C-reactive protein (CRP), TNF-α, and IL-6. Similarly, indirect biomarkers of chronic inflammation, such as IL-2 and IL-1β, may also be considered. Conclusions: Various types of specimens can be used to measure these biomarkers of stress and inflammation including blood, saliva, urine, sweat, hair, nails, and tears. Each type of specimen has different requirements for collection, storage, and assay. Future research would benefit from standardized biomarker levels across age and development in children and incorporation of other biomarkers.

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.

Salivary Oxytocin and Antioxidative Response to Robotic Touch in Adults with Autism Spectrum Disorder

Individuals with ASD are known to have a tendency to have tactile sensory processing issues that could be associated with their impairment as regards social communication. The alterations in tactile processing in autistic subjects are usually accompanied by hypersensitivity and other unpleasant emotions induced by tactile contact. In our study, we investigated the impact of the velocity and the force of a tactile stroke received impersonally by a custom-built robotic device. A total of 21 adults with ASD and 22 adults from a control group participated in our study. The participants' responses were assessed according to subjective scales, EEG changes, and the dynamics of saliva antioxidants and oxytocin. It was found that the oxytocin level was significantly lower in subjects with ASD but increased after tactile stimulation. However, contrary to expectations, the increase in the oxytocin level in the target group negatively correlated with the subjective pleasantness of tactile stimulation and was probably associated with a stress-induced effect. The basic levels of antioxidants did not differ between the TD and ASD groups; however, these had significantly increased in individuals with ASD by the end of the study. The EEG findings, which revealed enhanced antioxidant levels, contributed to the relief of the cognitive control during the study.

Continuity of psychopathology v. resilience across the transition to adolescence: role of hair cortisol and sensitive caregiving

BACKGROUND

The transition to adolescence implicates heightened vulnerability alongside increased opportunities for resilience. Contexts of early life stress (ELS) exacerbate risk; still, little research addressed biobehavioral mediators of risk and resilience across the adolescent transition following ELS. Utilizing a unique cohort, we tested biosocial moderators of chronicity in adolescents' internalizing disorders v. resilience.

METHOD

Families exposed to chronic war-related trauma, v. controls, were followed. We utilized data from three time-points framing the adolescent transition: late childhood (N = 177, Mage = 9.3 years ± 1.41), early adolescence (N = 111, Mage = 11 0.66 years ± 1.23), and late adolescence (N = 138, Mage = 15.65 years ± 1.31). In late childhood and late adolescence children's internalizing disorders were diagnosed. At early adolescence maternal and child's hair cortisol concentrations (HCC), maternal sensitivity, and mothers' post-traumatic symptoms evaluated.

RESULTS

War-exposed children exhibited more internalizing disorders of chronic trajectory and mothers were less sensitive and more symptomatic. Three pathways elucidated the continuity of psychopathology: (a) maternal sensitivity moderated the risk of chronic psychopathology, (b) maternal post-traumatic symptoms mediated continuity of risk, (c) trauma exposure moderated the association between child internalizing disorders at late childhood and maternal HCC, which linked with child HCC. Child HCC linked with maternal post-traumatic symptoms, which were associated with child disorders in late adolescence.

CONCLUSION

Results demonstrate the complex interplay of maternal and child's biosocial factors as mediators and moderators of risk chronicity across the adolescent transition following trauma. Findings are first to utilize maternal and child's HCC as biomarkers of chronic stress v. resilience during adolescence, a period of neural reorganization and personal growth that shapes the individual's lifetime adaptation.

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.

Household Social Needs, Emotional Functioning, and Stress in Low-Income Latinx Children and their Mothers

Latinx families may be particularly vulnerable to emotional dysfunction, due to higher rates of economic hardship and complex social influences in this population. Little is known about the impact of environmental stressors such as unmet social needs and maternal stress on the emotional health of Latinx children from low-income families. We conducted secondary analyses using survey and biomarker data from 432 Latinx children and mothers collected in a separate study. We used binomial and multinomial logistic regression to test if household social needs, or maternal perceived stress or hair cortisol concentration (HCC), predicted child measures of emotional functioning or child HCC, independent of relevant sociodemographic factors. Approximately 40% of children in the sample had symptoms consistent with emotional dysfunction, and over 37% of households reported five or more social needs. High perceived maternal stress predicted higher odds of child emotional dysfunction (OR = 2.15; 95% CI [1.14, 4.04]; p = 0.01), and high maternal HCC was positively associated with high child HCC (OR = 10.60; 95% CI [4.20, 26.74]; p < 0.01). Most individual household social needs, as well as the level of household social need, were not independently associated with child emotional dysfunction or child HCC. Our findings begin to define a framework for understanding emotional health, stress, and resilience when caring for Latinx children and mothers living with high levels of social need, and the need for integrated mental health and social needs screening and interventions in settings that serve this population.

Hair cortisol reduction and social integration enhancement after a mindfulness-based intervention in children

BACKGROUND

Over recent decades, chronic stress at an early age has become a worrying health problem in children. We seek to evaluate an intervention involving mindfulness-based practices and prosocial activities in 7- to 8-year-old children.

METHODS

Stress levels were determined using hair cortisol concentration (HCC), and social integration was measured by means of a sociogram. The program had previously proven to be effective in decreasing salivary cortisol levels and in favouring social integration in children. A total of 35 children participated in the study: 18 constituted the intervention group and 17 the wait-list group. In both groups, HCC and social integration were evaluated before and after the intervention conducted throughout an entire school year.

RESULTS

The experimental group showed a significant reduction in HCC, as well as significant enhancement of social integration levels, whereas no changes were observed in the wait-list group.

CONCLUSIONS

This is the first research to show that HCC, a reliable neuroendocrine indicator, decreased as a result of a mindfulness-based program. This successful outcome adds new evidence to previous findings regarding the reduction of chronic stress in children following participation in this program.

Pythagorean Self-Awareness Intervention Promoted Healthy Dietary Patterns, Controlled Body Mass Index, and Reduced Self-Reported Stress Levels of Primary School Children: Α One-Arm Pilot Study

Stress is common in childhood and an important factor that affects behavior later in adulthood. The aim of this study was to assess the effects of the Pythagorean Self-Awareness Intervention (PSAI), a holistic "cognitive reconstruction" technique to assess primary school children's stress levels, adherence to the Mediterranean diet, and body mass index. Secondary outcome measures included relations with peers, sleep, and hair cortisol concentrations. This one-arm pilot study took place in a primary school, from February to June 2019. Participants were 32 pupils attending the second grade of primary school who received the 8-week PSAI to adopt healthy behaviors and lifestyle. Self-report measures were applied for the evaluation of various variables at the beginning and the end of the eight-week intervention. There were statistically significant reductions in stress levels (p = 0.00), nightmares' frequency (p = 0.00), body mass index (p = 0.03), and bully scale (p = 0.00), and improvement in Mediterranean diet quality (p = 0.00). Hair cortisol concentrations increased (p = 0.02). The social scale significantly increased. Bedtime remained the same after the intervention. This pilot trial showed that the PSAI promoted healthy dietary patterns, controlled children's body mass index, and reduced their self-reported stress levels. Further research on the implementation of this holistic program on children is suggested, in well-powered randomized controlled trials.

Unmet Social Needs and Patterns of Hair Cortisol Concentration in Mother-Child Dyads

Background

Mothers and their children demonstrate dyadic synchrony of hypothalamic-pituitary-adrenal (HPA) axis function, likely influenced by shared genetic or environmental factors. Although evidence has shown that chronic stress exposure has physiologic consequences for individuals-including on the HPA axis-minimal research has explored how unmet social needs such as food and housing instability may be associated with chronic stress and HPA axis synchrony in mother-child dyads.

Methods

We conducted a secondary analysis of data from 364 mother-child dyads with low-income recruited during a randomized trial conducted in an urban pediatric clinic. We used latent profile analysis (LPA) to identify subgroups based on naturally occurring patterns of within-dyad hair cortisol concentration (HCC). A logistic regression model predicted dyadic HCC profile membership as a function of summative count of survey-reported unmet social needs, controlling for demographic and health covariates.

Results

LPA of HCC data from dyads revealed a 2-profile model as the best fit. Comparisons of log HCC for mothers and children in each profile group resulted in significantly "higher dyadic HCC" versus "lower dyadic HCC" profiles (median log HCC for mothers: 4.64 vs 1.58; children: 5.92 vs 2.79, respectively; P < .001). In the fully adjusted model, each one-unit increase in number of unmet social needs predicted significantly higher odds of membership in the higher dyadic HCC profile when compared to the lower dyadic HCC profile (odds ratio  =  1.13; 95% confidence interval [1.04-1.23]; P  =  .01).

Conclusion

Mother-child dyads experience synchronous patterns of physiologic stress, and an increasing number of unmet social needs is associated with a profile of higher dyadic HCC. Interventions aimed at decreasing family-level unmet social needs or maternal stress are, therefore, likely to affect pediatric stress and related health inequities; efforts to address pediatric stress similarly may affect maternal stress and related health inequities. Future research should explore the measures and methods needed to understand the impact of unmet social needs and stress on family dyads.

Collection of biospecimens from parent-child dyads in a community garden-based nutrition intervention: protocol and feasibility

BACKGROUND

Non-invasive human biospecimens, including stool, urine, and hair, are important in understanding the relationship between diet and changes in human physiologic processes that affect chronic disease outcomes. However, biospecimen collection can be difficult when collecting samples for research studies that occur away from a centralized location. We describe the protocol and feasibility in collecting stool, urine, and hair biospecimens from parents and their children at a remote location as a part of a summer community garden-based intervention.

METHODS

Stool, urine, and hair were collected as a part of the Summer Harvest Adventure (SHA) study, a randomized controlled, community garden-based intervention targeting children (ages 8-11 years) and their parents from low-resource neighborhoods. Biospecimens were collected from willing children and/or their parent/adult caregivers at baseline and post-intervention for evaluation of microbiome, metabolomics, and hair analyses among both intervention and control groups at a location distant from the academic laboratories conducting the analysis. The protocol used to assemble, deliver, collect, and process biospecimens are presented along with the frequencies with which specimens were successfully obtained.

RESULTS

One hundred forty six participants (73 parent-child dyads) were part of the larger SHA study and thus eligible to provide a biospecimen. A total of 126 participants, 115 participants, and 127 participants consented to provide their hair, stool and urine samples, respectively. Of the participants that consented to provide a sample, 44 children (69.8%) and 38 parents (60.3%) provided at least one hair sample, 27 children (48.2%) and 37 parents (62.7%) provided at least one stool sample, and 36 children (57.1%) and 42 parents (65.6%) provided at least one urine sample. Sample collection at the offsite location, transport, and handling at the academic center were successful and all biospecimens were deemed adequate for analyses. DNA and metabolomics yield on a subset of stool samples obtained provided excellent results in terms of an abundance of species and metabolities, as would be predicted. Urine and hair analyses are underway.

CONCLUSION

Our work is one of the first to describe the feasibility of collecting human biospecimens, specifically stool, urine, and hair, from both parents and their children from low-resourced neighborhoods in a non-traditional garden research setting. Future work will report findings related to mechanisms between diet, microbiome, metabolites, and clinical outcomes.

Association of maternal and paternal psychosocial stress and infant hair cortisol among Arab American immigrants: A pilot study

Acculturative stress is unique among immigrants and refers to the stress associated with maintaining cultural values and traditions in the host country. Immigrant parents confront psychosocial variables such as acculturative stress, anxiety, and depression that might result in intergenerational negative consequences on their infants. Measurement of hair cortisol concentration (HCC), an outcome of neuroendocrine dysregulation, is one relatively noninvasive approach to gauge stress in infants. No published studies have evaluated associations among parents' psychosocial variables and infants' HCC among immigrant families. Therefore, the purpose of this study was to: (1) examine the relationship between maternal and paternal psychosocial stress variables; and (2) examine the association between psychosocial variables of both parents (acculturative stress, anxiety, and depression) and infants' HCC among immigrant Arab American families. A sample of 31 immigrant Arab American triads (mother-father-infant) was recruited. During one home visit, each parent completed the study questionnaires separately when the baby was 6-24 months old and a hair sample was collected from the infant for HCC. Parents reported significant symptoms of anxiety (33% mothers; 45% fathers) and depression (33% mothers; 35.5% fathers). Paternal acculturative stress, anxiety, and depressive symptoms were significantly correlated to infants' HCC. Acculturative stress, anxiety, and depressive symptoms were significantly correlated between mother-father dyads. Future research should continue to focus on immigrant families and include both parents to better understand and improve infant health.

The unique relevance of executive functions and self-regulation behaviors for understanding early childhood experiences and preschoolers' outcomes in rural Pakistan

Performance-based measures of children's executive functions (EFs) do not capture children's application of these skills during everyday emotionally-laden and socially-mediated interactions. The current study demonstrates the value of using assessor report of self-regulation behaviors (inhibitory control and positive affect/engagement) in addition to EF tasks when studying early childhood experiences and development in a rural lower-middle-income country setting. In a sample of 1302 disadvantaged 4-year-olds living in rural Pakistan, we found that directly assessed EFs were significantly related to assessor observations of children's inhibitory control and positive affect/engagement during a structured assessment protocol. However, EFs and two types of self-regulation behaviors demonstrated unique associations with children's (1) contextual experiences, as indexed by family socio-economic resources, participation in parenting interventions, and children's physical growth; and (2) age-salient developmental outcomes, as indexed by direct assessment of pre-academic skills and maternal report of prosocial behaviors and behavior problems. First, family wealth uniquely predicted only observed positive affect/engagement, whereas maternal education uniquely predicted only EFs. Second, children's antecedent linear growth was a significant predictor of both EFs and positive affect/engagement, but exposure to an enhanced nutrition intervention during the first 2 years of life and preschoolers' hair cortisol concentration were associated only with observed self-regulation behaviors. Finally, both EFs and observed positive affect/engagement uniquely predicted children's pre-academic skills. In contrast, only assessors' ratings of positive affect/engagement uniquely predicted maternal report of prosocial behaviors and only assessors' ratings of inhibitory control uniquely predicted maternal report of behavioral problems.

Child's perceived stress: A concept analysis

PROBLEM

Child's perceived stress is a term used widely in literature, yet it is poorly defined. Perceived stress in childhood has been linked to negative health outcomes throughout the lifespan. Therefore, the ability of researchers and healthcare providers to conceptualize child's perceived stress and form accurate measures of the concept is of utmost importance.

ELIGIBILITY CRITERIA

Following the eight steps identified by Walker and Avant, a literature review was conducted to identify studies that measured perceived stress in school-age children over the last 10 years.

SAMPLE

Of 914 records identified, 136 were screened, and 16 met inclusion criteria.

RESULTS

Child's perceived stress is best defined as any actual or imagined threat, personal and specific to childhood, which overwhelms the child and leads to changes in emotional, psychological, developmental, and/or physiological domains.

CONCLUSIONS

While the concept of child's perceived stress is understood similarly throughout studies, there is notable variation in the way child's perceived stress is measured. Because of the specificity of perceived stress to childhood, and the wide range of what may be perceived as stressful by the child, the child is the best reporter of child's perceived stress.

IMPLICATIONS

Researchers and clinicians must use child self-report tools to measure the concept of child's perceived stress. Opportunities exist for healthcare workers to intervene, educate, and help children and families recognize and manage child's perceived stress. This concept analysis includes many resources that practitioners may use to help alleviate stress in children.

Early childhood stress responses to psychosocial stressors: The state of the science

The aim of this systematic review was to better understand whether and to what extent psychosocial stressors are associated with hypothalamic-pituitary-adrenal axis or autonomic nervous system stress responses in young children (1-6 years of age). Studies were classified by psychosocial stressors from the ecobiodevelopmental model: social and economic resources, maternal mental health, parent-child relationships, and the physical environment. Of the 2388 identified studies, 32 met full inclusion criteria, including over 9107 children. Child physiologic stress responses were measured as hair and urinary cortisol and cortisone, salivary diurnal and reactive cortisol, salivary reactive alpha-amylase, and respiratory sinus arrhythmia. There were 107 identified relations between psychosocial stressors and physiologic stress responses. Nearly two thirds of these relations suggested that children have dysregulated stress responses as either significantly blunted (n = 27) or increased (n = 37); 43 relations were not significant. Children most consistently had significantly dysregulated stress responses if they experienced postnatal maternal depression or anxiety. Some reasons for the mixed findings may be related to characteristics of the child (i.e., moderators) or stressor, how the stress response or psychosocial stressor was measured, unmeasured variables (e.g., caregiving buffering), researcher degrees of freedom, or publication bias.

Relationships among caregiving, stress, and self-regulation in toddlers living in poverty

PURPOSE

The Developmental Psychobiological Model of Experiential Canalization (DPMEC) proposes that conditions of poverty-related adversity influence child self-regulation through parental caregiving, stress hormones, and the child's genetics. However, empirical findings investigating these relationships with prolonged stress hormones are mixed. Further, the relationships among conditions of adversity with prolonged stress hormones have seldom been investigated in toddlers living in poverty. Guided by the DPMEC, we examined the relationships among maternal caregiving, prolonged stress, and self-regulation in toddlers living in poverty in the United States, to include examining whether toddler prolonged stress mediated relations between maternal caregiving and child self-regulation.

DESIGN AND METHODS

Participants were mothers and toddlers (20 to 24 months of age) living in poverty, who provided hair samples to measure four months of average cortisol concentration to estimate prolonged stress. We used observational measures to examine maternal caregiving and indirect report to measure children's self-regulation.

RESULTS

Findings did not support the role of toddler prolonged stress in mediating the relationship between maternal caregiving and toddler self-regulation. However, multiple linear regression models showed that higher levels of maternal emotionally supportive caregiving significantly predicted better toddler soothability (b = 0.90; p = .03; 95% CI [0.10, 1.69]; partial correlation = 0.26).

CONCLUSIONS

This study adds partial support for the DPMEC to represent associations between maternal caregiving and toddler self-regulation for mothers and toddlers experiencing poverty.

PRACTICE IMPLICATIONS

While these data come from an observational study, pediatric nurses may consider assessing maternal supportive caregiving upon reports of poor toddler soothability.

Definitions, theories, and measurement of stress in children

PROBLEM

Stress in children remains a complex concept to examine due to the inherent subjectivity and lack of specific manifestations, as well as the multiple ways stress can be defined and measured in children. Because stress is multifactorial,is experienced daily by children, and undergirds adolescent health and early mental illness, it is crucial to have a clear understanding of stress and the effects of stress in children from infancy through age twelve years.

ELIGIBILITY CRITERIA

To be included in this review, literature must pertain to and highlight theories, definitions/classifications, and measurements of stress in children from infancy to 12 years of age.

SAMPLE

The most pertinent articles identified through database searches (PubMed, Scopus, PsycINFO, CINAHL, Google Scholar), gray literature sources (e.g., child health websites), and reference lists of identified articles were included in this narrative overview.

RESULTS

The results of this review are organized by themes and include: classifications and definitions of stress, stress-related theories, and tools to measure stress in children.

CONCLUSIONS

Research addressing stressors and stress in children is limited, and there is wide variation in how researchers define and classify stress in children. Existing measures of stress in children younger than 12 address physiological, psychological, and observational components, but may be inconsistent and threaten validity of otherwise well-designed and well-executed studies.

IMPLICATIONS

Improving the understanding and accurate measurement of stress in children enables researchers and clinicians to curtail undesirable health outcomes.

The effect of cumulative early life adversities, and their differential mediation through hair cortisol levels, on childhood growth and cognition: Three-year follow-up of a birth cohort in rural India

Background: Early adversities negatively impact children's growth and development, putatively mediated by chronic physiological stress resulting from these adverse experiences. We aimed to estimate the associations between prospectively measured cumulative early adversities with growth and cognition outcomes in rural Indian preschool children and to explore if hair cortisol concentration (HCC), a measure of chronic physiological stress, mediated the above association. Methods: Participants were recruited from the SPRING cRCT in rural Haryana, India. Adversities experienced through pregnancy and the first year of life were measured in 1304 children at 12-months. HCC was measured at 12-months in 845 of them. Outcome measures were height-for-age-z-score (HAZ), weight-for-age-z-score (WAZ) and cognition, measured in 1124 children followed up at 3-years. Cognition was measured using a validated tablet-based gamified tool named DEEP. Results: Cumulative adversities at 12-months were inversely associated with all outcomes measures at 3-years. Each unit increase in adversity score led to a decrease of 0·08 units [95% confidence interval (CI):-0·11,-0·06] in DEEP-z-score; 0·12 units [-0·14,-0·09] in HAZ and 0·11 units [-0·13,-0·09] in WAZ. 12-month HCC was inversely associated with DEEP-z-score (-0·09 [-0·16,-0·01]) and HAZ (-0·12 [-0·20,-0·04]), but the association with WAZ was not significant (p = 0·142). HCC marginally mediated the association between cumulative adversities and HAZ (proportion mediated = 0·06, p = 0·014). No evidence of mediation was found for the cognition outcome. Conclusions: Cumulative early adversities and HCC measured at 12-months have persistent negative effects on child growth and cognition at 3-years. The association between adversities and these two child outcomes were differentially mediated by HCC, with no evidence of mediation observed for the cognitive outcome. Future studies should focus on other stress biomarkers, and alternate pathways such as the immune, inflammation and cellular ageing pathways, to unpack key mechanisms underlying the established relationship between early adversities and poor child outcomes.

The effect of cumulative early life adversities, and their differential mediation through hair cortisol levels, on childhood growth and cognition: Three-year follow-up of a birth cohort in rural India

Background: Early adversities negatively impact children’s growth and development, putatively mediated by chronic physiological stress resulting from these adverse experiences. We aimed to estimate the associations between prospectively measured cumulative early adversities with growth and cognition outcomes in rural Indian preschool children and to explore if hair cortisol concentration (HCC), a measure of chronic physiological stress, mediated the above association. Methods: Participants were recruited from the SPRING cRCT in rural Haryana, India. Adversities experienced through pregnancy and the first year of life were measured in 1304 children at 12-months. HCC was measured at 12-months in 845 of them. Outcome measures were height-for-age-z-score (HAZ), weight-for-age-z-score (WAZ) and cognition, measured in 1124 children followed up at 3-years. Cognition was measured using a validated tablet-based gamified tool named DEEP. Results: Cumulative adversities at 12-months were inversely associated with all outcomes measures at 3-years. Each unit increase in adversity score led to a decrease of 0·08 units [95% confidence interval (CI):-0·11,-0·06] in DEEP-z-score; 0·12 units [-0·14,-0·09] in HAZ and 0·11 units [-0·13,-0·09] in WAZ. 12-month HCC was inversely associated with DEEP-z-score (-0·09 [-0·16,-0·01]) and HAZ (-0·12 [-0·20,-0·04]), but the association with WAZ was not significant (p = 0·142). HCC marginally mediated the association between cumulative adversities and HAZ (proportion mediated = 0·06, p = 0·014). No evidence of mediation was found for the cognition outcome. Conclusions: Cumulative early adversities and HCC measured at 12-months have persistent negative effects on child growth and cognition at 3-years. The association between adversities and these two child outcomes were differentially mediated by HCC, with no evidence of mediation observed for the cognitive outcome. Future studies should focus on other stress biomarkers, and alternate pathways such as the immune, inflammation and cellular ageing pathways, to unpack key mechanisms underlying the established relationship between early adversities and poor child outcomes.

Impact of hair type, hair sample weight, external hair exposures, and race on cumulative hair cortisol

The biomarker cortisol assesses the impact of biopsychosocial stressors that activate the stress response system. Hair has emerged as a valid and non-invasive means of gauging cumulative cortisol deposited over month-long periods of time. Established protocols for the extraction of hair cortisol are being validated and refined in humans, yet methodological information about hair characteristics on cortisol remains limited. In addition to external hair exposures (e.g. dye, time spent outside), we examined hair categorization or type (e.g. kinky, straight) by extending a hair typing methodology for scientific use that is currently popular among hair care professionals. We then examined the interaction between hair type and race on cortisol levels with a hair questionnaire. Three studies were pooled to investigate how sample weight, hair type, race, heat exposures, and hair treatments impacted cumulative hair cortisol concentrations. Study 1 consisted of Adult Kenyan Medical Workers (N = 44); Study 2 Mexican and Mexican Americans (N = 106); and Study 3 American Youth (N = 107). We found significantly higher cortisol in 5 mg of hair when compared to larger sample weights, and higher cortisol in those who spent more time outdoors. Cortisol concentrations differed between racial groups and varied by hair type; moreover, there were directional differences in cumulative cortisol from straighter to curlier hair types which depended on racial group. In addition to demonstrating the impact of relatively novel control factors like hair sample weight, outdoor exposure, and hair type, the present study illustrates the importance of disentangling hair type and race to understand variability in cumulative hair cortisol. These influences should be included in future studies that measure hair cortisol.

Social Fear in US Infants: The Roles of Hair and Salivary Cortisol

Elevated social fear in infancy poses risk for later social maladjustment and psychopathology. Hair cortisol concentration (HCC), an index of cumulative cortisol exposure, and diurnal salivary cortisol slope, a biomarker of acute stress regulation, have been associated with social fear behaviors in childhood; however, no research has addressed their relations in infancy. Elucidating potential biomarkers of infant social fear behaviors, as well as environmental factors associated with these biomarkers, may grant insights into the ontogeny of fear behaviors that increase risk for internalizing and externalizing psychopathologies later in life. The current study used multiple linear regression to examine if infant HCC, infant diurnal cortisol slope, and income-to-needs ratios (ITN) were differentially associated with observed social fear responses to a Stranger Approach task at 12 months. Using a sample of 90 infants (M _age = 12.26m, SD = 0.81m, 50% female), results indicated that increased infant HCC was associated with increased distress vocalizations during the Stranger Approach task, while steeper diurnal cortisol slope was associated with fewer distress vocalizations. Ordinary least squares path analyses did not reveal group differences between economically strained and non-strained infants in how cortisol measures and social fear responses related. Findings underscore very early psychobiological correlates of fearfulness that may increase risk for fear-related disorders and adverse mental health symptomology across childhood.

Stress, Inflammation and Metabolic Biomarkers Are Associated with Body Composition Measures in Lean, Overweight, and Obese Children and Adolescents

The aim of this study was to examine the associations between multiple indices of stress, inflammation and metabolism vs. body composition parameters in 121 (43 boys, 78 girls) children and adolescents, aged 5–15 y. Subjects were divided into two groups: normal weight (N) (N = 40, BMI z-score = −0.1923 ± 0.6), and overweight/obese (OB) (N = 81, BMI z-score = 2.1947 ± 1.4). All subjects completed the State-Trait Anxiety Inventory for Children (STAIC) and Children’s Depression Inventory, and underwent cortisol measurements in hair, diurnal series of saliva, and morning serum. Circulating concentrations of high sensitivity C-reactive protein (hsCRP) and other inflammation biomarkers were also obtained. Body composition analysis was performed with a clinically validated, advanced bioimpedance apparatus (BIA), while heart rate variability (HRV) was measured as a stress biomarker by photoplethysmography (PPG). The OB group had a higher STAIC-state score, waist-to-hip ratio, skeletal muscle mass, and total and abdominal fat mass, and a lower percent fat-free mass (FFM) and bone density than the N group. HRV did not differ between the groups. In the entire population, percent fat mass correlated strongly with circulating hsCRP (r = 0.397, p = 0.001), ferritin, and other inflammatory biomarkers, as well as with indices of insulin resistance. A strong correlation between serum hsCRP and hair cortisol was also observed (r = 0.777, p < 0.001), suggesting interrelation of chronic stress and inflammation. Thus, body fat accumulation in children and adolescents was associated with an elevation in clinical and laboratory biomarkers of stress, inflammation, and insulin resistance. BIA-ACC and PPG can be utilized as a direct screening tool for assessing overweight- and obesity -related health risks in children and adolescents.

Salivary Cortisol and Sustained Auditory Attention in Children with and without Cleft Lip and Palate

Introduction Cortisol is a hormone involved in the response to stress. Attention is a function that can change due to exposure to stress.

Objectives To verify the correlation between the level of salivary cortisol and sustained auditory attention in children with cleft lip and palate, as well as to compare the results of the variables analyzed between female and male patients.

Methods In total, 103 children aged 6 to 11 years, were divided into 2 groups: those with cleft lip and palate (experimental group, EG; n = 69) and the control group (CG; n = 34). The Sustained Auditory Attention Ability Test (SAAAT) and salivary cortisol levels, measured by an enzyme immunoassay kit (Salimetrics, Stage College, PA, US), were calculated and compared regarding the two groups. The statistical tests used were the Mann-Whitney test and the Spearman correlation.

Results The median level of salivary cortisol was of 0.03615 µl/dL and 0.18000 µl/dL respectively for the EG and CG, with a significant difference between the groups (p = 0.000). Absence of statistical significance (total error score = 0.656; vigilance decrement = 0.051) was observed the for SAAAT among the EG (median total error score = 12.00; 25th percentile [25%] = 7.00; 75th percentile [75%] = 21.00; and vigilance decrement = 1.00; 25% = 0.00; 75% = 2.50) and the CG (median total error score = 12.00; 25% = 6.00; 75% = 24.00; and vigilance decrement = 0.00; 25% = -1.00; 75% = 2.00).

Conclusion All children had median levels of salivary cortisol and scores for sustained auditory attention within normal parameters. A significant correlation between the level of salivary cortisol and the ability to sustain auditory attention was observed in children without cleft lip and palate. There were no differences regarding the SAAAT and salivary cortisol between female and male patients.

Saliva Cortisol in Girls With Functional Abdominal Pain Disorders: A Randomized Controlled Dance and Yoga Intervention

INTRODUCTION

Functional abdominal pain disorders (FAPDs) are common among girls and has been associated with stress. Cortisol is one of the major stress hormones. Dance and yoga have been shown to reduce abdominal pain among girls with FAPDs.

AIM

To investigate the effect of an 8-month intervention with dance and yoga on cortisol levels in saliva among girls with FAPDs.

METHODS

A total of 121 girls aged 9-13 years with irritable bowel syndrome (IBS) or functional abdominal pain were included in the study. Participants were randomized into an intervention group and a control group. The intervention group attended a combined dance and yoga session twice a week for 8 months. Saliva samples were collected during 1 day, in the morning and evening, at baseline, and at 4 and 8 months. Subjective pain and stress were assessed as well.

RESULTS

No significant effects on saliva cortisol levels between groups were observed after completion of the intervention at 8 months. However, evening cortisol and evening/morning quotient were significantly reduced at 4 months in the intervention group compared to the control group (p = 0.01, p = 0.004). There was no association between cortisol quota and pain or stress.

CONCLUSION

Improvements in cortisol levels were seen in the intervention group at 4 months but did not persist until the end of the study. This indicates that dance and yoga could have a stress-reducing effect during the ongoing intervention.

Chemiluminescence analysis of saliva for the assessment of emotional stress in autistic children undergoing a medical examination

Purpose

An electroencephalography (EEG) examination may cause psychological stress in children with autism that can interfere with the examination results. The objective information on the presence or absence of psycho-emotional stress in patients can help interpret electroencephalograms. This paper aimed to demonstrate the potential of noninvasive objective diagnostics of emotional stress in autistic children undergoing an EEG examination based on analysis of saliva.

Design/methodology/approach

This study involved 19 children with autism spectrum disorder (ASD) (ICD-10 F84.0); the mean age was seven years. During EEG examination of the children, behavioral parameters were assessed. The activity of cytochrome P450 reductase (CYPOR) in saliva was measured before and after the EEG procedure using lucigenin-enhanced nicotinamide adenine dinucleotide phosphate-stimulated chemiluminescence assay.

Findings

Significant differences in CYPOR activity were found between the children who were distressed during an EEG examination and the children without behavioral disturbances (Mann–Whitney test, p = 0.002). Thus, the EEG examination resulted in an increase in CYPOR activity in saliva cells, which may prove the stressful effect of this procedure on autistic children.

Originality/value

The chemiluminescent indices reflecting the activity of microsomal CYPOR in cells presenting in saliva correlate with the absence or presence of psychological stress in children; this phenomenon can be explained by an increased metabolism of the stress hormone, cortisol, by the cytochrome P450 microsomal system. Furthermore, the proposed method is completely safe, noninvasive, rapid (recording time is 20 min), inexpensive and promising for an objective assessment of psycho-emotional stress in autistic children undergoing medical examinations.

Longitudinal hair cortisol in low-income young children: A useful biomarker of behavioral symptom change?

Early childhood is a developmental period characterized by significant plasticity, heterogeneity in behaviors and biological functioning. Yet, cumulative cortisol secretion, as measured by hair cortisol, has not been examined longitudinally in relation to change in behavioral problems in young children. The current study examined cross-sectional and longitudinal associations between hair cortisol and changes in behavior problems in a combined sample (N = 88) of two groups of young children from low-income families: 1) A trauma-exposed sample that participated in Child-Parent Psychotherapy (CPP) (n = 43; Mean Age = 4.31, SD = 1.16; 53% Female; 77% Hispanic), and 2) A community sample of children from families experiencing high stress (n = 45; Mean Age = 3.20, SD = 0.29; 67% Female; 58% Hispanic). Cortisol was assayed from hair collected from children at baseline and, on average, one year later. Mothers completed the Child Behavior Checklist at the same time hair samples were collected. Baseline hair cortisol in children was not associated with maternally-reported child behavioral problems at baseline and did not predict change in behavior problems over time. In contrast, increases in cortisol were associated with greater improvement in child behavior problems (b = -2.98, p < 0.05), controlling for group status and relevant covariates. Subgroup analyses showed that cortisol change across one year significantly differed between the two groups (p = 0.043): on average, community children exhibited a decrease, whereas CPP children demonstrated no change. Hair cortisol concentration was similarly related to improvements in mother-reported behavior problems across both CPP and community groups over time. In summary, there were no cross-sectional associations with hair cortisol, whereas increases were associated with improved child well-being. Findings demonstrate an important link between this increasingly common biomarker and child health, but suggest that changes over time may be more informative than cross-sectional associations.

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.

Sociodemographics and chronic stress in mother-toddler dyads living in poverty

Experiencing chronic stress early in life is associated with later health disparities, and poverty may be a significant stressor for both mothers and children. With a sample of primarily Black and White mothers (N = 75) and toddlers (N = 71) living in poverty in the United States, we examined the direct relations between sociodemographic conditions of poverty and chronic physiological stress. Mothers completed questionnaires on sociodemographics, including mother/toddler race, mother's education, father's education, poverty level, economic hardship, marital status, unemployment status, and toddler sex. Physiological chronic stress was measured by assaying the cortisol content of 4 cm samples of hair cut from the posterior vertex of mothers and toddlers (20-24 months of age) to represent 4 months of stress. Mothers' and toddlers' chronic stress was significantly, moderately, and positively associated. Toddlers had a trending relationship of moderately higher chronic stress if they were Black compared to not Black. Mothers had significantly, moderately higher chronic stress if they were Black or had a Black toddler (compared to not Black), not married (compared to married), or were working (compared to not working). The findings suggest that these mothers, simultaneously navigating poverty and parenting a toddler, need resources to reduce chronic stress.

Parental Stress and Scalp Hair Cortisol in Excessively Crying Infants: A Case Control Study

BACKGROUND

Caring for an excessively crying infant (ECI) can be stressful for mothers and fathers and is associated with mental and bonding problems. Hair cortisol offers a unique measure for the biological reaction of the body to stress over time.

METHODS

In this case-control study, scalp hair cortisol concentrations (HCC) were measured using liquid chromatography-tandem mass spectrometry (LC-MS) in 35 mothers and 23 fathers and their ECIs. The control group consisted of 64 mothers and 63 fathers of non-ECIs of similar age. Parental stress, depression, anxiety and bonding were assessed using validated questionnaires.

RESULTS

Mean HCC were significantly lower in mothers and fathers of ECIs (2.3 pg/mg, 95% CI 1.8-2.9 and 1.6 pg/mg, 95% CI 1.3-2.0) than that in control mothers and fathers (3.2 pg/mg, 95% CI 3.0-3.7 and 2.9 pg/mg, 95% CI 2.5-3.5). In the total group of parents and within the parents of ECIs, HCC were not associated with negative feelings. In the control group, HCC showed a positive association with stress and depression (r = 0.207, p = 0.020 and r = 0.221, p = 0.013). In infants, no differences were found in mean HCC between the ECI group and the control group. No associations were found between maternal and infant HCC, paternal and infant HCC and maternal and paternal HCC.

CONCLUSION

Parents of ECIs showed significantly lower HCC than control parents, reflecting a diminished response of the hypothalamic-pituitary-adrenal (HPA) axis. More research is needed to examine whether this decrease in response is pre-existing or caused by excessive infant crying.

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.

Hair Cortisol and Self-Injurious Behavior Among Children With Autism Spectrum Disorder

Elevated salivary cortisol levels have been documented in individuals who engage in self-injurious behavior (SIB), indicating acute physiological stress. Less is known about the chronicity of stress and SIB. We analyzed the relationship between parent ratings of problem behavior and hair cortisol concentrations (an index of chronic adrenocortical activity) in 23 children with autism spectrum disorder (ASD). Parent ratings of problem behavior were not significantly correlated with hair cortisol concentrations. When children were categorized into groups based on the frequency and severity of SIB, participants with the greatest frequency and severity of SIB had higher hair cortisol concentrations compared to children without SIB. Frequent and severe SIB may be associated with altered hypothalamic-pituitary-adrenal (HPA) axis activity in children with ASD.

Media exposure and language for toddlers from low-income homes

In the current study, we examined whether the quantity of toddlers' exposure to media was related to language skills and whether meeting the American Association of Pediatrics (AAP) recommendations of limiting media exposure to one hour or less per day was related to language skills. We examined these associations in a sample of toddlers (N = 157) living in low-income homes. Toddlers were about two years of age (M = 28.44 months, SD = 1.48 months) during the first visit when parents reported on toddlers' exposure to media in the home. Toddlers were about three years of age (M = 33.61 months, SD = 1.06 months) during the second visit when direct measures of toddlers' expressive and receptive language and receptive vocabulary skills were completed. Controls were child gender, race, mothers' education, marital status, work status, and center-based child care. Results indicated that more frequent exposure to media was related to lower expressive language, but not receptive language or receptive vocabulary. The predictor of AAP recommendation was not significantly related to any child language outcomes. These results suggest that media exposure may be related to the displacement of language-enhancing activities during a critical time for toddlers' language development. However, the AAP media recommendation of one hour may not be related to language development.

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.

Sleep and stress in mother-toddler dyads living in low-income homes

Optimal sleeping behaviors are critical for overall development, yet some evidence suggests stress and living in a low-income environment are associated with disruptions of sleeping behaviors early in life. In this study, we investigated the association of toddler sleeping behaviors, particularly difficulties initiating and/or maintaining sleep (DIMS), and maternal and toddler prolonged stress using hair cortisol from dyads living in low-income homes. Hair cortisol was mainly sampled at the posterior vertex of mothers and toddlers (age 20-24 months) and analyzed with immunoassay (n = 94). Toddler DIMS were assessed at 15-19 and 27-31 months of age through mother-rated reports using the Tayside Children's Sleep Questionnaire. We found no associations between toddler DIMS and maternal stress. Additionally, early DIMS did not predict toddler stress. However, while controlling for early DIMS and sociodemographic factors, we found that higher toddler stress predicted greater DIMS in later toddlerhood (b = -2.28, SE = 0.98, p = .02, d_s  = 0.64). These study findings highlight the importance of understanding the role of early life stress on later sleep patterns.

Lifetime stressors, hair cortisol, and executive function: Age-related associations in childhood

Extant research is mixed regarding the relations among lifetime exposure to stressors, adrenocortical activity, and executive function (EF), particularly in children. Aggregate measures of adrenocortical activity like hair cortisol concentration (HCC), timing of stress exposure, and age at assessment may clarify these associations. This cross-sectional study examined the association among parent-reported exposure to stressors, hair cortisol concentration (HCC), and children's EF via a tablet task in a community sample (n = 318, 52.5% female) of children across a wide age range (4-13 years, M = 9.4, SD = 2.3). Path analyses revealed that parent-reported child lifetime exposure to stressors, but not past-year stressful life events, negatively predicted HCC. There was also a marginally significant moderation by age such that HCC was associated negatively with EF for younger children (age < 9.7 years) but not older children. HCC did not significantly mediate the association between lifetime exposure to stressors and EF. Findings are consistent with the proposition that chronically high cortisol production has a neurotoxic effect on brain regions supporting EF. However, lifetime exposure to stressors predicted relatively lower cumulative cortisol production, consistent with a stress inoculation effect in this normative-risk sample.

A Timosaponin B-II containing scalp care solution for improvement of scalp hydration, dandruff reduction, and hair loss prevention: A comparative study on healthy volunteers before and after application

BACKGROUND

The plant species Anemarrhena asphodeloides has commonly been used for health and therapeutic purposes. Timosaponin B-II, which is present at a high concentration in A asphodeloides, was found to enhance the immune and anti-inflammatory responses of human bodies.

AIMS

To evaluate benefits of a timosaponin B-II containing scalp care solution on hair loss prevention and scalp healthiness in multiple physiological and biological profiles.

METHODS

Prior the study, 90 subjects applied scalp care solution base without timosaponin B-II for two weeks followed by application of the scalp care solution containing 0.5% timosaponin B-II for 28 days. The subject's hair follicle hydrocortisone level, hair fall number, hair luster level, dandruff level, sensation score, hydration level, lipid level, redness as well as the pH level of scalps were quantitatively assessed every 7 days.

RESULTS

Multiple parameters on hair and scalp conditions were promoted by application of the timosaponin B-II containing scalp care solution. Compared to baseline values, significant improvements in hair luster, scalp hydration, hair fall number, and scalp redness level could be observed.

CONCLUSION

Timosaponin B-II promotes multiple physiological factors on hair and scalps. The scalp care solution containing A asphodeloides extracts may benefit the scalp healthiness and hair loss prevention.

Hair cortisol moderates the association between obstetric complications and child wellbeing

Obstetric complications (OC) may have implications for later health outcomes. However, there is a lack of research examining the association between OC and behavior problems or quality of life (HRQoL). We aimed to close this gap and further investigate functioning of the hypothalamus-pituitary-adrenal (HPA)-axis as a potential physiological vulnerability moderating the association between OC and behavior problems and HRQoL. We investigated 232 mothers and their five to 12-year-old children. Presence of OC during the pre-, peri-, and postnatal phases was determined by interviewing mothers. Children's behavior problems (CBCL, TRF) and HRQoL (Kidscreen rated by mothers and children) were assessed. Children gave 3 cm strands of hair for analysis of hair cortisol (HC). Structural equation modeling analyses with a latent variable of child outcome ("distress"), OC as predictor and HC as a potential moderator were conducted. OC significantly predicted distress (β = .33, p < .01). The model showed a good fit to the data: χ2(14)=15.66, p < .33, CFI=.99, TLI=.99, RMSEA=.02, 90 %CI [.00, .06], SRMR=.04. In addition, HC moderated the association between OC and distress (β=-.32, p < .01). The moderation model also showed a good fit: χ2(14) =7.13, p = .93, CFI=1.00, TLI=1.06, RMSEA=.00, 90 %CI [.00, .02], SRMR=.03. Results indicated that the association between OC and distress was significant only when children had low HC-levels. This was also the case for both externalizing and internalizing behavior problems. Our results underline the notion of OC as a risk factor for child behavior problems and wellbeing and point to an important role of the children's physiological set-up such as HPA-functioning.

Association of maternal depression and home adversities with infant hypothalamic-pituitary-adrenal (HPA) axis biomarkers in rural Pakistan

BACKGROUND

Each year, almost 35% of children are exposed to maternal depression and more grow up in persistent poverty, increasing the risk for stress-related disease and other socio-developmental deficits later in life. These impacts are likely related to chronic stress via the hypothalamic-pituitary-adrenal (HPA) axis. However, there is little evidence relating early windows of child HPA axis activity to multiple exposures.

METHODS

We investigated chronic measures of hair-derived HPA axis hormones (cortisol and dehydroepiandrosterone (DHEA)) in 104 one-year old infants from rural Pakistan and longitudinal measures of maternal depression, intimate partner violence (IPV), socio-economic status (SES), and the home environment.

RESULTS

Estimates from adjusted linear mixed effects models did not reveal consistent significant associations between infant cortisol and maternal depression or home adversities. By contrast, infants exposed to maternal depression during pregnancy had lower DHEA levels (ß= -0.18 95% confidence interval [CI]: -0.34, -0.02) as did those whose mothers experienced multiple types of IPV (ß=-4.14 95% CI: -7.42, -0.79) within one year postpartum. Higher SES had a significant positive association with infant DHEA levels (ß= 0.77 95% CI: 0.08, 1.47). Depression severity and chronicity at one year postpartum had near significant associations with infant DHEA. Measures of home environment had no observable impacts on infant HPA axis activity.

LIMITATIONS

Limitations include the modest sample size and aggregation of hair samples for analysis.

CONCLUSION

Results point to possible early HPA axis dysregulation driven by changes in DHEA activity, but not cortisol at one year of age. Findings contribute to growing research examining intergenerational transmissions of maternal depression, IPV, and household environment on infant stress-response systems.

Association of screen time with long-term stress and temperament in preschoolers: results from the DAGIS study

Screen time is increasing rapidly in young children. The aim of this study was to examine associations of long-term stress and temperament with screen time in Finnish preschool children and the moderating role of socioeconomic status. Cross-sectional DAGIS data were utilized. Long-term stress was assessed using hair cortisol concentration, indicating values of the past 2 months. Temperament was reported by the parents using the Children's Behavior Questionnaire (the Very Short Form), and three broad temperament dimensions were constructed: surgency, negative affectivity, and effortful control. Screen time was reported by the parents over 7 days. The highest education level in the household was used as an indicator of socioeconomic status. In total, 779 children (mean age, 4.7 ± 0.9 years, 52% boys) were included in the study. Of the temperament dimensions, a higher effortful control was associated with less screen time (B = - 6.70, p = 0.002). There was no evidence for an association between hair cortisol concentration and screen time nor a moderating role of socioeconomic status in the associations (p > 0.05).Conclusion: Our findings indicate that preschool children with a higher score in effortful control had less screen time. Because effortful control reflects general self-regulatory abilities, promoting these skills may be effective in reducing screen time in young children. What is Known: • Screen time has increased rapidly during the last decades, and higher screen time has been linked with numerous adverse health consequences in children. • There are no previous studies investigating associations of long-term stress and temperament with screen time in young children. What is New: • Of the temperament dimensions, effortful control was associated with higher screen time in preschool children, but there was no association found between long-term stress and screen time. • Since effortful control reflects general self-regulatory abilities, promoting these skills may be effective in reducing screen time in young children.

Hair sampling for cortisol analysis with mother-toddler dyads living in low-income homes

BACKGROUND

A first step to advance stress science research in young children is understanding the relationship between chronic stress in a mother and chronic stress in her child. One non-invasive measure of chronic stress is hair cortisol. However, little is known about strategies for hair sampling in mother-toddler dyads living in low-income homes in the U.S. To address prior limitations, the purpose of this study was to understand the feasibility of sampling hair for cortisol analysis in mother-toddler dyads living in low-income homes in the U.S. We examined feasibility related to participation, eligibility, and gathering an adequate hair sample weight.

METHODS

We approached 142 low-income, racially diverse, urban-dwelling mothers who were participating in an ongoing longitudinal birth cohort study for informed consent to cut approximately 150 hairs from the posterior vertex of their scalp and their toddlers' (20-24 months) scalp. We demonstrated the process of sampling hair with a hairstyling doll during home visits to the mother and toddler using rounded-end thinning shears.

RESULTS

Overall, 94 of 142 mother-toddler dyads (66 %) participated in hair sampling. The most common reason for participation refusal was related to hairstyle. All but three hair samples were of adequate weight for cortisol extraction.

DISCUSSION

The findings from this study can help researchers address sampling feasibility concerns in hair for cortisol analysis research in mother-toddler dyads living in low-income homes in the U.S.

Do stressed children have a lot on their plates? A cross-sectional study of long-term stress and diet among Finnish preschoolers

We examined the association between hair cortisol concentration (HCC) - an indicator of long-term stress - and diet among preschoolers in a cross-sectional design. The participants were 597 Finnish 3-6-year-olds, and the data were collected in 2015-16. We used 4-cm hair samples to analyze HCC during the past four months. Food consumption was assessed using a food frequency questionnaire, and we used consumption frequencies of selected food groups as well as data-driven dietary pattern scores in the analyses. The parents of the participating children reported their educational level and family income. The researchers measured the children's weight and height. We examined the associations between HCC and diet using multilevel linear mixed models adjusted for age, gender, the highest education in the family, household relative income, and child BMI. Higher HCCs were associated with less frequent consumption of fruit and berries (B estimate -1.17, 95% CI -2.29, -0.05) and lower scores in a health-conscious dietary pattern (B estimate -0.38, 95% CI -0.61, -0,14). Higher HCCs were also associated with more frequent consumption of sugary beverages (B estimate 1.30, 95% CI 0.06, 2.54) in a model adjusted for age, gender and highest education in the family, but the association attenuated after further adjustments. Our results are parallel with previous studies that show a link between stress and unhealthy diet. In the future, longitudinal studies are needed to establish a causal relationship between stress and diet among children.