Cortisol patterns at home and child care: Afternoon differences and evening recovery in children attending very high quality full-day center-based child care

Psychophysiological adjustment to formal education varies as a function of peer status and socioeconomic status in children beginning kindergarten

The transition to kindergarten can be stressful as children adjust to novel separations from their caregivers and become accustomed to their peer group. A 9-month study of 96 children (M_age  = 5.37 years, SD = 0.42) from Barranquilla, Colombia, assessed socioeconomic differences in hypothalamic-pituitary-adrenal (HPA) axis functioning across the kindergarten year. Children were from four different classrooms in one school. Saliva samples were collected twice a day across 3 consecutive days at the beginning and end of the school year. We examined whether change in HPA axis activation across the year varied as a function of a child's socioeconomic status (SES) and experience in the peer group. We found that rejected children and lower SES children had lower cortisol levels early in the morning. Rejected children had a flatter morning cortisol slope. Lower SES children had higher cortisol than their higher SES peers at the end of the school year and a flatter morning cortisol slope. Taken together, these findings suggest that diurnal cortisol in children beginning kindergarten may be influenced by both peer rejection and SES.

Children's diurnal cortisol output and temperament in two different childcare settings at 2 and 3.5 years of age

Prior research suggests that child temperament may play an important role in early childhood stress regulation. We compared children's diurnal cortisol and the association between cortisol and temperament in two different childcare settings. Cortisol was measured from saliva samples over 2 days in children (N = 84) attending out-of-home childcare and in children (N = 27), who were cared for at home at the age of 3.5 years. There was no difference between the childcare groups in total diurnal cortisol. However, of the individual measurements, afternoon cortisol levels were higher in the out-of-home childcare group during their childcare day when compared with their home day. Child temperament was not associated with total diurnal cortisol. Comparison with our prior measurements showed that the association between temperamental surgency/extroversion and total diurnal cortisol diminished along with the child age from 2 to 3.5 years in both childcare settings. This may indicate that more extroverted children are physiologically more reactive to environmental stimuli when they are younger, but this association does not appear as the children develop. Our results further suggest that the afternoon hours in the out-of-home childcare may be demanding and accelerate the hypothalamus-pituitary-adrenal axis activation in young children independent of their age.

Glucocorticoid-Mediated Developmental Programming of Vertebrate Stress Responsivity

Glucocorticoids, vertebrate steroid hormones produced by cells of the adrenal cortex or interrenal tissue, function dynamically to maintain homeostasis under constantly changing and occasionally stressful environmental conditions. They do so by binding and thereby activating nuclear receptor transcription factors, the Glucocorticoid and Mineralocorticoid Receptors (MR and GR, respectively). The GR, by virtue of its lower affinity for endogenous glucocorticoids (cortisol or corticosterone), is primarily responsible for transducing the dynamic signals conveyed by circadian and ultradian glucocorticoid oscillations as well as transient pulses produced in response to acute stress. These dynamics are important determinants of stress responsivity, and at the systemic level are produced by feedforward and feedback signaling along the hypothalamus-pituitary-adrenal/interrenal axis. Within receiving cells, GR signaling dynamics are controlled by the GR target gene and negative feedback regulator fkpb5. Chronic stress can alter signaling dynamics via imperfect physiological adaptation that changes systemic and/or cellular set points, resulting in chronically elevated cortisol levels and increased allostatic load, which undermines health and promotes development of disease. When this occurs during early development it can "program" the responsivity of the stress system, with persistent effects on allostatic load and disease susceptibility. An important question concerns the glucocorticoid-responsive gene regulatory network that contributes to such programming. Recent studies show that klf9, a ubiquitously expressed GR target gene that encodes a Krüppel-like transcription factor important for metabolic plasticity and neuronal differentiation, is a feedforward regulator of GR signaling impacting cellular glucocorticoid responsivity, suggesting that it may be a critical node in that regulatory network.

Emotional Competence of Early Childhood Educators and Child Socio-Emotional Wellbeing

BACKGROUND

Early childhood educators are attachment figures for babies and play an important role in emotion socialization. This study aims to analyze the role of educators as emotional socializers and its relationship with infants' social competence and attachment security, considering various characteristics of educators (age, years of experience, level of knowledge of development and parenting) and the context (day-care center-family communication).

METHODS

563 infants attending day-care centers (age: M = 25.98 months SD = 5.41) and their 223 early childhood educators (age: M = 42.61 SD = 11.02) took part in this study. The educators completed: CEESQ-Crèche Educator Emotional Style Questionnaire, Information Sources Questionnaire, two sub-scales of KIDI-Knowledge of Infant Development Inventory, QRS-F-Questionnaire on the Relationship between Services and Families, QPI-Questionnaire on Peer Interactions, and AQS-Attachment-Q-Sort.

RESULTS

Results showed that the educator's coaching style has a relationship with attachment security and social skills and is positively correlated with the educators' emotional self-efficacy and with the level of communication between day-care centers and families, while the correlation with knowledge of parenting is weak.

CONCLUSIONS

These findings highlight the importance of enhancing not only educators' knowledge about educative strategies, but above all their emotional competence to promote children adaptation to day-care centers.

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.

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.

Toddlers' diurnal cortisol levels affected by out-of-home, center-based childcare and at-home, guardian-supervised childcare: comparison between different caregiving contexts

Previous research suggests that attending non-parental out-of-home childcare is associated with elevated cortisol levels for some children. We aimed to compare diurnal saliva cortisol levels between children having out-of-home, center-based childcare or those having at-home, guardian-supervised childcare in Finland. A total of 213 children, aged 2.1 years (SD = 0.6), were drawn from the ongoing Finnish birth cohort study. Saliva samples were collected over 2 consecutive days (Sunday and Monday), with four samples drawn during each day: 30 min after waking up in the morning, at 10 am, between 2 and 3 pm, and in the evening before sleep. These results suggest that the shapes of the diurnal cortisol profiles were similar in both childcare groups following a typical circadian rhythm. However, the overall cortisol levels were on average 30% higher (95% CI: [9%, 54%], p = .004) with the at-home childcare in comparison with the out-of-home childcare group. Furthermore, a slight increase in the diurnal cortisol pattern was noticed in both groups and in both measurement days during the afternoon. This increase was 27% higher ([2%, 57%], p = .031) in the out-of-home childcare group during the out-of-home childcare day in comparison with the at-home childcare day. The elevated afternoon cortisol levels were partly explained by the afternoon naps, but there were probably other factors as well producing the cortisol rise during the afternoon hours. Further research is needed to define how a child's individual characteristic as well as their environmental factors associate with cortisol secretion patterns in different caregiving contexts.

Poverty, Caregiving, and HPA-Axis Activity in Early Childhood

The association between poverty and the activity of the hypothalamic pituitary adrenal (HPA) axis in early childhood is well established. Both ecological and transactional theories suggest that one way in which poverty may influence children's HPA-axis activity is through its effects on parents' behaviors, and over the past three decades a substantial literature has accumulated indicating that variations in these behaviors are associated with individual differences in young children's HPA-axis activity. More recent research suggests that non-parental caregiving behaviors are associated with HPA-axis activity in early childhood as well. Here we systematically review the literature on the association between both parental and non-parental caregiving behaviors in the context of poverty and the activity of the HPA-axis in early childhood. We conclude by noting commonalities across these two literatures and their implications for future research.

Impact of a social skills program on children's stress: A cluster randomized trial

BACKGROUND

Most preschool children in Western industrialized countries attend child care during the day while parents work. Studies suggest that child care may be stressful to young children, perhaps because they still lack the social skills to interact daily in a group setting away from parents. This gap in social abilities may be greater for children in lower-income families, who may face more adversity at home, with fewer resources and more social isolation.

METHODS

We conducted a cluster-randomized controlled trial in 2013-2014 to test whether a social skills intervention led by early childhood educators within the child care center could reduce diurnal cortisol levels to more typical patterns expected of children this age. We randomized 19 public child care centers (n = 361 children) in low-income neighborhoods of Montreal, Canada, to either: 1) the Minipally program - intervention group (n = 10 centers; 186 children), or 2) waiting list - control group (n = 9 centers; 175 children). Saliva samples for cortisol levels were collected 3 times/day, pre- and post-implementation. The Minipally puppet program consists of 2 workshops/month for 8 months for the development of social skills and self-regulation in 2-5-year-olds, with reinforcement activities between workshops. Educators received 2-days' training and 12 h' supervision in Minipally.

RESULTS

Linear mixed models for repeated measures revealed a significant interaction between intervention status and time of day of cortisol sampling (β = -0.18, p =  0.04). The intervention group showed patterns of decreasing diurnal cortisol secretion (β = -0.32, p < 0.01), whereas the control group showed increasing slopes (β = 0.20, p < 0.01). Moreover, family income was a moderator; children in lower-income families benefited most from the intervention.

CONCLUSION

Results suggest that a social skills training program, when integrated into a preschool education curriculum, can foster an environment more conducive to typical childhood patterns of cortisol secretion.

Environmental characteristics of early childhood education and care, daily movement behaviours and adiposity in toddlers: A multilevel mediation analysis from the GET UP! Study

STUDY OBJECTIVE

This study aimed to examine the direct effects of environmental characteristics of early childhood education and care (ECEC) centres on adiposity, and the indirect effects through daily movement behaviours (physical activity, sedentary time and naps).

METHODS

274 children (average age 19.73 ± 4.15 months) from 27 ECEC centres participated in this study. Environmental characteristics of ECEC centres were rated using the Infant/Toddler Environment Rating Scale-revised edition (ITERS-R). Daily movement behaviours were assessed using 24-h accelerometry. Body mass index z-scores were used to indicate adiposity.

RESULTS

There were no significant direct effects or indirect effects of environmental characteristics on toddlers' adiposity through daily movement behaviours. However, the environmental characteristics of "personal care routine" (B=0.72, p = 0.041) and "activity" (B = 0.87, p < 0.050) were positively associated with the percentage of time these toddlers spent in moderate-to-vigorous physical activity (MVPA). "Listening and talking" was also positively associated withnap(s) durations (B = 4.08 p = 0.001).

CONCLUSION

The relationships between environmental characteristics of ECEC centres and adiposity in toddlers, as well as, the mediating roles of daily movement behaviours still need confirmation by future longitudinal and experimental studies with long follow-up periods. At the same time, a broader spectrum of environmental characteristics of these settings needs to be examined with toddlers' adiposity in future studies; other potential mediators may also need to be taken into considerations.

Prenatal intimate partner violence exposure predicts infant biobehavioral regulation: Moderation by the brain-derived neurotrophic factor (BDNF) gene

The ability to regulate stress is a critical developmental milestone of early childhood that involves a set of interconnected behavioral and physiological processes and is influenced by genetic and environmental stimuli. Prenatal exposure to traumatic stress and trauma, including intimate partner violence (IPV), increases risk for offspring biobehavioral regulation problems during childhood and adolescence. Although individual differences in susceptibility to prenatal stress have been largely unexplored, a handful of studies suggest children with specific genetic characteristics are most vulnerable to prenatal stress. We evaluated the brain-derived neurotrophic factor Val66Met gene (BDNF) as a moderator of the effect of prenatal IPV exposure on infant temperamental and cortisol regulation in response to a psychosocial challenge. Ninety-nine mother–infant dyads recruited from the community were assessed when infants (51% female) were 11 to 14 months. Maternal reports of IPV during pregnancy and infant temperament were obtained, and infant saliva was collected for genotyping and to assess cortisol reactivity (before and after the Strange Situation Task). Significant genetic moderation effects were found. Among infants with the BDNF Met allele, prenatal IPV predicted worse temperamental regulation and mobilization of the cortisol response, while controlling for infant postnatal exposure to IPV, other maternal traumatic experiences, and infant sex. However, prenatal IPV exposure was not associated with temperamental or cortisol outcomes among infant carriers of the Val/Val genotype. Findings are discussed in relation to prenatal programming and biological susceptibility to stress.

Classroom social experiences in early elementary school relate to diurnal cortisol levels

Social stress has been linked to altered hypothalamic-pituitary-adrenocorticol (HPA) axis activation. During elementary school, children can become exposed to negative peer relations, such as poor appraisal among classroom peers, which is considered a social stressor. However, little is known about the association between classroom peer appraisal and the physiological stress system in children. The goal of this study was to examine the association of peer acceptance and peer non-acceptance with diurnal cortisol concentrations in 222 children from 20 mainstream elementary schools (Mage=6.97years, SD=0.99, 55% boys) in the Netherlands. Saliva samples were collected at awakening, 30min post-awakening, at noon and at 8 pm during a weekend day. From these assessments, the Cortisol Awakening Response (CAR), diurnal cortisol concentration (AUC_g) and diurnal cortisol slope were calculated. Peer nominations of peer acceptance (being liked), and peer non-acceptance (being disliked) were collected across a one year interval. Associations were controlled for peer victimization, age, sex and SES and children's levels of emotional problems and behavioural problems. Results showed that low peer acceptance was associated with heightened diurnal cortisol concentration (i.e., heightened AUG_g), lower cortisol reductions across the day (i.e., less decreasing cortisol slope) and heightened cortisol awakening response (i.e., heightened CAR). Peer non-acceptance and the interaction between peer acceptance and peer non-acceptance (known as peer rejection) were not associated with AUCg, cortisol slope or the CAR. The findings emphasize the association between poor appraisal among classroom peers and children's heightened HPA-axis activation. This underscores the importance of the physiological stress system in studying the consequences of negative peer relations in children.

Transition to Kindergarten: Negative Associations between the Emotional Availability in Mother-Child Relationships and Elevated Cortisol Levels in Children with an Immigrant Background

Background: The transition to child care is a challenging time in a child's life and leads to elevated levels of cortisol. These elevations may be influenced by the quality of the mother-child relationship. However, remarkably little is known about cortisol production in response to the beginning of child care among children-at-risk such as children with an immigrant background. However, attending kindergarten or any other child day-care institution can for example have a compensating effect on potential language deficits thus improving the educational opportunities of these children. Method: Data of a subsample of N = 24 "hard-to-reach" mother-child dyads was collected in the context of the psychoanalytic early prevention project FIRST STEPS. The project focuses on the earliest integration of children with an immigrant background by supporting parenting capacities in the critical phase of migration and early parenthood. Children's hair cortisol concentration (HCC) was assessed 1 week before (mean age = 38.77 months) and 3 months after kindergarten entry (mean age = 42.26 months). Hair analysis was conducted for both times of measurement, reflecting the first 3 months after kindergarten entry and 3 months prior. Furthermore, the emotional quality of the mother-child relationship was assessed with the help of the Emotional Availability Scales (EAS; Biringen, 2008) shortly before kindergarten entry when the children were about 3 years old (mean age = 37.2). Results and Conclusion: Children's mean cumulated HCC was higher after kindergarten entry than before. The increase correlated negatively with several dimensions of the EAS. Repeated measures ANCOVA revealed that particularly responsive children and children who had experienced less intrusive mother-child relationships demonstrated lower elevations in HCC after kindergarten entry. Furthermore, a decreased EA score was found in all EA dimensions, besides the dimension "mother's non-hostility," indicating problematic EA within the mother-child relationships of the sample. The results suggest that children with an immigrant background who experience more emotional available mother-child relationships seem to regulate stress induced by kindergarten entry more effectively, indicated by lower cortisol elevations after entry. This implicates that supporting early mother-child relationships by intervention may have a positive effect on the children's ability to regulate stress induced by kindergarten entry thus promoting child development.

Children's physiological responses to childcare

This review focuses on children's physiological responses to out-of-home childcare. The finding that children's cortisol levels are higher at childcare than at home has been well-replicated. Here we summarize recent evidence examining possible correlates of elevated cortisol levels. Reviewed studies suggest that childcare quality matters, whereas group sizes and type of care do not. As for child characteristics, elevated cortisol at childcare is more pronounced in toddlers than in infants, and in inhibited and aggressive children. We discuss recent advances focusing on hair cortisol analysis and immunomarkers of stress, and suggest that there is a need for experimental and longitudinal studies to examine causal relations and possible negative long-term consequences for children's health and development.

Cortisol levels of infants in center care across the first year of life: links with quality of care and infant temperament

Cortisol concentrations of older children in childcare centers have been found to be higher than at home. This study focuses on infant cortisol in childcare centers throughout the first year of life, and aims to investigate whether inter-individual differences can be explained by temperament, the quality of maternal behavior, and the quality of center care. Sixty-four infants were followed for 9 months after entering care at 3 months of age. Salivary samples were taken at 10.00 h and 16.00 h in center care (in post-entry weeks 1, 2, 3, 4, 8, 12, 16, 24, and 36) and at home (in post-entry weeks 1, 24, and 36). Prior to entry, mothers completed a temperament questionnaire and the quality of maternal behavior (sensitivity and cooperation) was observed during routine bathing sessions. Subsequently, the infants were visited three times at center care to observe the quality of infant's interactive experiences with their professional caregiver. Longitudinal regression models showed that both morning and afternoon cortisol were higher in center care compared to home. Longitudinal regression models showed that infants receiving higher quality of maternal behavior displayed higher morning cortisol in center care, compared to infants receiving lower quality of maternal behavior. Higher quality of maternal behavior was also related to higher afternoon cortisol in center care, but only in infants high in negative emotionality. Center care quality was not related to cortisol. In sum, young infants show higher cortisol concentrations in center care that are related to infant temperament and quality of maternal behavior at home.

The Impact of Program Structure on Cortisol Patterning in Children Attending Out-of-Home Child Care

Full-day center-based child care has repeatedly been associated with rising levels of cortisol, a hormone that helps the body manage challenge, across the day at child care. This article presents findings from two studies examining the relationship between child care program structure (number of days per week, and hours per day) and cortisol production across the day. Study 1 presents findings comparing cortisol production in 3- to 5-year-old children enrolled in either full-day (N = 55) or half-day (N = 63) Head-Start-funded programs. Study 2 presents findings comparing young children enrolled in either full-day full-time (5 days per week; N = 37) or full-day part-time (2-3days/week; N = 41) primarily tuition-funded programs. Using multilevel modeling and controlling for a number of child factors, attending full-day, full-time programs (as compared to either half-day or part-time programs) was associated with increased cortisol production across the day on child care and home days. Implications for early childhood educators are discussed.

Closing the achievement gap through modification of neurocognitive and neuroendocrine function: results from a cluster randomized controlled trial of an innovative approach to the education of children in kindergarten

Effective early education is essential for academic achievement and positive life outcomes, particularly for children in poverty. Advances in neuroscience suggest that a focus on self-regulation in education can enhance children's engagement in learning and establish beneficial academic trajectories in the early elementary grades. Here, we experimentally evaluate an innovative approach to the education of children in kindergarten that embeds support for self-regulation, particularly executive functions, into literacy, mathematics, and science learning activities. Results from a cluster randomized controlled trial involving 29 schools, 79 classrooms, and 759 children indicated positive effects on executive functions, reasoning ability, the control of attention, and levels of salivary cortisol and alpha amylase. Results also demonstrated improvements in reading, vocabulary, and mathematics at the end of kindergarten that increased into the first grade. A number of effects were specific to high-poverty schools, suggesting that a focus on executive functions and associated aspects of self-regulation in early elementary education holds promise for closing the achievement gap.

Cortisol levels in response to starting school in children at increased risk for social phobia

BACKGROUND

Research on depression has identified hyperactivity of the HPA axis as a potential contributory factor to the intergenerational transmission of affective symptoms. This has not yet been examined in the context of social phobia. The current study compared HPA axis activity in response to a universal social stressor (starting school) in children of 2 groups of women: one with social phobia and one with no history of anxiety (comparison group). To determine specificity of effects of maternal social phobia, a third group of children were also examined whose mothers had generalised anxiety disorder (GAD).

METHOD

Children provided salivary cortisol samples in the morning, afternoon and at bedtime across 3 time-blocks surrounding the school start: a month before starting school (baseline), the first week at school (stress response), and the end of the first school term (stress recovery). Child behavioural inhibition at 14 months was assessed to explore the influence of early temperament on later stress responses.

RESULTS

All children displayed an elevation in morning and afternoon cortisol from baseline during the first week at school, which remained elevated until the end of the first term. Children in the social phobia group, however, also displayed an equivalent elevation in bedtime cortisol, which was not observed for comparison children or for children of mothers with GAD. Children in the social phobia group who were classified as 'inhibited' at 14 months displayed significantly higher afternoon cortisol levels overall.

SUMMARY

A persistent stress response to school in the morning and afternoon is typical for all children, but children of mothers with social phobia also display atypical elevations in evening cortisol levels when at school--signalling longer-term disruption of the circadian rhythm in HPA axis activity. This is the first study to report HPA axis disruption in children at increased risk of developing social phobia. Future research should determine whether this represents a pathway for symptom development, taking early temperament into account.

Stress, cortisol and well-being of caregivers and children in home-based child care: a case for differential susceptibility

BACKGROUND

We examined whether children cared for by stressed caregivers show lower socio-emotional well-being and more stress, compared with children cared for by less stressed caregivers.

METHODS

Perceived stress and cortisol levels of professional caregivers (n = 44), and associations with children's (n = 44) well-being and cortisol levels in home-based child care were examined.

RESULTS

Caregiver perceived stress and cortisol levels were related to children's well-being but not to children's cortisol levels. Children's social fearfulness acted as a moderator between caregivers' mean ratio of diurnal change in cortisol and children's well-being. When caregiver cortisol levels decreased, more fearful children were reported higher on well-being than less fearful peers. In contrast, when caregiver cortisol levels increased, more fearful children were reported lower on well-being.

CONCLUSIONS

The findings point to differential susceptibility. Child care organizations and parents need to notice that a non-stressful child care environment is in particular important for children with a difficult temperament.

Understanding Cortisol Reactivity across the Day at Child Care: The Potential Buffering Role of Secure Attachments to Caregivers

Full-day center-based child care has been repeatedly associated with rising cortisol across the child care day. This study addressed the potential buffering role of attachment to mothers and lead teachers in 110 preschoolers while at child care. Using multi-level modeling and controlling for a number of child, family, and child care factors, children with more secure attachments to teachers were more likely to show falling cortisol across the child care day. Attachment to mothers interacted with child care quality, with buffering effects found for children with secure attachments attending higher quality child care. Implications for early childhood educators are discussed.

Hypocortisolism as a potential marker of allostatic load in children: associations with family risk and internalizing disorders

Although the majority of research attention to the hypothalamic-pituitary-adrenal (HPA) axis in stress-related disorders and as a marker of allostatic load has focused on overactivation of this stress system, theory and data clearly indicate that underactivation is also an important type of dysregulation. In the current study we focused on low cortisol, exploring a constellation of risk factors including stress exposure, maternal depression, and attenuated basal and stress reactive cortisol in two samples of children. The first sample was comprised of 110 preschoolers living in high-stress environments. Cortisol was assessed across the day at home and at child care as well as across two stress paradigms. These data were used to classify whether children's HPA axis activity was attenuated. Serious family financial strain, maternal depression, and attenuated cortisol all made unique contributions in models predicting current clinical levels of internalizing symptoms as rated by mothers and teachers. The second sample was 166 third, sixth, and ninth graders studied five times across a 1-year period. Maternal and child depression were determined through structured clinical interviews, and stress exposure was assessed via checklist and interview techniques with the child and parent. Cortisol was assessed multiple times across a lab visit at Time 1, and these data were combined into a single continuous measure. Cortisol concentrations across the lab visit interacted with stress exposure across the year such that children with lower average cortisol at Time 1 and increased stress across the 12 months showed elevated levels of internalizing symptoms. Based on these and related data we propose that prior to puberty low cortisol may be an important marker of allostatic load, particularly for risk of depression and anxiety.

Child care setting affects salivary cortisol and antibody secretion in young children

Elevated afternoon levels of cortisol have been found repeatedly in children during child care. However, it is unclear whether these elevations have any consequences. Because physiologic stress systems and the immune system are functionally linked, we examined the relationship between salivary cortisol concentration and antibody secretion across the day at home and in child care, and their relationships with parent-reported illnesses. Salivary antibody provides a critical line of defense against pathogens entering via the mouth, but little is known about its diurnal rhythm in young children or the effect of different environmental contexts. Saliva samples were taken at approximately 10:30 a.m., 3:30 p.m. and 8:00 p.m. on two child care and two home days in a sample of 65 3-5-year-old children attending very high quality, full time child care centers. Results indicated that (1) a rising cortisol profile at child care, driven by higher afternoon levels, predicted lower antibody levels on the subsequent weekend, (2) higher cortisol on weekend days was related to greater parent-reported illness, and (3) a declining daily pattern in sIgA was evident on weekend and child care days for older preschoolers, but only on weekend days for younger preschoolers. The results suggest that elevated cortisol in children during child care may be related to both lowered antibody levels and greater illness frequency.