Evening Activities as a Potential Confound in Research on the Adrenocortical System in Children

Experiences of adversity in childhood and adolescence and cortisol in late adolescence

Early life adversity influences the diurnal cortisol rhythm, yet the relative influence of different characteristics of adversity remains unknown. In this study, we examine how developmental timing (childhood vs. adolescence), severity (major vs. minor), and domain of early life adversity relate to diurnal cortisol rhythms in late adolescence. We assessed adversity retrospectively in early adulthood in a subsample of 236 participants from a longitudinal study of a diverse community sample of suburban adolescents oversampled for high neuroticism. We used multilevel modeling to assess associations between our adversity measures and the diurnal cortisol rhythm (waking and bedtime cortisol, awakening response, slope, and average cortisol). Major childhood adversities were associated with flatter daily slope, and minor adolescent adversities were associated with greater average daily cortisol. Examining domains of childhood adversities, major neglect and sexual abuse were associated with flatter slope and lower waking cortisol, with sexual abuse also associated with higher cortisol awakening response. Major physical abuse was associated with higher waking cortisol. Among adolescent adversities domains, minor neglect, emotional abuse, and witnessing violence were associated with greater average cortisol. These results suggest severity, developmental timing, and domain of adversity influence the association of early life adversity with stress response system functioning.

Infant diurnal cortisol predicts sleep

The sleep-wake system is immature at birth and develops in parallel with the hypothalamic-pituitary-adrenal axis, a biological stress system of which the end product is cortisol. Perturbations in one system during infancy can maladaptively influence the maturation of the other system, leading to lasting sleep and cortisol system dysregulation and heightening the risk of enduring health problems. To better understand the early interplay between these systems, we examined whether actigraphy-derived measures of night-time sleep duration and onset were associated with cumulative exposure to cortisol, indexed by hair cortisol concentration, in 12-month-old children. Overall, early sleep onset predicted lower hair cortisol above and beyond sleep duration, family income and chaos experienced at home. Furthermore, both sleep and cortisol levels vary day to day, and temporal dependencies between daily sleep and cortisol regulation are not well understood. Thus, we assessed how the sleep characteristics on a particular evening related to salivary cortisol levels the following day and how daytime and evening cortisol related to the sleep characteristics on the same night. Lower total exposure to cortisol on a particular day was related to longer night-time sleep duration the same night, but not sleep onset. Lower salivary cortisol levels on a given evening related to earlier sleep onset the same night, but not to night-time sleep duration. Sleep duration and onset on a given night were unrelated to total cortisol exposure the following day. Findings suggest that in early development, the day-to-day relation between sleep and cortisol is not bidirectional, but more driven by diurnal cortisol.

Pubertal transition with current life stress and support alters longitudinal diurnal cortisol patterns in adolescents exposed to early life adversity

Current and early life stress (ELS) are associated with diurnal cortisol patterns, which themselves are associated with mental and physical health. The pubertal recalibration hypothesis suggests that the social environment can impact dysregulated cortisol patterns for previously ELS-exposed youth as they transition through puberty. This study examined longitudinal change in cortisol awakening response (CAR) and diurnal slope (DS) across puberty as a function of ELS in infancy, current stress, and social support (N = 290, 7-17 years). The CAR and DS were examined thrice annually with an accelerated longitudinal design with nurse-assessed puberty to assess associations between diurnal cortisol and pubertal recalibration with ELS and the current social environment. Exposure to ELS was associated with less steep DS but not changes in CAR, and no evidence of pubertal calibration was found. The DS became less steep for youth in later pubertal stages and as youth progressed through puberty. The CAR was steeper for youth in later pubertal stages. Across the cohort, current life stress and support were associated with changes in the DS and the CAR through the pubertal transition. The pubertal stage and the peripubertal and pubertal social environment may have important implications for adrenocortical functioning with or without exposure to ELS.

Sex-Differentiated Associations among Negative Parenting, Emotion-Related Brain Function, and Adolescent Substance Use and Psychopathology Symptoms

Parenting is a critical factor in adolescent social-emotional development, with maladaptive parenting leading to risk for the development of psychopathology. However, the emotion-related brain mechanisms underlying the influence of parenting on psychopathology symptoms are unknown. The present study utilized functional magnetic resonance imaging and laboratory measures to examine sex-differentiated associations among parenting, adolescent emotion-related brain function, and substance use and psychopathology symptoms in 66 12-14 year olds. Maternal parenting behaviors (warmth, negative parenting) were observed in a laboratory task. Adolescent brain responses to negative emotional stimuli were assessed in emotion processing regions of interest (left [L] and right [R] amygdala, anterior insula, anterior cingulate cortex [ACC]). Adolescents reported on substance use and depressive, anxiety, and externalizing symptoms. Maternal negative parenting predicted adolescent brain activation differently by sex. For girls, negative parenting predicted heightened R ACC activation to negative emotional stimuli. For boys, negative parenting predicted blunted L and R anterior insula and L ACC activation. Furthermore, for girls, but not boys, heightened L anterior insula and heightened L and R ACC activation were associated with substance use and depressive symptoms, respectively. Findings suggest neural response to negative emotion as a possible sex-specific pathway from negative parenting to psychopathology.

Bullying the Brain? Longitudinal Links Between Childhood Peer Victimization, Cortisol, and Adolescent Brain Structure

Background: Childhood peer victimization is a stressful life experience associated with long-lasting adverse psychological consequences. While there is some evidence that victimization is associated with alterations in brain function, little is known about effects on brain structure. This study explored the relationships between childhood peer victimization, cortisol, and adolescent ventrolateral prefrontal cortex (vlPFC) structure in a sample of healthy children.

Methods: A total of 50 (M_age = 9.29 years at baseline) children participated in this longitudinal study. We examined whether diurnal cortisol levels (assessed at baseline) moderated the link between children’s self-reported peer victimization (assessed at baseline) and vlPFC surface area, gray matter volume, and thickness 5 years later.

Results: For boys, cortisol levels moderated the association between victimization and brain structure. For boys with a low daily cortisol output (assessed as area under the curve; AUC), high victimization was associated with a smaller right vlPFC surface area, and for boys with a high AUC, high victimization was associated with a larger right vlPFC surface area. In addition, for boys with a steeper diurnal slope, high victimization was associated with a smaller right vlPFC surface area, and for boys with a low flatter diurnal slope, high victimization was associated with a larger right vlPFC surface area.

Conclusion: These results indicate the differential influence of cortisol on the relationship between victimization and brain structure. Findings suggest that victimization may have differential effects on brain development in boys who are more versus less biologically sensitive to stress.

Maternal Emotional and Physiological Reactivity: Implications for Parenting and the Parenting-Adolescent Relationship

OBJECTIVE

Parent physiology and emotion may play an important role in parenting and parent-child relationship quality, yet little research has examined these associations in parents of adolescents. This study employed a naturalistic laboratory-based approach to observe maternal reactivity (mothers' cardiovascular and negative emotional responses) during a parent-adolescent interaction task (PAIT) and associations with parenting behavior and parent-adolescent relationship quality. We also examined possible indirect effect of maternal reactivity on parent-adolescent relationship quality through parenting variables.

METHODS

Mothers (n = 196) of 12-14 year olds completed the PAIT, a 10-minute laboratory task in which mothers and adolescents discussed a family conflict topic. Mother-rated negative emotional experience, mother heart rate (HR), and systolic and diastolic blood pressure (BP) responses to PAIT were collected. Additionally, observed maladaptive and positive parenting during PAIT and reported parent-adolescent relationship quality were collected.

RESULTS

We found that mothers' heightened negative emotional experience in PAIT was associated with heightened observed and reported maladaptive parenting and lower parent-adolescent relationship quality (p<.001). Additionally, blunted HR reactivity was related to higher positive parenting in PAIT (p<.05). Lastly, we found an indirect effect of HR on parent-adolescent relationship through positive parenting and an indirect effect of maternal negative emotional experience on parent-adolescent relationship quality through maladaptive and positive parenting. In sum, high emotional reactivity and blunted HR predicted poorer parenting, and directly and indirectly affected parent-adolescent relationship quality.

CONCLUSIONS

Parent reactivity may be important to consider in interventions.

Affective and physiological response to a novel parent-adolescent conflict stressor

Few laboratory paradigms exist that expose adolescents to conflict that might commonly be experienced in parent-adolescent relationships. Given the continued importance of parent-adolescent relationships on adolescent development, as well as the changing expectations in these relationships, we examined the effect of a novel parent-adolescent conflict paradigm on physiological and affective response in a sample of 52 adolescents. The parent-adolescent conflict stressor (PACS) involved adolescent participants (50% girls; M = 14.75, SD = 0.88) watching a 12-minute scripted video that asked youth to imagine that they were the teenager in the video, which consisted of parent and adolescent actors having discussions about conflict in their relationship and solving this conflict in either a positive, typical, or hostile manner. Cortisol, alpha amylase, and self-report of negative and positive affect were collected at baseline, following the video, and during a recovery period. Heart rate also was taken continuously while adolescents watched the videos. Hierarchical linear modeling (HLM) analyses indicated significant linear change in alpha amylase and linear and quadratic change in negative affect to the PACS. There also was a significant linear and quadratic change in heart rate during the portion of the video where teens and parents discussed issues of personal responsibility. The PACS marks a preliminary but important first step in developing a parent-adolescent conflict paradigm that can be used across studies to understand the impact of parent-adolescent conflict on affective and physiological markers associated with stress response.

The role of stress response in the association between autonomy and adjustment in adolescents

Developing autonomy is an important developmental task that has implications for adolescent adjustment and may be impacted by adolescents' response to stress. This study examined whether stress reactivity (i.e., cortisol and heart rate reactivity) to a parent-adolescent conflict interaction moderates the effect of autonomy on adjustment assessed one year later in 100 adolescents (M age = 15.09; 68% girls). Multiple group models suggested that youth who evidenced higher stress reactivity when compared to those with lower stress reactivity were more likely to report decreased externalizing problems and internalizing problems when their parents granted more autonomy. In contrast, youth who evidenced higher stress reactivity who experienced undermining of autonomy were more likely to report increased externalizing and internalizing problems than youth who evidenced lower stress reactivity. Results support biological sensitivity to context theory and highlight the importance of considering individual differences in the effect of developmental milestones on adolescents' adjustment.

Global variation in diurnal cortisol rhythms: evidence from Garisakang forager-horticulturalists of lowland Papua New Guinea

The hypothalamic-pituitary-adrenal (HPA) axis represents an important and evolutionarily ancient biological pathway linking physical and psychological stressors with human health. Despite considerable research exploring the physiological stress response among developed populations, few studies have examined HPA activity in non-industrialized contexts, restricting understanding of variation in human stress reactivity across global socio-ecological diversity. The present study addresses this shortcoming by investigating diurnal cortisol rhythms among Garisakang forager-horticulturalists of remote, lowland Papua New Guinea. Using a large sample of repeated salivary cortisol measurements from 169 participants (age 4-70 years), multilevel growth curve models were constructed to assess Garisakang waking cortisol concentrations and diurnal cortisol slopes. As predicted, results demonstrate identifiable but substantially diminished diurnal cortisol rhythms relative to those of industrialized populations. Sample-wide, Garisakang cortisol concentrations are highest upon waking (mean = 4.86 nmol/L) and decrease throughout the day at a mean rate of only -0.18 nmol/L/h or -6.20%/h. Age and sex significantly predict evaluated cortisol parameters in ways not consistently reported among industrialized populations, suggesting that Garisakang diurnal cortisol rhythms are defined by distinct ontogenetic trajectories across the lifespan. These findings highlight cross-cultural diversity in HPA activity and have important implications for understanding basic mechanisms of the physiological stress response in contexts of chronic physical stressors such as limited nutrition, heavy burden of infectious disease, and high levels of physical activity.

Psychosocial Influences on Acceptability and Feasibility of Salivary Cortisol Collection From Community Samples of Children

Salivary cortisol is considered to be a safe and noninvasive measure of hypothalamic-pituitary-adrenal axis functioning, and is a commonly measured biomarker of the human stress response in pediatric research. However, cortisol is highly variable and sensitive to a wide range of factors, creating a challenge for reliable salivary cortisol collection in the community setting. Furthermore, the acceptability of salivary cortisol collection in community samples of children is largely unknown. The purpose of this integrative review was to investigate current evidence on the acceptability and feasibility of salivary cortisol collection in community samples of children. In an analysis framed by the Theory of Planned Behavior, data extracted from 31 studies revealed six categories of psychosocial influences on acceptability and feasibility: uncertainty and misconceptions, cultural and ethnic values, family rules and values, difficulty following protocols and procedures, burden of multiple samples, and child refusal or resistance. Further research is required to fully understand the factors that influence acceptability and feasibility of salivary cortisol collection in community samples of children. Understanding individual, family, and community perceptions of biobehavioral research will lead to more culturally sensitive and feasible community-based research methods. © 2016 Wiley Periodicals, Inc.

Effect of Pet Dogs on Children's Perceived Stress and Cortisol Stress Response

The present study tested whether pet dogs have stress-buffering effects for children during a validated laboratory-based protocol, the Trier Social Stress Test for Children (TSST-C). Participants were 101 children aged 7-12 years with their primary caregivers and pet dogs. Children were randomly assigned in the TSST-C to a pet present condition or one of two comparison conditions: parent present or no support figure present. Baseline, response, and recovery indices of perceived stress and cortisol levels were computed based on children's self-reported feelings of stress and salivary cortisol. Results indicated that in the alone (no social support) condition, children showed the expected rise for both perceived stress and cortisol response to stress. Pet dog presence significantly buffered the perceived stress response in comparison to children in the alone and parent present conditions. No main condition effect was observed for cortisol; however, for children experiencing the stressor with their pet present, lower cortisol response to stress was associated with more child-initiated petting and less dog proximity-seeking behavior. The results support the notion that pet dogs can provide socio-emotional benefits for children via stress buffering.

Associations Among Academic Achievement, Attention, and Adrenocortical Reactivity in Caribbean Village Children

This study examined associations among academic achievement problems, attention problems, and cortisol levels in 86 children (ages 5 to 12) in St. Vincent, the West Indies. Findings revealed that morning cortisol levels were more elevated at school than at home. Attention problems contributed negatively to academic scores. Children with the most attention problems showed greater school relative to home cortisol elevations than did other children. Once the variance due to attention problems was accounted for, the interaction between attention problems and cortisol elevation explained additional variance in academic scores. There was some evidence that attention problems and cortisol reactivity were associated. Furthermore, greater cortisol reactivity was correlated with the academic difficulties of children who exhibited more attention problems.

Associations between parents' marital functioning, maternal parenting quality, maternal emotion and child cortisol levels

Associations between family functioning and children's stress hormone levels are explored, by examining how aspects of the interparental relationship (parents' marital satisfaction and parent conflict styles), the mother—child relationship (maternal involvement and warmth) and maternal emotional functioning (depression, anxiety and self-esteem) relate to children's cortisol levels. Parents of 63 children (32 kindergarten-aged children, 31 adolescents) completed questionnaires regarding family and individual functioning, and children's salivary cortisol samples were collected on two consecutive weekdays at home immediately upon waking and at bedtime, such that wakeup, bedtime and average levels and the slope of their diurnal cortisol rhythms could be estimated. Higher marital functioning was significantly and independently associated with lower child cortisol levels (average levels and wakeup levels), while maternal parenting quality and emotional functioning were not significant when included in the same regression model. Associations between parents' marital functioning and children's bedtime cortisol levels and diurnal slopes were moderated by child age, with higher parent marital functioning being associated with a significantly greater lowering of bedtime levels and steeper diurnal slopes for kindergarten-aged children as compared to adolescents. Higher maternal parenting quality was found to be significantly related to steeper diurnal cortisol rhythms.

Parental-adolescent drug use discussions: physiological responses and associated outcomes

PURPOSE

Although talking to youth about drugs is often recommended to parents, we know little about how parents actually discuss drugs with their children in the moment and how parental advice is linked to youth arousal and substance use. This study examined observed parental drug use advice and parenting behaviors during parent-adolescent drug use discussions and associations with adolescent physiological responses and substance use.

METHODS

Fifty-eight 12-17 year olds and their primary caregivers participated in a laboratory session in which parents and youth discussed the topic of alcohol and/or drug use for 10 minutes. This discussion was videotaped and coded for drug use advice (rules against drug use, information on drug use consequences, scenarios or learning advice [discussing drug use scenarios and what the child has learned about drugs]) and general parenting behaviors (parental warmth and/or support, negative and/or critical parenting). Before, during, and after the discussions, adolescents' heart rate, blood pressure (BP), and salivary cortisol levels were assessed.

RESULTS

Parental discussion of scenarios and/or learning was associated with lower adolescent BP responses to the discussions and lower likelihood of substance use. Parental discussion of rules against drug use was associated with higher heart rate and BP responses and greater likelihood of substance use. Criticism and/or negative parenting was associated with higher cortisol responses and greater likelihood of substance use at a trend level.

CONCLUSIONS

Parenting characterized by greater discussion of drug use scenarios and less stating of rules against drug use and criticism may make youth feel more comfortable and be linked to lower substance use.

Regulatory skill as a resilience factor for adults with a history of foster care: a pilot study

Individuals with a history of foster care (FC) are at elevated risk for emotion regulation-related mental illness. The purpose of the current study was to characterize regulatory function in a group of adults with a history of FC (N = 26) relative to those without a history of FC (N = 27) and how regulatory function moderates adverse caregiving-related outcomes (daily cortisol production and trait anxiety). Self-report items (anxiety, emotion regulation strategies, inhibitory control, caregiving history) were collected along with more objective measures (computerized task and salivary cortisol). Inhibitory control was assessed via self-report and a computerized task (emotional face go/nogo). Results showed that for adults with a history of FC, higher levels of inhibitory control were associated with higher accuracy on the emotional face go/nogo task and greater reported use of the emotion regulation strategy cognitive reappraisal. Greater use of cognitive reappraisal in turn was associated with healthier stress-related outcomes (decreased trait anxiety and steeper sloped cortisol production throughout the day). Dose-response associations were observed between self-reported regulatory skills and FC experiences (i.e., number of placements and age when exited foster care). These findings suggest that adverse caregiving can have long-term influences on mental health that extend into adulthood; however, individual differences in regulatory skills moderate these outcomes and may be an important target for intervention following caregiving adversity.

Prenatal cocaine exposure differentially affects stress responses in girls and boys: associations with future substance use

Prenatal cocaine exposure may affect developing stress response systems in youth, potentially creating risk for substance use in adolescence. Further, pathways from prenatal risk to future substance use may differ for girls versus boys. The present longitudinal study examined multiple biobehavioral measures, including heart rate, blood pressure, emotion, and salivary cortisol and salivary alpha amylase (sAA), in response to a stressor in 193 low-income 14- to 17-year-olds, half of whom were prenatally cocaine exposed (PCE). Youth's lifetime substance use was assessed with self-report, interview, and urine toxicology/breathalyzer at Time 1 and at Time 2 (6-12 months later). PCE × Gender interactions were found predicting anxiety, anger, and sadness responses to the stressor, with PCE girls showing heightened responses as compared to PCE boys on these indicators. Stress Response × Gender interactions were found predicting Time 2 substance use in youth (controlling for Time 1 use) for sAA and sadness; for girls, heightened sadness responses predicted substance use, but for boys, dampened sAA responses predicted substance use. Findings suggest distinct biobehavioral stress response risk profiles for boys and girls, with heightened arousal for girls and blunted arousal for boys associated with prenatal risk and future substance use outcomes.

Predicting Treatment Response for Oppositional Defiant and Conduct Disorder Using Pre-treatment Adrenal and Gonadal Hormones

Variations in adrenal and gonadal hormone profiles have been linked to increased rates of oppositional defiant disorder (ODD) and conduct disorder (CD). These relationships suggest that certain hormone profiles may be related to how well children respond to psychological treatments for ODD and CD. The current study assessed whether pre-treatment profiles of adrenal and gonadal hormones predicted response to psychological treatment of ODD and CD. One hundred five children, 6 - 11 years old, participating in a randomized, clinical trial provided samples for cortisol, testosterone, dehydroepiandrosterone, and androstenedione. Diagnostic interviews of ODD and CD were administered up to three years post-treatment to track treatment response. Group-based trajectory modeling identified two trajectories of treatment response: 1) a High-response trajectory where children demonstrated lower rates of an ODD or CD diagnosis throughout follow-up, and 2) a Low-response trajectory where children demonstrated higher rates of an ODD or CD diagnosis throughout follow-up. Hierarchical logistic regression predicting treatment response demonstrated that children with higher pre-treatment concentrations of testosterone were four times more likely to be in the Low-response trajectory. No other significant relationship existed between pre-treatment hormone profiles and treatment response. These results suggest that higher concentrations of testosterone are related to how well children diagnosed with ODD or CD respond to psychological treatment over the course of three years.

The role of daily activities in youths' stress physiology

PURPOSE

This study examined links between diurnal patterns of the stress hormone cortisol and time spent by adolescents in nine common daily activities.

METHODS

During eight consecutive nightly telephone interviews, 28 youths (n = 12 girls), 10-18 years of age, reported their daily activities. On 4 days, four saliva samples were also collected and assayed for cortisol. Multilevel models assessed within- and between-person associations between time in each activity and cortisol area under the curve (AUC), cortisol awakening response (CAR), morning peak (30 minutes after wake up), and daily decline (morning peak to bedtime).

RESULTS

Links with AUC were found for most activities; significant associations with cortisol rhythms suggested that most effects were due to anticipation of the day's activities. Specifically, on days when youths spent more time than usual on video games and television, they had lower AUCs, with lower morning peaks. Youths who spent more time reading (within-person) and in computer-related activities (between-person) had higher AUCs, with stronger CARs (within-person). Youths who slept more had lower AUCs, with lower morning peaks on both the between- and within-person levels. Amounts of time spent in clubs, and for older adolescents in sports, were also linked to lower AUCs. Finally, youths who spent more time in school/schoolwork had lower average AUCs, but on days when youths spent more time than usual in school, they had higher AUCs, stronger CARs, and steeper daily declines.

CONCLUSION

Beyond their known implications for psychological adjustment, youths' everyday activities are linked to stress physiology.

Diurnal cortisol rhythms among Latino immigrants in Oregon, USA

One of the most commonly used stress biomarkers is cortisol, a glucocorticoid hormone released by the adrenal glands that is central to the physiological stress response. Free cortisol can be measured in saliva and has been the biomarker of choice in stress studies measuring the function of the hypothalamic-pituitary-adrenal axis. Chronic psychosocial stress can lead to dysregulation of hypothalamic-pituitary-adrenal axis function and results in an abnormal diurnal cortisol profile. Little is known about objectively measured stress and health in Latino populations in the United States, yet this is likely an important factor in understanding health disparities that exist between Latinos and whites. The present study was designed to measure cortisol profiles among Latino immigrant farmworkers in Oregon (USA), and to compare quantitative and qualitative measures of stress in this population. Our results indicate that there were no sex differences in average cortisol AUCg (area under the curve with respect to the ground) over two days (AvgAUCg; males = 1.38, females = 1.60; P = 0.415). AUCg1 (Day 1 AUCg) and AvgAUCg were significantly negatively associated with age in men (P<0.05). AUCg1 was negatively associated with weight (P<0.05), waist circumference (P<0.01) and waist-to-stature ratio (P<0.05) in women, which is opposite of the expected relationship between cortisol and waist-to-stature ratio, possibly indicating hypothalamic-pituitary-adrenal axis dysregulation. Among men, more time in the United States and immigration to the United States at older ages predicted greater AvgAUCg. Among women, higher lifestyle incongruity was significantly related to greater AvgAUCg. Although preliminary, these results suggest that chronic psychosocial stress plays an important role in health risk in this population.

Parent-adolescent conflict interactions and adolescent alcohol use

OBJECTIVE

One important factor in adolescents' development of problem alcohol use is their family environment. Yet, the mechanisms that relate parenting to youth alcohol use are not well characterized. This study employed a naturalistic laboratory-based approach to observe parenting behaviors (support, structure, criticism) and adolescents' physiological and emotional responses to parent-adolescent interactions to examine associations with adolescent alcohol use.

METHOD

Fifty eight 10-16year olds and their parents completed a 10minute Parent Adolescent Interaction Task (PAIT) in which they discussed a mutually highly-rated conflict topic. Parental support, structure, and criticism were coded from the interaction. Adolescents' heart rate (HR), blood pressure (BP), reported emotions, and salivary cortisol were assessed before, during, and after the interaction.

RESULTS

Findings indicated that lower parental structure and support were associated with youth's greater diastolic BP and anger arousal in response to the PAIT. Furthermore, higher HR, systolic BP, and cortisol responses to the interaction were associated with youth's alcohol use.

CONCLUSIONS

Findings suggest that heightened emotional and physiological responses to parent-adolescent conflict interactions in youth may be one pathway by which parenting is associated with adolescent alcohol use and risk for abuse.

Latent state trait modeling of children's cortisol at two points of the diurnal cycle

One challenge in examining stable individual differences in basal activity of the HPA axis is controlling for internally or externally based situational factors that lead to day-to-day variation in ambulatory cortisol. Disturbed basal activity is of particular interest in studies with children, for whom a dysregulated HPA axis may play an etiologic role in emotional or health outcomes. The purpose of this study was to determine whether trait vs. situationally specific sources of variation can be identified at different points of the diurnal cycle in children and if so, whether state and trait components vary according to time of measurement. Early morning and late evening salivary cortisol was collected from 164 children aged 7 to 11 years. Samples were collected 30 min after wake-up and 30 min before bedtime on 3 weekdays. State, trait, and error components of cortisol levels were assessed using a latent state trait model. Possible influences of sampling day and outlier treatment on parameter estimates were examined. The results showed that a latent trait factor superimposed on state residuals and measurement error was identified for both early morning and late evening cortisol. Model fit was excellent and criteria for invariance tests were met. Trait factors accounted for 41% and 57% of the variance in morning and evening cortisol, respectively. These findings suggest cortisol attributed to trait factors can be identified and are of substantial magnitude at both the peak and nadir of the diurnal cycle. Latent state trait modeling is a potentially useful tool in understanding the role of stable individual differences in cortisol levels for development and health.

Growth delay as an index of allostatic load in young children: predictions to disinhibited social approach and diurnal cortisol activity

The goal of this study was to examine whether growth delay can serve as an index of allostatic load during early development, as it is well known that the activity of stress-mediating systems inhibits growth. The participants were children adopted internationally from institutional care (n = 36), children adopted internationally from foster care (n = 26), and nonadopted children (n = 35). For the adopted children, height for age and weight for height were assessed at adoption; for all children, disinhibited social approach (DSA; termed elsewhere as "indiscriminate friendliness") and diurnal cortisol were assessed at 6-8 years (M = 6.9 years). For internationally adopted children in general, and postinstitutionalized children specifically, linear growth delay assessed at the time of adoption was associated with more dysregulated behavior in response to an unfamiliar adult (i.e., greater DSA) and a more dysregulated diurnal cortisol rhythm (i.e., higher late afternoon and evening values). Further, among the most growth-delayed children, higher cortisol levels later in the day were correlated with DSA. The potential for using growth delay as an allostatic load indicator and the possible problems and limitations in its use in child populations are discussed.

Prenatal cocaine exposure, gender, and adolescent stress response: a prospective longitudinal study

Prenatal cocaine exposure is associated with alterations in arousal regulation in response to stress in young children. However, relations between cocaine exposure and stress response in adolescence have not been examined. We examined salivary cortisol, self-reported emotion, heart rate, and blood pressure (BP) responses to the Trier Social Stress Test (TSST) in 49 prenatally cocaine and other drug exposed (PCE) and 33 non-cocaine-exposed (NCE) adolescents. PCE adolescents had higher cortisol levels before and after stress exposure than NCE adolescents. PCE girls showed an elevated anxiety response to stress (compared to NCE girls) and PCE boys showed a dampened diastolic BP response (compared to NCE boys). Girls showed higher anger response and lower pre-stress systolic BP than boys. Group differences were found controlling for potential confounding variables and were not moderated by caregiver-child relationship quality (although relationship quality predicted HPA axis and anxiety response). The findings suggest that prenatal drug exposure is associated with altered stress response in adolescence and that gender moderates this association.

Cortisol and alpha amylase reactivity and timing of puberty: vulnerabilities for antisocial behaviour in young adolescents

The theoretical framework proposed that cortisol and saliva alpha amylase (sAA) reactivitiy are vulnerabilities for antisocial behaviour. These indices of hypothalamic-pituitary-adrenal (HPA) and sympathetic-adrenal-medulary (SAM) components of the stress system, respectively, were considered vulnerabilities that also interact with the putative stressful transition of timing of puberty to predispose adolescents toward antisocial behaviour. The sample consisted of 8- to-13-year-old boys and girls (N=135) and a parent. For boys, timing of puberty moderated the association between cortisol and sAA reactivity and antisocial behaviour. Higher cortisol reactivity in later timing boys was related to a composite index of antisocial behaviour and rule-breaking behaviour problems. In contrast, lower sAA reactivity and earlier timing of puberty in boys was related to rule breaking and conduct disorder symptoms. The interaction between timing of puberty and HPA or SAM regulation and timing of puberty in boys suggests that reproductive, neuroendocrine mechanisms may be involved in the extensively documented adverse consequences of off-time pubertal development.

Assessing salivary cortisol in large-scale, epidemiological research

Salivary cortisol measures are increasingly being incorporated into large-scale, population-based, or epidemiological research, in which participants are selected to be representative of particular communities or populations of interest, and sample sizes are in the order of hundreds to tens of thousands of participants. These approaches to studying salivary cortisol provide important advantages but pose a set of challenges. The representative nature of sampling, and large samples sizes associated with population-based research offer high generalizability and power, and the ability to examine cortisol functioning in relation to: (a) a wide range of social environments; (b) a diverse array individuals and groups; and (c) a broad set of pre-disease and disease outcomes. The greater importance of high response rates (to maintain generalizability) and higher costs associated with this type of large-scale research, however, requires special adaptations of existing ambulatory cortisol protocols. These include: using the most efficient sample collection protocol possible that still adequately address the specific cortisol-related questions at hand, and ensuring the highest possible response and compliance rates among those individuals invited to participate. Examples of choices made, response rates obtained, and examples of results obtained from existing epidemiological cortisol studies are offered, as are suggestions for the modeling and interpretation of salivary cortisol data obtained in large-scale epidemiological research.

Salivary cortisol among American Indians with and without posttraumatic stress disorder (PTSD): gender and alcohol influences

Disruptions in hypothalamic-pituitary-adrenal regulation and immunity have been associated with posttraumatic stress disorder (PTSD). We examined the association of PTSD with diurnal rhythms in salivary cortisol in a convenience sample from a population-based study of male and female American Indians. Subjects with and without PTSD were identified from American Indians living on/near a Northern Plains reservation as part of a larger study. Over two days diurnal saliva samples were collected by staff at the University of Colorado Denver Clinical Research Center at waking, 30min after waking, before lunch, and before dinner. Generalized estimating equations linear regression models investigated the influence of PTSD on cortisol over time. The association of a lifetime diagnosis of PTSD with salivary cortisol level was assessed in subjects with complete data (PTSD: n=27; no PTSD n=32) for age, gender, and alcohol consumption in the past month. Subject mean age was 44 years, and 71% were women. When stratified by gender, women with a lifetime diagnosis of PTSD had significantly higher mean cortisol levels throughout the day than women without PTSD (p=0.01); but there was no significant association between PTSD and cortisol levels in men (p=0.36). The cortisol awakening response - the difference in cortisol levels from waking to 30min after waking - was not associated with PTSD in men or women. A lifetime diagnosis of PTSD may influence diurnal cortisol among American Indian women. These effects were independent of influences of current alcohol use/abuse. The unexpected elevation in cortisol in American Indian women with a lifetime diagnosis of PTSD may reflect acute anxiety associated with experiencing a number of novel tests in a strange location (e.g., cardiac imaging, medical, dental exams, etc.), or concurrent depression.

Variation in hypothalamic-pituitary-adrenal axis activity among bullied and non-bullied children

We examined the relationship between being bullied during childhood and activity of the hypothalamic-pituitary-adrenal (HPA) axis as assessed through repeated measures of salivary cortisol. A non-clinical sample of 154 (74 boys) predominantly Caucasian middle-class 12-year-olds each provided detailed information about their experiences with bullying and six saliva samples were standardized across time and day. Children with a history of child maltreatment, diagnosed psychiatric illness, foster care placement, medication use (psychotropic and oral contraception) and aggression directed toward peers and/or family members were excluded. Using multilevel regression and applying orthogonal polynomial contrasts to model the observed circadian pattern in the data, we found that occasional and frequent verbal peer victimization was associated with hyposecretion of cortisol when controlling for sex, pubertal status, age, depression and anxiety. This relation, however, was moderated by sex. For boys, occasional exposure was associated with higher cortisol levels, whereas for girls exposure was associated with lower cortisol levels. The present study highlights the need to consider the plight of peer-victimized children seriously, as it is associated with alterations to the HPA axis that affect males and females differently, and likely diminishes a person's ability to cope with stress, possibly placing them at risk for psychopathology and ill health.

The stress response in adolescents with inattentive type ADHD symptoms

OBJECTIVE

To investigate the hypothalamic pituitary adrenal (HPA) axis response to a stressor in adolescents with inattentive type attention-deficit hyperactivity disorder symptoms (ADHD-I).

METHOD

Salivary cortisol was measured in threshold inattentive (TI, n = 7), moderately inattentive (MI, n = 13) and no symptom (comparison) (n = 19) groups of healthy, young adolescents, based on symptom counts, prior to and after an induced social/cognitive stressor.

RESULTS

The TI group displayed a significant decrease in cortisol post stressor whereas both the MI and comparison groups showed an increase in cortisol.

CONCLUSION

The diagnostic threshold of inattentive type ADHD shows HPA axis dysregulation whereas the more mild form does not show dysfunction.

Measurement and meaning of salivary cortisol: a focus on health and disease in children

Measurement of salivary cortisol can provide important information about hypothalamic-pituitary-adrenal (HPA) axis activity under normal conditions and in response to stress. However, there are many variables relating to the measurement of cortisol in saliva which may introduce error and therefore may render difficult the comparison and interpretation of data between, and within, laboratories. This review addresses the effects of gender, age, time and location of sampling, units of measurement, assay conditions and compliance with the protocol, all of which have the potential to impact upon the precision, accuracy and reliability of salivary cortisol measurements in the literature. Some of these factors are applicable to both adults and children, but the measurement of salivary cortisol in children introduces aspects of unique variability which demand special attention. The specific focus of this review is upon the somewhat neglected area of methodological variability of salivary cortisol measurement in children. In addition to these methodological issues, the review highlights the use of salivary cortisol measurements to provide information about HPA axis dysfunction associated with psycho- and patho-physiological conditions in children. Novel applications for salivary cortisol measurements in future research into HPA axis activity in children are also discussed.

Early deprivation and home basal cortisol levels: a study of internationally adopted children

Animal studies reveal that early deprivation impairs regulation of the hypothalamic-pituitary-adrenocortical (HPA) axis, potentially increasing vulnerability to stressors throughout life. To examine early deprivation effects on basal HPA axis activity in humans, basal cortisol levels were examined in 164 internationally adopted children who had experienced varying degrees of preadoption deprivation. Duration of institutional care, age at adoption, and parent ratings of preadoption neglect indexed a latent factor of Deprived Care. Adoption measures of height and weight standardized to World Health Organisation norms indexed a latent factor of Growth Delay that was viewed as another reflection of deprivation. Cortisol samples were collected 3.3-11.6 years postadoption (Md = 7.3 years) at home on 3 days approximately 30 min after wakeup and before bedtime. Both early a.m. levels and the decrease in cortisol across the day were examined. A structural equation model revealed that preadoption Deprived Care predicted Growth Delay at adoption and Growth Delay predicted higher morning cortisol levels and a larger diurnal cortisol decrease.

Effects of a therapeutic intervention for foster preschoolers on diurnal cortisol activity

Atypical diurnal patterns of hypothalamic-pituitary-adrenal (HPA) axis activity have been observed in samples of individuals following early life adversity. A characteristic pattern arising from disrupted caregiving is a low early-morning cortisol level that changes little from morning to evening. Less well understood is the plasticity of the HPA axis in response to subsequent supportive caregiving environments. Monthly early-morning and evening cortisol levels were assessed over 12 months in a sample of 3-6-year-old foster children enrolled in a randomized trial of a family-based therapeutic intervention (N=117; intervention condition, n=57; regular foster care condition, n=60), and a community comparison group of same-aged, non-maltreated children from low-income families (n=60). Latent growth analyses revealed stable and typical diurnal (morning-to-evening) cortisol activity among non-maltreated children. Foster children in the intervention condition exhibited cortisol activity that became comparable to the non-maltreated children over the course of the study. In contrast, children in regular foster care condition exhibited increasingly flattened morning-to-evening cortisol activity over the course of the study. In sum, improvements in caregiving following early adversity appear to have the potential to reverse or prevent disruptions in HPA axis functioning.

Association of hypothalamic-pituitary-adrenal axis function with neuropsychological performance in children with mild/moderate asthma

The present study examines the relationship between hypothalamic-pituitary-adrenal (HPA) axis function and child psychological/neuropsychological function in a group of children with mild to moderate asthma. The goal of the study was to determine whether child neuropsychological functioning and psychological functioning were associated with cortisol production in response to adrenocorticotropic hormone(ACTH) stimulation when assessed as area under the curve. Data for this study were gathered from 63 children who participated in an ancillary study within the Childhood Asthma Management Program (CAMP) during the pre-randomization phase of the CAMP trial. At 2 of the 8 CAMP clinical centers participants completed an ACTH stimulation test after an overnight stay in the General Clinical Research Center. Gender differences on baseline cortisol and change in cortisol 30 minutes after infusion of ACTH were present. Results further indicated significant associations between cortisol production and measures of child neuropsychological function. Stepwise multiple regression analysis revealed that cortisol change could be predicted by measures of gender, working memory, and arousal maintenance, providing support for the hypothesis that cortisol plays a modest role in the neuropsychological function of children with mild and moderate asthma. In contrast, cortisol production was not associated with child reports of psychological functioning. Limitations to the methods employed in this study are discussed.

Determinants of salivary cortisol levels in 10-12 year old children; a population-based study of individual differences

The hypothalamic-pituitary-adrenal (HPA)-axis is a central component of the body's neuroendocrine response to stress. Its major end-product cortisol has profound effects on mood and behavior. Although it has often been suggested, it remains unknown whether differences in HPA-axis physiology are part of an individual's vulnerability to psychopathology, and constitute a causal factor in its development. In order to study the contribution of HPA-axis physiology to the development of psychopathology, we measured HPA-axis physiology in a community-cohort of 1768 10-12 year-old children. The aims of the here presented study were twofold: (1) to obtain data on HPA-axis function in a large cohort of pre- and early-adolescent children, both in terms of total hormonal output and in terms of the dynamics of cortisol secretion (by means of the cortisol awakening response); and (2) to study potential confounders of the cortisol-psychopathology relationship in this age group, such as season of sampling, age, gender, pubertal development, perinatal variables and BMI. We found a wide interindividual variability in HPA-axis function. An increase in cortisol in the first 30 min after awakening was present in 70.7% of children, but the increase appears lower in children than in adults. In addition, this study suggests that season of sampling and gender may act as potential confounders in the cortisol-psychopathology relationship. We will follow these children longitudinally for the development of psychopathology in the period from childhood into adulthood. This period covers adolescence, which is a critical time for the appearance and development of psychiatric disorders.