Examining the role of socioeconomic status and temperament in the hair cortisol levels of infants

Association of childhood adversity with HPA axis activity in children and adolescents: A systematic review and meta-analysis

Childhood adversity (CA) is associated with alteration of the hypothalamus-pituitary-adrenal (HPA) axis. We conducted a meta-analysis to synthesize existing evidence on the association between CA and HPA axis activity among children and adolescents and investigate four research questions: (1) Is CA associated with different aspects of the HPA axis (i.e., diurnal cortisol, acute stress response, chronic cortisol levels)?, (2) Does this association vary by the child's age?, (3) Are threat and deprivation dimensions of CA differentially associated with HPA axis activity?, and (4) Does this association depend on both the dimension and timing of CA? Meta-analyses were conducted with 129 studies reporting 506 effect sizes. Results showed significant associations between CA with higher afternoon cortisol levels (r = 0.053), a flatter diurnal slope (r = 0.048), more blunted reactivity (r = -0.043), and higher hair cortisol concentration (r = 0.098), but not other cortisol indicators (morning cortisol, cortisol awakening response, daily output, and cortisol recovery). Older children and adolescents had more pronounced blunted reactivity and steeper recovery with CA than younger children. Threat and deprivation did not differ in overall impact for any cortisol indicator; however, there are timing-dependent associations specific to threat or deprivation for some cortisol indicators. For instance, threat was associated with heightened reactivity when occurred before middle childhood, and with blunted reactivity when occurred after age 15 years; in contrast, deprivation was associated with blunted reactivity regardless of its timing. Findings could inform targeted interventions to reduce negative impacts of CA on development.

The determination of endogenous steroids in hair and fur: A systematic review of methodologies

BACKGROUND

Endogenous steroid hormone assessment is essential for clinical practice. These hormones are typically measured in blood. More recently, measurement of steroids in hair samples has been gaining in popularity, so we have reviewed the methodologies used for this to-date.

METHODS

Ovid Medline, CINAHL, Psychinfo, and EMBASE were searched to identify manuscripts that analysed cortisol, testosterone, androstenedione, 17-hydroxyprogesterone (17OHP), dehydroepiandrosterone sulphate (DHEAS), and/or 25-hydroxyvitamin D (25(OH)D), in hair or fur. Data related to sampling and measurement procedures were extracted and analysed.

RESULTS

The systematic review included a total of 180 papers, with 82 % published in the past 8 years; 67 % were human and 33 % animal studies. Cortisol was by far the most common analyte. Incomplete reporting on sample harvest, preparation, and measurement procedures was common. Typically, samples were collected from posterior vertex of humans or back/neck of animals, weighing between 11 and 50 mg (with a range of 1.25-1000 mg). Samples were usually stored at room temperature, often using aluminium foil. Isopropanol was the most common cleaning solution. Hair was normally powdered or segmented prior to extraction. Extraction was typically carried out over 18-24 hours using methanol. Validation and precision information was provided in 47 % of studies.

CONCLUSIONS

This systematic review highlights the lack of standardisation in the analysis of endogenous steroids in hair. Reporting was typically incomplete, and assay validations were partial or absent. Together, these limit the value of these exciting new methods and hold back transition to clinical use.

Hair collection protocol in 12-month-old infants

Purpose

Most studies assessing hair cortisol were conducted with adults. As specific guidelines for infant hair collection are lacking, we developed a hair collection protocol for 12-month-old infants and assessed its acceptability and feasibility.

Results

Out of the total (N = 45), 95.6 % (n = 43) of caregivers consented to the procedure, while one caregiver did not consent (2.2 %), and another requested the procedure to be halted before required amount of hair had been reached (2.2 %). Furthermore, two (4.4 %) infants did not have enough hair for collection. There was no attrition due to infant fussiness/crying.

Discussion

We learned five lessons which can help to enhance reproducibility, mother's consent, and mother-infant comfort and acceptance of the procedure. The first lesson is to have the infant sit on the caregiver's lap to ensure the infant feels safe and remains relatively still. The second is to reassure caregivers by showing hair samples representing the amount to be cut as well as by clarifying no unaesthetic gaps would be visible. The third is to caress the infant's head to habituate them to the hair manipulation and to make soap bubbles as distractors. The fourth is to take extra care when securing the lock of hair for cutting because the infant scalp is thin and malleable. The fifth is to place a precision scale in the collection room to ensure the necessary weight is reached.

Conclusion

Our hair collection protocol developed for 12-month-old infants was deemed feasible and acceptable, filled an important literature gap concerning the absence of published protocols for infants, and will contribute to increase the replicability and collection efficiency for other research teams.

Psychological and Physiological Stress and Stressors in Early Childhood Educators: An Observational Pilot Study

While early childhood educators' mental health is important, it may also affect the well-being and education of their students. Yet, little research has described the stress and stressors of early childhood educators (ECEs), particularly as the pandemic wanes. This pilot study aimed to (1) describe ECEs' psychological and physiological stress and (2) examine the association between ECEs' psychological and physiological stress levels with stressors. A convenience sample of 67 ECEs, serving children 0-5 years old from 13 early educational centers completed surveys on psychological stress (perceived stress, anxiety, and depression), stressors (economic hardship, food insecurity, adverse childhood experiences), and demographics in Fall 2021. A subsample of ECEs provided hair samples, analyzed for cortisol, to estimate physiologic stress. Regarding stress, 63% met the criteria for major depressive disorder and 41% for generalized anxiety disorder. Only 26% were taking medications to manage mental health. About 25% experienced the stressors of food insecurity and economic hardship; 80% experienced at least one adverse childhood experience. Only education level significantly predicted perceived stress and depression - above and beyond stressors, household income, race, and age. The results have policy and practice implications for implementing evidence-based solutions to buffer stress and stressors in early childhood educators.

Is economic hardship associated with young children's cortisol levels?

Economic hardship during childhood has been linked to poor physical and mental health. This study examines cross-sectional and longitudinal associations of a summed economic hardship score of poverty, food insecurity, and financial hardship with hair cortisol in young children. Data from 24-month (Time 1, mean age 5 years) and 36-month (Time 2, mean age 6 years) follow-up from the NET-Works obesity prevention trial (NET-Works, NCT0166891) were used. Hair cortisol measures obtained at each time point were log-transformed and regressed on economic hardship at Time 1 and a cumulative economic hardship from Time 1 to Time 2, using generalized linear regressions. All models were adjusted for child age, sex, race/ethnicity, and intervention (prevention vs. control) arm. The final analytic sample sizes ranged from 248 to 287. Longitudinal analyses indicated that for every 1-unit higher economic hardship score at Time 1, hair cortisol at Time 2 follow-up was on average 0.07 log-picograms per milligram (pg/mg) higher (95% confidence interval [CI]: 0.01, 0.13). For every 1-unit increase in the cumulative economic hardship score between Time 1 and 2, there was a 0.04 log-pg/mg (95% CI: 0.00, 0.07) average higher level of hair cortisol at Time 2 follow-up. Results show suggestive but limited evidence for an association between economic hardship and cortisol in young children.

Association between the timing of family socioeconomic deprivation and adolescence hair cortisol among adolescent twins: A study of the genetic and environmental processes involved

BACKGROUND

While evidence shows that lower socioeconomic status (SES) is related to dysregulated hair cortisol concentration (HCC), the genetic and environmental processes underlying this association remain understudied.

OBJECTIVES

(1) to examine whether childhood and adolescence SES are phenotypically related to late adolescence HCC and to what extent these associations are explained by common underlying genetic factors (2) to estimate whether the genetic and environmental etiology of HCC varies according to SES and the timing of these experiences.

METHODS

Participants were 422 twin pairs for whom SES was measured in childhood (ages 0-5 years) and adolescence (age 14 years). Hair cortisol was assessed at age 19.

RESULTS

Additive genetic factors explained 39% of variability in HCC, whereas nonshared environmental factors accounted for the remaining 61%. A significant negative association emerged between HCC and family SES assessed in adolescence (β=-.11,p = .02), which was entirely explained by common underlying environmental influences. We also found evidence of stronger genetic contributions to HCC among youths who lived in more disadvantaged households during childhood in comparison to those from wealthier backgrounds.

CONCLUSIONS

This study provides first-time evidence that the association between adolescence SES and HCC is environmentally-explained and that genetic influences underlying HCC are not uniformly distributed across the family SES continuum measured during childhood. These findings may pave the way for a fuller understanding of the impact of early adversity on HPA axis activity.