Genetic and environmental influences on pubertal hormones in human hair across development

Hair hormone data from Syrian refugee children: Perspectives from a two-year longitudinal study

For numerous issues of convenience and acceptability, hair hormone data have been increasingly incorporated in the field of war trauma and forced displacement, allowing retrospective examination of several biological metrics thought to covary with refugees' mental health. As a relatively new research method, however, there remain several complexities and uncertainties surrounding the use of hair hormones, from initial hair sampling to final statistical analysis, many of which are underappreciated in the extant literature, and restrict the potential utility of hair hormones. To promote awareness, we provide a narrative overview of our experiences collecting and analyzing hair hormone data in a large cohort of Syrian refugee children (n = 1594), across two sampling waves spaced 12 months apart. We highlight both the challenges faced, and the promising results obtained thus far, and draw comparisons to other prominent studies in this field. Recommendations are provided to future researchers, with emphasis on longitudinal study designs, thorough collection and reporting of hair-related variables, and careful adherence to current laboratory guidelines and practices.

Fathers and sons, mothers and daughters: Sex-specific genetic architecture for fetal testosterone in a wild mammal

Testosterone plays a critical role in mediating fitness-related traits in many species. Although it is highly responsive to environmental and social conditions, evidence from several species show a heritable component to its individual variation. Despite the known effects that in utero testosterone exposure have on adult fitness, the heritable component of individual testosterone variation in fetuses is mostly unexplored. Furthermore, testosterone has sex-differential effects on fetal development, i.e., a specific level may be beneficial for male fetuses but detrimental for females, producing sexual conflict. Such sexual conflict may be resolved by the evolution of a sex-specific genetic architecture of the trait. Here, we quantified fetal testosterone levels in a wild species, free-ranging nutrias (Myocastor coypus) using hair-testing and estimated testosterone heritability between parent and offspring from the same and opposite sex. We found that in utero accumulated hair testosterone levels were heritable between parents and offspring of the same sex. Moreover, there was a low additive genetic covariance between the sexes, and a low cross-sex genetic correlation, suggesting a potential for sex-specific trait evolution, expressed early on, in utero.

Hair-Based Assessment of Sex Steroid Hormones in Patients with Anorexia Nervosa

Anorexia nervosa (AN) is a complex psychiatric disorder accompanied by a variety of endocrine effects. Altered levels of the sex steroid hormones progesterone and dehydroepiandrosterone (DHEA) have been shown to occur in patients with AN using short-term hormonal measurement methods based on blood, saliva, and urine samples. However, since sex steroid hormone levels fluctuate during the menstrual cycle, these measurement methods require a great deal of effort due to the need to collect multiple samples in order to correctly determine the basal level of sex hormones. In contrast, hair-based assessments provide a marker of accumulated longer-term hormone exposure using a single, non-invasive sample. The aim of this study was to investigate sex steroid hormone levels via hair-based assessments in acutely underweight AN in comparison with healthy, age-matched, female control participants. Additionally, we compared progesterone and DHEA hair levels longitudinally during inpatient treatment in AN. Collected hair samples were analyzed using liquid chromatography-mass spectrometry (LC-MS/MS) to determine a monthly hormone level of progesterone and DHEA. Our results indicate that DHEA hair hormone levels were similar across groups but progesterone was suppressed in underweight AN compared with healthy controls. In the longitudinal design, no significant change in hair hormone levels during partial weight restoration in patients with AN was observed. Our findings suggest that hair analysis can be used to detect suppressed progesterone levels in severe AN, and that progesterone does not increase during short-term weight restoration.

Ubiquitous bias and false discovery due to model misspecification in analysis of statistical interactions: The role of the outcome's distribution and metric properties

Studies of interaction effects are of great interest because they identify crucial interplay between predictors in explaining outcomes. Previous work has considered several potential sources of statistical bias and substantive misinterpretation in the study of interactions, but less attention has been devoted to the role of the outcome variable in such research. Here, we consider bias and false discovery associated with estimates of interaction parameters as a function of the distributional and metric properties of the outcome variable. We begin by illustrating that, for a variety of noncontinuously distributed outcomes (i.e., binary and count outcomes), attempts to use the linear model for recovery leads to catastrophic levels of bias and false discovery. Next, focusing on transformations of normally distributed variables (i.e., censoring and noninterval scaling), we show that linear models again produce spurious interaction effects. We provide explanations offering geometric and algebraic intuition as to why interactions are a challenge for these incorrectly specified models. In light of these findings, we make two specific recommendations. First, a careful consideration of the outcome's distributional properties should be a standard component of interaction studies. Second, researchers should approach research focusing on interactions with heightened levels of scrutiny. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Influence of gonadal steroids on cortical surface area in infancy

Sex differences in the human brain emerge as early as mid-gestation and have been linked to sex hormones, particularly testosterone. Here, we analyzed the influence of markers of early sex hormone exposure (polygenic risk score (PRS) for testosterone, salivary testosterone, number of CAG repeats, digit ratios, and PRS for estradiol) on the growth pattern of cortical surface area in a longitudinal cohort of 722 infants. We found PRS for testosterone and right-hand digit ratio to be significantly associated with surface area, but only in females. PRS for testosterone at the most stringent P value threshold was positively associated with surface area development over time. Higher right-hand digit ratio, which is indicative of low prenatal testosterone levels, was negatively related to surface area in females. The current work suggests that variation in testosterone levels during both the prenatal and postnatal period may contribute to cortical surface area development in female infants.

Heritability of Urinary Amines, Organic Acids, and Steroid Hormones in Children

Variation in metabolite levels reflects individual differences in genetic and environmental factors. Here, we investigated the role of these factors in urinary metabolomics data in children. We examined the effects of sex and age on 86 metabolites, as measured on three metabolomics platforms that target amines, organic acids, and steroid hormones. Next, we estimated their heritability in a twin cohort of 1300 twins (age range: 5.7–12.9 years). We observed associations between age and 50 metabolites and between sex and 21 metabolites. The monozygotic (MZ) and dizygotic (DZ) correlations for the urinary metabolites indicated a role for non-additive genetic factors for 50 amines, 13 organic acids, and 6 steroids. The average broad-sense heritability for these amines, organic acids, and steroids was 0.49 (range: 0.25–0.64), 0.50 (range: 0.33–0.62), and 0.64 (range: 0.43–0.81), respectively. For 6 amines, 7 organic acids, and 4 steroids the twin correlations indicated a role for shared environmental factors and the average narrow-sense heritability was 0.50 (range: 0.37–0.68), 0.50 (range; 0.23–0.61), and 0.47 (range: 0.32–0.70) for these amines, organic acids, and steroids. We conclude that urinary metabolites in children have substantial heritability, with similar estimates for amines and organic acids, and higher estimates for steroid hormones.

Children's hair cortisol and hair testosterone concentrations in response to environmental changes: from summer holidays to school

Elevated hair cortisol concentrations in children have been linked to several stress-related conditions, including school-related demands. However, little is known about changes in hair testosterone in children. The present study investigated changes in hair cortisol and hair testosterone concentrations in the time course of four months - from summer holidays until mid of autumn of the following school year - in 60, 10-12-year-old (11.31 ± 0.63) school children (29 girls). Children's mental health was assessed by the strengths and difficulties questionnaire (SDQ) and related to hair cortisol and hair testosterone levels. Body mass index, waist-to-height ratio, and parental education were evaluated as potential confounders. In girls, the expected increase of hair cortisol concentrations was observed during school as compared to summer holidays, partly accounted for by peer- and emotional problems and the increase of HTC. In boys, hair cortisol and testosterone concentrations were significantly higher. Hair cortisol increased only slightly, while hair testosterone decreased significantly during school. The findings suggest a reciprocal influence of the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axis, differentially affecting girls' and boys' hormone production in response to environmental changes.

Genetic and Epigenetic Control of Puberty

Puberty is a complex transitional phase in which reproductive capacity is achieved. There is a very wide variation in the age range of the onset of puberty, which follows a familial, ethnic, and sex pattern. The hypothalamic-pituitary-gonadal axis and several genetic, environmental, and nutritional factors play an important role in the onset of and throughout puberty. Recently, there has been significant progress in identifying factors that affect normal pubertal timing. Different studies have identified single nucleotide polymorphisms (SNPs) that affect pubertal timing in both sexes and across ethnic groups. Single genes are implicated in both precocious and delayed puberty, and epigenetic mechanisms have been suggested to affect the development and function of the GnRH neuronal network and responsiveness of end organs. All these factors can influence normal puberty timing, precocious puberty, and delayed puberty. The objective of this review is to describe recent findings related to the genetic and epigenetic control of puberty and highlight the need to deepen the knowledge of the regulatory mechanisms of this process in the normal and abnormal context.

Weak and uneven associations of home, neighborhood, and school environments with stress hormone output across multiple timescales

The progression of lifelong trajectories of socioeconomic inequalities in health and mortality begins in childhood. Dysregulation in cortisol, a stress hormone that is the primary output of the hypothalamus-pituitary-adrenal (HPA) axis, has been hypothesized to be a mechanism for how early environmental adversity compromises health. However, despite the popularity of cortisol as a biomarker for stress and adversity, little is known about whether cortisol output differs in children being raised in socioeconomically disadvantaged environments. Here, we show that there are few differences between advantaged and disadvantaged children in their cortisol output. In 8-14-year-old children from the population-based Texas Twin Project, we measured cortisol output at three different timescales: (a) diurnal fluctuation in salivary cortisol (n = 400), (b) salivary cortisol reactivity and recovery after exposure to the Trier Social Stress Test (n = 444), and (c) cortisol concentration in hair (n = 1210). These measures converged on two moderately correlated, yet distinguishable, dimensions of HPA function. We tested differences in cortisol output across nine aspects of social disadvantage at the home (e.g., family socioeconomic status), school (e.g., average levels of academic achievement), and neighborhood (e.g., concentrated poverty). Children living in neighborhoods with higher concentrated poverty had higher diurnal cortisol output, as measured in saliva; otherwise, child cortisol output was unrelated to any other aspect of social disadvantage. Overall, we find limited support for alteration in HPA axis functioning as a general mechanism for the health consequences of socioeconomic inequality in childhood.

Hormonal and neural correlates of prosocial conformity in adolescents

The dual hormone hypothesis, which centers on the interaction between testosterone and cortisol on social behavior, offers a compelling framework for examining the role of hormones on the neural correlates of adolescent peer conformity. Expanding on this hypothesis, the present study explored the interaction between testosterone and cortisol via hair concentrations on adolescents' conformity to peers. During fMRI, 136 adolescents (51 % female) ages 11-14 years (M = 12.32; SD = 0.6) completed a prosocial decision-making task. Participants chose how much of their time to donate to charity before and after observing a low- or high-prosocial peer. Conformity was measured as change in behavior pre- to post-observation. High testosterone with low cortisol was associated with greater conformity to high-prosocial peers but not low prosocial peers. Focusing on high prosocial peers, whole-brain analyses indicated greater activation post- vs. pre-observation as a function of high testosterone and low cortisol in regions implicated in social cognition, salience detection, and reward processing: pSTS/TPJ, insula, OFC, and caudate nucleus. Results highlight the relevance of hormones for understanding the neural correlates of adolescents' conformity to prosocial peers.

Adolescent Big Five personality and pubertal development: Pubertal hormone concentrations and self-reported pubertal status

In early adolescence, levels of conscientiousness and agreeableness have been found to temporarily decrease, with levels of neuroticism increasing, indicating a dip in personality maturation. It is unknown whether these changes are related to the process of puberty, a major developmental milestone with numerous changes for children. Here, we first replicated the dip in personality maturity in early adolescence (N = 2640, age range 8-18, 51% girls, 65% non-Hispanic white, 21% Hispanic/Latino, 10% African American, 9% other, roughly 33% of families received means-tested public assistance) and tested associations between the Big Five personality dimensions and pubertal development and timing across late childhood and adolescence (n = 1793). Pubertal development was measured using both hormonal assays (DHEA, testosterone, and progesterone) and self-reports of secondary sex characteristics. Of hormonal measures, only higher DHEA concentrations were associated with lower conscientiousness and openness. Nonparametric moderation analyses using LOSEM indicated Complex Age × Sex interactions involving all three hormones. Self-reported pubertal development was associated with lower extraversion, conscientiousness, agreeableness, and openness. More advanced pubertal timing was also related to lower levels of extraversion, conscientiousness, and agreeableness. All associations were small. As some evidence was found for small associations between pubertal development and lower levels of conscientiousness and agreeableness, a dip in personality maturation in these personality traits may be partly due to pubertal development in early adolescence. Overall, results did not indicate that pubertal development was the primary explanation of the maturity dip in adolescent personality. Many small influences likely accumulate to explain the dip in personality maturity in early adolescence. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Testosterone and hippocampal trajectories mediate relationship of poverty to emotion dysregulation and depression

There is robust evidence that early poverty is associated with poor developmental outcomes, including impaired emotion regulation and depression. However, the specific mechanisms that mediate this risk are less clear. Here we test the hypothesis that one pathway involves hormone mechanisms (testosterone and DHEA) that contribute to disruption of hippocampal brain development, which in turn contributes to perturbed emotion regulation and subsequent risk for depression. To do so, we used data from 167 children participating in the Preschool Depression Study, a longitudinal study that followed children from preschool (ages 3 to 5 y) to late adolescence, and which includes prospective assessments of poverty in preschool, measures of testosterone, DHEA, and hippocampal volume across school age and adolescence, and measures of emotion regulation and depression in adolescence. Using multilevel modeling and linear regression, we found that early poverty predicted shallower increases of testosterone, but not DHEA, across development, which in turn predicted shallower trajectories of hippocampal development. Further, we found that early poverty predicted both impaired emotion regulation and depression. The relationship between early poverty and self-reported depression in adolescence was explained by serial mediation through testosterone to hippocampus to emotion dysregulation. There were no significant interactions with sex. These results provide evidence about a hormonal pathway by which early poverty may contribute to disrupted brain development and risk for mental health problems later in life. Identification of such pathways provide evidence for potential points of intervention that might help mitigate the impact of early adversity on brain development.

Longitudinal effects of family psychopathology and stress on pubertal maturation and hormone coupling in adolescent twins

Adolescents experience profound neuroendocrine changes, including hormone "coupling" between cortisol, testosterone, and dehydroepiandrosterone. Emerging research has only begun to elucidate the role of hormone coupling, its genetic and environmental etiology, and the extent to which coupling is impacted by gender, puberty, and family context. We included measures on parent and child mental health, parenting stress, and family conflict of 444 twin pairs and their parents across two timepoints, when youth were on average 8 and 13 years old, respectively. Structural equation models examined the impact of family context effects on coupling during adolescence. Biometric twin models were then used to probe additive genetic, shared, and non-shared environmental effects on hormone coupling. Hormones were more tightly coupled for females than males, and coupling was sensitive to parental depression and co-twin psychopathology symptoms and stress exposure in females. The association between family context and coupling varied across specific neuroendocrine measures and was largely distinct from pubertal maturation. Biometric models revealed robust shared and non-shared environmental influences on coupling. We found that family antecedents modify the strength of coupling. Environmental influences account for much of the variation on coupling during puberty. Gender differences were found in genetic influences on coupling.

Measurement of cortisol, dehydroepiandrosterone, and testosterone in the hair of children: Preliminary results and promising indications

Hormone analysis is a valuable tool for understanding how physiology and behavior interact. Cortisol in hair has recently been examined as a measure of longer-term hormone output. The aim of this study was to investigate the relationships between other androgens in hair and anthropometric measures. In a child sample (n = 114, mean age: 8.5 years, 66 females) levels of cortisol, dehydroepiandrosterone (DHEA) and testosterone were assayed in the 0-3 cm section proximal to scalp. The 3-6 cm segment within a subsample of female participants (n = 35) was examined and compared. Results showed that testosterone strongly correlated with DHEA, and moderately correlated with cortisol (0-3 cm only). Higher hormone concentrations were present in the 3-6 cm segment. Finally, there was a weak positive association between DHEA and height. The replication of previously identified associations between androgens, particularly testosterone-DHEA, and with developmental measures suggests hair may offer a valid method of hormone measurement for DHEA and testosterone.