Socioeconomic status, hair cortisol and internalizing symptoms in parents and children

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

INTRODUCTION

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

METHODS

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

RESULTS

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

DISCUSSION

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

Mothers in stress: Hair cortisol of mothers living in marginalised Roma communities and the role of socioeconomic disadvantage

Roma living in marginalised communities are among the most disadvantaged groups in Slovakia. Socioeconomic disadvantage is associated with higher hair cortisol concentrations (HCC), including in parents. The aim of this study is therefore to assess differences in HCC, reflecting the levels of stress, between mothers living in MRCs and from the majority population, to assess the association of socioeconomic disadvantage with HCC, and whether disadvantage mediates the MRC/majority differences in HCC. Participants were mothers of children aged 15-18 months old living in MRCs (N=61) and from the Slovak majority population (N=90). During preventive paediatric visits, visits at community centres and home visits, hair samples and data by questionnaire were collected. HCC differed significantly between mothers living in MRCs and mothers from the majority population, with the mean HCC value being twice as high in mothers living in MRCs (22.98 (95% confidence interval, CI, 15.70-30.30) vs. 11.76 (8.34-15.20), p<0.05). HCC was significantly associated with education, household equipment and household overcrowding, but not with billing, socioeconomic stress and social support. The difference in HCC between mothers living in MRCs and mothers from the majority population was partially mediated by poor house equipment, such as no access to running water, no flushing toilet or no bathroom (the indirect effect of B=7.63 (95% CI: 2.12-13.92)). Practitioners and policymakers should be aware of high stress levels among mothers living in MRCs and aim at enhancing their living and housing conditions.

Influence of early childhood parental hostility and socioeconomic stress on children's internalizing symptom trajectories from childhood to adolescence

Introduction

Children and adolescents with elevated internalizing symptoms are at increased risk for depression, anxiety, and other psychopathology later in life. The present study examined the predictive links between two bioecological factors in early childhood-parental hostility and socioeconomic stress-and children's internalizing symptom class outcomes, while considering the effects of child sex assigned at birth on internalizing symptom development from childhood to adolescence.

Materials and Methods

The study used a sample of 1,534 children to test the predictive effects of socioeconomic stress at ages 18 and 27 months; hostile parenting measured at child ages 4-5; and sex assigned at birth on children's internalizing symptom latent class outcomes at child ages 7-9, 10-12, 13-15, and 16-19. Analyses also tested the mediating effect of parenting on the relationship between socioeconomic stress and children's symptom classes. Other covariates included parent depressive symptoms at child ages 4-5 and child race and ethnicity.

Results

Analyses identified three distinct heterogenous internalizing symptom classes characterized by relative symptom levels and progression: low (35%); moderate and increasing (41%); and higher and increasing (24%). As anticipated, higher levels of parental hostility in early childhood predicted membership in the higher and increasing symptom class, compared with the low symptom class (odds ratio (OR) = .61, 95% confidence interval (CI) [.48,.77]). Higher levels of early childhood socioeconomic stress were also associated with the likelihood of belonging to the higher-increasing symptom class compared to the low and moderate-increasing classes (OR = .46, 95% CI [.35,.60] and OR = .56, 95% CI [.44,.72], respectively). The total (c = .61) and direct (c' = .57) effects of socioeconomic stress on children's symptom class membership in the mediation analysis were significant (p <.001).

Discussion

Study findings suggest that intervening on modifiable bioecological stressors-including parenting behaviors and socioeconomic stressors-may provide important protective influences on children's internalizing symptom trajectories.

Early Childhood in Marginalized Roma Communities: Health Risks and Health Outcomes

Objectives

This study aims to compare selected early childhood health risks and health outcomes of children from marginalized Roma communities (MRCs) in Slovakia with those of the majority.

Methods

We obtained cross-sectional data from mother-child dyads from the majority (N = 109) and MRCs (N = 143) via questionnaires and from medical records. Socioeconomic status, health risks and health outcomes were compared using chi-square and Mann-Whitney U tests in SPSS.

Results

Mothers from MRCs reported significantly worse socioeconomic status. Air quality in the households in MRCs was significantly worse, affected by heating with stoves, burning fresh wood and indoor smoking. The diet composition of children from MRCs was characterized by shorter breastfeeding and unhealthy diet composition less fresh fruits and vegetables, more processed meat products, and sweet and salty snacks. Children from MRCs more often suffered from respiratory and diarrheal diseases, used antibiotics and were hospitalized.

Conclusion

The health and healthy development of children living in MRCs is endangered by various poverty-related factors. Persistent differences in exposures and health in early childhood should be a priority goal of the state's social and health policies.

A Qualitative Study of Maternal Perceptions of Stress and Parenting During Early Childhood

OBJECTIVE

Exposure to maternal stress in early childhood can increase risk for learning and behavior challenges. We sought to gain in-depth understanding of how mothers perceive stressors to impact child wellbeing and identify mothers' strategies for navigating stressors with their young children.

METHODS

We recruited English- and Spanish-speaking mothers from a primary care clinic serving predominantly publicly insured children. Twenty-one mothers (aged >18 years) of children (aged 6-29 months) participated in in-depth, semi-structured interviews to discuss their experiences and beliefs regarding stress and parenting. Interviews were recorded, transcribed verbatim, and analyzed using the constant comparative method associated with a grounded theory approach.

RESULTS

We developed the following hypothesized explanatory model based on our key thematic findings: Mothers described a dyadic model of stress, whereby both their children's and their own experiences of and responses to stressors are interdependent. Mothers use preventive and responsive buffering to mitigate the impact of stress on their children; however, their access to resources, including social and financial support, shapes their capacity for implementing such strategies. Affection and other forms of relational support may function to protect against the negative impacts of stress.

CONCLUSION

In the setting of poverty-related chronic stressors, mothers play an active role in mitigating the impact of stress on their children's wellbeing through responsive caregiving. Policies aimed at reducing poverty-related stress exposures and experiences among low-income families may be key interventions for promoting responsive caregiving during a critical time in child development.

Immigration, Educational Attainment, and Subjective Health in the United States

Objectives

Although educational attainment is a major social determinant of health, according to Marginalization-related Diminished Returns (MDRs), the effect of education tends to be weaker for marginalized groups compared to the privileged groups. While we know more about marginalization due to race and ethnicity, limited information is available on MDRs of educational attainment among US immigrant individuals.

Aims

This study compared immigrant and non-immigrant US adults aged 18 and over for the effects of educational attainment on subjective health (self-rated health; SRH).

Methods

Data came from General Social Survey (GSS) that recruited a nationally representative sample of US adults from 1972 to 2022. Overall, GSS has enrolled 45,043 individuals who were either immigrant (4,247; 9.4%) and non-immigrant (40,796; 90.6%). The independent variable was educational attainment, the dependent variable was SRH (measured with a single item), confounders were age, gender, race, employment and marital status, and moderator was immigration (nativity) status.

Results

Higher educational attainment was associated with higher odds of good SRH (odds ratio OR = 2.08 for 12 years of education, OR = 2.81 for 13-15 years of education, OR = 4.38 for college graduation, and OR = 4.83 for graduate studies). However, we found significant statistical interaction between immigration status and college graduation on SRH, which was indicative of smaller association between college graduation and SRH for immigrant than non-immigrant US adults.

Conclusions

In line with MDRs, the association between educational attainment and SRH was weaker for immigrant than non-immigrant. It is essential to implement two sets of policies to achieve health inequalities among immigrant populations: policies that increase educational attainment of immigrants and those that increase the health returns of educational attainment for immigrants.

Associations between maternal stress and infant resting brain activity among families residing in poverty in the U.S

Growing evidence suggests that maternal experiences of stress shape children's functional brain activity in the first years of life. Individuals living in poverty are more likely to experience stress from a variety of sources. However, it is unclear how stress is related to resting brain activity among children born into poverty. The present study examines whether infants born into households experiencing poverty show differences in brain activity associated with maternal reports of experiencing stress. The analytic sample comprised 247 mother-infant dyads who completed maternal questionnaires characterizing stress, and for whom recordings of infant resting brain activity were obtained at 1 year of age (M=12.93 months, SD=1.66; 50% female). Mothers (40% Black, non-Hispanic, 40% Hispanic, 12% White, non-Hispanic) who reported higher stress had infants who showed more resting brain activity in the lower end of the frequency spectrum (relative theta power) and less resting brain activity in the middle range of the frequency spectrum (relative alpha power). While statistically detectable at the whole-brain level, follow-up exploratory analyses revealed that these effects were most apparent in electrodes over frontal and parietal regions of the brain. These findings held after adjusting for a variety of potentially confounding variables. Altogether, the present study suggests that, among families experiencing low economic resources, maternal reports of stress are associated with differences in patterns of infant resting brain activity during the first year of life.

Excessive hair cortisol concentration as an indicator of psychological disorders in children

Cortisol in hair is a new biomarker assessing long-term hypothalamic-pituitary-adrenal (HPA) axis activity, which is related to emotion regulation. We compare hair cortisol concentrations (HCC), in clinically referred children with disruptive mood dysregulation disorder (DMDD) (n = 19), children with other types of psychological disorders (n = 48), and healthy subjects (n = 36). We also investigate the association between HCC and irritability, age, and sex. Our results show that children with DMDD or other types of psychological disorders have higher HCC than healthy subjects, p < .001, ηp2 = .39. No difference between children with DMDD and those with other types of psychological disorders was found, p = .91, nor an association between HCC and irritability in the clinical sample, p = .32. We found a significant negative correlation between HCC and age in those with DMDD, r = -0.54, p < .05, but not in the normative sample, r = -0.20, p = .25. No differences in HCC between girls and boys were found in the normative sample, p = .49. Children in need of psychological treatment, including those with DMDD, seem to have dysregulated HPA-axis activity over time. Excessive accumulated cortisol concentrations in hair could be an indicator of a psychological disorder in children.

Childbirth-related posttraumatic stress symptoms - examining associations with hair endocannabinoid concentrations during pregnancy and lifetime trauma

Evidence has linked alterations of the endocannabinoid system with trauma exposure and posttraumatic stress disorder (PTSD). Childbirth-related PTSD symptoms (CB-PTSS) affect about every eighth woman and can negatively influence the entire family. While aetiological models of CB-PTSD include psychological risk factors such as maternal trauma history and negative subjective birth experience (SBE), they lack biological risk indicators. We investigated whether lifetime trauma and CB-PTSS were associated with long-term endocannabinoid concentrations during pregnancy. Further, we tested endocannabinoids as mediators between lifetime trauma and CB-PTSS and whether SBE moderated such mediational paths. Within the prospective cohort study DREAMHAIR, 263 expectant mothers completed trauma assessments and provided hair samples for quantification of long-term endocannabinoid levels (anandamide [AEA], 2-arachidonoylglycerol [1-AG/2-AG], and N-acyl-ethanolamides [NAE]) prior to their anticipated birth date. Two months postpartum, CB-PTSS and SBE were measured. Regression models controlling for relevant confounders showed no association between lifetime trauma and hair endocannabinoids during pregnancy, yet higher number of lifetime trauma events and lower hair AEA were significantly associated with CB-PTSS, with the latter finding not remaining significant when Bonferroni corrections due to multiple testing were applied. While hair AEA did not mediate the association between lifetime trauma and CB-PTSS, the effect of lower hair AEA on CB-PTSS was stronger upon negative SBE. Results suggest greater lifetime trauma and reduced maternal hair AEA during pregnancy may be associated with increased risk for CB-PTSS, particularly upon negative SBE. Findings confirm lifetime trauma as a CB-PTSS risk factor and add important preliminary insights on the role of endocannabinoid ligand alterations and SBE in CB-PTSS pathology.

The Association Between Maternal Cortisol and Infant Amygdala Volume Is Moderated by Socioeconomic Status

Background

It has been well established that socioeconomic status is associated with mental and physical health as well as brain development, with emerging data suggesting that these relationships begin in utero. However, less is known about how prenatal socioeconomic environments interact with the gestational environment to affect neonatal brain volume.

Methods

Maternal cortisol output measured at each trimester of pregnancy and neonatal brain structure were assessed in 241 mother-infant dyads. We examined associations between the trajectory of maternal cortisol output across pregnancy and volumes of cortisol receptor-rich regions of the brain, including the amygdala, hippocampus, medial prefrontal cortex, and caudate. Given the known effects of poverty on infant brain structure, socioeconomic disadvantage was included as a moderating variable.

Results

Neonatal amygdala volume was predicted by an interaction between maternal cortisol output across pregnancy and socioeconomic disadvantage (standardized β = -0.31, p < .001), controlling for postmenstrual age at scan, infant sex, and total gray matter volume. Notably, amygdala volumes were positively associated with maternal cortisol for infants with maternal disadvantage scores 1 standard deviation below the mean (i.e., less disadvantage) (simple slope = 123.36, p < .01), while the association was negative in infants with maternal disadvantage 1 standard deviation above the mean (i.e., more disadvantage) (simple slope = -82.70, p = .02). Individuals with disadvantage scores at the mean showed no association, and there were no significant interactions in the other brain regions examined.

Conclusions

These data suggest that fetal development of the amygdala is differentially affected by maternal cortisol production at varying levels of socioeconomic advantage.

Linking specific biological signatures to different childhood adversities: findings from the HERO project

BACKGROUND

Although investigations have begun to differentiate biological and neurobiological responses to a variety of adversities, studies considering both endocrine and immune function in the same datasets are limited.

METHODS

Associations between proximal (family functioning, caregiver depression, and anxiety) and distal (SES-D; socioeconomic disadvantage) early-life adversities with salivary inflammatory biomarkers (IL-1β, IL-6, IL-8, and TNF-α) and hair HPA markers (cortisol, cortisone, and dehydroepiandrosterone) were examined in two samples of young U.S. children (N = 142; N = 145).

RESULTS

Children exposed to higher SES-D had higher levels of TNF-α (B = 0.13, p = 0.011), IL-1β (B = 0.10, p = 0.033), and DHEA (B = 0.16, p = 0.011). Higher family dysfunction was associated with higher cortisol (B = 0.08, p = 0.033) and cortisone (B = 0.05, p = 0.003). An interaction between SES-D and family dysfunction was observed for cortisol levels (p = 0.020) whereby children exposed to lower/average levels of SES-D exhibited a positive association between family dysfunction and cortisol levels, whereas children exposed to high levels of SES-D did not. These findings were partially replicated in the second sample.

CONCLUSIONS

Our results indicate that these biological response systems may react differently to different forms of early-life adversity.

IMPACT

Different forms of early-life adversity have varied stress signatures, and investigations of early-life adversities with inflammation and HPA markers are lacking. Children with higher socioeconomic disadvantage had higher TNF-α, IL-1β, and DHEA. Higher family dysfunction was associated with higher hair cortisol and cortisone levels, and the association between family dysfunction and cortisol was moderated by socioeconomic disadvantage. Biological response systems (immune and endocrine) were differentially associated with distinct forms of early-life adversities.

Maternal hair cortisol predicts periodic and aperiodic infant frontal EEG activity longitudinally across infancy

Maternal stress is known to be an important factor in shaping child development, yet the complex pattern of associations between stress and infant brain development remains understudied. To better understand the nuanced relations between maternal stress and infant neurodevelopment, research investigating longitudinal relations between maternal chronic physiological stress and infant brain function is warranted. In this study, we leveraged longitudinal data to disentangle between- from within-person associations of maternal hair cortisol and frontal electroencephalography (EEG) power at three time points across infancy at 3, 9, and 15 months. We analyzed both aperiodic power spectral density (PSD) slope and traditional periodic frequency band activity. On the within-person level, maternal hair cortisol was associated with a flattening of frontal PSD slope and an increase in relative frontal beta. However, on the between-person level, higher maternal hair cortisol was associated with steeper frontal PSD slope, increased relative frontal theta, and decreased relative frontal beta. The within-person findings may reflect an adaptive neural response to relative shifts in maternal stress levels, while the between-person results demonstrate the potentially detrimental effects of chronically elevated maternal stress. This analysis offers a novel, quantitative insight into the relations between maternal physiological stress and infant cortical function.

Hair glucocorticoids during pregnancy in the context of trauma exposure and their predictive value for the development of childbirth-related posttraumatic stress disorder symptoms

BACKGROUND

Childbirth-related posttraumatic stress disorder (CB-PTSD) is gaining attention as a mental disorder with negative sequela for mothers and their offspring. Maternal trauma history is a well-known vulnerability factor for CB-PTSD symptoms (CB-PTSS). Furthermore, alterations of the hypothalamus-pituitary-adrenal axis have been linked to both trauma exposure and PTSD development. Hence, we investigated whether trauma history was associated with long-term glucocorticoid (GC) levels during pregnancy and their predictive role for CB-PTSS. Further, we examined whether GCs act as a mediator in the relationship between trauma history and CB-PTSS and whether this was moderated by the subjective birth experience.

METHODS

212 women participating in the prospective cohort study DREAM_HAIR provided hair samples for quantification of long-term integrated cortisol and cortisone levels prior to their anticipated birth date accompanied by measures of trauma history. CB-PTSS and subjective birth experience were assessed two months postpartum.

FINDINGS

Trauma history predicted elevated hair cortisol and hair cortisone during the third trimester of pregnancy, however associations did not remain significant when Bonferroni correction due to multiple testing was applied. Trauma history also predicted higher CB-PTSS. Hair GC levels during pregnancy neither predicted CB-PTSS two months after birth nor mediated the relationship between trauma history and CB-PTSS. The subjective birth experience moderated the relationship of hair cortisol and cortisone with CB-PTSS.

CONCLUSION

Our data suggest that a history of trauma contributes to a higher risk to develop CB-PTSS and elevated long-term GC levels during the third pregnancy trimester. Further, the predictive role of hair cortisol and cortisone levels for CB-PTSS may depend on subjective birth experience. This highlights the need to consider the latter in future investigations when examining the role of stress-related biomarkers in more severely affected samples.

The effect of the COVID-19 pandemic on infant development and maternal mental health in the first 2 years of life

We investigated how exogenous variation in exposure to the COVID-19 pandemic during the first year of life is related to infant development, maternal mental health, and perceived stress. Ninety-three socioeconomically diverse pregnant women were recruited before the pandemic to participate in a longitudinal study. Infants ranged in age at the beginning of lockdown (0-9.5 months old), thus experiencing different durations of pandemic exposure across the first year of life. The duration of pandemic exposure was not associated with family demographic characteristics, suggesting it captured exogenous variability. We tested associations between this exogenous variation in pandemic exposure and child and family outcomes. We also examined whether mother-reported disruptive life events were correlated with child and family outcomes. We found no association between duration of pandemic exposure in the first year of life and infant socioemotional problems, infant language development, or maternal mental health and perceived stress symptoms, at 12 or 24 months. However, we found that self-reported exposure to pandemic-related disruptive life events predicted greater maternal depression, anxiety, and perceived stress at 12 months, and greater depression and anxiety at 24 months. Socioeconomic status did not moderate these associations. These findings suggest cautious optimism for infants raised during this period.

Child care and family processes: Bi-directional relations between child care quality, home environments, and maternal depression

The current study examined whether within-family changes in child care quality and quantity predicted subsequent changes in home environment quality and maternal depression across early childhood (6 to 54 months of age). Data were drawn from the NICHD Study of Early Child Care and Youth Development (n = 1239; 77% White; 48% female; data collection from 1991 to 1996), and were analyzed using Random Intercept Cross-Lagged Panel Models. Within-family increases in child care quality predicted modest increases in home environment quality (β = .13-.17). These effects were most robust from child age 6 to 15 months. Increases in child care quality produced small, statistically non-significant, reductions in depression. Time-specific increases in child care quantity were not consistently predictive of either outcome.

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

Background

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

Methods

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

Results

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

Conclusion

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

Household Income, Cortisol, and Obesity During Early Childhood: A Prospective Longitudinal Study

OBJECTIVE

To prospectively evaluate the relationship between household income, children's cortisol, and body mass index (BMI) trajectories over a 3-year period in early childhood.

STUDY DESIGN

Household income, child hair cortisol levels, and BMI were measured at baseline, 12-, 24-, and 36-month follow-up visits in the Now Everybody Together for Amazing and Healthful Kids (NET-Works) Study (n = 534, children ages 2-4 years, and household income <$65 000/year at baseline). Relationships were examined between very low household income (<$25 000/year) at baseline, income status over time (remained <$25 000/year or had increasing income), cortisol accumulation from hair samples, and BMI percent of the 95th percentile (BMIp95) trajectories using adjusted linear growth curve modeling. Households with baseline income between $25 000 and $65 000/year were the reference group for all analyses.

RESULTS

Children from very low-income households at baseline had annual changes in BMIp95 that were higher (P < .001) than children from reference group households (0.40 vs -0.62 percentage units/year). Annual increases in BMIp95 were also greater among children from households that remained very low income (P < .01, .34 percentage units/year) and among those with increasing income (P = .01, .51 percentage units/year) compared with the reference group (-0.61 percentage units/year). Children from households that remained very low income had higher hair cortisol accumulations (0.22 pg/mg, P = .02) than reference group children, whereas hair cortisol concentrations of children from households with increasing income (0.03 pg/mg) did not differ significantly from the reference group. Cortisol was not related to BMIp95.

CONCLUSIONS

The economic circumstances of families may impact children's BMI trajectories and their developing stress systems, but these processes may be independent of one another.

Co-Rooming Accounts for Socioeconomic Disparities in Infant Sleep Quality among Families Living in Urban Environments

Poor infant sleep quality is associated with negative maternal and infant health outcomes. This study measures socioeconomic disparities in infant sleep quality, and assesses whether child sleep location and maternal stress mediate associations between socioeconomic status (SES) and infant sleep quality. The study includes 86 socioeconomically diverse, mother-infant dyads living in an urban area with infants aged 6–12 months. Mothers reported socioeconomic demographics, infant sleep quality (Brief Infant Sleep Questionnaire) and maternal subjective stress (Perceived Stress Scale). Maternal objective stress was measured via hair cortisol concentration (HCC). The associations among SES, infant sleep quality, infant co-rooming, and maternal stress were assessed. Infants from families with lower income-to-needs (ITN) ratios had poorer infant sleep quality. The association between familial ITN and infant sleep quality was mediated by whether the child co-rooms with parents. Maternal perceived stress was independently associated with infant sleep quality, but HCC was not associated with infant sleep quality.

Sex differences in autonomic responses to stress: implications for cardiometabolic physiology

Chronic stress is a significant risk factor for negative health outcomes. Furthermore, imbalance of autonomic nervous system control leads to dysregulation of physiological responses to stress and contributes to the pathogenesis of cardiometabolic and psychiatric disorders. However, research on autonomic stress responses has historically focused on males, despite evidence that females are disproportionality affected by stress-related disorders. Accordingly, this mini-review focuses on the influence of biological sex on autonomic responses to stress in humans and rodent models. The reviewed literature points to sex differences in the consequences of chronic stress, including cardiovascular and metabolic disease. We also explore basic rodent studies of sex-specific autonomic responses to stress with a focus on sex hormones and hypothalamic-pituitary-adrenal axis regulation of cardiovascular and metabolic physiology. Ultimately, emerging evidence of sex differences in autonomic-endocrine integration highlights the importance of sex-specific studies to understand and treat cardiometabolic dysfunction.

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

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

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

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

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

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

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

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

Childhood Threat Is Associated With Lower Resting-State Connectivity Within a Central Visceral Network

Childhood adversity is associated with altered or dysregulated stress reactivity; these altered patterns of physiological functioning persist into adulthood. Evidence from both preclinical animal models and human neuroimaging studies indicates that early life experience differentially influences stressor-evoked activity within central visceral neural circuits proximally involved in the control of stress responses, including the subgenual anterior cingulate cortex (sgACC), paraventricular nucleus of the hypothalamus (PVN), bed nucleus of the stria terminalis (BNST) and amygdala. However, the relationship between childhood adversity and the resting-state connectivity of this central visceral network remains unclear. To this end, we examined relationships between childhood threat and childhood socioeconomic deprivation, the resting-state connectivity between our regions of interest (ROIs), and affective symptom severity and diagnoses. We recruited a transdiagnostic sample of young adult males and females (n = 100; mean age = 27.28, SD = 3.99; 59 females) with a full distribution of maltreatment history and symptom severity across multiple affective disorders. Resting-state data were acquired using a 7.2-min functional magnetic resonance imaging (fMRI) sequence; noted ROIs were applied as masks to determine ROI-to-ROI connectivity. Threat was determined by measures of childhood traumatic events and abuse. Socioeconomic deprivation (SED) was determined by a measure of childhood socioeconomic status (parental education level). Covarying for age, race and sex, greater childhood threat was significantly associated with lower BNST-PVN, amygdala-sgACC and PVN-sgACC connectivity. No significant relationships were found between SED and resting-state connectivity. BNST-PVN connectivity was associated with the number of lifetime affective diagnoses. Exposure to threat during early development may entrain altered patterns of resting-state connectivity between these stress-related ROIs in ways that contribute to dysregulated neural and physiological responses to stress and subsequent affective psychopathology.

Mother and child hair cortisol during the COVID-19 pandemic: Associations among physiological stress, pandemic-related behaviors, and child emotional-behavioral health

The current study assessed the associations between pandemic-related stressors and physiological stress, as indexed by hair cortisol concentration (HCC), for mothers and their children (N = 180) aged 5-14-years old (M = 8.91). The associations between maternal HCC and children's HCC and children's behavioral adjustment were also examined. Mothers reported on COVID-19-related behaviors and children's adjustment, and both mother and child participants collected and mailed hair samples between August and November of 2020. Results indicated that higher maternal HCC was correlated with living in a more urban environment, job loss, working from home, exposure to pandemic-related news, and social isolation. Child HCC was correlated with family job loss and social isolation. Mother HCC and child HCC were significantly associated, and this association was moderated by child age; younger children's HCC was more strongly associated with mothers' HCC than older children's HCC. Finally, maternal HCC was associated with greater child internalizing symptoms, but was not associated with children's externalizing symptoms. Child HCC was not associated with child behavior.

Moderating or mediating effects of family characteristics on socioeconomic inequalities in child health in high-income countries - a scoping review

BACKGROUND

By explaining the development of health inequalities, eco-social theories highlight the importance of social environments that children are embedded in. The most important environment during early childhood is the family, as it profoundly influences children's health through various characteristics. These include family processes, family structure/size, and living conditions, and are closely linked to the socioeconomic position (SEP) of the family. Although it is known that the SEP contributes to health inequalities in early childhood, the effects of family characteristics on health inequalities remain unclear. The objective of this scoping review is to synthesise existing research on the mediating and moderating effects of family characteristics on socioeconomic health inequalities (HI) during early childhood in high-income countries.

METHODS

This review followed the methodology of "Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews". To identify German and English scientific peer-reviewed literature published from January 1^st, 2000, to December 19^th, 2019, the following search term blocks were linked with the logical operator "AND": (1) family structure/size, processes, living conditions, (2) inequalities, disparities, diversities, (3) income, education, occupation, (4) health and (5) young children. The search covered the electronic databases PubMed, PsycINFO, and Scopus.

RESULTS

The search yielded 7,089 records. After title/abstract and full-text screening, only ten peer-reviewed articles were included in the synthesis, which analysed the effects of family characteristics on HI in early childhood. Family processes (i.e., rules /descriptive norms, stress, parental screen time, parent-child conflicts) are identified to have mediating or moderating effects. While families' living conditions (i.e., TVs in children's bedrooms) are suggested as mediating factors, family structure/size (i.e., single parenthood, number of children in the household) appear to moderate health inequalities.

CONCLUSION

Family characteristics contribute to health inequalities in early childhood. The results provide overall support of models of family stress and family investment. However, knowledge gaps remain regarding the role of family health literacy, regarding a wide range of children's health outcomes (e.g., oral health, inflammation parameters, weight, and height), and the development of health inequalities over the life course starting at birth.

Pediatric Cancer Survivorship: Impact Upon Hair Cortisol Concentration and Family Functioning

A clearer understanding of the association between a biomarker of long-term stress reactivity and family functioning among pediatric cancer survivors may guide both survivorship research and clinical practice. The current study examined the relationship between a long-term measure of hypothalamic-pituitary-adrenal (HPA) activity (cortisol concentration; CORT_HAIR) and parent-reported family functioning (Family Environment Scale; FES) in a cross-sectional sample of survivors (n = 26) and controls (n = 53). Child CORT_HAIR was not different in survivors and controls, though treatment severity was significantly related to child survivor CORT_HAIR. Child CORT_HAIR and parent CORT_HAIR were positively correlated. Cancer survivor parents reported greater FES Organization. Child CORT_HAIR was inversely associated with FES Independence, while parent CORT_HAIR was inversely correlated with FES Organization. Parent CORT_HAIR and FES Independence were significant and unique predictors of child CORT_HAIR. Our results provide preliminary evidence for a relationship between a stress biomarker, child CORT_HAIR, and family functioning among pediatric cancer survivors and controls.

The Association of Childhood Maltreatment, Sex, and Hair Cortisol Concentrations With Trajectories of Depressive and Anxious Symptoms Among Adult Psychiatric Inpatients

OBJECTIVE

Depression and anxiety symptoms are commonly observed among clinical populations, especially among women and maltreated individuals. Few investigations have, however, assessed the existence of distinct symptoms trajectories among clinical populations and how these relate to childhood maltreatment, sex differences, and stress physiology indexed by hair cortisol concentrations (HCCs). The current study a) identified distinct depression and anxious trajectories in a sample of psychiatric inpatients followed up prospectively from their admission to a psychiatric emergency service, and b) examined whether HCC, childhood maltreatment, and sex independently and jointly predict these trajectories.

METHODS

Adult inpatients (n = 402; 55% women) were recruited upon admission to psychiatric emergency service (T1) during which HCC (reflecting cortisol secretion for the last 3 months), childhood maltreatment, and depression and anxiety symptoms were assessed. Symptoms were reevaluated when patients were discharged from the hospital (T2), admitted to outpatient clinics (T3), and 12 months later or at the end of outpatient treatment (T4).

RESULTS

Three trajectories were identified for depression and anxiety symptoms. Among men, higher HCC predicted higher odds of evincing chronic depressive symptoms compared with a low stable trajectory (odds ratio [OR] = 3.46, 95% confidence interval [CI] = 1.43-8.40). Greater childhood maltreatment among men predicted higher chances of exhibiting chronic anxious symptoms than the low stable (OR = 1.47, 95% CI = 1.07-2.02) and the high decreasing trajectories (OR = 0.70, 95% CI = 0.51-0.95). Opposite findings were noted for women.

CONCLUSIONS

Childhood maltreatment and HCC should be further investigated as predictors of anxious and depressive trajectories, during which sex-specific associations ought to be considered.

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

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

Mother's hair cortisol and symptoms of attention deficit hyperactivity disorder in her preschool child

Children with attention deficit hyperactivity disorder (ADHD) require increased caregiver assistance and supervision, and their parents have shown high perceived parenting stress. Hence, physiological adjustment processes in the caregivers, involving the hypothalamic-pituitary-adrenal axis, seem plausible. We analyzed the association between maternal hair cortisol concentration (HCC) and symptoms of ADHD in preschool-aged children. 150 mothers of 4-5-year-old children participated in the study. To determine the HCC, the first scalp-near 3 cm hair segment was used. ADHD symptoms of the child were measured using teacher- and parent-report questionnaires and a clinical interview with the mother. When controlling for several putative confounders, teacher-reported ADHD symptoms were significantly positively associated with mothers' HCC. No associations of HCC with the mother-reported ADHD symptoms of the child emerged. It is possible that teacher-reported ADHD symptoms of the child reflect relevant ADHD symptoms more validly. As our study is the first on this issue, cross-validation is needed.

Stress and Loss of Ovarian Function: Novel Insights into the Origins of Sex-Based Differences in the Manifestations of Respiratory Control Disorders During Sleep

The respiratory system of women and men develops and functions in distinct neuroendocrine milieus. Despite differences in anatomy and neural control, homeostasis of arterial blood gases is ensured in healthy individuals regardless of sex. This convergence in function differs from the sex-based differences observed in many respiratory diseases. Sleep-disordered breathing (SDB) results mainly from episodes of upper airway closure. This complex and multifactorial respiratory disorder shows significant sexual dimorphism in its clinical manifestations and comorbidities. Guided by recent progress from basic research, this review discusses the hypothesis that stress is necessary to reveal the sexual dimorphism of SDB.

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

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

Parental education, parent-child relations and diagnosed mental disorders in childhood: prospective child cohort study

BACKGROUND

Mental disorder in childhood is an important public health issue. We aimed to examine the prospective association between parental education at childbirth and diagnosed mental disorders in young children and explore whether this association was mediated or modified by parent-child relations in infancy.

METHODS

Prospective cohort study of all newborn was from 2002 to 2010 from 16 municipalities in the capital region of Copenhagen, Denmark, with follow-up until their 8th birthday, N = 40 762. Baseline data included information from national population registers and from health visitors' records at child aged 0 to 10 months. Outcome variable: any mental disorder diagnosed at hospital from age 11 months to 8 years.

RESULTS

Low parental education was predictive of diagnosed child mental disorder, adjusted odds ratio (AOR) = 1.83 (95% CI 1.49-2.23). Problematic parent-child relation at age 8-10 months was also predictive of mental disorder, AOR = 2.06 (1.57-2.70) but did not mediate the association between parental education and mental disorder. AOR for mental disorders was 3.24 (2.03-5.16 for the combination vocational training and problematic parent-child relation and 2.49 (1.42-4.38) for the combination primary school and problematic parent-child relation.

CONCLUSIONS

Low parental education and problematic parent-child relation were independent risk factors for diagnosed mental disorders in the age span of 11 months to 8 years.

Father involvement in infancy predicts behavior and response to chronic stress in middle childhood in a low-income Latinx sample

Fathers' involvement in early childhood is important for children's physical, emotional, and cognitive development, particularly in low-income families. However, little is known about the longitudinal relations between early father involvement and children's later physiological responses to chronic stress and behaviors impacted by stress in the context of poverty. These issues are particularly important among Latinx immigrant families who face significant psychosocial and poverty-related risk. In the current study, we examined the relationship between father involvement in infancy and physiological chronic stress in the middle childhood period, as measured through hair cortisol concentration (HCC), and several behavioral measures (attention problems, working memory) in a Latinx immigrant sample with low income. Father involvement in infancy predicted children's later HCC, and working memory in second to third grade. Father involvement also moderated the effect of HCC on working memory, such that increased HCC predicted better working memory when fathers were not involved. These findings suggest that the fathers' involvement in infancy has lasting impacts on health and behavior and that associations between physiological and behavioral measures of stress may be moderated by differences in early father involvement.

Hair cortisol concentrations among urban and rural-dwelling mother-child dyads, La Romana, Dominican Republic

Hair cortisol concentrations (HCC) were studied in mother-child dyads of La Romana, Dominican Republic (DR), a low-income city, and of the surrounding bateyes, sugarcane plantation villages with inhabitants frequently of Haitian descent. Populations of low socioeconomic status (SES) experience hypothalamic-pituitary-adrenal (HPA) axis dysregulation. Urban communities may be increasingly exposed to stressors such as crime and concentrated poverty whereas rural communities may be devoid of important community resources. As a result, the experience of stress in poverty may differ by place of residence. The goal of this study was to examine differences in HCC among urban and rural-dwelling mother-child dyads in socioeconomically disadvantaged communities surrounding La Romana, DR. Forty-five mother/child dyads were enrolled in La Romana and 45 at several bateyes surrounding La Romana. Mothers were ≥18 years and children were between 7 and 14 years. Mothers self-reported perceived stress and demographic factors. Hair samples were collected from mothers and children, and HCC was assessed using enzyme-linked immunosorbent assays. General linear models examined associations between socioeconomic factors and HCC, and between maternal and child HCC. HCC were measured in 88 maternal and 87 child samples (N = 175). Mothers living in a batey had higher HCC than those living in La Romana (p = 0.001). HCC was positively associated among maternal-child dyads (p = 0.001). Further, Haitian-born mothers as a population who frequently live in a rural batey experienced higher HCC (p = 0.025) that may partially be explained by discriminatory practices in the DR. This research helps to elucidate the impact of urban and rural environmental settings on HCC.Lay summaryThis study focuses on chronic stress, measured by hair cortisol levels, among a low-income population of Dominican and Haitian mother-child pairs who live in urban and rural settings. We found that Haitian-born mothers, who frequently live in a rural batey, had higher hair cortisol levels than Dominican born mothers. Hair cortisol levels between mothers and their children were positively associated. This study addresses the impact of urban and rural environments on the stress response among socioeconomically disadvantaged persons living in an upper middle income country who bear an excessive burden of psychosocial stress.

Associations of socioeconomic and other environmental factors with early brain development in Bangladeshi infants and children

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Research from high-income countries shows that experiences impact neural development.

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We examine EEG in relation to wealth and psychosocial factors in 6 and 36-month-olds from Bangladesh.

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Wealth and maternal stress is associated with EEG oscillations in 36-month-olds.

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Neither wealth nor maternal stress is associated with EEG oscillations in 6-month-olds.

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Environmental influences on EEG may emerge between 6 and 36 months of age.

Studies of infants growing up in high-income countries reveal developmental changes in electroencephalography (EEG) power whereby socioeconomic factors - specifically, low SES and low income - are associated with lower EEG power in infants aged newborn to nine months. In the current paper we explore relationships of spectral EEG power across three regions (frontal, central, and parietal) and four frequency bands (theta, alpha, beta, and gamma) with socioeconomic and psychosocial factors in a cohort of n = 160 6-month-old infants and n = 187 36-month-old children living in Dhaka, Bangladesh. Household wealth is assessed as a multi-dimensional composite score encompassing income, assets, and housing materials. Psychosocial factors include maternal perceived stress and family caregiving activities. Among the 6-month-old infants we do not observe any association of household wealth or psychosocial factors with EEG power. Among the 36-month-old children, we find that household wealth is negatively associated absolute power in the beta and gamma bands across frontal, central, and parietal electrodes. We also find that higher reports of maternal perceived stress are associated with more absolute theta power in frontal and central regions in the 36-month-old children. The finding of a negative relationship of household wealth with beta and gamma power in 36-month-old children differs from findings previously observed in infants in high-income countries. Overall, findings suggest that children’s environment continues to influence the development of EEG oscillations and provide support for the utility of EEG to quantify developmental effects of early life experiences on neural functional outcomes in low income countries.

Sex-Specific Effects of Stress on Respiratory Control: Plasticity, Adaptation, and Dysfunction

As our understanding of respiratory control evolves, we appreciate how the basic neurobiological principles of plasticity discovered in other systems shape the development and function of the respiratory control system. While breathing is a robust homeostatic function, there is growing evidence that stress disrupts respiratory control in ways that predispose to disease. Neonatal stress (in the form of maternal separation) affects "classical" respiratory control structures such as the peripheral O₂ sensors (carotid bodies) and the medulla (e.g., nucleus of the solitary tract). Furthermore, early life stress disrupts the paraventricular nucleus of the hypothalamus (PVH), a structure that has emerged as a primary determinant of the intensity of the ventilatory response to hypoxia. Although underestimated, the PVH's influence on respiratory function is a logical extension of the hypothalamic control of metabolic demand and supply. In this article, we review the functional and anatomical links between the stress neuroendocrine axis and the medullary network regulating breathing. We then present the persistent and sex-specific effects of neonatal stress on respiratory control in adult rats. The similarities between the respiratory phenotype of stressed rats and clinical manifestations of respiratory control disorders such as sleep-disordered breathing and panic attacks are remarkable. These observations are in line with the scientific consensus that the origins of adult disease are often found among developmental and biological disruptions occurring during early life. These observations bring a different perspective on the structural hierarchy of respiratory homeostasis and point to new directions in our understanding of the etiology of respiratory control disorders. © 2021 American Physiological Society. Compr Physiol 11:1-38, 2021.

Socioeconomic factors, stress, hair cortisol, and white matter microstructure in children

Socioeconomic disadvantage has been linked to increased stress exposure in children and adults. Exposure to stress in childhood has been associated with deleterious effects on cognitive development and well-being throughout the lifespan. Further, exposure to stress has been associated with differences in brain development in children, both in cortical and subcortical gray matter. However, less is known about the associations among socioeconomic disadvantage, stress, and children's white matter development. In this study, we investigated whether socioeconomic disparities would be associated with differences in white matter microstructure in the cingulum bundle, as has been previously reported. We additionally investigated whether any such differences could be explained by differences in stress exposure and/or physiological stress levels. White matter tracts were measured via diffusion tensor imaging in 58 children aged 5-9 years. Results indicated that greater exposure to stressful life events was associated with higher child hair cortisol concentrations. Further, physiological stress, as indexed by hair cortisol concentrations, were associated with higher fractional anisotropy in the cingulum bundle. These results have implications for better understanding how perceived and physiological stress may alter neural development during childhood.

Associations between social adversity and young children's hair cortisol: A systematic review

Psychosocial and socioeconomic adversity in early childhood (termed 'social adversity') can have lifelong detrimental effects on health and development. Physiological stress is one proposed mechanism by which social adversity 'gets under the skin'. There is substantial research interest in whether hair cortisol, a biomarker proposed to measure the cumulative physiological stress response over time, can illustrate this mechanism. As a result, a growing number of studies have tested for associations between indicators of social adversity and child hair cortisol. The aim of this paper is to conduct a comprehensive, systematic review of the evidence for associations between indicators of social adversity and hair cortisol, specifically in young children (birth to 8 years) published any time up to 31 December 2019. The literature search identified 44 published studies that met inclusion criteria. The studies examined associations between one or more indicators of social adversity and child hair cortisol across 35 independent cohorts comprising 8370 children. Indicators of adversity examined in the identified literature included socioeconomic factors (e.g. low parental education, low income and unemployment), psychosocial factors (e.g. parent stress, poor mental health and family violence), and children's direct exposure to maltreatment, abuse and stressful events. Across all indicators of adversity, a total of 142 associations with hair cortisol were examined. Evidence of associations was limited and inconsistent; 34/142 (24%) showed evidence of a positive association between adversity and higher hair cortisol, 8/142 (6%) showed a negative association, and more than two thirds (100/142, 70%) of all examined associations were null. The collective evidence appears insufficient to conclude that there is a relationship between social adversity and hair cortisol, as a measure of physiological stress response, in young children.

Hair Cortisol Concentrations Are Associated with Dental Anxiety during Pregnancy

Dental anxiety (DA) and hair cortisol concentrations (HCC) are associated with psychological symptoms and vary during pregnancy. We aimed to examine the association between HCC and DA at two points of pregnancy. Participants were pregnant mothers (n = 533) drawn from the FinnBrain Birth Cohort Study donating a hair sample at gestational week (gwk) 24 (n = 442) and/or at delivery (n = 176) and completed questionnaires on DA. Two groups, HCC1 and HCC2, treated as separate in the analyses, were formed according to the hair sample donation time i.e., gwk24 and delivery. 85 subjects were included in both groups. MDAS, EPDS, and SCL-90 were used to measure DA, depressive and anxiety symptoms, respectively, at gwk14 for the HCC1 group and gwk34 for the HCC2 group. The association between DA and HCC was studied with a binary logistic regression model, adjusted for anxiety and depressive symptoms, age, BMI, and smoking status. Individuals with high DA had lower HCC levels at gwk24 (OR = 0.548; 95% CI = 0.35–0.86; p = 0.009), but the association was not statistically significant at the delivery (OR = 0.611; 95% CI = 0.28–1.33; p = 0.216). The independent association between HCC and DA in pregnant women suggests that long-term cortisol levels could play a role in the endogenous etiology of DA. Further studies are however, needed.

Cumulative exposure to socioeconomic and psychosocial adversity and hair cortisol concentration: A longitudinal study from 5 months to 17 years of age

BACKGROUND

Exposure to early adversity has been associated with long-lasting risks for poor health and functioning. Prior research suggests that the hypothalamic-pituitary-adrenal (HPA) axis, and its main end-product glucocorticoid hormone cortisol, may be at play. This study tested whether an index of cumulative socioeconomic and psychosocial adversity assessed prospectively, from infancy to adolescence, was associated with hair cortisol concentration (HCC), and if this association differed by sex.

METHODS

The sample comprised 556 adolescents (42.0% males) who provided hair for cortisol measurement at 17 years of age. Adversity indicators (young and single motherhood, low socioeconomic status (SES), maternal alcohol use, hostile-reactive parenting, and depressive symptoms, as well as peer victimization and neighborhood dangerousness) were repeatedly reported by mothers or youths between the ages of 5 months and 15 years.

RESULTS

Chronic adversity was non-linearly associated with HCC; youth exposed to lower and higher levels of adversity had moderate-to-higher HCC compared to lower HCC noted in participants with moderate levels of adversity, for both males and females. None of the indicators taken separately, except the perception of neighborhood dangerousness, were significantly associated with HCC.

CONCLUSION

Our findings support the hypothesis that HPA axis activity varies according to cumulative adversity, albeit non-linearly, which may bear consequences for later health and functioning.

Opposing relationships of childhood threat and deprivation with stria terminalis white matter

While stress may be a potential mechanism by which childhood threat and deprivation influence mental health, few studies have considered specific stress‐related white matter pathways, such as the stria terminalis (ST) and medial forebrain bundle (MFB). Our goal was to examine the relationships between childhood adversity and ST and MFB structural integrity and whether these pathways may provide a link between childhood adversity and affective symptoms and disorders. Participants were young adults (n = 100) with a full distribution of maltreatment history and affective symptom severity. Threat was determined by measures of childhood abuse and repeated traumatic events. Socioeconomic deprivation (SED) was determined by a measure of childhood socioeconomic status (parental education). Participants underwent diffusion spectrum imaging. Human Connectome Project data was used to perform ST and MFB tractography; these tracts were used as ROIs to extract generalized fractional anisotropy (gFA) from each participant. Childhood threat was associated with ST gFA, such that greater threat was associated with less ST gFA. SED was also associated with ST gFA, however, conversely to threat, greater SED was associated with greater ST gFA. Additionally, threat was negatively associated with MFB gFA, and MFB gFA was negatively associated with post‐traumatic stress symptoms. Our results suggest that childhood threat and deprivation have opposing influences on ST structural integrity, providing new evidence that the context of childhood adversity may have an important influence on its neurobiological effects, even on the same structure. Further, the MFB may provide a novel link between childhood threat and affective symptoms.

Examining longitudinal associations between self-reported depression, anxiety and stress symptoms and hair cortisol among mothers of young children

BACKGROUND

Maternal mental health is critically important given its impacts on both women's and children's outcomes. Hair cortisol concentrations (HCC) may provide insight into physiological processes underpinning mental health. This study investigated associations between mothers' self-reported mental health symptoms and their HCC at 1, 2 and 3 years postpartum.

METHODS

Longitudinal study of Australian mothers recruited for their experience of adversity in pregnancy ('right@home' trial, N=722). Mental health symptoms were self-reported using the Depression, Anxiety and Stress Scales (DASS). Associations between DASS total and subscale scores and HCC were estimated using linear regression and generalized estimating equation (GEE) models, examining associations: at each age; across all ages (multivariate GEE); and with persistence of high symptom severity. Missing data were addressed using multiple imputation.

RESULTS

546/722 (76%) women provided at least one hair sample (71% at 1, 61% at 2, 49% at 3 years). Associations between DASS total or subscale scores and HCC were not evident across time points. Only dichotomized high depression symptom severity was associated with higher HCC in the GEE models (β=0.12, p=0.04). There was no evidence of associations between persistence of high DASS symptom severity and HCC at 3 years.

LIMITATIONS

The DASS measured self-reported symptoms for the preceding week whereas HCC captured average cortisol over three months. Associations amongst mothers experiencing adversity may not represent patterns in the general population.

CONCLUSIONS

Considered in context with existing literature, these findings suggest that HCC provides limited insight into the mental health of mothers experiencing adversity across the early postpartum years.

Stressed-Out Oral Immunity: A Gateway From Socioeconomic Adversity to Periodontal Disease

OBJECTIVE

It has been suggested that adverse socioeconomic conditions "get under the skin" by eliciting a stress response that can trigger periodontal inflammation. We aimed to a) estimate the extent to which socioeconomic position (SEP) is associated with periodontal disease (PD) and proinflammatory oral immunity, and b) determine the contribution of psychosocial stress and stress hormones to these relationships.

METHODS

In this cross-sectional study (n = 102), participants (20-59 years old) completed financial and perceived stress questionnaires and underwent full-mouth periodontal examinations. SEP was characterized by annual household income and educational attainment. Cortisol, a biological correlate of chronic stress, was assessed in hair samples. Oral immunity was characterized by assessing oral inflammatory load and proinflammatory oral neutrophil function. Blockwise Poisson and logistic regression models were applied.

RESULTS

Compared with lower SEP, individuals in the middle- and higher-income categories had a significantly lower probability of PD (incidence rate ratio [IRR] = 0.5 [confidence interval {CI} = 0.3-0.7] and IRR = 0.4 [95% CI = 0.2-0.7]) and oral inflammatory load (IRR = 0.6 [95% CI = 0.3-0.8] and IRR = 0.5 [95% CI = 0.3-0.7]) and were less likely to have a proinflammatory oral immune function (odds ratio [OR] = 0.1 [95% CI = 0.0-0.7] and OR = 0.1 [95% CI = 0.0-0.9]). PD and oral immune parameters were significantly associated with financial stress and cortisol. Adjusting for financial stress and cortisol partially attenuated the socioeconomic differences in PD to IRR = 0.7 (95% CI = 0.5-0.8) and IRR = 0.6 (95% CI = 0.5-0.7) for the middle- and higher-income categories, respectively. Similar results were observed for proinflammatory immunity (OR = 0.2 [95% CI = 0.0-1.8] and OR = 0.3 [95% CI = 0.0-2.3]).

CONCLUSION

These findings suggest that psychosocial stress may contribute to a proinflammatory immunity that is implicated in PD pathobiology and provide insight into social-to-biological processes in oral health.

Cortisol and socioeconomic status in early childhood: A multidimensional assessment

The hypothalamic-pituitary-adrenal (HPA) axis is sensitive to early life stress, with enduring consequences for biological stress vulnerability and health (Gunnar & Talge, 2008). Low socioeconomic status (SES) is associated with dysregulation of the stress hormone cortisol in early childhood. However, a mechanistic understanding of this association is lacking. Multidimensional assessment of both SES and cortisol is needed to characterize the intricate relations between SES and cortisol function in early childhood. We assessed parent-reported family income, parent education, occupational prestige, neighborhood risk, food insecurity, and household chaos for 12-month-old infants (N = 90) and 3.5-year-old children (N = 91). Hair cortisol concentration (HCC) was obtained from parent and child, indexing chronic biological stress, and diurnal salivary cortisol was measured in the children. Controlling for parent HCC, parent education uniquely predicted infant and child HCC and, in addition, neighborhood risk uniquely predicted infant HCC. Household chaos predicted bedtime salivary cortisol concentration (SCC) for both infants and children, and infant daily cortisol output. Food insecurity was associated with flattened cortisol slope in 3.5-year-old children. Parental sensitivity did not mediate relations between SES and cortisol. Results highlight the utility of SES measures that index unpredictable and unsafe contexts, such as neighborhood risk, food insecurity, and household chaos.

Addressing educational inequalities and promoting learning through studies of stress physiology in elementary school students

To be ready to learn, children need to be focused, engaged, and able to bounce back from setbacks. However, many children come to school with heightened or diminished physiological arousal due to exposure to poverty-related risks. While stress physiology plays a role in explaining how adversity relates to processes that support students' cognitive development, there is a lack of studies of physiological stress response in educational settings. This review integrates relevant studies and offers future directions for research on the role of stress physiology in the school adaptation of elementary school students, focusing on these important questions: (a) What are the links between physiological stress response and learning-related skills and behaviors, and do they vary as a function of proximal and distal experiences outside of school? (b) How are school experiences associated with students' physiological stress response and related cognitive and behavioral adaptations? (c) How can we leverage measures of students' physiological stress response in evaluations of school-based interventions to better support the school success of every student? We hope to stimulate a new wave of research that will advance the science of developmental stress physiology, as well as improve the application of these findings in educational policy and practice.

Associations between developmental trajectories of peer victimization, hair cortisol, and depressive symptoms: a longitudinal study

BACKGROUND

Peer victimization has been associated with long-lasting risks for mental health. Prior research suggests that stress-related systems underlying adaptation to changing environments may be at play. To date, inconsistent findings have been reported for the hypothalamic-pituitary-adrenal (HPA) axis, and its end product cortisol. This study tested whether peer victimization was associated with hair cortisol concentrations (HCC), and whether this association varied according to sex, timing, and changes in exposure. We also examined whether peer victimization differentially predicted depressive symptoms according to HCC.

METHODS

The sample comprised 556 adolescents (42.0%; 231 males) who provided hair for cortisol measurement at 17 years of age. Peer victimization was reported at seven occasions between the ages of 6 and 15 years.

RESULTS

Peer victimization was nonlinearly associated with HCC for boys only, whereas changes in peer victimization were related to HCC for boys and girls. Peer victimization predicted more depressive symptoms for all participants, except those with lower HCC.

CONCLUSIONS

Our findings provide further support for persistent dysregulation of the HPA axis following exposure to chronic adversity, of which the expression may change according to sex and the severity of victimization.

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

BACKGROUND

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

METHODS

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

RESULTS

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

LIMITATIONS

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

CONCLUSION

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

DISCUSSION

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

Resting EEG, Hair Cortisol and Cognitive Performance in Healthy Older People with Different Perceived Socioeconomic Status

Successful aging depends upon several internal and external factors that influence the overall aging process. Objective and subjective socioeconomic status emerge as potential psychosocial factors in the ethiopathophysiology of aging-related disorders. Presumably, low socioeconomic status can act as a psychosocial stressor that can affect humans’ physiology via psychoneuroendocrine mechanisms, that may, in turn, affect the brain physiology. In resting-state electroencephalography (EEG), excess theta and delta activity has been related to cognitive decline and dementia. The main aim of this study was to analyze the effect of objective and subjective socioeconomic status (SES) on cognition and brain electrical activity through EEG measures. The present research constitutes a cross-sectional study with thirty healthy older adults (61–82 years old) separated into two clusters: high socioeconomic (HS) and low socioeconomic (LS) status; they were evaluated and compared in cognitive terms using the Wechsler Adult Intelligence Scale (WAIS-IV). An EEG at rest was recorded to measure brain activity and, as an indicator of long-term stress exposure, hair cortisol concentrations (HCC) were measured. Our results show that lower SES is related to a worse performance in working memory tasks (p = 0.009), higher delta (p = 0.002) and theta power (p = 0.039), and lower alpha activity (p = 0.028). However, it seems that SES does not significantly affect HCC in this population of healthy older adults. The effects of SES on long-term cortisol exposure, brain electrical activity, and cognitive functions in healthy older people emphasize the role of psychosocial factors in aging from an integrative perspective that will allow us to implement better prevention programs to target cognitive decline in adults.