Daycare attendance, stress, and mental health

Parents' perceptions of their children's mental health during COVID-19: Evidence from Canada

OBJECTIVE

This study examined several factors affecting the perception of Canadian parents about their children's mental health during COVID-19. The contribution of this research included fresh evidence from examining the demographic and sociological factors influencing children's well-being during COVID-19 using the Canadian context.

METHODS

We used a cross-sectional dataset from Statistics Canada titled Impacts of COVID-19 on Canadians - Parenting during the Pandemic (2020). We relied on an ordered logit model and computed the respective odds ratios.

RESULTS

Our results showed that parents with a university degree and those working from home are less concerned about their children's mental health. Nonetheless, having a disabled child, belonging to a minority, having children aged six-to fourteen-years old, and having lost a job or experienced a drop in working hours increased parents' worry. Additionally, having worries about being connected with family and friends, being concerned about work-life balance, feeling lonely at home, and waiting for the reopening of childcare services all increased the likelihood of parents' anxiety about their child's mental health. When running the analysis by province, we saw that being an immigrant and belonging to a minority increased parents' worry only in Ontario and British Columbia.

CONCLUSIONS

Policymakers are encouraged to foster working-from-home practices as working from home has been linked to less worry about child mental health, mainly among mothers, as indicated in our gender heterogeneity analysis. In addition, it is advised that families with a disabled child, and families belonging to a minority received additional support. Lastly, policymakers are advised to consider the social cost of preventive measures and incorporate this into any future preventative policymaking as the social impact variables were robust across all models.

A matter of habit? Stressful life events and cognitive flexibility in 15-month-olds

Exposure to chronic stress is associated with habitual learning in adults. We studied the origins of this association by examining the link between stressful life events and infant cognitive flexibility. The final sample consisted of N = 72 fifteen-month-old infants and their mothers. Mothers completed a survey on pre- and postnatal negative life events. To assess chronic stress physiologically, infant and maternal hair cortisol concentrations were determined for cortisol accumulation during the past 3 months. Each infant participated in two cognitive tasks in the laboratory. An instrumental learning task tested infants' ability to disengage from a habituated action when this action became ineffective (Seehagen et al., 2015). An age-adequate version of the A-not-B task tested infants' ability to find a toy at location B after repeatedly finding it at location A. Correlations between cortisol concentrations and postnatal negative life events (number, perceived impact) did not yield significance. Infant and maternal hair cortisol concentrations were not correlated. Infants' ability to shift to a new action in either task, controlled for acute stress, correlated neither with pre- and postnatal negative life events nor with cortisol concentrations. Taken together, these results indicate that the potential link between long-term stress exposure and cognitive flexibility might not be present in samples with low levels of psychosocial stress.

A Quantitative Study of Early Childhood Care and Education Services Under the Age of Three: Evidence From Sichuan Province, China

In China, early childhood care and education services for children under the age of three are neglected to some extent. Based on survey data from the Health Commission in Sichuan Province of China, this study analyzes the situation of early childhood care and education services in Sichuan through a qualitative method, using an analytical framework of matching the demand and supply. The findings reveal a mismatch between demand and supply of early childhood care and education services. This gap is likely to have a negative impact on children's self-development, family stability, and even the construction of national early childhood care and education service system. Drawing on the findings, suggestions for improving the mismatch between demand and supply are provided at the state, community and institution levels.

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.

Infants' stress responses and protest behaviors at childcare entry and the role of care providers

During the transition from home to childcare, 70 15-month-old infants were videotaped, and their negative emotions were rated. Infants' attachments to mothers were assessed prior to child care entry and to care providers five months later using the Strange Situation Procedure (SSP). Infant heart rate was monitored at home, during adaptation to childcare (mothers present), and during subsequent separations. Respiratory sinus arrhythmia (RSA) was computed from the beat-to-beat measures of heart rate to reflect vagal tone, which is reduced during chronic states of stress, and was collected upon Arrival, during in-group Play, and when in the Group more generally. All infants responded to childcare entry with low RSA levels indicating stress. However, during adaptation with the mother present, RSA was higher for securely attached infants. On the first separation day, 35.3% of the infants fussed and cried extensively. These intense protests predicted later secure attachments to care providers, which adaptively helped to reduce stress, especially in infants who protested extensively, as if summoning their mothers back. Because extensive protest suggests limited regulatory capacities, infants risk overburdening the stress system when left unsupported.

Reframing High-Quality Public Preschool as a Vehicle for Narrowing Child Health Disparities Based on Family Income

Past research shows that high-quality public preschool may disproportionately support low-income children's school readiness because low-income children tend to arrive at school with fewer of the academic skills needed for success. This suggests a compensatory process in human development in which the children who benefit most from a promotive factor are those who stand to gain the most. We propose that high-quality public preschool may similarly confer its greatest health rewards to low-income children, who are generally in poorer health than their peers. If that is true, preschool has the potential to narrow health disparities by income, which without intervention, persist into adulthood. To date, no one has articulated all the pathways through which high-quality public preschool may improve children's health, much less those that should disproportionately benefit those from low-income families. Drawing on the bioecological paradigm of human development, we propose a model identifying specific mechanisms likely to promote equity in child health. These mechanisms reflect core characteristics of high-quality public preschool that may disproportionately benefit low-income children's health. This model serves as a working template for a program of future research.

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.

Child Temperament and Total Diurnal Cortisol in Out-of-Home Center-Based Child Care and in At-Home Parental Care

The association between child temperament characteristics and total diurnal saliva cortisol in 84 children (M = 2.3 years, SD = 0.6) attending out‐of‐home, center‐based child care and 79 children (M = 2.0 years, SD = 0.5) attending at‐home parental care was examined. Saliva samples were collected during two consecutive days, that is, Sunday and Monday, with four samples taken per day. While children higher in surgency had higher total diurnal cortisol production, we did not find evidence that temperament moderated the associations between child‐care context and total diurnal cortisol. Negative affectivity and effortful control were not related to cortisol output. Our findings suggest that temperamental surgency may be associated with higher total cortisol production in early childhood across child‐care settings.

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.

A comparison of child development, growth and illness in home-care and day-care center settings

Purpose

Childcare is an essential part of early life environment that has a significant influence on lifelong physical and mental health. This study aimed to examine the relationship between development, growth and frequency of illness in different types of care.

Design/methodology/approach

This cross-sectional study recruited 177 children aged 30–36 months and their caregivers. Of these 66 were being cared for at home and 111 were attending out-of-home day-care facilities. An interview form, growth measurement and the Denver Developmental Screening Test II were collected. The association between child developmental, growth and illness variables was analyzed with Chi-square, Fisher's exact and Mann–Whitney U tests.

Findings

This study found that the development and growth results did not show statistically significant differences between the home-care and day-care groups. The number of minor illnesses was significantly lower in home-care children than in day-care children (OR = 0.33, 95% CI = 0.15-0.72).

Research limitations/implications

This study indicated that the risk of infection is increased in the children attending day care. Provision of a healthy and safe childcare environment needs to be an essential health promotion strategy to improve family and child well-being.

Originality/value

As the number of women's participation in the labor market has increased rapidly over the past decades, so did the number of children in nonparental care. The study findings reflect that the development of a day-care center for children was unclear, whereas the risk of infection was increased. Therefore, provision of a healthy and safe childcare environment needs to be an essential health promotion strategy to improve family and child well-being.

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.

Children's cortisol response to the transition from preschool to formal schooling: A review

This review examines the current state of knowledge regarding children's biological stress response during the transition from preschool to compulsory formal schooling, focusing on longitudinal studies that include repeated measures of cortisol concentrations in saliva or scalp hair. In all, eight independent studies (ten publications) were found and their results support the hypothesis that the transition from preschool to formal schooling coincides with an increase in cortisol concentration in both saliva and hair. Evidence of recovery (i.e. decrease in stress response over time) is more limited and suggests that it could take as many as 3-6 months before kindergarten children's cortisol concentration returns to baseline levels. However, important individual differences are observed. Potential predictors that have received some empirical support include child temperament (fearfulness/inhibition or surgency/extroversion) and prenatal maternal stress or anxiety. Very few studies, however, have examined whether there are actual functional consequences of individual differences in children's cortisol response associated with this transition. Finally, current methodological limitations and avenues for future studies are discussed.

Testing the impact of a social skill training versus waiting list control group for the reduction of disruptive behaviors and stress among preschool children in child care: the study protocol for a cluster randomized trial

Background

Most preschoolers growing up in western industrialized countries receive child care services (CCS) during the day, while their parents are at work. Meta-analytic data suggest that CCS represent a stressful experience for preschoolers. This may be because preschoolers have not yet developed the social skills necessary to cope with the new and rapidly fluctuating social contexts of CCS. We tested the effectiveness of a child care-based social skill training program aiming to improve children’s social behaviors and reduce the stress they experience.

Method and design

We used a cluster randomized control trial (cRCT) to compare children’s social behaviors and stress levels in pre- and post-intervention according to whether they received a social skill training intervention or not. Nineteen (n = 19) public CCS (n = 362, 3-years-old preschoolers) of underprivileged neighborhoods (Montreal, Canada) were randomized to one of two conditions: 1) social skills training (n = 10 CCS); or 2) waiting list control group (n = 9 CCS). Educators in the intervention group conducted bi-weekly social skills training sessions over a period of 8 months. The intervention covered four topics: making social contacts, problem solving, emotional self-regulation, as well as emotional expression and recognition. Main outcome measures included preschoolers’ disruptive (e.g. aggression, opposition, conflicts) and prosocial behaviors (e.g. sharing toys, helping another child), and stress levels assessed by salivary cortisol sampling at pre and post intervention assessments. Educators’ practices will be tested as potential mediators of the expected changes in behaviors and neuroendocrine stress.

Discussion

To our knowledge, this is the first cRCT to test the effectiveness of a child care based social skill training program on the reduction of disruptive behaviors and levels of stress. Significant challenges include the degree of adherence to the intervention protocol as well educators and preschoolers’ turnover.

Trial registration

Current clinical trial number is ISRCTN84339956 (Ongoing study, Retrospectively registered on March 2017) No amendment to initial protocol.

Electronic supplementary material

The online version of this article (doi:10.1186/s40359-017-0197-9) contains supplementary material, which is available to authorized users.

Social Buffering of Stress in Development: A Career Perspective

This review provides a broad overview of my research group's work on social buffering in human development in the context of the field. Much of the focus is on social buffering of the hypothalamic-pituitary-adrenocortical (HPA) system, one of the two major arms of the mammalian stress system. This focus reflects the centrality of the HPA system in research on social buffering in the fields of developmental psychobiology and developmental science. However, buffering of the cardiovascular and autonomic nervous system is also discussed. The central developmental question in this area derives from attachment theory, which argues that the infant's experience of stress and arousal regulation in the context of her early attachment relationships is not an immature form of social buffering experienced in adulthood but rather the foundation out of which individual differences in the capacity to gain stress relief from social partners emerges. The emergence of social buffering in infancy, changes in social buffering throughout childhood and adolescence, the influence of early experience on later individual differences in social buffering, and critical gaps in our knowledge are described.

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.

Cohort profile for the Nurture Observational Study examining associations of multiple caregivers on infant growth in the Southeastern USA

PURPOSE

Childcare has been associated with obesity in children in cross-sectional and longitudinal studies, although some observed no association. Few studies have focused on care during infancy, a period when children may be especially vulnerable.

PARTICIPANTS

The Nurture Study is an observational birth cohort designed to assess longitudinal associations of childcare and the presence of multiple caregivers on infant adiposity and weight trajectories throughout the first year of life. We examine as potential mediators feeding, physical activity, sleep and stress. We completed recruitment in 2015. Of the 860 women who enrolled during pregnancy, 799 delivered a single live infant who met our inclusion criteria. Of those, 666 mothers (77.4%) agreed to participate in the study for themselves and their infants.

FINDINGS TO DATE

Among the 666 women in the study, 472 (71%) identified as black, 127 (19%) as white, 7 (1%) as Asian or Asian American, 6 (1%) as Native American and 49 (7%) as other race or more than one race; 43 (7%) identified as Hispanic/Latina. Just under half (48%) had a high school diploma or less, 61% had household incomes <$20 000/year and 59% were married or living with a partner. The mean (SD) infant gestational age was 41.28 weeks (2.29) and birth weight for gestational age z-score was -0.31 (0.93). Just under half (49%) of infants were females, 69% received some human milk and 40% were exclusively breast fed at hospital discharge. Data collection began in 2013, is currently underway, and is scheduled to conclude in late 2016.

FUTURE PLANS

Results will help assess the magnitude of associations between childcare in infancy and subsequent obesity. Findings will also inform intervention and policy efforts to improve childcare environments and help prevent obesity in settings where many infants spend time.

TRIAL REGISTRATION NUMBER

Clinicaltrials.gov, NCT01788644.

Child Care and Cortisol Across Infancy and Toddlerhood: Poverty, Peers, and Developmental Timing

Evidence suggests that relations between child care and children's development-behaviorally and physiologically-likely differ between children from high-versus low-risk contexts. Using data from the Family Life Project (N = 1,155), the authors tested (a) whether within- and between-child differences in children's child care experiences (i.e., quantity, type, caregiver responsivity, and peer exposure) were predictive of their cortisol levels across infancy and toddlerhood and (b) whether these relations differed for children experiencing different levels of environmental risk. They found some evidence of such interactive effects. For children from high-risk contexts, within-child increases in child care hours were predictive of cortisol decreases. The inverse was evident for children from low-risk contexts. This relation grew across toddlerhood. Whereas a history of greater center-based child care was predictive of heightened cortisol levels for low-risk families, this was not the case for children from high-risk families. Irrespective of risk, greater peer exposure (between children) was associated with lower cortisol levels.

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.

[Formula: see text]Higher cortisol is associated with poorer executive functioning in preschool children: The role of parenting stress, parent coping and quality of daycare

Child executive functions (cognitive flexibility, inhibitory control, working memory) are key to success in school. Cortisol, the primary stress hormone, is known to affect cognition; however, there is limited information about how child cortisol levels, parenting factors and child care context relate to executive functions in young children. The aim of this study was to examine relationships between child cortisol, parenting stress, parent coping, and daycare quality in relation to executive functions in children aged 3-5 years. We hypothesized that (1) poorer executive functioning would be related to higher child cortisol and higher parenting stress, and (2) positive daycare quality and positive parent coping style would buffer the effects of child cortisol and parenting stress on executive functions. A total of 101 children (53 girls, 48 boys, mean age 4.24 years ±0.74) with complete data on all measures were included. Three saliva samples to measure cortisol were collected at the child's daycare/preschool in one morning. Parents completed the Behavior Rating Inventory of Executive Function - Preschool Version (BRIEF-P), Parenting Stress Index (PSI), and Ways of Coping Questionnaire (WCQ). The Early Childhood Environment Rating Scale - Revised (ECERS-R) was used to measure the quality of daycare. It was found that children with poorer executive functioning had higher levels of salivary cortisol, and their parents reported higher parenting stress. However, parent coping style and quality of daycare did not modulate these relationships. Identifying ways to promote child executive functioning is an important direction for improving school readiness.

Correlation between maternal and infant cortisol varies by breastfeeding status

OBJECTIVE

The objective of this study was to examine associations of mother and infant salivary cortisol, measured three times over the course of a day, and assess whether these varied by breastfeeding status.

METHODS

We conducted a cross-sectional study of 54 mothers and their infants aged 4-11 months. Mothers collected their own saliva and that of their infants upon awakening, 30min after waking and at bedtime. Breastfeeding status was reported by mothers and cortisol level was measured in saliva in μg/dl using standard techniques. We used generalized linear models to evaluate relationships between maternal and infant cortisol levels, and assessed whether the relationship differed by breastfeeding status: formula only compared to partial and full breastfeeding, adjusting for infant sex, race, age, maternal education, and family income.

RESULTS

Thirty-four infants received formula only and 20 were either partially or fully breastfed. Breastfeeding was associated with higher household income, higher maternal education, and white race. Cortisol levels were higher among breastfed infants at all three time points. After adjustment, maternal cortisol levels were related with infant cortisol at bedtime only (regression estimate 0.06; 95% CI: 0.10, 1.1; p=0.02). The adjusted association between bedtime maternal and infant cortisol was stronger among breastfeeding dyads than among formula-feeding dyads (regression estimate 1.0; 95% CI: 0.1, 2.0; p=0.04 vs. 0.6; CI: -0.1, 1.3; p=0.10). In addition, we assessed the influence of maternal education and household income in our adjusted model; income strengthened the observed association, whereas maternal education did not change the estimate.

CONCLUSIONS

Breastfeeding mothers and infants had significant correlations for cortisol at bedtime, while formula-feeding dyads did not. These data suggest that several factors may contribute to cortisol synchrony observed in mother/infant dyads, including the transfer of cortisol in human milk, physical interaction such as skin-to-skin contact, and shared environment. In addition, our findings support household income as a possible contributor.

Examining change in cortisol patterns during the 10-week transition to a new child-care setting

The transition to out-of-home child care brings a number of challenges for children, including complex peer interactions and extended separations from parents. Children often show a midmorning to afternoon rise in cortisol on child-care days, compared to the typical diurnal decline seen at home. Changes in cortisol were examined in a wide age range of children (N = 168; 1.2 months to 8 years, M = 3.27 years) during the 10-week transition to a new child-care setting. Structural equation modeling using latent change scores showed that children experienced an increase in the cortisol rise at child care across the 10-week transition. Furthermore, child age moderated the difference between home- and child-care cortisol patterns. Findings are placed in a developmental context, and potential implications and future directions are discussed.

Neonatal amygdala lesions alter basal cortisol levels in infant rhesus monkeys

The amygdala is mostly thought to exert an excitatory influence on the hypothalamic-pituitary-adrenal (HPA) axis, although its role regulating HPA basal tone is less clear, particularly during primate development. The current study examined the effects of neonatal amygdala lesions on basal HPA function and the postnatal testosterone (T) surge of rhesus monkeys reared with their mothers in large outdoor social groups. An early morning basal blood sample was collected at 2.5 months of age, whereas at 5 months samples were collected not only at sunrise, but also at mid-day and sunset to examine the diurnal rhythm of cortisol. At 2.5 months of age sham-operated males exhibited higher cortisol than females, but this sex difference was abolished by neonatal amygdalectomy, with lesioned males also showing lower basal cortisol than controls. Although neonatal amygdalectomy did not alter the postnatal T surge, there was a positive relationship between T and basal cortisol levels. At 5 months of age, neither the sex difference in cortisol, nor its correlation with T levels were apparent any longer. Instead, the diurnal cortisol rhythm of both males and females with amygdalectomy showed a blunted decline from mid-day to sunset compared to controls. These results indicate that neonatal amygdala damage alters basal HPA function in infant rhesus monkeys, affecting males only at early ages (at 2.5 months), while leaving the postnatal T surge intact, and resulting in a flattened diurnal rhythm in both genders at the later ages. Thus, the primate amygdala has a critical influence on the HPA axis in the first few months of life.

Salivary cortisol measurement in developmental research: where do we go from here?

Salivary cortisol has been measured extensively in developmental research over the last three decades. The purpose of this article is to summarize the contributions to and limitations of salivary cortisol measurement in developmental research and propose future directions for research that includes salivary cortisol measurement. The properties of cortisol, the history of its burgeoning popularity, and the utility and limitations of (a) cortisol as a biological indicator, (b) saliva as a source of cortisol, and (c) various saliva collection methodologies are described. The current state of understanding about what is and is not reliably predictable from cortisol is summarized and the value of salivary cortisol measurement in developmental research is discussed, addressing whether methodology could be driving research design. Recommendations are made for streamlining study design and reporting within developmental research.

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.

Larger amygdala but no change in hippocampal volume in 10-year-old children exposed to maternal depressive symptomatology since birth

Maternal separation and poor maternal care in animals have been shown to have important effects on the developing hippocampus and amygdala. In humans, children exposed to abuse/maltreatment or orphanage rearing do not present changes in hippocampal volumes. However, children reared in orphanages present enlarged amygdala volumes, suggesting that the amygdala may be particularly sensitive to severely disturbed (i.e., discontinous, neglectful) care in infancy. Maternal depressive symptomatology has been associated with reductions in overall sensitivity to the infant, and with an increased rate of withdrawn, disengaged behaviors. To determine if poor maternal care associated with maternal depressive symptomatology has a similar pattern of association to the volumes of the hippocampus and amygdala in children, as is the case for severely disturbed infant care (orphanage rearing), we measured hippocampal and amygdala volumes as well as stress hormone (glucocorticoid) levels in children exposed (n = 17) or not (n = 21) to maternal depressive symptomatology since birth. Results revealed no group difference in hippocampal volumes, but larger left and right amygdala volumes and increased levels of glucocorticoids in the children of mothers presenting depressive symptomatology since birth. Moreover, a significant positive correlation was observed between mothers' mean depressive scores and amygdala volumes in their children. The results of this study suggest that amygdala volume in human children may represent an early marker of biological sensitivity to quality of maternal care.

Differential susceptibility to long-term effects of quality of child care on externalizing behavior in adolescence?

Much research on the quality of child care reveals it —in the case of low-quality child care—to be related to poorer child functioning, net of confounding factors, perhaps especially in the case of cognitive-linguistic performance. Recent work using data from the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care and Youth Development (USA) makes clear that when children’s early negative emotionality/difficult temperament is taken into account, it also predicts externalizing problems reported by teachers through the primary school years. More negatively emotional infants are more affected—for better and for worse—by child care quality than less difficult ones, such that the latter appear unaffected by it but the former benefit from good quality care and are adversely affected by poor quality care. Here we determine whether the same is true when children are restudied in adolescence and the focus is their own reports of externalizing problems, impulsivity and risk taking. Results prove more consistent with a diathesis-stress model of environmental action than a differential-susceptibility-related one, in that 15-year-olds who were highly negative as infants report more externalizing behavior (but not risk taking or impulsivity) if they experienced low-quality child care, but not fewer problems if they experienced high-quality care relative to their counterparts with less difficult temperaments in infancy. Results are discussed in relation to physiological stress, with possible explanations offered as to why the predictive nature of child care experience might change over time.

Early care, education, and child development

Children growing up in the United States today typically spend a substantial portion of their early childhood years in early care and education (ECE) settings. These settings are thus an essential element of any effort to understand the ecology of early development. Research aimed at identifying the short- and long-term impacts of ECE experiences has a long history, the results of which now point to three key conclusions. (a) Although parents are the most important influence on children's development, ECE experiences have both short- and long-term impacts on a wide range of developmental outcomes that are best understood in interaction with family effects. (b) The quality of adult-child interactions in ECE settings is the most potent source of variation in child outcomes, although the amount of exposure to these settings also plays a role, perhaps especially with regard to social-emotional development. (c) Some children, notably those growing up in poverty, appear to be more vulnerable to variation in the quality of ECE settings than do other children. The frontiers of ECE research are addressing individual differences in children's responses to child care and approaching these settings both as sites for intervention research and as part of a wider web of important settings in young children's lives.

The effect of day care attendance on infant and toddler's growth

AIM

We aimed to study the association between day care attendance and changes in the height, weight and weight/height ratio over a 6-month period.

METHODS

Data were retrieved from three maternal and child health care centres. Parents were asked to fill a short questionnaire regarding the infant/toddler life style, the day care facilities and the family demographic information.

RESULTS

One hundred and seventy infants participated in the study. The research group consisted of 85 infants that had placed in day care centre prior to the age of 18 months. The control group consisted of 85 infants who had placed in day care at a later age. The research group had significantly shorter stature 3 months after day care enrolment (mean height percentiles of 56.9 versus 66.3, respectively, p = 0.024,). This trend was more pronounced after 6 months (mean height percentiles of 52.3 versus 63.7, p = 0.022). We could not, however, demonstrate a concomitant significant deceleration in weight or weight/height percentiles.

CONCLUSIONS

The explanation for this rather dramatic finding remains speculative. Possible mechanisms are stress-related growth hormone suppression. Our findings reinforce the importance of monitoring infant/toddler weight and height growth velocities, especially when he/she is introduced to day care.

Association between attendance of day care centres and increased prevalence of eczema in the German birth cohort study LISAplus

BACKGROUND

Day care centre attendance is much more common in East than in West Germany. Although there is evidence that early day care might be protective against atopic diseases, several studies have shown a higher prevalence of childhood eczema in East Germany compared to West Germany.

OBJECTIVES

To compare prevalence and cumulative incidence of eczema in a birth cohort study in East and West Germany and to identify risk factors that are associated with eczema, which might explain regional differences.

METHODS

We used data from the ongoing population-based birth cohort study Influence of Life-style factors on the development of the Immune System and Allergies in East and West Germany Plus the influence of traffic emissions and genetics. In 1997, 3097 children from study areas in East and West Germany were recruited. Cumulative incidence and 1-year prevalences of eczema up to the age of 6 years were determined from yearly questionnaires. Cox regression and generalized estimating equations/logistic regression were used to quantify regional differences and to identify risk factors that might explain them.

RESULTS

Prevalence and incidence of eczema were higher in children living in East Germany than those living in West Germany. We identified 11 risk factors that showed significant regional differences. From these factors, only 'day care attendance during the first 2 years of life' was significantly associated with eczema (odds ratio 1.56, 95% confidence interval CI 1.31-1.86). The regional differences in eczema could be explained by differences in early day care utilization.

CONCLUSION

Day care centre attendance is associated with an increased prevalence and incidence of eczema. Regional differences in eczema prevalence could be explained by regional differences in utilization of early day care.

The rise in cortisol in family day care: associations with aspects of care quality, child behavior, and child sex

This study examined the increase in salivary cortisol from midmorning to midafternoon in 151 children (3.0-4.5 years) in full-time home-based day care. Compared to cortisol levels at home, increases were noted in the majority of children (63%) at day care, with 40% classified as a stress response. Observations at day care revealed that intrusive, overcontrolling care was associated with the cortisol rise. For girls, the cortisol rise was associated with anxious, vigilant behavior, while for boys the rise was associated with angry, aggressive behavior. Child behavior did not mediate or moderate relations between care quality and the cortisol rise, except for evidence that boys scoring low on angry, aggressive behavior were more sensitive to variations in warm, supportive care than boys scoring high on this behavior.

Associations among child care, family, and behavior outcomes in a nation-wide sample of preschool-aged children

Canadian data based on maternal reports for a nationally representative sample of 4,521 4—5-year-olds were used to examine associations among child care, family factors, and behaviors in preschool-aged children. Linear regressions testing for direct and moderated associations indicated that regulated home-based care was associated with less physical aggression and less prosocial behavior while high process quality in home-based care was associated with greater prosocial behavior. Among children in home-based settings, being in at least one additional current child care arrangement was linked with greater physical aggression, and low child care stability was linked to greater hyperactivity-inattention, internalizing behavior, and prosocial behaviors. For family factors, parenting behaviors and maternal depression were associated with greater behavioral problems while low household income was linked with greater hyperactivity-inattention among children in home-based care. There was a significant interaction between process quality and household income for physical aggression and internalizing behavior and between structure quality and parenting consistency for prosocial behavior for children in home-based care. Results suggest that child care matters for preschool behavioral outcomes, even after controlling for socio-demographic factors. High quality care appears particularly important for children in home-based care from low-income families so issues around child care quality and regulation should be considered. Findings also underscore the importance of family factors on young children’s behaviors and show that child care and family influences work together to impact child outcomes.

Diurnal cortisol secretion at home and in child care: a prospective study of 2-year-old toddlers

BACKGROUND

Previous studies indicate that children may experience disrupted cortisol secretion in child care. The extent to which this is a transient or long-term disruption is not known, as most studies have relied on cross-sectional designs, and age-heterogeneous small sample sizes. This study aims to (a) compare cortisol secretion measured at home and in child care at 2 and 3 years of age, (b) investigate cortisol changes from 2 to 3 years of age, (c) examine whether age at initiation of child care is associated with cortisol secretion, and (d) investigate whether cortisol secretion in child care is linked to behavioural problems.

METHODS

Saliva samples were collected in a cohort of children recruited at 2 years of age from a larger population sample composed of women seen for the first time during pregnancy. Saliva was sampled twice a day (morning and afternoon) over two consecutive days at home and in child care at 2 (n = 155) and 3 years of age (n = 116). Interviews regarding the familial socioeconomic background and child care history were conducted with the mothers.

RESULTS

At 2 years of age, children showed a flat diurnal cortisol pattern in child care and a decreasing pattern at home. At age 3 years, children showed decreasing patterns both at home and in child care. Also at 3 years, children with less child care experience (i.e., entry after 16 months) had higher cortisol levels in child care and lower levels at home. In contrast, those with more experience (i.e., entry prior to 8 months) had lower cortisol in child care and higher cortisol at home.

CONCLUSION

The different patterns of diurnal secretion observed in child care as compared to home is transient for most children, diminishing as they get older, whereas home and child care overall levels later on may be influenced by the cumulated experience with child care.

Early family and child-care antecedents of awakening cortisol levels in adolescence

This study examined early observed parenting and child-care experiences in relation to functioning of the hypothalamic-pituitary-adrenocortical axis over the long term. Consistent with the attenuation hypothesis, individuals (n = 863) who experienced: (a) higher levels of maternal insensitivity and (b) more time in child-care centers in the first 3 years of life had lower awakening cortisol levels at age 15. Associations were small in magnitude. Nonetheless, results were (a) additive in that both higher levels of maternal insensitivity and more experience with center-based care uniquely (but not interactively) predicted lower awakening cortisol, (b) not accounted for by later caregiving experiences measured concurrently with awakening cortisol at age 15 or by early demographic variables, and (c) not moderated by sex or by difficult temperament.

Effects of stress throughout the lifespan on the brain, behaviour and cognition

Chronic exposure to stress hormones, whether it occurs during the prenatal period, infancy, childhood, adolescence, adulthood or aging, has an impact on brain structures involved in cognition and mental health. However, the specific effects on the brain, behaviour and cognition emerge as a function of the timing and the duration of the exposure, and some also depend on the interaction between gene effects and previous exposure to environmental adversity. Advances in animal and human studies have made it possible to synthesize these findings, and in this Review a model is developed to explain why different disorders emerge in individuals exposed to stress at different times in their lives.