Relationship between hair cortisol concentration (HCC) and stress-related psychological measures are inconclusive, possibly due to overlooked heterogeneity regarding childhood trauma and a lack of comprehensive research on stress-related psychological factors. This study aims to compare young adults without history of childhood trauma to young adults who experienced childhood trauma using HCC and various stress-related psychological factors, as well as investigate the impacts of childhood trauma on the association between HCC and stress-related psychological measures.
A total of 206 young, healthy adults were recruited. We divided participants into two groups depending on whether or not they had suffered moderate-to-severe childhood trauma (CT+ and CT-) and compared HCC and various stress-related psychological measures between groups. Using multiple linear regression analyses, we assessed the associations between HCC and stress-related psychological measures for each group.
We found no difference between the groups in HCC or the reported number of stressful life events in the past year; however, CT+ individuals reported higher stress perception, more depressive and anxiety-related symptoms, and more difficulties in emotion regulation than CT- individuals. HCC was associated with emotion dysregulation among the CT- individuals, but not among the CT+ individuals.
These findings suggest that history of childhood trauma should be considered in studies using HCC as a biomarker for stress in young adults. Furthermore, HCC might be a useful biomarker of stress and stress-related emotion dysregulation in individuals without moderate-to-severe childhood trauma.
Cortisol levels change when individuals are under stress via the hypothalamus-pituitary-adrenal (HPA) axis [
Despite efforts to use HCC as a biomarker of stress, associations between cortisol concentrations and stress-related psychological factors are inconsistent [
Another possible reason for the inconsistent association between cortisol and stress-related psychological factors is that various measures of psychological stress were not analyzed comprehensively. HPA axis and cortisol levels have been shown to respond differently to various psychological factors; while they were not associated with self-reported stress perception [
We examined the impacts of childhood trauma on the relationship between HCC and various stress-related psychological measures in young, healthy adults. We hypothesized that compared with young adults with no history of childhood trauma, young adults with a history of childhood trauma would have more difficulties in stress perception and emotion regulation but would not have a correspondingly elevated HCC due to the negative effects of childhood trauma on the HPA axis. Furthermore, given that people with childhood trauma have exhibited changes in stress-related psychological factors and cortisol levels, we hypothesized that the association between HCC and stress-related psychological measures would be different in individuals with a history of childhood trauma than in individuals without such history.
Two hundred six individuals, 105 females and 101 males, ranging in age from 19 to 30 years old were recruited via internet job advertisement or posters at Severance Hospital of the Yonsei University Health System, Seoul, Korea. Participants were assessed using the Structured Clinical Interview in the Diagnostic and Statistical Manual of Mental Disorders IV and found to have no major psychiatric illness. Individuals were excluded if they had history of one or more of the following: 1) neurological illness; 2) head trauma accompanied by loss of consciousness; 3) a medical or surgical condition requiring hospitalization; 4) discharge from a hospital in the past six months; 5) use of glucocorticoid medication, oral contraceptives, or hormone replacement therapy; or 6) current pregnancy or breastfeeding. This study was approved by the Institutional Review Boards at Severance Hospital of the Yonsei University Health System, Seoul, Korea (4-2014-0744). Written informed consent was obtained from all participants.
The participants were divided into two groups depending whether or not they had a history of moderate-to-severe childhood trauma as determined by the 28-item Childhood Trauma Questionnaire (CTQ) [
Multiple psychological measures for different aspects of stress were assessed. The Korean version of the Social Readjustment Rating Scale (K-SRRS) was used to identify major stressful life events that occurred over the last year [
Approximately 10 strands or 10 mg of hair were collected using scissors. To minimize variance due to the hair growth rate, the hair sample was collected from the posterior vertex of the head [
All statistical analyses were conducted using SPSS version 25 (IBM Corp., Armonk, NY, USA). To produce a normal distribution of responses, logarithmic transformation was applied to the HCC. HCC had a skewness level that were acceptable for statistical analysis (<1.0) after transformation. Chi-square tests and independent t-tests were used to compare baseline and clinical characteristics between groups. For each group, multiple linear regression models were developed to assess the associations between stress-related psychological measures and HCC. Sex was included as an independent variable in all regression analyses. Each model was built using stepwise forward selection (p-value threshold: ≤0.05 to enter, ≥0.10 to remove). Participants with missing data were not included in the corresponding regression analyses. The significance threshold was p<0.05 for all analyses.
Eighty study participants reported moderate-to-severe childhood trauma (CT+). All participants were psychotropic drug naïve. The results of between-group analyses of baseline characteristics, HCC, and stress-related measures are shown in
For the CT- group, emotion dysregulation was significantly associated with HCC (B=0.010, p=0.018) in the regression model (R2=0.046; F=5.798; p=0.018) (
We investigated the associations between stress-related psychological factors and HCC in a cohort of young adults stratified by history of childhood trauma. Even without major psychiatric illness or stressful events, CT+ group had significant disturbance in stress perception, depressive symptoms, trait anxiety and emotion regulation. However, there was no difference in HCC itself between CT+ and CT- group. HCC was associated with difficulty in emotion regulation among individuals without history of childhood trauma. However, no psychological factors were associated with HCC in the CT+ group, suggesting that the relationship between psychological factors and HCC was different between adults without childhood trauma and adults with childhood trauma. These results underscore the importance of considering childhood trauma when conducting research on psychological stress, especially when cortisol level is used as an indicator of stress.
Compared with the CT- individuals, the CT+ individuals showed disturbances in stress perception, emotional states, and emotion regulation, despite the fact that none of the participants had major psychiatric illness. Previous reports of elevated scores on self-assessments of depression and anxiety [
Difficulty in emotion regulation was a predictor of increased HCC in CT- individuals. Considering that emotion regulation has a moderating effect on stress and HCC [
Among the CT+ individuals, none of the stress-related psychological measures was associated with HCC. This lack of association in CT+ individuals could provide explanation to our prior results that showed no difference in HCC between CT+ and CT- group, although there were significant differences in stress-related psychological factors. Chronic exposure to elevated corticotropin-releasing hormone levels has been linked to down-regulation and dysregulation of the HPA axis in adults with history of childhood trauma [
Our study has a few limitations. First, we cannot determine causality between the variables because of the cross-sectional nature of data. Hence, future longitudinal studies would be beneficial. Second, although we excluded individuals with severe medical diseases, detailed medical factors and anthropometric factors were not used in the analysis. The effect of those factors would be negligible in young, healthy adults; however, consideration of factors such as inflammatory state or body mass index might eliminate potential confounding effects. Third, there were differences in the time scales of the psychological assessments and the HCC measurement. For example, 3 cm of hair represents roughly 3 months of cortisol levels, whereas the K-SRRS asks about stressful events over the previous year. Fourth, since hair characteristics have been suggested to be considered as covariates [
In conclusion, our findings suggest that HCC might be a useful biomarker for stress-related psychological factors, especially difficulty in emotion regulation, in people without history of moderate-to-severe childhood trauma.
The datasets generated or analyzed during the study are available from the corresponding author on reasonable request.
Minji Bang, a contributing editor of the
Conceptualization: Won Jae Kim, Hye Yoon Park, Eun Lee. Data curation: Kyung Mee Park, Jung Tak Park, Eunchong Seo, Minji Bang, Suk Kyoon An. Formal analysis: Won Jae Kim, Hye Yoon Park. Funding acquisition: Eun Lee. Investigation: Won Jae Kim, Hye Yoon Park. Methodology: Won Jae Kim, Hye Yoon Park, Eun Lee. Project administration: Hye Yoon Park, Eun Lee. Resources: Kyung Mee Park, Jung Tak Park, Eunchong Seo, Minji Bang, Suk Kyoon An. Supervision: Kyung Mee Park, Jung Tak Park, Eunchong Seo, Minji Bang, Suk Kyoon An. Visualization: Won Jae Kim, Hye Yoon Park. Writing—original draft: Won Jae Kim. Writing—review & editing: all authors.
The National Research Foundation of Korea funded by the Ministry of Science, ICT & Future Planning, Republic of Korea, supported the present work (Grant number: 2017R1A2B3008214 to Eun Lee).
Baseline characteristics and stress-related psychological measures of the study participants
No childhood trauma (N=126) | Childhood trauma (N=80) | p-value |
|
---|---|---|---|
Sex, male/female | 61/65 | 40/40 | 0.824 |
Age, years | 23.0 (2.7) | 23.0 (2.5) | 0.903 |
Education |
14.3 (1.5) | 14.5 (1.3) | 0.465 |
Type of childhood trauma | |||
Emotional abuse | - | 10 | |
Physical abuse | - | 22 | |
Sexual abuse | - | 9 | |
Emotional neglect | - | 54 | |
Physical neglect | - | 44 | |
HCC, pg/μg | 7,254.4 (8371.7) | 8,183.7 (9136.1) | 0.455 |
Stress-related psychological measures | |||
K-SRRS |
594.6 (1027.4) | 634.5 (1405.1) | 0.815 |
PSS | 24.7 (5.6) | 27.0 (5.6) | 0.005 |
GARS |
21.6 (11.2) | 25.6 (12.0) | 0.016 |
BDI |
4.3 (4.3) | 7.3 (9.8) | 0.012 |
SAI | 35.8 (9.2) | 38.0 (8.8) | 0.094 |
TAI | 40.1 (6.8) | 42.5 (7.8) | 0.017 |
DERS | 70.0 (16.4) | 78.4 (19.0) | 0.001 |
Data are presented as the N or mean (SD).
level of education, GARS, and BDI data were available for 125 participants without childhood trauma and for all participants with childhood trauma;
K-SRRS data were available for 125 participants without childhood trauma and for 79 participants with childhood trauma;
independent t-tests and chi-square tests were used to compare the two groups.
BDI, Beck Depression Inventory; DERS, Difficulty in Emotion Regulation Scale; GARS, Global Assessment of Recent Stress; HCC, hair cortisol concentration; K-SRRS, Korean version of the Social Readjustment Rating Scale; PSS, Perceived Stress Scale; SAI, State Anxiety Inventory; SD, standard deviation; TAI, Trait Anxiety Inventory
Stepwise multiple linear regression of hair cortisol concentration on stress-related psychological measures
Childhood trauma | Independent variable | B | SE | β | t | p-value | Model properties |
---|---|---|---|---|---|---|---|
Absent (N=123) | (Constant) | 7.810 | 0.313 | 24.967 | <0.001 | R2=0.046 | |
DERS | 0.010 | 0.004 | 0.214 | 2.408 | 0.018 | adj. R2=0.038 | |
F=5.798 | |||||||
p=0.018 | |||||||
Present (N=79) | No variables were entered into the equation |
DERS, Difficulty in Emotion Regulation Scale; SE, standard error