Individual differences in preschoolers' salivary cortisol and alpha-amylase reactivity: relations to temperament and maladjustment

Patterns of stress-related change in salivary alpha-amylase and cortisol among young children: Associations with maternal psychosocial risk factors

Our understanding of associations between family-level risk factors and children's stress physiology is largely derived from studies that apply "mean-based" rather than "person-level" approaches. In this study, we employed group-based trajectory modeling, a person-centered approach, to identify children with similar patterns of stress-related sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA) axis activation, and explored associations between these patterns and maternal psychosocial risk. Participants were five-year-old children (N=147; 52 % female; 62 % Black/African American) and their mothers. Children's saliva was sampled four times during a series of emotional stressor tasks and later assayed for sAA and cortisol, indexing SNS and HPA activity, respectively. Mothers reported their depressive and anxiety symptoms, parenting stress, financial stress, and income. Results revealed two task-related patterns of change for sAA (Low-Stable vs. High-Increasing) and cortisol (Low-Stable vs. High-Decreasing) concentrations. Children from families with lower income were more likely to exhibit the High-Increasing SNS pattern, [OR=0.78, 95 % CI (0.64, 0.95)], and children of mothers reporting more anxiety symptoms [OR=1.06, 95 % CI (1.00, 1.12)] and more parenting stress [OR=1.04, 95 % CI (1.00, 1.07)] were more likely to show the High-Decreasing HPA pattern. Implications of this person-centered approach and findings for advancing our understanding of associations between family-level risk factors and children's stress physiology are discussed.

The association between cortisol-AA coordination in response to stress, negative urgency, and antisocial behavior in an urban adult sample

Prior study has found that the interplay of the hypothalamic-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS) influences behavior problems in youth. Yet, little is known regarding this relationship in adults and traits related to the coordination of the stress systems. This study aims to extend the findings of a youth sample that the coordination between HPA and ANS, measured as cortisol and alpha-amylase (AA) respectively, was associated with antisocial behavior in adults. Additionally, this study tests whether cortisol-AA coordination was associated with a conceptually relevant trait, negative urgency. A heterogeneous sample of 124 adults (college students, active offenders, and demographically matched controls) was recruited from a southern city. Participants filled out instruments for negative urgency and antisocial behavior, completed a modified Trier Social Stress Test (mTSST), and provided four saliva samples before and after mTSST to assay for cortisol and AA. Results showed that cortisol-AA stress coordination was stronger among offenders than other groups. Cortisol-AA stress coordination was also positively associated with antisocial behavior and with negative urgency. This study found support for the interpretation that cortisol-AA stress coordination may indicate an overshooting ANS response at high emotional distress, and highlight the importance of the multisystem approach in gaining new insights into behavior research.

Associations between hair and salivary cortisol, salivary alpha-amylase, and temperament dimensions among 3-6-year-olds

Associations between hair cortisol concentration (HCC), diurnal salivary cortisol (sCort) and alpha-amylase (sAA), and temperament dimensions were examined among 3-6-year-old Finnish children (n = 833). Children's hair samples were collected at preschool, while parents collected five saliva samples from children during one weekend day and completed a questionnaire assessing child's temperament dimensions i.e. surgency, negative affectivity, and effortful control (HCC, n = 677; AUCg of sAA, n = 380; AUCg of sCort, n = 302; temperament dimensions, n = 751). In linear regression analysis, diurnal sCort associated positively with HCC, the association persisting after adjustments (β 0.31, 95% CI 0.20-0.42). In logistic regression analysis, increasing scores in effortful control associated with higher likelihood of having high HCC (OR 1.47, 95% CI 1.07-2.03), the association slightly attenuating to non-significant after adjustments. Otherwise, no clear indication for associations between temperament and stress-related biomarkers were found.

Towards an understanding of neurophysiological self-regulation in early childhood: A heuristic and a new approach

Self-regulation in early childhood encompasses both "top down," volitional processes, as well as the "bottom up" activity of three neurophysiological systems: the parasympathetic nervous system (PNS), the sympathetic nervous system (SNS), and the hypothalamic-pituitary-adrenal (HPA) axis. In this paper we briefly review the structure, function, and early development of each of these systems and then explain why neurophysiological self-regulation is most accurately defined as a function of their joint activity. We note that while there are a number of predictive models that employ this definition, the field would benefit from a straightforward heuristic and aligned methods of visualization and analysis. We then present one such heuristic, which we call neurophysiological space, and outline how it may facilitate a new, collaborative approach to building a better understanding of self-regulation in early childhood. We conclude with a presentation of early education as one setting in which our heuristic and methods could be applied.

The within-person coordination of HPA and ANS activity in stress response: Relation with behavior problems

This study tests the within-person coordination of HPA and ANS activity in response to stress and examines for the first time the association between such coordination and behavior problems in minority urban children. Participants, ages 11-12 (N = 419; 50 % male; 80 % African American) completed the Youth Self Report for externalizing and internalizing problems and a modified Trier Social Stress Task (mTSST). They also provided saliva samples for cortisol and alpha-amylase (AA) prior to and 5, 20 and 40 min post-mTSST. Analyses revealed a positive cortisol-sAA coordination, with a 1% increase in cortisol corresponding to a 0.20 % average increase in sAA in response to stress. Higher degrees of within-person cortisol-sAA coordination predicted more behavior problems. The cortisol-sAA coordination explained 28 % and 10 % of the variance in externalizing and internalizing problems, much larger than when stress dynamics of single systems or the interaction of cortisol (AUCi) and sAA (AUCi) were predictors. Findings highlight the importance of multisystem interplay in stress responding in understanding behavior problems. Individuals with more behavior problems may have difficulty turning off their "fight or flight" ANS response, with this system remaining active to the stimulating influence of cortisol even when cortisol's stimulating effects should have dissipated.

Long-Term Associations Between Prenatal Maternal Cortisol and Child Neuroendocrine-Immune Regulation

BACKGROUND

Advancing understanding of the developmental origins of neuroendocrine-immune (NEI) functioning is key to elucidating the biological mechanisms involved in health and disease risk across the lifespan. This study examined whether prenatal maternal hypothalamic-pituitary-adrenal (HPA) activity moderates child NEI relations and explored the consistency of this moderating effect across gestation.

METHODS

Pregnant women participated in five prenatal study visits from 24 to 38 weeks gestation. At each visit, women provided a saliva sample. In a 5-year follow-up study, children (n_female = 25, n_male=20) provided four saliva samples and participated in behavioral assessments and challenge tasks. Prenatal maternal saliva samples were assayed for cortisol. Child saliva samples were assayed for cortisol and cytokines (IL-1β, IL-6, IL-8, TNFα) as indices of HPA and inflammatory activity. Multilevel mixed-effects models examined the moderation of child NEI relations by prenatal maternal cortisol.

RESULTS

Among males, average prenatal maternal cortisol did not moderate child NEI relations. Among females, average prenatal maternal cortisol moderated some child NEI relations with higher prenatal cortisol associated with more positive cortisol-cytokine relations at age five. When examined by gestational time point, there were more significant NEI moderation effects by maternal cortisol from later gestation (≥ 30 weeks) than earlier.

CONCLUSIONS

The findings suggest prenatal maternal HPA activity may moderate child NEI functioning. Additional research conducted with more heterogeneous and larger samples is needed to fully understand these relations. Furthering our knowledge of NEI development has important research and clinical implications, particularly for understanding and addressing conditions with inflammatory pathophysiologies, such as depression and cardiovascular disease.

Neuroendocrine coordination and youth behavior problems: A review of studies assessing sympathetic nervous system and hypothalamic-pituitary adrenal axis activity using salivary alpha amylase and salivary cortisol

Externalizing and internalizing behavior problems can have deleterious psychosocial consequences for youth. Both sympathetic nervous system (SNS) and hypothalamic-pituitary adrenal (HPA) axis activity and reactivity may contribute to behavior problems but have largely been studied separately, with inconsistent findings. Because the SNS and HPA axis interact to carry out physiological processes (e.g., responding to stressors), considering SNS and HPA axis activity jointly may elucidate disparate findings. This review discusses studies that simultaneously assessed SNS and HPA axis (re)activity and youth behavior problems using measures of salivary alpha amylase (sAA) and salivary cortisol. Multiple patterns of SNS and HPA axis coordination were associated with problem behaviors, especially when considering individual differences and youth's psychosocial context. Importantly, many study findings may be artifacts of widespread methodological differences. The reviewed studies lay the foundation for future research on neuroendocrine coordination as a contributing factor to youth problem behaviors and some recommendations for future research are discussed.

Language Proficiency, Parenting Styles, and Socioemotional Adjustment of Young Dual Language Learners

Dual language learners (DLLs) make up 32% of all children in the U.S. Past research showed that proficiency in a heritage language (HL) was associated with better psychological adjustment in school-aged children and adolescents, but the associations of HL and English (EL) proficiency to preschool-aged DLLs' socioemotional adjustment remain understudied. This study included a sample of low-income Mexican and Chinese immigrant families with preschool-aged DLLs (N = 90). Children's HL and EL proficiencies were assessed using language tests. Parents rated their own cultural orientations, parenting styles, and children's socioemotional adjustment. Children's expressed anger/frustration and sadness were observed from an emotion-evoking task. Path analyses were conducted to test: 1) the unique relations of children's HL and EL proficiency and parents' American and heritage cultural orientations to parenting styles, and 2) the relations of parenting styles to children's adjustment. Results showed that children's expressive HL proficiency and parents' American and heritage cultural orientations were positively associated with authoritative parenting, which in turn, was associated with children's lower externalizing problems and higher prosocial behaviors. Children's expressive EL was negatively associated with parents' use of authoritarian parenting, and both expressive and receptive HL were negatively associated with children's expressed sadness. These results indicate that children's HL development and parents' host and heritage cultural orientations are associated with socioemotional benefits for young DLLs growing up in low-income immigrant families.

Associations between oxytocin and cortisol reactivity and recovery in response to psychological stress and sexual arousal

Previous research suggests a dynamic regulatory relationship between oxytocin and cortisol, but the specific nature of this relationship and its context-specificity have not been fully specified. In the present study, we repeatedly assessed both salivary oxytocin and salivary cortisol during two experimental sessions (one inducing sexual arousal and one inducing psychological stress), conducted two weeks apart with the same group of 63 female participants. Baseline cortisol and baseline oxytocin were significantly correlated in both sessions. Cortisol levels showed significantly different patterns of change during the stress assessment than during the sexual arousal assessment, but oxytocin showed similar patterns of change across both assessments. Greater cortisol stress reactivity predicted higher oxytocin levels immediately after the stressor, but a different pattern emerged during the arousal assessment: Greater oxytocin arousal reactivity predicted attenuated post-arousal reductions in cortisol. For both cortisol and oxytocin, individual differences in women's reactivity to sexual arousal did not predict their reactivity to psychological stress. These findings contribute new insights regarding associations between cortisol and oxytocin reactivity and recovery in different psychological contexts.

Febrile seizures and increased stress sensitivity in children: How it relates to seizure characteristics

BACKGROUND

Studies suggest that the relationship between seizures and stress starts early in life. However, evidence of long-term altered stress reactivity following early-life seizures is lacking. Our objectives were to assess alterations in stress hormone reactivity in children with past febrile seizures (FS) and investigate how these alterations relate to clinical characteristics.

METHOD

This case-control study compared a convenience sample of children with simple FS (n = 24), complex FS (n = 18), and matched healthy controls (n = 42). Stress was induced by electrode placement for an electroencephalography (EEG) exam. Salivary cortisol to stress, using three samples collected before and after the stressor, was compared between groups and sex. The relationship between stress reactivity and clinical characteristics (i.e., FS duration, age at first FS, time since the last FS) was investigated.

RESULTS

Cortisol reactivity to stress was significantly different depending on study groups, F(1, 78) = 6.415, p = 0.003, η²_p = 0.141, but not sex nor was there a significant interaction between group and sex (p ≥ 0.581). Participants with simple FS showed higher cortisol reactivity to stress (M = 14.936, Standard deviation (SD) = 26.852) compared with those with complex FS (M = -4.663, SD = 18.649, p = 0.015) and controls (M = -3.817, SD = 18.907, p = 0.003). There was no significant difference between participants with complex FS and controls (p > 0.999). Stress reactivity was not linked to clinical characteristics.

CONCLUSIONS

Children with past simple FS showed greater changes in salivary cortisol following stress, suggesting enhanced stress sensitivity. As similar results were not found in a population with complex FS, our study shows that stress alterations are not caused by seizure severity. Future studies are needed to investigate whether stress sensitivity may be premorbid to simple FS and may contribute to simple FS incidence.

Effects of sex and menstrual cycle phase on cardiac response and alpha- amylase levels in psychosocial stress

The impact of sex and the menstrual cycle phase on the autonomic response to psychosocial stress remains controversial. This study explored autonomic nervous system activity through salivary alpha-amylase, heart rate, and heart rate variability responses to the Trier Social Stress Test (TSST) in healthy young people. The sample was composed of 25 men, 26 women in the luteal phase, and 25 women in the follicular phase, from 18 to 25 years of age. Participants were exposed to the TSST or a control condition. The results indicate that women in their follicular phase showed a blunted alpha-amylase response to stress compared to men and women in the luteal phase. In addition, men showed higher sympatho-vagal activity in the stress condition compared to the two groups of women. These results confirm that sex and the menstrual cycle phase are potential modulators of autonomic nervous system reactivity to psychosocial stress.

Children's stress regulation mediates the association between prenatal maternal mood and child executive functions for boys, but not girls

Prenatal exposure to maternal mood disturbances shapes children's cognitive development reflected in the critical construct of executive functions (EFs). Little is known, however, about underlying mechanisms. By examining cortisol responses in both everyday and lab challenge settings, we tested whether the child/offspring hypothalamic-pituitary-adrenal axis mediates effects of prenatal maternal mood on child EFs at age 6. In 107 Canadian children born to women with a wide range of anxious and depressive symptoms during pregnancy, we found that in boys but not girls, depressed and/or anxious prenatal maternal mood is associated with heightened diurnal cortisol levels in everyday settings, as well as heightened cortisol reactivity to a lab challenge and that this heightened reactivity was associated with poorer EFs. Among boys we also observed that cortisol reactivity but not diurnal cortisol mediated the association between depressed and/or anxious prenatal maternal mood and EFs. Depressed and/or anxious prenatal maternal mood was related to child EFs for both girls and boys. To our knowledge, this is the first study to demonstrate a mediating role for child stress regulation in the association between prenatal maternal stress-related mood disturbances and child EFs, providing evidence of a mechanism contributing to fetal programming of cognition.

Age-Adapted Stress Task in Preschoolers Does not Lead to Uniform Stress Responses

Acute stress response measures serve as an indicator of physiological functioning, but have previously led to contradictory results in young children due to age-related cortisol hypo-responsivity and methodological inconsistencies in assessment. The aim of this study was to investigate stress responses during a validated age-adapted socio-evaluative stress task in children aged 2-6 years in a child care environment and to detect socio-demographic, task- and child-related characteristics of stress responses. Stress responses were assessed in 323 children for salivary cortisol and salivary alpha amylase (sAA), and in 328 children for changes in heart rate variability (HRV). These data were then associated with socio-demographic (e.g. SES), task-related (e.g. task length) and child-related characteristics (e.g. self-regulation) of stress responses using multilevel models. Analyses revealed elevated sympathetic reactivity (sAA: Coeff=0.053, p=0.004) and reduced HRV (Coeff=-0.465, p<0.001), but no hypothalamic-pituitary-adrenal (HPA) response (Coeff=0.017, p=0.08) during the stress task. Child's age (Coeff=-5.82, p<0.001) and movement during the task (Coeff=-0.17, p=0.015) were associated with acute cortisol release, while diurnal sAA was associated with acute sAA release (Coeff=0.24, p<0.001). Age (Coeff=-0.15, p=0.006) and duration of the task (Coeff=0.13, p=0.015) were further associated with change of HRV under acute stress condition. Children showed inconsistent stress responses which contradicts the assumption of a parallel activation of both stress systems in a valid stress task for young children and might be explained by a pre-arousal to the task of young children in a child care setting. Further results confirm that child- and task-related conditions need to be considered when assessing stress responses in these young children.

Annual Research Review: Early adversity, the hypothalamic-pituitary-adrenocortical axis, and child psychopathology

BACKGROUND

Research on early adversity, stress biology, and child development has grown exponentially in recent years.

FINDINGS

We review the current evidence for the hypothalamic-pituitary-adrenocortical (HPA) axis as a stress-mediating mechanism between various forms of childhood adversity and psychopathology. We begin with a review of the neurobiology of the axis and evidence for relations between early adversity-HPA axis activity and HPA axis activity-psychopathology, as well as discuss the role of regulatory mechanisms and sensitive periods in development.

CONCLUSIONS

We call attention to critical gaps in the literature to highlight next steps in this research including focus on developmental timing, sex differences, stress buffering, and epigenetic regulation. A better understanding of individual differences in the adversity-HPA axis-psychopathology associations will require continued work addressing how multiple biological and behavioral systems work in concert to shape development.

Income, Family Context, and Self-Regulation in 5-Year-Old Children

OBJECTIVE

Self-regulation (SR) is a core aspect of child development with enduring effects on health and wellbeing across the lifespan. Early childhood poverty may shape SR development. This study examined the cross-sectional relationship among family income, family context, and SR in 5-year-old children.

METHODS

A total of 140 five-year-old children and their mothers participated in the study. Children completed a battery of SR tasks; mothers completed questionnaires. Cognitive and emotional SR composite scores were generated based on a principal component analysis of the SR tasks. The SR scores were first regressed on family income (in 10 levels ranging from <5000 to 150,000+) adjusting for age, sex, and race of the child; family context variables were subsequently added to the models.

RESULTS

Controlling for age, sex, and race, each level increase in family income was associated with 0.04 SD increase in emotional SR (p = .32) and 0.08 SD increase in cognitive SR (p = .01). In fully adjusted models, exposure to household instability and experiencing 10 or more negative life events was associated with worse emotional SR; exposure to mother's depressive symptoms was associated with worse cognitive SR. Higher income buffered children's SR from some contextual risk factors. Family contextual variables explained 62% of the correlation between higher income and better cognitive SR scores.

CONCLUSION

Income-based cognitive SR disparities were associated with family contextual factors. Screening for family adversity in pediatric care and linking families to needed resources may protect children's developing SR capacities, with benefits to health and well-being.

Child temperament and teacher relationship interactively predict cortisol expression: The prism of classroom climate

Entry into kindergarten is a developmental milestone that children may differentially experience as stressful, with implications for variability in neurobiological functioning. Guided by the goodness-of-fit framework, this study tested the hypothesis that kindergarten children's (N = 338) daily cortisol would be affected by the "match" or "mismatch" between children's temperament and qualities of the classroom relational context. The robustness of these associations was also explored among a separate sample of children in third grade (N = 165). Results among kindergarten children showed negative affectivity and overcontrolled temperament were positively related to cortisol expression within classrooms characterized by lower levels of teacher motivational support, but there was no relation between temperament and cortisol when motivational support was higher. Among third-grade children, negative affectivity was marginally positively related to cortisol at lower levels of teacher-child closeness and unrelated at higher levels of teacher-child closeness. Findings suggest children's cortisol expression depends on the extent to which specific temperamental characteristics "fit" within the relational and contextual qualities of the classroom environment, particularly as children navigate the new roles and relationships that emerge during the transition to formal schooling. Developmentally informed neurobiological research in classrooms may contribute to tailored programmatic efforts to support children's school adjustment.

Is HPA axis reactivity in childhood gender-specific? A systematic review

BACKGROUND

In adults, hypothalamus-pituitary-adrenal (HPA) axis activity shows sexual dimorphism, and this is thought to be a mechanism underlying sex-specific disease incidence. Evidence is scarce on whether these sex differences are also present in childhood. In a meta-analysis, we recently found that basal (non-stimulated) cortisol in saliva and free cortisol in 24-h urine follow sex-specific patterns. We explored whether these findings could be extended with sex differences in HPA axis reactivity.

METHODS

From inception to January 2016, PubMed and EMBASE.com were searched for studies that assessed HPA axis reactivity in healthy girls and boys aged ≤18 years. Articles were systematically assessed and reported in the categories: (1) diurnal rhythm, (2) cortisol awakening response (CAR), (3) protocolled social stress tests similar or equal to the Trier Social Stress Test for children (TSST-C), (4) pharmacological (ACTH and CRH) stress tests, and (5) miscellaneous stress tests.

RESULTS

Two independent assessors selected 109 out of 6158 records for full-text screening, of which 81 studies (with a total of 14,591 subjects) were included. Studies showed that girls had a tendency towards a more variable diurnal rhythm (12 out of 29 studies), a higher CAR (8 out of 18 studies), and a stronger cortisol response to social stress tests (9 out of 21 studies). We found no evidence for sex differences in cortisol response after a pharmacological challenge or to miscellaneous stress tests.

DISCUSSION

Sex differences in HPA axis reactivity appear to be present in childhood, although evidence is not unequivocal. For a better evaluation of sex differences in HPA axis reactivity, standardization of protocols and reports of stress tests is warranted.

Adolescent Antisocial Behavior Explained by Combining Stress-Related Parameters

Abstract. Many stress-related parameters have been associated with antisocial behavior, including low cortisol awakening responses (CAR), as well as low cortisol and alpha-amylase reactivity to stress. These parameters reflect different, yet interrelated components of the stress system, yet it remains to be determined whether they exert joint or independent effects. Therefore, this study examined them in concert, as this may offer a better explanation of the psychophysiological mechanism’s underlying antisocial behavior. Antisocial behavior was assessed through self-report by 197 general population boys and girls (Mage = 17.31, SD = 0.44). The CAR was assessed, as well as cortisol and alpha-amylase reactivity to a public speaking task. Neither stress-related parameter was independently related to antisocial behavior. The best explanation was provided by a CAR × Cortisol reactivity interaction, indicating that in youth with a low CAR, antisocial behavior was positively associated with cortisol reactivity. In youth with a high CAR, no association between antisocial behavior and cortisol reactivity was found. Between cortisol and alpha-amylase reactivity a trend toward an interaction appeared, indicating a negative association between cortisol reactivity and antisocial behavior in those with low alpha-amylase reactivity, and a positive association in those with high alpha-amylase reactivity. These findings indicate that in order to understand the mechanisms underlying antisocial behavior, the stress system should be studied comprehensively rather than focus on single parameters. Particularly cortisol parameters appear to be jointly related to antisocial behavior, the additional value of alpha-amylase reactivity to cortisol reactivity may however be limited.

The mediating roles of cortisol reactivity and executive functioning difficulties in the pathways between childhood histories of emotional insecurity and adolescent school problems

This study tested a hypothesized cascade in which children's insecure representations of the interparental relationship increase their school problems by altering children's cortisol reactivity to stress and their executive functioning. Participants included 235 families. The first of five measurement occasions occurred when the children were in kindergarten (M age = 6 years), and they were followed through the transition to high school. The results indicated that children's histories of insecure representations of the interparental relationship during the early school years were associated with executive functioning difficulties in adolescence (M age = 14 years). This in turn predicted subsequent increases in school adjustment difficulties 1 year later. In addition, elevated cortisol reactivity to interadult conflict mediated the association between early histories of insecurity and subsequent executive function problems in adolescence.

Gender-specific differences in hypothalamus-pituitary-adrenal axis activity during childhood: a systematic review and meta-analysis

BACKGROUND

Gender-specific differences in hypothalamus-pituitary-adrenal (HPA) axis activity have been postulated to emerge during puberty. We conducted a systematic review and meta-analysis to test the hypothesis that gender-specific differences in HPA axis activity are already present in childhood.

METHODS

From inception to January 2016, PubMed and EMBASE.com were searched for studies that assessed non-stimulated cortisol in serum or saliva or cortisol in 24-h urine in healthy males and females aged ≤18 years. Studies that conform with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement were reported. Standardized mean differences (95% CIs) were calculated and analyzed using fixed-effect meta-analysis stratified for age: <8 years (prepubertal) and 8-18 years (peri-/postpubertal). For comparison, we ran the same analyses using random-effects models.

RESULTS

Two independent assessors selected 413 out of 6158 records (7%) for full-text screening, of which 79 articles were included. Of these, 58 (with data on 16,551 subjects) were included in the meta-analysis. Gender differences in cortisol metabolism differed per age group. Boys aged <8 years had 0.18 (0.06; 0.30) nmol/L higher serum and 0.21 (0.05; 0.37) nmol/L higher salivary cortisol levels, while between 8 and 18 years, boys had 0.34 (0.28; 0.40) nmol/L lower serum and 0.42 (0.38; 0.47) nmol/L lower salivary cortisol levels. In 24-h urine, cortisol was consistently higher in boys, being 0.34 (0.05; 0.64) and 0.32 (0.17; 0.47) μg/24 h higher in the <8- and 8-18-year groups, respectively. However, gender-differences in serum cortisol <8 years and between 8 and 18 years were absent when using random-effects models.

CONCLUSIONS

Gender differences in cortisol metabolism are already present in childhood, with higher salivary cortisol in boys aged <8 years compared to girls. This pattern was reversed after the age of 8 years. In contrast, the gender-specific difference in cortisol production as assessed through 24-h urine did not change with age. Although differences were small, and analyses of gender differences in serum cortisol were inconclusive, they might contribute to gender-specific origins of health and disease.

Effects of a Humor Therapy Program on Stress Levels in Pediatric Inpatients

OBJECTIVE

Disease and hospitalization generate stress, which can affect the response to treatment. Humor has been used in many hospitals to decrease stress. The aim of this study was to evaluate the impact of a humor therapy program on stress levels in pediatric inpatients.

METHODS

In the first phase, an intervention and a control group were studied over 2 consecutive 3-month periods; the interventions were performed by a team of artists trained in humor therapy. Salivary cortisol levels were measured by enzyme-linked immunosorbent assay, and the Weisz test, a pictorial chart that determines subjective stress perception, and the Parker test, which assesses objective stress, were applied. In the second phase, salivary cortisol levels were measured and the Weisz test was administered before and after the interventions.

RESULTS

A total of 306 patients were recruited into this study: 198 in the first phase (94 in the intervention group and 104 in the nonintervention group) and 108 in the second phase. There were no differences between groups regarding age, sex, or medical diagnosis. The children in the intervention group presented lower cortisol levels, lower scores on the Parker test, and higher scores on the Weisz test than children in the nonintervention group. In the second phase, the children showed lower salivary cortisol levels and higher scores on the Weisz test after the intervention.

CONCLUSIONS

Humor therapy has beneficial effects on stress and cortisol levels in pediatric inpatients. This supports the implementation and reinforcement of these therapies in pediatric hospitals.

Endocrine and emotional response to exclusion among women and men; cortisol, salivary alpha amylase, and mood

BACKGROUND AND OBJECTIVES

Social exclusion is ubiquitous and painful. Evolutionary models indicate sex differences in coping with social stress. Recent empirical data suggest different sex patterns in hypothalamic-pituitary-adrenal (HPA) and sympathetic-adrenal-medullary (SAM) reactivity. The present study sought to test this hypothesis.

DESIGN

We examined differences in endocrine and emotional response to exclusion by using a virtual ball tossing paradigm (Cyberball). Saliva samples and mood ratings were collected to reflect levels before, and repeatedly following, exclusion.

METHODS

The sample included 21 women and 23 men. Cortisol and salivary alpha amylase (sAA), biomarkers of the HPA and SAM systems, respectively, were used as indices of two arms of stress response.

RESULTS

Following exclusion, all participants experienced mood worsening followed by mood improvement, with men reporting less distress than women. Women evinced decline in cortisol following the Cyberball task, whereas men's cortisol levels showed a non-significant rise, and then decline, following exclusion.

CONCLUSIONS

Our results concur with previous findings showing SAM reactivity to be gender-neutral and HPA reactivity to be gender-divergent. Additional studies are needed to examine sex-specific response to social exclusion. Implications for individual differences in recovery from stress are discussed.

Cortisol stress responses and children's behavioral functioning at school

The present study investigated whether cortisol stress responses of 6‐year‐olds were associated with their behavioral functioning at school. Additionally, the moderating role of stress in the family environment was examined. To this end, 149 healthy children (M_age = 6.09 years; 70 girls) participated in an age‐appropriate innovative social evaluative stress test. Saliva cortisol samples were collected six times during the stress test to calculate two indices of the cortisol stress response: cortisol stress reactivity and total stress cortisol. Teachers assessed children's internalizing, externalizing, and prosocial behaviors. Stress in the family environment was operationalized as maternally reported parenting stress. Results indicated a significant increase in cortisol concentrations in response to the stressor. No significant associations were found between cortisol stress responses and behavioral functioning at school and there was no evidence for moderation by maternal parenting stress. Potential theoretical and methodological explanations for these results are discussed.

Maternal distress and child neuroendocrine and immune regulation

RATIONALE

Neuroendocrine-immune regulation is essential for maintaining health. Early-life adversity may cause dysregulation in the neuroendocrine-immune network through repeated activation of the stress response, thereby increasing disease risk.

OBJECTIVE

This paper examined the extent to which maternal psychological well-being moderates neuroendocrine-immune relations in children.

METHODS

We used data from a laboratory-based study of mothers and their five-year old children (n = 125 mother-child pairs) conducted from 2011 to 2013 in Baltimore, Maryland. Child saliva was assayed for markers of immune function (i.e., cytokines: interleukin [IL]-1β, IL-6, IL-8, tumor necrosis factor alpha [TNF-α]) and hypothalamic-pituitary-adrenal activity (i.e., cortisol). A composite score for depressive symptoms, anxiety, and parenting stress characterized maternal psychological distress. Multilevel mixed models examined the relationship between maternal psychological well-being and child neuroendocrine-immune relations.

RESULTS

Significant cytokine × maternal distress interactions indicated that as maternal distress increased, expected inverse cytokine-cortisol relations within children became weaker for IL-1β, IL-6, and TNF-α. Sex-stratified models revealed that these interactions were only significant among girls. Among boys, there were inverse cytokine-cortisol relations for all cytokines, and, while in the same direction as observed among girls, the cytokine × maternal distress interactions were non-significant.

CONCLUSION

The findings suggest that maternal distress is associated with child neuroendocrine-immune relations in saliva and may alter the sensitivity of inflammatory immune processes to cortisol's inhibitory effects. This desensitization may place the child at risk for inflammatory diseases. The findings support efforts for the early detection and treatment of at-risk mothers to protect maternal and child health and well-being.

Biological Sensitivity to Family Income: Differential Effects on Early Executive Functioning

The study examined how the interplay between children's cortisol response and family income is related to executive function (EF) skills. The sample included one hundred and two 5- to 6-year-olds (64% minority). EF skills were measured using laboratory tasks and observer ratings. Physiological reactivity was assessed via cortisol response during a laboratory visit. A consistent, positive association between family income and EF skills emerged only for children who showed high cortisol response, a marker of biological sensitivity to context. In contrast, family income was not related to EF skills in children who displayed low cortisol response. Follow-up analyses revealed a disordinal interaction, suggesting that differential susceptibility can be detected at the level of basic cognitive and self-regulatory skills that support adaptive functioning.

The influence of prenatal intimate partner violence exposure on hypothalamic–pituitary–adrenal axis reactivity and childhood internalizing and externalizing symptoms

This prospective longitudinal study examines the long-term influence of intimate partner violence (IPV) exposure in utero. We hypothesized that (a) prenatal IPV increases risk for internalizing and externalizing problems as well as for a profile of dysregulated cortisol reactivity, and (b) patterns of cortisol hyper- and hyporeactivity are differentially associated with internalizing and externalizing problems. The participants were 119 10-year-old children. Their mothers reported their IPV experiences and distress during pregnancy. Child and maternal reports of internalizing and externalizing problems as well as lifetime IPV exposure were obtained. Salivary cortisol was assessed at baseline, 20 min, and 40 min after challenge. The results partially supported our hypotheses: Exposure to IPV during pregnancy predicted child-reported internalizing and externalizing problems, mother ratings of child externalizing problems, and a profile of high cortisol secretion before and after stress challenge. The results were significant above and beyond the influence of maternal distress during pregnancy and IPV that occurred during the child's life. In addition, a profile of high cortisol secretion was associated with maternal reports of child internalizing behaviors. Findings support the growing consensus that prenatal stress can lead to lasting disruptions in adaptation and highlight the need for more longitudinal examinations of prenatal IPV exposure.

Salivary alpha amylase diurnal pattern and stress response are associated with body mass index in low-income preschool-aged children

Physiological stress responses are proposed as a pathway through which stress can "get under the skin" and lead to health problems, specifically obesity. We tested associations of salivary alpha amylase (sAA) diurnal patterns and stress responses with body mass index (BMI) in young, low-income children (51% male; 54% non-Hispanic white). Diurnal saliva samples were collected three times per day across three days for 269 children (M age 50.8 months, SD 6.3). Individual sAA intercept and slope values were calculated using random effect models to represent morning sAA levels and rate of sAA change across the day. A subset of children (n=195; M age 56.6 months, SD 6.9) participated in a lab-based behavioral stress protocol. Area under the curve increase (AUCI) across four timepoints was calculated to represent increase in sAA output during stress elicitation. Children were weighed and height measured and BMI z-score was calculated. Linear regression was used to evaluate associations of sAA intercept, sAA slope, and sAA AUCI with BMI z-score, controlling for child age, sex, and race/ethnicity; maternal weight status; and family income-to-needs ratio. Diurnal and stress-response sAA patterns were related to child adiposity: for each 1-standard deviation unit (SDU) decrease in morning sAA level, the child's BMI z-score increased by 0.11 (SE 0.05) SDU's (p<.04); for each 1-SDU increase in sAA slope across the day, the child's BMI z-score increased by 0.12 (SE 0.05) SDU's (p<.03); and for each 1-SDU decrease in sAA AUCI during the stress elicitation, the child's BMI z-score increased by 0.14 (SE 0.06) SDU's (p<.03). Blunted stress responses and atypical diurnal patterns of sAA have been found following exposure to chronic life stressors such as poverty. Findings suggest that associations of stress, sAA, and elevated body mass index may develop very early in the lifespan.

Salivary cytokines as a minimally-invasive measure of immune functioning in young children: correlates of individual differences and sensitivity to laboratory stress

There is growing interest in minimally-invasive measures of environmentally-responsive biological systems in developmental science. Contributing to that endeavor, this study explores the intercorrelations, correlates, and task-sensitivity of proinflammatory salivary cytokines in childhood. Saliva was sampled from 125 healthy five-year old children (49% male) across a series of cognitive and emotional challenge laboratory tasks. Samples were assayed for cytokines (IL-1β, IL-6, IL-8, TNFα), and markers of hypothalamic-pituitary-adrenal (HPA) and autonomic nervous system (ANS) activation (salivary cortisol and alpha-amylase [sAA]). Cytokines were positively intercorrelated and task-sensitivity varied. Except IL-8, cytokines were elevated in children with oral health issues and tobacco smoke exposure. Among boys, cytokines were positively related to sAA and negatively related to cortisol. The findings suggest that in healthy children, salivary cytokine levels reflect compartmentalized oral immune activity. Associations between ANS and HPA activity and cytokines in saliva may present opportunities for minimally-invasive methods to explore neuroendocrine-immune interactions during development.

The developmental course of salivary alpha-amylase and cortisol from 12 to 36 months: Relations with early poverty and later behavior problems

This study examined the development of baseline autonomic nervous system (ANS) and hypothalamic-pituitary-adrenal (HPA) physiological activity from 12 to 36 months as well as antecedents (poverty) and consequents (behavior problems) of individual differences in physiological development. Children (N=179; 50% poor; 56% African American; 52% male) provided saliva samples at 12, 18, 24, 30, and 36 months of age. Latent growth curve models indicated that nonlinear change was evident for both sAA and cortisol, with sAA increasing and cortisol decreasing with age. Children residing in poor households exhibited lower initial levels of sAA, but not cortisol. African-American children showed slightly smaller decreases in cortisol over time. Initial levels of sAA predicted higher levels of internalizing behaviors at 36 months and both initial levels of and total change in sAA predicted higher levels of externalizing behaviors at 36 months. There was no evidence that sAA or cortisol mediated the relationship between poverty and later behavior problems.

Rated and measured impulsivity in children is associated with diminished cardiac reactions to acute psychological stress

This study examined the association between impulsivity and heart rate reactions to a brief psychological stress in pre-adolescent children. Impulsivity was assessed by two response inhibition tasks and maternal self-report. Heart rate was measured at rest and in response to a mental arithmetic challenge. Children high in impulsivity showed blunted cardiac stress reactions. This result resonates with previous findings that blunted stress reactivity is characteristic of a range of problematic behaviours often associated with impulsivity.

Effortful control and context interact in shaping neuroendocrine stress responses during childhood

Trait and contextual factors can shape individual and group differences in hypothalamic-pituitary-adrenal (HPA) response to stress; but the ways in which these factors may interact with each other to modulate stress activity have rarely been examined. Here, we investigated whether the association between a temperamental self-regulatory trait - Effortful Control (EC) - and HPA axis stress response is moderated by type of laboratory stress in sixty-five children (35 boys). EC was measured at ages 3 and 6 using age-appropriate laboratory batteries as well as mother reports. HPA axis responses were measured at age 7 by randomly assigning children to one of two laboratory stress tasks (frustration vs. fear). Results indicated that EC interacted with stress context in predicting cortisol response. Specifically, lower EC was associated with greater cortisol response (steeper reactivity slopes) in the context of a frustration stressor but this was reversed in a fear context where lower EC was associated with flatter, more gradual activation. It is likely that different components of EC, such as emotion regulation and attention, differentially interact with the stress context. These types of effects and interactions need to be more thoroughly understood in order to meaningfully interpret cortisol reactivity data and better characterize the role of the HPA axis in human psychopathology.

Children's negative emotions and ego-resiliency: longitudinal relations with social competence

We examined the relations of negative emotions in toddlerhood to the development of ego-resiliency and social competence across early childhood. Specifically, we addressed whether fear and anger/frustration in 30-month-old children (N = 213) was associated with the development of ego-resiliency across 4 time points (42 to 84 months), and, in turn, whether ego-resiliency predicted social competence at 84 months. Child anger/frustration negatively predicted the intercept of ego-resiliency at 42 months (controlling for prior ego-resiliency at 18 months) as well as the slope. Fear did not significantly predict either the intercept or slope of ego-resiliency in the structural model, although it was positively correlated with anger/frustration and was negatively related to ego-resiliency in zero-order correlations. The slope of ego-resiliency was positively related to children's social competence at 84 months; however, the intercept of ego-resiliency (set at 42 months) was not a significant predictor of later social competence. Furthermore, the slope of ego-resiliency mediated the relations between anger/frustration and children's later social competence. The results suggest that individual differences in anger/frustration might contribute to the development of ego-resiliency, which, in turn, is associated with children's social competence.

Stress reactivity in war-exposed young children with and without posttraumatic stress disorder: Relations to maternal stress hormones, parenting, and child emotionality and regulation

The current study examined biomarkers of stress in war-exposed young children and addressed maternal and child factors that may correlate with children's stress response. Participants were 232 Israeli children aged 1.5–5 years, including 148 children exposed to continuous war. Similarly, 56 were diagnosed with posttraumatic stress disorder (PTSD) and 92 were defined as exposed-no-PTSD. Child cortisol (CT) and salivary alpha amylase (sAA), biomarkers of the hypothalamic–pituitary–adrenal and sympathetic–adrenal–medullary arms of the stress response, were measured at baseline, following challenge, and at recovery. Maternal CT and sAA, PTSD symptoms, and reciprocal parenting, and child negative emotionality and regulatory strategies were assessed. Differences between war-exposed children and controls emerged, but these were related to child PTSD status. Children with PTSD exhibited consistently low CT and sAA, exposed-no-PTSD displayed consistently high CT and sAA, and controls showed increase in CT following challenge and decrease at recovery and low sAA. Exposed children showed higher negative emotionality; however, whereas exposed-no-PTSD children employed comfort-seeking strategies, children with PTSD used withdrawal. Predictors of child CT included maternal CT, PTSD symptoms, low reciprocity, and negative emotionality. Findings suggest that high physiological arousal combined with approach strategies may be associated with greater resilience in the context of early trauma.

Salivary nerve growth factor reactivity to acute psychosocial stress: a new frontier for stress research

OBJECTIVE

Neurotrophins such as nerve growth factor (NGF) may represent a stress-responsive system complementing the better known neuroendocrine (hypothalamic-pituitary-adrenal axis) and autonomic nervous system, but there is little evidence for NGF response to acute stress in humans because noninvasive measures have not been available. We investigated salivary NGF (sNGF) in 40 healthy young adults confronting a romantic conflict stressor.

METHODS

Five saliva samples-two collected before and three after the conflict-were assayed for sNGF, cortisol (hypothalamic-pituitary-adrenal marker), and α-amylase (sAA; ANS marker). In addition, a control group (n = 20) gave saliva samples at the same time intervals to determine whether sNGF changes were specific to the conflict stressor.

RESULTS

sNGF showed significant reactivity from entry to the first poststress sample among study participants (β = .13, p = .001), with nonsignificant change across poststress samples. Control participants showed no change in sNGF across the same period. Within-person changes in sNGF were generally aligned with both cortisol (β = .17, p = .003) and sAA (β = .17, p = .021) responses. Preconflict negative emotion predicted lower sNGF reactivity (β = -.08, p = .009) and less alignment with sAA (β = -.09, p = .040), whereas positive emotion predicted less alignment with cortisol (β = -.10, p = .019).

CONCLUSIONS

This study is the first to document sNGF as a marker that responds to stress in humans.

Longitudinal associations between infections and atopic disorders across childhood and dysregulated adrenocortical functioning in early adolescence

The present study sought to determine if exposure to common childhood medical problems (i.e., infections and atopic disorders [e.g., allergies, asthma]) may dysregulate the hypothalamic-pituitary-adrenal (HPA) axis. Longitudinal data from 96 youth were used to examine this possibility. Medical records were drawn from government databases indicating the frequency of visits to healthcare facilities for infections and atopic disorders from infancy to early adolescence. During early adolescence, participants provided salivary cortisol samples from awakening until bedtime over 2 consecutive days. Individuals with a history of increased number visits for infections across childhood displayed elevated levels of cortisol at awakening whereas individuals with childhood histories of visits for atopic disorders displayed blunted diurnal cortisol slopes. These findings build on previous research documenting associations between infections and atopic disorders and cortisol by identifying longitudinal linkages from early health problems to later HPA axis functioning.

Asymmetry in children's salivary cortisol and alpha-amylase in the context of marital conflict: links to children's emotional security and adjustment

Recent research supports the promise of examining interactive models of physiological processes on children's adjustment. The present study investigates interactions between children's autonomic nervous system activity and adrenocortical functioning in the context of marital discord; specifically, testing models of concurrent responses proposed by Bauer et al. ([2002] Developmental and Behavioral Pediatrics 23:102-113) in the prediction of children's behavioral responses to conflict and adjustment. Asymmetry and symmetry in children's salivary alpha-amylase and cortisol were examined in 195 children (M age = 8 years) in response to viewing conflict vignettes. Results were partially consistent with an interactive model in the context of high marital discord; asymmetry among higher alpha-amylase and lower cortisol related to higher emotional insecurity and concurrent and subsequent maladjustment. In contrast, patterns of symmetrical responses were related to greater maladjustment for children exposed to lower levels of marital discord, supporting an additive model. Findings support the importance of a multisystem approach to investigating the adaptiveness of children's physiological stress responses, while also highlighting the value of considering physiological responses in the context of family risk.

Gender differences in emotion expression in children: a meta-analytic review

Emotion expression is an important feature of healthy child development that has been found to show gender differences. However, there has been no empirical review of the literature on gender and facial, vocal, and behavioral expressions of different types of emotions in children. The present study constitutes a comprehensive meta-analytic review of gender differences and moderators of differences in emotion expression from infancy through adolescence. We analyzed 555 effect sizes from 166 studies with a total of 21,709 participants. Significant but very small gender differences were found overall, with girls showing more positive emotions (g = -.08) and internalizing emotions (e.g., sadness, anxiety, sympathy; g = -.10) than boys, and boys showing more externalizing emotions (e.g., anger; g = .09) than girls. Notably, gender differences were moderated by age, interpersonal context, and task valence, underscoring the importance of contextual factors in gender differences. Gender differences in positive emotions were more pronounced with increasing age, with girls showing more positive emotions than boys in middle childhood (g = -.20) and adolescence (g = -.28). Boys showed more externalizing emotions than girls at toddler/preschool age (g = .17) and middle childhood (g = .13) and fewer externalizing emotions than girls in adolescence (g = -.27). Gender differences were less pronounced with parents and were more pronounced with unfamiliar adults (for positive emotions) and with peers/when alone (for externalizing emotions). Our findings of gender differences in emotion expression in specific contexts have important implications for gender differences in children's healthy and maladaptive development.

Refining the multisystem view of the stress response: coordination among cortisol, alpha-amylase, and subjective stress in response to relationship conflict

This study investigated associations among young adults' hypothalamic-pituitary-adrenal axis activity, autonomic nervous system activity, and subjective stress in response to interpersonal conflict to better characterize coordination across stress systems. Seven saliva samples were collected from 199 young adult opposite-sex couples before, during, and after they discussed an unresolved relationship conflict. Samples were later assayed for cortisol and alpha-amylase (sAA). Couples rated anticipatory stress prior to the conflict and perceived stress immediately following the task. Growth curve modeling was used to examine two possible levels of within-person coordination across physiological systems: alignment between cortisol and sAA responses throughout the sampling period ("matched phase coordination"), and association between overall levels of cortisol and sAA in response to conflict ("average level coordination"). Whereas both partners showed the former type of coordination, only women showed the latter type. Positive anticipation of the stressor predicted stronger cortisol-sAA matched phase coordination for women. Pre-task ratings related to women's sAA, and post-task ratings related to both partners' cortisol responses. Implications for a multisystem interpretation of normal and pathological responses to daily stress are discussed.

Effortful control and parenting: associations with HPA axis reactivity in early childhood

While activation of the hypothalamic-pituitary-adrenal (HPA) axis is an adaptive response to stress, excessive HPA axis reactivity may be an important marker of childhood vulnerability to psychopathology. Parenting, including parent affect during parent-child interactions, may play an important role in shaping the developing HPA system; however, the association of parent affect may be moderated by child factors, especially children's emerging self-regulatory skills. We therefore tested the relationship between parent affectivity and 160 preschoolers' cortisol reactivity during a laboratory visit, examining children's effortful control (EC) as a moderator. Greater parent negative affectivity was related to greater initial and increasing cortisol over time, but only when children were low in EC. Higher parent positive affectivity was related to a higher baseline cortisol for children with low EC and lower baseline cortisol for children with high EC. Results indicate that children's EC moderates the extent to which parent affect shapes stress reactive systems in early childhood.

Sociodemographic risk, parenting, and effortful control: relations to salivary alpha-amylase and cortisol in early childhood

Early sociodemographic risk, parenting, and temperament were examined as predictors of the activity of children's (N = 148; 81 boys, 67 girls) hypothalamic-pituitary-adrenal axis and autonomic nervous system. Demographic risk was assessed at 18 months (T1), intrusive/overcontrolling parenting and effortful control were assessed at 30 months (T2), and salivary cortisol and alpha-amylase were collected at 72 (T3) months of age. Demographic risk at T1 predicted lower levels of children's effortful control and higher levels of mothers' intrusive/overcontrolling parenting at T2. Intrusive/overcontrolling parenting at T2 predicted higher levels of children's cortisol and alpha-amylase at T3, but effortful control did not uniquely predict children's cortisol or alpha-amylase levels. Findings support the open nature of stress responsive physiological systems to influence by features of the early caregiving environment and underscore the utility of including measures of these systems in prevention trials designed to influence child outcomes by modifying parenting behavior.