Hormone changes in peripubertal girls

Life stress influences the relationship between sex hormone fluctuation and affective symptoms in peripubertal female adolescents

Female adolescents have a greatly increased risk of depression starting at puberty, which continues throughout the reproductive lifespan. Sex hormone fluctuation has been highlighted as a key proximal precipitating factor in the development of mood disorders tied to reproductive events; however, hormone-induced affective state change is poorly understood in the pubertal transition. The present study investigated the impact of recent stressful life events on the relationship between sex hormone change and affective symptoms in peripubertal female participants. Thirty-five peripubertal participants (ages 11-14, premenarchal, or within 1 year of menarche) completed an assessment of stressful life events, and provided weekly salivary hormone collections [estrone, testosterone, dehydroepiandrosterone (DHEA)] and mood assessments for 8 weeks. Linear mixed models tested whether stressful life events provided a context in which within-person changes in hormones predicted weekly affective symptoms. Results indicated that exposure to stressful life events proximal to the pubertal transition influenced the directional effects of hormone change on affective symptoms. Specifically, greater affective symptoms were associated with increases in hormones in a high stress context and decreases in hormones in a low stress context. These findings provide support for stress-related hormone sensitivity as a diathesis for precipitating affective symptoms in the presence of pronounced peripubertal hormone flux.

The effect of GnRH analog treatment on BMI in children treated for precocious puberty: a systematic review and meta-analysis

INTRODUCTION

The purpose of the present meta-analysis was to systematically evaluate the effect of GnRHa treatment on the BMI of children with precocious puberty after GnRHa treatment as compared to before, and to analyze the effect of GnRHa treatment on the body composition of children with precocious puberty at different BMIs by classifying into normal body mass, overweight, and obese groups according to BMI at the time of initial diagnosis.

CONTENT

A meta-analysis was performed using Stata 12.0 software by searching PubMed, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI), Chinese Scientific Journal Database (VIP database), and Wan fang database for relevant literature on standard deviation score of body mass index (BMI-SDS) after GnRHa treatment as compared to before in children with precocious puberty.

SUMMARY

A total of eight studies were included with a total sample size of 715 cases, and the results of meta-analysis showed that BMI-SDS increased in children with precocious puberty after GnRHa treatment as compared to before starting [(weighted mean difference (WMD)=0.23, 95 % CI: 0.14-0.33, p=0.000)] and also increased in children with normal body mass [(WMD=0.37, 95 % CI: 0.28-0.46, p=0.000)], and there was no significant change in BMI-SDS in children in the overweight or obese group [(WMD=0.01, 95 % CI: -0.08-0.10, p=0.775)].

OUTLOOK

Overall, there was an observed increase in BMI-SDS at the conclusion of GnRHa treatment in children with precocious puberty. Additionally, it was found that the effect of GnRHa treatment on body composition varied among children with different BMI status. Clinicians should emphasize the promotion of a healthy lifestyle and personalized dietary management for children.

Role of stress and physical activity on primary dysmenorrhea: A cross-sectional study

The initial physiological change in adolescent girls is the onset of menstruation. The most prevalent challenge they face regarding menstruation is primary dysmenorrhea, characterized by persistent or intermittent pelvic pain in the lower abdomen. The aim of this study was to investigate the influences of stress levels and physical activities on primary dysmenorrhea. A cross-sectional was conducted in Cirebon, Indonesia, in 2023 included young women who had never given birth (nullipara), aged 17-25 years old, had menstruated, and had no history of smoking and alcohol. The data were collected using a set of questionnaires consisting of the Numeric Rating Scale (NRS) to determine primary dysmenorrhea pain, the Depression Anxiety Stress Scales 42 (DASS 42) to determine the level of stress and the International Physical Activity Questionnaire (IPAQ) to determine physical activity. Pearson's correlation test was used to assess the correlation between the variables (stress levels, physical activity, and dysmenorrhea). A total of 150 young women were included in the study. Moderate stress levels (23.3%) and high physical activity (90.7%) were the most prevalent category observed among studied participants. Approximately 42% of them experienced mild dysmenorrhea pain. Our analysis indicated that stress levels and physical activities had strong positive and negative correlations with dysmenorrhea pain levels, with r=0.782 and r=-0.748, respectively, with both had p<0.001. This highlights that controlling stress could be beneficial in preventing dysmenorrhea pain among young women.

Brain network connectivity during peer evaluation in adolescent females: Associations with age, pubertal hormones, timing, and status

Despite copious data linking brain function with changes to social behavior and mental health, little is known about how puberty relates to brain functioning. We investigated the specificity of brain network connectivity associations with pubertal indices and age to inform neurodevelopmental models of adolescence. We examined how brain network connectivity during a peer evaluation fMRI task related to pubertal hormones (dehydroepiandrosterone and testosterone), pubertal timing and status, and age. Participants were 99 adolescents assigned female at birth aged 9-15 (M = 12.38, SD = 1.81) enriched for the presence of internalizing symptoms. Multivariate analysis revealed that within Salience, between Frontoparietal - Reward and Cinguloopercular - Reward network connectivity were associated with all measures of pubertal development and age. Specifically, Salience connectivity linked with age, pubertal hormones, and status, but not timing. In contrast, Frontoparietal - Reward connectivity was only associated with hormones. Finally, Cinguloopercular - Reward connectivity related to age and pubertal status, but not hormones or timing. These results provide evidence that the salience processing underlying peer evaluation is jointly influenced by various indices of puberty and age, while coordination between cognitive control and reward circuitry is related to pubertal hormones, pubertal status, and age in unique ways.

Doxorubicin-induced cardiotoxicity and risk factors

Doxorubicin (DOX) is an anthracycline antibiotic widely used as a chemotherapeutic agent to treat solid tumours and hematologic malignancies. Although useful in the treatment of cancers, the benefit of DOX is limited due to its cardiotoxic effect that is observed in a large number of patients. In the literature, there is evidence that the presence of various factors may increase the risk of developing DOX-induced cardiotoxicity. A better understanding of the role of these different factors in DOX-induced cardiotoxicity may facilitate the choice of the therapeutic approach in cancer patients suffering from various cardiovascular risk factors. In this review, we therefore discuss the latest findings in both preclinical and clinical research suggesting a link between DOX-induced cardiotoxicity and various risk factors including sex, age, ethnicity, diabetes, dyslipidaemia, obesity, hypertension, cardiovascular disease and co-medications.

Association Between Markers of Adiposity During Childhood and Puberty Onset in Latino Girls

CONTEXT

Prepubertal adiposity is associated with earlier puberty. It is unclear when this association starts, if all adiposity markers are similarly associated, and whether all pubertal milestones are similarly affected.

OBJECTIVE

To evaluate the association between different adiposity markers during childhood and the timing of different pubertal milestones in Latino girls.

DESIGN, SETTING, AND PARTICIPANTS

Longitudinal follow-up of 539 female participants of the Chilean Growth and Obesity Cohort recruited from childcare centers (mean age 3.5 years) from the southeast area of Santiago, Chile. Participants were singletons born between 2002 and 2003 within the normal birthweight range. Since 2006, a trained dietitian measured weight, height, waist circumference (WC) and skinfolds to estimate body mass index (BMI) Centers for Disease Control and Prevention percentiles, central obesity, percentage of fat mass (%FM), and fat mass index (FMI, fat mass/height2).

MAIN OUTCOME

Since 2009, sexual maturation was assessed every 6 months to assess age at (1) thelarche, (2) pubarche, (3) menarche, and (4) peak height velocity (PHV).

RESULTS

At thelarche, 12.5% were obese and 2% had central obesity. The median age of pubarche, menarche, and PHV were all associated with markers of adiposity at different time points during childhood whereas thelarche only with %FM and FMI. Adiposity clusters models showed that children with trajectories of high WC, %FM, and FMI during childhood were related with earlier thelarche, pubarche, menarche, and PHV but BMI trajectories only with menarche and PHV.

CONCLUSIONS

Higher WC, %FM, and FMI were associated with earlier age at thelarche, pubarche, menarche, and PHV. The effect of BMI was less consistent.

Sex differences of microglia in the healthy brain from embryonic development to adulthood and across lifestyle influences

Microglia, the central nervous system innate immune cells, play a critical role in maintaining a homeostatic environment in the brain throughout life. These cells exhibit an impressive range of functions and characteristics that help to ensure proper functioning of the brain. Notably, microglia can present differences in their genetic and physical traits, which can be influenced by a range of factors, including age, environmental exposures, disease, and sex. Remarkably, microglia have been found to express receptors for sex hormones, suggesting that these hormones may play a role in modulating microglial behavior and potentially contribute to sex differences. Additionally, sex-chromosomal factors were shown to impact microglial genetics and functioning. In this review, we will examine how microglial responses in homeostasis are impacted by their interaction with sex hormones and sex chromosomes. Specifically, our investigation will focus on examining this interaction from embryonic development to adulthood, and the influence of lifestyle elements on various microglial features, including density and distribution, morphology, transcriptome, and proteome.

Exposure to Perfluoroalkyl Substances and Associations with Pubertal Onset and Serum Reproductive Hormones in a Longitudinal Study of Young Girls in Greater Cincinnati and the San Francisco Bay Area

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS), endocrine disrupting chemicals with worldwide exposure, cause changes in mammary gland development in rodents. A few human studies report delay in pubertal events with increasing perfluorooctanoic acid (PFOA) exposure, but to our knowledge none have examined reproductive hormone levels at thelarche.

METHODS

In a cohort of Greater Cincinnati (GC) and San Francisco Bay Area (SFBA) girls recruited at 6-8 years of age, clinical examinations were conducted annually or semiannually with sequential Tanner staging. PFAS concentrations were measured in the first serum sample of 704 girls. In 304 GC girls, estradiol (E 2 ), estrone (E 1 ), testosterone (T), and dihydroepiandrosterone sulfate (DHEAS) were measured in serum at four time points around puberty. Relationships between PFAS and age at thelarche, pubarche, and menarche were analyzed using survival and structural equation models. The association between PFAS and reproductive hormones was assessed using linear regression models.

RESULTS

Median PFOA serum concentrations in GC (N = 353 , 7.3  ng / mL ) and the SFBA (N = 351 , 5.8  ng / mL ) were higher than in the U.S.

POPULATION

In multivariable Cox proportional hazard models [adjusted for race, body mass index (BMI)], increasing serum log-transformed PFOA was associated with a delay in pubarche [hazard ratio  ( HR ) = 0.83 ; 95% CI: 0.70, 0.99] and menarche (HR = 0.04 ; 95% CI: 0.01, 0.25). Structural equation models indicated a triangular relationship between PFOA, BMI percentile, and the age at the pubertal milestone. Increased PFOA had a statistically significant direct effect of delay on all three milestones, as did BMI. Perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDeA), and 2-(N -methyl-perfluorooctane sulfonamido) acetic acid (Me-PFOSA-AcOH) also were associated with later thelarche, and Me-PFOSA-AcOH also with later pubarche. PFOA was inversely associated with DHEAS (p < 0.01 ), E 1 (p = 0.04 ), and T (p = 0.03 ) concentrations at 6 months prior to puberty.

CONCLUSIONS

PFAS may delay pubertal onset through the intervening effects on BMI and reproductive hormones. The decreases in DHEAS and E 1 associated with PFOA represent biological biomarkers of effect consistent with the delay in onset of puberty. https://doi.org/10.1289/EHP11811.

Biobehavioral mechanisms underlying testosterone and mood relationships in peripubertal female adolescents

The pubertal transition is characterized by pronounced sex hormone fluctuation, refinement of affective neural circuitry, and an increased risk of depression in female adolescents. Sex hormones, including testosterone, exert modulatory effects on frontal-limbic brain networks and are associated with emotion dysregulation and depressive symptoms. Weekly changes in hormones predict affective symptoms in peripubertal female adolescents, particularly in the context of stress; however, the biobehavioral mechanisms underlying hormone change and mood relationships during the pubertal transition have yet to be determined and was the objective of the present study. Forty-three peripubertal female adolescents (ages 11-14) collected 8-weekly salivary hormone (estrone, testosterone) samples and mood assessments to evaluate hormone-mood relationships, followed by a biobehavioral testing session with psychosocial stress and EEG. Within-person correlations between weekly hormone changes and corresponding mood were performed to determine individual differences in mood sensitivity to weekly hormone change. Increased frontal theta activity indexing emotion reactivity, reduced cortisol reactivity, and reduced vagal efficiency predicted the strength of the relationship between testosterone and mood. Further, testosterone-sensitivity strength was associated with the enhancement of negative affect following stress testing. Results identify divergent frontal theta and stress responses as potential biobehavioral mechanisms underlying mood sensitivity to peripubertal testosterone fluctuation.

Multi-omics analysis reveals changes in tryptophan and cholesterol metabolism before and after sexual maturation in captive macaques

Rhesus macaques (Macaca mulatta, RMs) are widely used in sexual maturation studies due to their high genetic and physiological similarity to humans. However, judging sexual maturity in captive RMs based on blood physiological indicators, female menstruation, and male ejaculation behavior can be inaccurate. Here, we explored changes in RMs before and after sexual maturation based on multi-omics analysis and identified markers for determining sexual maturity. We found that differentially expressed microbiota, metabolites, and genes before and after sexual maturation showed many potential correlations. Specifically, genes involved in spermatogenesis (TSSK2, HSP90AA1, SOX5, SPAG16, and SPATC1) were up-regulated in male macaques, and significant changes in gene (CD36), metabolites (cholesterol, 7-ketolithocholic acid, and 12-ketolithocholic acid), and microbiota (Lactobacillus) related to cholesterol metabolism were also found, suggesting the sexually mature males have stronger sperm fertility and cholesterol metabolism compared to sexually immature males. In female macaques, most differences before and after sexual maturity were related to tryptophan metabolism, including changes in IDO1, IDO2, IFNGR2, IL1Β, IL10, L-tryptophan, kynurenic acid (KA), indole-3-acetic acid (IAA), indoleacetaldehyde, and Bifidobacteria, indicating that sexually mature females exhibit stronger neuromodulation and intestinal immunity than sexually immature females. Cholesterol metabolism-related changes (CD36, 7-ketolithocholic acid, 12-ketolithocholic acid) were also observed in female and male macaques. Exploring differences before and after sexual maturation through multi-omics, we identified potential biomarkers of sexual maturity in RMs, including Lactobacillus (for males) and Bifidobacterium (for females) valuable for RM breeding and sexual maturation research.

Pre- and Post-Sexual Maturity Liver-specific ERα Knockout Does Not Impact Hepatic Mitochondrial Function

Compared with males, premenopausal women and female rodents are protected against hepatic steatosis and present with higher functioning mitochondria (greater hepatic mitochondrial respiration and reduced H2O2 emission). Despite evidence that estrogen action mediates female protection against steatosis, mechanisms remain unknown. Here we validated a mouse model with inducible reduction of liver estrogen receptor alpha (ERα) (LERKO) via adeno-associated virus (AAV) Cre. We phenotyped the liver health and mitochondrial function of LERKO mice (n = 10-12 per group) on a short-term high-fat diet (HFD), and then tested whether timing of LERKO induction at 2 timepoints (sexually immature: 4 weeks old [n = 11 per group] vs sexually mature: 8-10 weeks old [n = 8 per group]) would impact HFD-induced outcomes. We opted for an inducible LERKO model due to known estrogen-mediated developmental programming, and we reported both receptor and tissue specificity with our model. Control mice were ERαfl/fl receiving AAV with green fluorescent protein (GFP) only. Results show that there were no differences in body weight/composition or hepatic steatosis in LERKO mice with either short-term (4-week) or chronic (8-week) high-fat feeding. Similarly, LERKO genotype nor timing of LERKO induction (pre vs post sexual maturity) did not alter hepatic mitochondrial O2 and H2O2 flux, coupling, or OXPHOS protein. Transcriptomic analysis showed that hepatic gene expression in LERKO was significantly influenced by developmental stage. Together, these studies suggest that hepatic ERα is not required in female protection against HFD-induced hepatic steatosis nor does it mediate sexual dimorphism in liver mitochondria function.

Fronto-amygdala resting state functional connectivity is associated with anxiety symptoms among adolescent girls more advanced in pubertal maturation

Early adolescence, with the onset of puberty, is an important period when sex differences in anxiety emerge, with girls reporting significantly higher anxiety symptoms than boys. This study examined the role of puberty on fronto-amygdala functional connectivity and risk of anxiety symptoms in 70 girls (age 11-13) who completed a resting state fMRI scan, self-report measures of anxiety symptoms and pubertal status, and provided basal testosterone levels (64 girls). Resting state fMRI data were preprocessed using fMRIPrep and connectivity indices were extracted from ventromedial prefrontal cortex (vmPFC) and amygdala regions-of-interest. We tested moderated mediation models and hypothesized that vmPFC-amygdala would mediate the relation between three indices of puberty (testosterone and adrenarcheal/gonadarcheal development) and anxiety, with puberty moderating the relation between connectivity and anxiety. Results showed a significant moderation effect of testosterone and adrenarcheal development in the right amygdala and a rostral/dorsal area of the vmPFC and of gonadarcheal development in the left amygdala and a medial area of the vmPFC on anxiety symptoms. Simple slope analyses showed that vmPFC-amygdala connectivity was negatively associated with anxiety only in girls more advanced in puberty suggesting that sensitivity to the effects of puberty on fronto-amygdala function could contribute to risk for anxiety disorders among adolescent girls.

The role of brain structure in the association between pubertal timing and depression risk in an early adolescent sample (the ABCD Study®): A registered report

BACKGROUND

Earlier pubertal timing is associated with higher rates of depressive disorders in adolescence. Neuroimaging studies report brain structural associations with both pubertal timing and depression. However, whether brain structure mediates the relationship between pubertal timing and depression remains unclear.

METHODS

The current registered report examined associations between pubertal timing (indexed via perceived pubertal development), brain structure (cortical and subcortical metrics, and white matter microstructure) and depressive symptoms in a large sample (N = ∼5000) of adolescents (aged 9-13 years) from the Adolescent Brain Cognitive Development (ABCD) Study. We used three waves of follow-up data when the youth were aged 10-11 years, 11-12 years, and 12-13 years, respectively. We used generalised linear-mixed models (H1) and structural equation modelling (H2 & H3) to test our hypotheses.

HYPOTHESES

We hypothesised that earlier pubertal timing at Year 1 would be associated with increased depressive symptoms at Year 3 (H1), and that this relationship would be mediated by global (H2a-b) and regional (H3a-g) brain structural measures at Year 2. Global measures included reduced cortical volume, thickness, surface area and sulcal depth. Regional measures included reduced cortical thickness and volume in temporal and fronto-parietal areas, increased cortical volume in the ventral diencephalon, increased sulcal depth in the pars orbitalis, and reduced fractional anisotropy in the cortico-striatal tract and corpus callosum. These regions of interest were informed by our pilot analyses using baseline ABCD data when the youth were aged 9-10 years.

RESULTS

Earlier pubertal timing was associated with increased depressive symptoms two years later. The magnitude of effect was stronger in female youth and the association remained significant when controlling for parental depression, family income, and BMI in females but not in male youth. Our hypothesised brain structural measures did not however mediate the association between earlier pubertal timing and later depressive symptoms.

CONCLUSION

The present results demonstrate that youth, particularly females, who begin puberty ahead of their peers are at an increased risk for adolescent-onset depression. Future work should explore additional biological and socio-environmental factors that may affect this association so that we can identify targets for intervention to help these at-risk youth.

Migraine and its association with pubertal maturation and behavioral traits among adolescent girls

OBJECTIVE

To determine if the ages at pubertal milestones are associated with the prevalence of adolescent migraine.

BACKGROUND

Migraine headaches are a common disease in adolescent girls. Past studies have evaluated the relationship between age of onset of menarche and migraine headache, but none have studied earlier pubertal milestones such as thelarche and pubarche.

METHODS

In this cross-sectional study, a previously validated questionnaire was administered to girls (15-18 years) in Breast Cancer and the Environment Research Program puberty cohort to ascertain if they met criteria for migraine over the past year. Ages of pubertal development were ascertained by serial examinations beginning at 6-8 years of age and ending in late puberty. Logistic regression analyses determined if age of onset of each pubertal milestone (thelarche, pubarche, menarche separately) was associated with adolescent migraine after adjusting for other risk factors.

RESULTS

Of 761girls, 222 (29.2%) met the criteria for migraine. Later thelarche was associated with a lower odds of adolescent migraine (OR 0.83; 95% CI 0.72-0.97, p = 0.019). In models further adjusted for BASC-2 internalizing problems (n = 490), both later thelarche (OR 0.78; 95% CI 0.64-0.96, p = 0.016) and later menarche (OR 0.81; 95%CI 0.67-0.98, p = 0.026) were associated with a lower migraine prevalence. Internalizing problems (OR 1.05; 95% CI 1.03-1.07) externalizing problems (OR 1.05; 95% CI 1.02-1.07) and behavioral symptoms (OR 1.05; 95% CI 1.03-1.08) were associated with increased prevalence of migraine in separate models.

CONCLUSIONS

Age of onset of thelarche and menarche, and internalizing, externalizing, and behavioral symptoms were all associated with adolescent migraine.

The Association between Sex Hormones, Pubertal Milestones and Benzophenone-3 Exposure, Measured by Urinary Biomarker or Questionnaire

Experimental studies have suggested benzophenone-3 (BP-3), a sunscreen ingredient, may have endocrine-disrupting properties. A cohort of girls were recruited at ages 6-7 years and returned semi-annually for pubertal maturation staging, provided blood for serum hormone analyses [estradiol, estrone, testosterone, dehydroepiandrosterone-sulfate (DHEA-S)], and urine to measure BP-3 concentrations. We found a significant negative linear association between amount of reported sunscreen use and testosterone levels at the onset of puberty (N = 157, adjusted β = -0.0163, 97.5% CI:-0.0300,-0.0026). The 2nd quartile of the BP-3 biomarker had earlier thelarche compared to the 1st quartile (N = 282, adjusted HR = 1.584, 97.5% CI:1.038,2.415). Results suggest that higher report of sunscreen use may be associated with lower testosterone levels at thelarche and a non-linear relationship between the BP-3 urinary biomarker and onset of puberty, although the clinical significance of the finding is limited and may be a random effect. Improved methods of BP-3 exposure characterization are needed.

Trends Toward Earlier Puberty Timing in Girls and Its Likely Mechanisms

This is the first of two installments examining early puberty in girls. The first paper will discuss secular trends in onset of puberty and the possible mechanisms to explain these developments. The potential etiologies examined will include the role of endocrine-disrupting chemicals and obesogens, the impact of body mass index and obesity, genetic and biologic pathways, and the influence of lifestyle behaviors. The second paper of the two-part series will examine the potential health impacts of early puberty on young and adult women and offer suggestions for clinical management and public health prevention.

High levels of FSH before puberty are associated with increased risk of metabolic syndrome during pubertal transition

BACKGROUND

During perimenopause, the rise in serum follicle-stimulating hormone (FSH) is associated with increased adiposity, insulin resistance (IR), and metabolic syndrome (MetS). However, data for the pubertal period, which is characterized by increasing FSH levels and changing body composition, are limited.

OBJECTIVES

To investigate the relationships between FSH and anthropometric changes, IR markers, and development of MetS in the peripubertal period.

METHODS

Uppsala Longitudinal Study of Childhood Obesity (ULSCO) is an ongoing study that aims to understand the factors contributing to childhood obesity and the development of obesity-related diseases. We analysed the subset of participants who were prepubertal at the first visit (n = 95, 77 with obesity). Mean follow-up time was 3.0 ± 1.4 years.

RESULTS

Higher serum FSH levels at the first visit were associated with an increased likelihood of elevation in body mass index (BMI SDS) (p = 0.025, OR = 16.10) and having MetS (p = 0.044, OR = 4.67) at the follow-up. We observed nonlinear relationships between varying serum FSH levels and markers of adiposity and IR, especially in girls. At the first visit, when girls were prepubertal, FSH was negatively associated with BMI (β = -0.491, p = 0.005) and positively associated with sex hormone-binding globulin (SHBG) (β = 0.625, p = 0.002). With the progression of puberty, negative associations between BMI and SHBG disappeared while FSH became positively associated with HOMA-IR (β = 0.678, p = 0.025) and fasting insulin (β = 0.668, p = 0.027).

CONCLUSIONS

Higher serum FSH levels in prepubertal children were associated with an increased risk of MetS development during pubertal transition. Along with nonlinear associations between varying serum FSH levels and IR markers, our results might imply a relationship between FSH and IR of puberty.

Methods for characterizing ovarian and adrenal hormone variability and mood relationships in peripubertal females

Peripubertal females are at elevated risk for developing affective illness compared to males, yet biological mechanisms underlying this sex disparity are poorly understood. Female risk for depression remains elevated across a woman's reproductive lifespan, implicating reproductive hormones. A sensitivity to normal hormone variability during reproductive transition events (e.g., perimenopause) precipitates affective disturbances in susceptible women; however, the extent of hormone variability during the female pubertal transition and whether vulnerability to peripubertal hormone flux impacts affective state change in peripubertal females has not been studied. 52 healthy peripubertal females (ages 11-14) provided 8 weekly salivary samples and mood ratings. 10 salivary ovarian and adrenal hormones (e.g., estrone, testosterone, dehydroepiandrosterone (DHEA)) were analyzed weekly for 8 weeks using an ultrasensitive assay to characterize the female peripubertal hormone environment and its association with affective state. Hormone variability indices, including standard deviation, mean squared and absolute successive differences of the 8 weekly measurements were analyzed by menarche status. Within-person partial correlations were computed to determine the strength of the relationship between weekly change in hormone level and corresponding mood rating for each participant. As expected, results indicated that hormone variability was greater for post- relative to pre-menarchal females and with advancing pubertal development, yet pregnenolone-sulfate and aldosterone did not differ by menarche status. Mood sensitivity to changes in estrone was exhibited by 57% of participants, whereas 37% were sensitive to testosterone and 6% were sensitive to DHEA changes. The present results offer novel evidence that a substantial proportion of peripubertal females appear to be mood sensitive to hormone changes and may inform future investigations on the biological mechanisms underlying hormone-induced affect dysregulation in peripubertal females.

Influence of Maturity Status on Kinanthropometric and Physical Fitness Variables in Adolescent Female Volleyball Players

The aim of this research was to analyze differences in kinanthropometric characteristics and physical performance in relation to maturity status, as well as to determine if age, maturity offset or kinanthropometric variables could predict better performance in physical fitness tests. A total of 152 female volleyball players (14.16 ± 1.25 years old) underwent a kinanthropometric assessment, followed by a physical fitness assessment composed of different tests. The age at peak height velocity (APHV) was calculated, and the sample was divided according to biological maturation into three groups. Significant differences were observed in kinanthropometric variables (p < 0.001–0.026), with early maturers showing higher values. Age, body mass, Cormic index, relative arm span, ∑8 skinfolds, fat mass, corrected arm and thigh girths, muscle mass and biacromial and biiliocristal breadths were the variables that best predicted performance in the physical tests (p < 0.001–0.024). The more mature players showed higher values in most of the kinanthropometric variables, with the more remarkable differences being in body mass, height, arm span and sitting height, and those related to adiposity and absolute body composition, and with structural variables being the most influential on the physical tests. Age had a determinant influence on the differences found between groups in strength and power-related test performance.

Raging Hormones: Why Age-Based Etiological Conceptualizations of the Development of Antisocial Behavior Are Insufficient

Developmental science, particularly developmental neuroscience, has substantially influenced the modern legal system. However, this science has typically failed to consider the role of puberty and pubertal hormones on development when considering antisocial behavior. This review describes major theoretical positions on the developmental neuroscience of antisocial behavior and highlights where basic developmental neuroscience suggests that the role of puberty and pubertal hormones should be considered. The implications of the current state of the science with respect to developmental neuroscience is considered, particularly what is known in light of development beyond puberty. This review shows that development continues to an older age for many youth than the legal system typically acknowledges. The plasticity of the brain that this continued development implies has implications for the outcome of interventions in the legal system in ways that have not been explored. Future directions for both developmental scientists and legal professions are recommended.

The Impact of Macronutrient Intake on Sex Steroids During Onset of Puberty

INTRODUCTION

Increased fiber intake has been associated with decreased breast cancer risk, while increased animal protein intake with increased risk. The objective of this study is to examine the relationship of dietary fiber and protein intake to estrogen and sex hormone-binding globulin (SHBG) concentrations at puberty onset.

METHODS

These analyses were conducted using the Cincinnati puberty cohort of the Breast Cancer and the Environment Research Program, with girls followed every 6 months from ages 6 and 7. The analyses included serum measurements at 6-month intervals for estrogen and SHBG concentrations, from 18 months prior to breast stage 2 (onset of puberty). Dietary intake was documented via 24-hour dietary recalls every 3 months. Dietary factors of interest included total energy intake; total and animal protein; total, soluble, and insoluble fiber; and lignan and flavanol intake.

RESULTS

This study included 260 participants who generated 871 serum specimens and 3,000 days of diet intake. In longitudinal models, estradiol was associated inversely with insoluble fiber intake; estrone positively with animal protein intake; SHBG with greater insoluble fiber and lower total protein intake; and ratio of estrone to SHBG, a measure of bioavailable estrogen, positively with animal protein.

CONCLUSIONS

Greater protein intake, especially animal protein, led to greater estrogen concentrations and lower SHBG; greater animal protein and greater caloric intake led to increased bioavailable estrogen. This relationship may have served an evolutionary advantage in the past for greater fertility with adequate high-quality protein; in contemporary women, a modest decrease in animal protein may be beneficial in reducing breast cancer risk.

Can Body Mass Index Affect Height Growth at Menarche among Girls Receiving Treatment for Early Puberty? A Retrospective Study in Korean Girls

Gonadotropin-releasing hormone agonist (GnRHa) therapy is used to control puberty progression and it preserves height potential in patients with idiopathic central precocious puberty (ICPP). This study evaluated the correlation between weight and height gain at menarche following GnRHa treatment among girls with ICPP and relatively central early puberty (EP). We investigated height/weight trends and changes in height from diagnosis to menarche in girls with ICPP and EP treated with GnRHa. The mean difference in height (Δheight) from treatment cessation to menarche was 9.79 ± 3.53 cm. Girls were divided into girls with Δheight ≥ 9.79 cm (Group 1) and girls with Δheight < 9.79 cm (Group 2). Although near adult height was significantly higher in Group 1, the mean body mass index (BMI) and weight were significantly lower at diagnosis, treatment discontinuation, and menarche. The BMI and weight at the three time points were negatively correlated with height. Girls with higher BMI at all three time points had slower growth rates during the study period. Considering that BMI and body weight were closely related to Δheight, proper management of BMI and body weight of girls receiving early puberty treatment might contribute to growth during and after GnRHa treatment.

The Vaginal Microbiome: I. Research Development, Lexicon, Defining "Normal" and the Dynamics Throughout Women's Lives

OBJECTIVE

This series of articles, titled The Vaginal Microbiome, written on behalf of the International Society for the Study of Vulvovaginal Disease, aims to summarize the current findings and understanding of the vaginal bacterial microbiota, mainly regarding areas relevant to clinicians specializing in vulvovaginal disorders.

MATERIALS AND METHODS

A database search of PubMed was performed, using the search terms "vaginal microbiome" (VMB) with "research," "normal," "neonate," "puberty," "adolescent," "menopause," and "ethnicities," as well as "human microbiome project." Full article texts were reviewed. Reference lists were screened for additional articles.

RESULTS

In the last 2 decades, many studies applying molecular techniques were performed, intending to characterize the vaginal microbiota. These studies advanced our understanding of how vaginal health is defined. The first article in this series focuses on the advancement of VMB research, technical definitions, the definition of "normal" VMB, and the dynamics of VMB throughout women's lives.

CONCLUSIONS

Understanding how microorganisms inhabiting the vagina interact with each other and with the host is important for a more complete understanding of vaginal health. The clinical application of microbial community sequencing is in its beginning, and its interpretation regarding practical clinical aspects is yet to be determined.

The impact of BMI on long-term anthropometric and metabolic outcomes in girls with idiopathic central precocious puberty treated with GnRHas

BACKGROUND

Gonadotropin-releasing hormone analogs (GnRHas) are effective in increasing the final height of children with idiopathic central precocious puberty (ICPP). However, in previous years, some transient metabolic complications have been described during this treatment, for which there are no long-term outcome data. Our study aimed to evaluate the efficacy of GnRHas and clarify if body mass index (BMI) at diagnosis of ICPP could influence long-term outcomes.

METHODS

This was an observational, retrospective study that recruited a cohort of girls with ICPP. Data for anthropometric measures, fasting lipid profile, and glucose metabolism were collected at baseline [when GnRHas treatment started (T1)], at the end of the treatment (T2), and near-final height (nFH) or final height (FH) (T3). Predicted adult height (PAH) was calculated at T1 following Bayley and Pinneau's method. Analysis was carried out using BMI standard deviation score (SDS) categories at T1 (group A, normal weight, vs. group B, overweight/obese).

RESULTS

Fifty-seven girls with ICPP who were treated with GnRHas were enrolled in the study (group A vs. group B: 33 vs. 24 patients, aged 7.86 ± 0.81 vs. 7.06 ± 1.61 years, respectively; p < 0.05). In the study population, nFH/FH was in line with the target height (TH) (p = 0.54), with a mean absolute height gain of 11.82 ± 5.35 cm compared with PAH. Even if the length of therapy was shorter (group A vs. group B: 1.84 ± 2.15 vs. 2.10 ± 0.81 years, respectively; p < 0.05) and the age at menarche was younger (group A vs. group B: 10.56 ± 1.01 vs. 11.44 ± 0.85 years, respectively; p < 0.05) in group B than in group A, the nFH/FH gain was still comparable between the two groups (p = 0.95). At nFH/FH, BMI SDS was still greater in group B than in group A (p = 0.012), despite the fact that BMI SDS significantly increased in group A only (p < 0.05). Glucose metabolism got worst during GnRHa with a complete restoring after it, independently from pre-treatment BMI. The ratio of low-density to high-density lipoprotein cholesterol transiently deteriorated during treatment with GnRHas in group A only (p = 0.030).

CONCLUSIONS

Our results confirm the effectiveness of treatment with GnRHas on growth and do not support the concern that being overweight and obese can impair the long-term outcomes of GnRHas therapy. However, the observed transient impairment of metabolic parameters during treatment suggests that clinicians should encourage ICPP girls treated with GnRHas to have a healthy lifestyle, regardless of their pretreatment BMI.

The effects of puberty and its hormones on subcortical brain development

Puberty triggers a period of structural “re-organization” in the brain, when rising hormone levels act via receptors to influence morphology. However, our understanding of these neuroendocrine processes in humans remains poor. As such, the current longitudinal study characterized development of the human subcortex during puberty, including changes in relation to pubertal (Tanner) stage and hormone (testosterone, dehydroepiandrosterone [DHEA]) levels. Beyond normative group-level patterns of development, we also examined whether individual differences in the rate of pubertal maturation (i.e., “pubertal/hormonal tempo”) were associated with variations in subcortical trajectories. Participants (N = 192; scans = 366) completed up to three waves of MRI assessments between 8.5 and 14.5 years of age. Parents completed questionnaire assessments of pubertal stage at each wave, and adolescents provided hormone samples on a subset of waves. Generalized additive mixture models were used to characterize trajectories of subcortical development. Results showed that development of most subcortical structures was related to pubertal stage, although findings were mostly non-significant when controlling for age. Testosterone and DHEA levels were related to development of the amygdala, hippocampus and pallidum in both sexes, and findings in the amygdala remained significant when controlling for age. Additionally, we found that variability in hormonal (specifically testosterone) tempo was related to right hippocampal development in males, with an accelerated pattern of hippocampal development in those with greater increases in testosterone levels. Overall, our findings suggest prominent hormonal influences on the amygdala and hippocampus, consistent with the prevalence of androgen and estrogen receptors in these regions. We speculate that these findings are most likely reflective of the important role of adrenarcheal processes on adolescent brain development.

There are widespread associations between physical and hormonal indices of puberty and subcortical development.

Effects of testosterone and DHEA are strongest in the amygdala, hippocampus and pallidum.

Individual differences in the tempo of rising testosterone are related to variability in hippocampal development in males.

Pubertal Development: What's Normal/What's Not

Onset of puberty, as defined by breast stage 2, appears to be starting at younger ages since the 1940s. There is an ongoing controversy regarding what is normative, as well as what is normal, and the evaluation that is deemed necessary for girls maturing before 8 years of age. There are potential implications of earlier pubertal timing, including psychosocial consequences during adolescence, as well as longer term risks, such as breast cancer and cardiometabolic risks. There are additional consequences derived from slower pubertal tempo, for age of menarche has not decreased as much as age of breast development; these include longer interval between sexual initiation and intentional childbearing, as well as a broadened window of susceptibility to endocrine-related cancers.

Dynamic alterations in linear growth and endocrine parameters in children with obesity and height reference values

BACKGROUND

Obesity can affect linear growth of children but there is uncertainty regarding the dynamics and potential causes.

METHODS

In the population-based LIFE Child and the obesity-enriched Leipzig Obesity Childhood cohorts (8,629 children, 37,493 measurements), recruited from 1999 to 2018 in Germany, we compared height, growth, and endocrine parameters between normal-weight and children with obesity (0-20 years). Derived from the independent German CrescNet registry (12,703 children) we generated height reference values specific for children with obesity (data collected from 1999 to 2020).

FINDINGS

Children with obesity were significantly taller than normal-weight peers, differing at maximum by 7·6 cm (1·4 height, standard deviation scores or SDS) at age 6-8 years. Already at birth, children with obesity were slightly taller and thereafter had increased growth velocities by up to 1·2 cm/year. This growth acceleration was unrelated to parental height, but was accompanied by increased levels of insulin-like growth factor-1 (IGF-1), insulin and leptin. During puberty, children with obesity showed a catch-down in height SDS. The reduction in pubertal growth velocity by up to 25% coincided with a decrease in levels of IGF-1 (by 17%) and testosterone (by 62%) in boys and estradiol (by 37%) in girls. We confirmed these alterations in growth in the independent CrescNet cohort and furthermore provide height reference values for children with obesity for open access.

INTERPRETATION

Dynamics of linear growth are altered distinctively in different developmental phases in children with obesity. Early emergence before other profound comorbidities implies predisposition, environmental, and/or endocrine factors affecting growth in early life. Height reference values for children with obesity may enhance the precision of clinical health surveillance.

FUNDING

German Research Foundation, German Diabetes Association, EU, ESF, ERDF, State of Saxony, ESPE, Hexal, Novo Nordisk, Pfizer Pharma.

Longitudinal Investigation of Pubertal Milestones and Hormones as a Function of Body Fat in Girls

CONTEXT

Epidemiologic studies have demonstrated that overweight/obese girls (OW/OB) undergo thelarche and menarche earlier than normal weight girls (NW). There have been no longitudinal studies to specifically investigate how body weight/fat affects both clinical and biochemical pubertal markers in girls.

OBJECTIVE

To investigate the effect of total body fat on reproductive hormones and on the maturation of estrogen-sensitive tissues during puberty in girls.

METHODS

Ninety girls (36 OW/OB, 54 NW), aged 8.2 to 14.7 years, completed 2.8 ± 1.7 study visits over 4 years. Visits included dual-energy x-ray absorptiometry to calculate total body fat (TBF), Tanner staging, breast ultrasound for morphological staging (BMORPH; A-E), pelvic ultrasound, hormone tests, and assessment of menarchal status. The effect of TBF on pubertal markers was determined using a mixed, multistate, or Cox proportional hazards model, controlling for baseline BMORPH.

RESULTS

NW were older than OW/OB (11.3 vs 10.2 years, P < .01) at baseline and had more advanced BMORPH (P < .01). Luteinizing hormone, estradiol, and ovarian and uterine volumes increased with time with no effect of TBF. There was a time × TBF interaction for follicle-stimulating hormone, inhibin B, estrone, total and free testosterone, and androstenedione: Levels were initially similar, but after 1 year, levels increased in girls with higher TBF, plateaued in girls with midrange TBF, and decreased in girls with lower TBF. Girls with higher TBF progressed through BMORPH stage D more slowly but achieved menarche earlier than girls with lower TBF.

CONCLUSION

In late puberty, girls with higher TBF demonstrate differences in standard hormonal and clinical markers of puberty. Investigation of the underlying causes and clinical consequences of these differences in girls with higher TBF deserves further study.

Urinary and salivary endocrine measurements to complement Tanner staging in studies of pubertal development

Background

Many studies investigating pubertal development use Tanner staging to assess maturation. Endocrine markers in urine and saliva may provide an objective, sensitive, and non-invasive method for assessing development.

Objective

Our objective was to examine whether changes in endocrine levels can indicate the onset of pubertal development prior to changes in self-rated Tanner stage.

Methods

Thirty-five girls and 42 boys aged 7 to 15 years were enrolled in the Growth and Puberty (GAP) study, a longitudinal pilot study conducted from 2007–2009 involving children of women enrolled in the Agricultural Health Study (AHS) in Iowa. We collected saliva and urine samples and assessed pubertal development by self-rated Tanner staging (pubic hair, breast development (girls), genital development (boys)) at three visits over six months. We measured dehydroepiandrosterone (DHEA) in saliva and creatinine-adjusted luteinizing hormone (LH), testosterone, follicle stimulating hormone (FSH), estrone 3-glucuronide (E₁3G) and pregnanediol 3-glucuronide (Pd3G) concentrations in first morning urine. We evaluated the relationships over time between Tanner stage and each biomarker using repeated measures analysis.

Results

Among girls still reporting Tanner breast stage 1 at the final visit, FSH levels increased over the 6-month follow-up period and were no longer lower than higher stage girls at the end of follow-up. We observed a similar pattern for testosterone in boys. By visit 3, boys still reporting Tanner genital stage 1 or pubic hair stage 1 had attained DHEA levels that were comparable to those among boys reporting Tanner stages 2 or 3.

Conclusions

Increasing concentrations of FSH in girls and DHEA and testosterone in boys over a 6-month period revealed the start of the pubertal process prior to changes in self-rated Tanner stage. Repeated, non-invasive endocrine measures may complement the more subjective assessment of physical markers in studies determining pubertal onset.

Common Childhood Viruses and Pubertal Timing: The LEGACY Girls Study

Earlier pubertal development is only partially explained by childhood body mass index; the role of other factors, such as childhood infections, is less understood. Using data from the LEGACY Girls Study (North America, 2011-2016), we prospectively examined the associations between childhood viral infections (cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV) 1, HSV2) and pubertal timing. We measured exposures based on seropositivity in premenarcheal girls (n = 490). Breast and pubic hair development were classified based on mother-reported Tanner Stage (TS) (TS2+ compared with TS1), adjusting for age, body mass index, and sociodemographic factors. The average age at first blood draw was 9.8 years (standard deviation, 1.9 years). The prevalences were 31% CMV+, 37% EBV+, 14% HSV1+, 0.4% HSV2+, and 16% for both CMV+/EBV+ coinfection. CMV+ infection without coinfection was associated with developing breasts an average of 7 months earlier (hazard ratio (HR) = 2.12, 95% confidence interval (CI): 1.32, 3.40). CMV infection without coinfection and HSV1 and/or HSV2 infection were associated with developing pubic hair 9 months later (HR = 0.41, 95% CI: 0.24, 0.71, and HR = 0.42, 95% CI: 0.22, 0.81, respectively). Infection was not associated with menarche. If replicated in larger cohorts with blood collection prior to any breast development, this study supports the hypothesis that childhood infections might play a role in altering pubertal timing.

Adjusting for Pubertal Status Reduces Overweight and Obesity Prevalence in the United States

OBJECTIVE

To compare pediatric overweight and obesity prevalence among non-Hispanic white, Mexican American, and non-Hispanic black US youths before and after adjusting body mass index (BMI) for pubertal status, as assessed by Tanner stage.

STUDY DESIGN

We analyzed cross-sectional anthropometric and pubertal data from non-Hispanic white, Mexican American, and non-Hispanic black youths in the National Health and Nutrition Examination Survey (NHANES) III. We developed specialized Tanner stage and chronological age-adjusted models to establish Tanner-stage adjusted BMI z-scores, which were then used to determine adjusted overweight/obesity prevalence. We compared pediatric overweight/obesity prevalence before and after pubertal status adjustment.

RESULTS

Among 3206 youths aged 8-18 years (50% male; 26% non-Hispanic white, 35% Mexican American, 39% non-Hispanic black), adjusting BMI for Tanner stage significantly reduced overweight (males, from 29% to 21%; females, from 29% to 17%) and obesity (males, from 14% to 7%; females, from 11% to 5%) prevalence across all races/ethnicities. The obesity prevalence reduction was more pronounced in Mexican Americans (males, 11% reduction; females, 9% reduction) and non-Hispanic blacks (males and females, 10% reduction) compared with non-Hispanic whites (males, 6% reduction; females, 5% reduction). Similar patterns were seen in overweight prevalence.

CONCLUSIONS

Adjusting for pubertal status reduced the prevalence of overweight/obesity in non-Hispanic white, Mexican American, and non-Hispanic black youth. This suggests that adjusting for puberty incorporates changes otherwise not captured when only considering the age of a child. Adjusting BMI for pubertal status may be important when interpreting a youth's weight status and consideration for obesity management, as well as when interpreting pediatric overweight/obesity prevalence data.

Methodological Considerations for Studies in Sport and Exercise Science with Women as Participants: A Working Guide for Standards of Practice for Research on Women

Until recently, there has been less demand for and interest in female-specific sport and exercise science data. As a result, the vast majority of high-quality sport and exercise science data have been derived from studies with men as participants, which reduces the application of these data due to the known physiological differences between the sexes, specifically with regard to reproductive endocrinology. Furthermore, a shortage of specialist knowledge on female physiology in the sport science community, coupled with a reluctance to effectively adapt experimental designs to incorporate female-specific considerations, such as the menstrual cycle, hormonal contraceptive use, pregnancy and the menopause, has slowed the pursuit of knowledge in this field of research. In addition, a lack of agreement on the terminology and methodological approaches (i.e., gold-standard techniques) used within this research area has further hindered the ability of researchers to adequately develop evidenced-based guidelines for female exercisers. The purpose of this paper was to highlight the specific considerations needed when employing women (i.e., from athletes to non-athletes) as participants in sport and exercise science-based research. These considerations relate to participant selection criteria and adaptations for experimental design and address the diversity and complexities associated with female reproductive endocrinology across the lifespan. This statement intends to promote an increase in the inclusion of women as participants in studies related to sport and exercise science and an enhanced execution of these studies resulting in more high-quality female-specific data.

Pubertal Growth, IGF-1, and Windows of Susceptibility: Puberty and Future Breast Cancer Risk

PURPOSE

Risk markers for breast cancer include earlier onset of menarche (age at menarche [AAM]) and peak height velocity (PHV). Insulin-like growth factor-1 (IGF-1) is associated with pubertal milestones, as well as cancer risk. This study examined the relationships between pubertal milestones associated with breast cancer risk and hormone changes in puberty.

METHODS

This is a longitudinal study of pubertal maturation in 183 girls, recruited at ages 6-7, followed up between 2004 and 2018. Measures included age at onset of puberty, and adult height attained; PHV; AAM; adult height, and serum IGF-1, and estrone-to-androstenedione (E:A) ratio.

RESULTS

PHV was greatest in early, and least in late maturing girls; length of the pubertal growth spurt was longest in early, and shortest in late maturing girls. Earlier AAM was related to greater PHV. IGF-1 concentrations tracked significantly during puberty; higher IGF-1 was related to earlier age of PHV, earlier AAM, greater PHV, and taller adult height. Greater E:A ratio was associated with earlier AAM.

CONCLUSIONS

Factors driving the association of earlier menarche and pubertal growth with breast cancer risk may be explained through a unifying concept relating higher IGF-1 concentrations, greater lifelong estrogen exposure, and longer pubertal growth period, with an expanded pubertal window of susceptibility.

Pubertal mammary gland development is a key determinant of adult mammographic density

Mammographic density refers to the radiological appearance of fibroglandular and adipose tissue on a mammogram of the breast. Women with relatively high mammographic density for their age and body mass index are at significantly higher risk for breast cancer. The association between mammographic density and breast cancer risk is well-established, however the molecular and cellular events that lead to the development of high mammographic density are yet to be elucidated. Puberty is a critical time for breast development, where endocrine and paracrine signalling drive development of the mammary gland epithelium, stroma, and adipose tissue. As the relative abundance of these cell types determines the radiological appearance of the adult breast, puberty should be considered as a key developmental stage in the establishment of mammographic density. Epidemiological studies have pointed to the significance of pubertal adipose tissue deposition, as well as timing of menarche and thelarche, on adult mammographic density and breast cancer risk. Activation of hypothalamic-pituitary axes during puberty combined with genetic and epigenetic molecular determinants, together with stromal fibroblasts, extracellular matrix, and immune signalling factors in the mammary gland, act in concert to drive breast development and the relative abundance of different cell types in the adult breast. Here, we discuss the key cellular and molecular mechanisms through which pubertal mammary gland development may affect adult mammographic density and cancer risk.

Concentrations of urinary parabens and reproductive hormones in girls 6-17 years living in Canada

BACKGROUND

Parabens are chemical substances used as preservatives for their antibacterial and antifungal properties in many personal care products, and sometimes in pharmaceutical and food products. Concerns for adverse human health effects arise from animal studies showing endocrine disrupting effects, such as changes in the timing of puberty and alterations in reproductive hormone activity. Our objective was to examine the association between urinary concentrations of parabens and serum concentrations of estradiol, progesterone, follicle stimulating hormone [FSH], and luteinizing hormone [LH]) in girls from the general population.

METHODS

We conducted a cross-sectional study in girls ages 6-17 years, using data from the Canadian Health Measures Survey (2014-2015). The association between concentrations of creatinine-standardized urinary parabens and serum hormone concentrations was analyzed with multivariable linear regressions, adjusting for potential confounders (i.e., age, body mass index, ethnicity, household income, sampling season; prenatal exposure to cigarette smoke for girls 6-11 years).

RESULTS

The 382 girls and teens included in the study had a mean age of 11.0 years; 76% were white and 73% had a body mass index in the range normal/underweight. Most participants (92%) had least one paraben detected in their urine. Girls with higher urinary paraben concentrations had significantly lower serum concentrations of estradiol, LH, and FSH, but not of progesterone. A doubling in the sum of urinary parabens was associated with 5.8% lower estradiol (95% CI -9.3, -2.1), 4.2% lower FSH (95% CI -7.9, -0.3), and 10.8% lower LH (95% CI -17.4, -3.7). The analysis of individual compounds showed that all four parabens were similarly associated with lower concentrations of estradiol, FSH, and LH. We further analyzed younger girls (6-11 years) and found that urinary parabens were similarly associated with lower estradiol and LH (doubling in the sum of parabens associated with 5.9% lower estradiol [95% CI -10.5, -1.0] and 10.9% lower LH [95% CI -20.2, -0.6]). In this younger subgroup, the association estimate for FSH, however, was attenuated and no longer statistically significant.

DISCUSSION

We observed that exposure to parabens was associated with reduced concentrations of circulating reproductive hormones, suggesting that these chemicals could alter the development and function of the endocrine system in girls. Further prospective research using long-term assessment of parabens exposure and of reproductive development may better determine endocrine disrupting effects of parabens.

Onset of Puberty: Mother Knows Best

STUDY OBJECTIVE

Several strategies have been proposed to determine onset of puberty without examination by a trained professional. This study sought to evaluate a novel approach to determine onset of puberty in girls.

DESIGN, SETTING, AND PARTICIPANTS

This study used the Cincinnati cohort of the Breast Cancer and the Environment Research Program. Girls were recruited at 6-7 years of age and followed every 6 months in the initial 6 years, and annually thereafter. Breast maturation and foot length were performed at each visit by health professionals certified in those methods. Mothers were asked to provide the age at which they believed that their daughter's shoe size had increased more rapidly.

RESULTS

These analyses include 252 participants. Age at increase in shoe size was correlated to age at onset of puberty (r = 0.21) and increase in foot length (r = 0.24). The difference of reported age of increased shoe size was 0.46 years before breast development.

CONCLUSION

Reported increase in shoe size occurred somewhat earlier and was significantly correlated to age of breast development. These preliminary results suggest that mother's report of increase in shoe size appear to be as accurate as reports of other indirect methods of determining onset of puberty, such as self- or maternal estimates of breast development.

Reproductive hormones during pubertal transition in girls with transient Thelarche

CONTEXT

Transient thelarche (TT), that is, the appearance, regression and subsequent reappearance of breast buds, is a frequent phenomenon, but little is known about pubertal transition in these girls.

OBJECTIVE

To describe pubertal progression, growth, genotypes, reproductive hormones and growth factors in girls with TT compared to those who do not present TT (non-TT).

DESIGN

Retrospective analysis of a longitudinal population-based study.

PATIENTS OR OTHER PARTICIPANTS

Girls (n = 508) of the Chilean Growth and Obesity cohort.

MEASUREMENTS

Pubertal progression, reproductive hormones, follicle stimulating hormone (FSH) beta subunit/FSH receptor gene single nucleotide polymorphisms and growth.

RESULTS

Thirty-seven girls (7.3%) were presented TT. These girls entered puberty by pubarche more frequently (51%) than girls with normal progression (non-TT; n = 471; 23%, P = .005). Girls with TT who were under 8 years old had lower androgens, anti-Müllerian hormone (AMH), luteinizing hormone (LH) and oestradiol (all P < .05) than older girls with TT. At the time of Tanner breast stage 2 (B2), girls with TT had higher androgens, LH, FSH, IGF1, LH, insulin and oestradiol (P < .01) than at the time of TT. TT girls were older at B2 (10.3 ± 1.1 vs. 9.2 ± 1.2 years, P < .001) and menarche (12.3 ± 0.8 vs. 12.0 ± 1.0 years, P = .040) than their counterparts (non-TT). No differences in anthropometric variables or FSHB/FSHR genotypes were detected.

CONCLUSION

Transient thelarche is a frequent phenomenon that does not appear to be mediated by hypothalamic-pituitary-gonadal axis activation or by adiposity. Hormonal differences between earlier TT and later TT suggest that their mechanisms are different.

Sex modifies the association between the CLOCK variant rs1801260 and BMI in school-age children

Disruption of circadian rhythms and variations in the FTO gene may interfere with energy homeostasis and play a role in the development of obesity. The current study assessed the association of common polymorphisms in the CLOCK and FTO genes with standardized body mass index scores (BMI z-scores) and their potential modification of the impact of a culinary nutrition and physical activity intervention in school-age children. Anthropometric measurements were collected in 121 children at the baseline and one-year follow-up of a controlled trial of a school-based culinary nutrition and physical activity intervention. Genotypes of the CLOCK polymorphism (rs1801260) and the FTO polymorphism (rs9939609) were obtained from buccal swabs. Linear mixed-effects regression was applied to evaluate the genetic association and adjust for clusters within families and schools. In our participants, obesity affected 6.6% (8/121) of the children at the baseline and 6.4% (7/109) of the children at the follow-up. The associations between the age- and sex-adjusted BMI z-scores and the two polymorphisms did not reach statistically significance. Yet, sex potentially modified the association between rs1801260 and BMI z-scores. In girls, the G allele carriers had a higher BMI z-scores at the baseline and the follow-up. These polymorphisms did not modify the effect of our culinary nutrition and physical activity intervention on BMI z-scores. Sex is a potential modifier for the association between the CLOCK polymorphism, rs1801260, and BMI z-scores in school-age children. Further investigation is warranted to delineate the sex-dependent role of the CLOCK polymorphisms in the development of childhood obesity.

Influence of pubertal development on urinary oxidative stress biomarkers in adolescent girls in the New York LEGACY cohort

Puberty is a time of intense growth and differentiation of breast tissue and a window of susceptibility (WOS) for breast cancer. Although oxidative stress markers have been associated with breast cancer risk, it is unclear whether oxidative stress levels are different during the pubertal WOS, and if so, whether these differences are related to breast cancer susceptibility. We measured urinary biomarkers of whole body oxidative stress (urinary F2-Isoprostanes and 8-oxodeoxyguanosine (8-oxodG)) in 158 girls (ages 6-13 years), 71 with and 87 without a breast cancer family history (BCFH) from a cohort of adolescent girls from the New York site of the LEGACY cohort (Lessons in Epidemiology and Genetics in Adults Cancer from Youth). We compared levels of urinary oxidative stress biomarkers (F2-Isoprostanes and 8-oxodG) across the pubertal window, defined by Tanner Stage (TS) of breast development, both cross-sectionally and longitudinally within girls over an 18-month follow up period. Urinary oxidative stress biomarkers were unrelated to pubertal stages in cross-sectional analyses after considering adjustments for body mass index (BMI) and BCFH. In our longitudinal analysis, we found that urinary 8-oxodG levels, but not F2-Isoprostane levels, increased with age in BCFH + girls (β = 6.12, 95% CI = 0.08-12.16) compared to BCFH-girls. Higher BMI was associated with higher level of F2-Isoprostane in both cross-sectional (β = 0.02, 95% CI = 0.0004-0.05) and longitudinal analysis (β = 0.02, 95% CI = 0.0002-0.05). These findings support that higher BMI increases oxidative stress biomarkers over the pubertal window and that there are changes in 8-oxodG oxidative stress biomarkers in girls with a BCFH compared to girls without a BCFH.

Biological Maturation and Hormonal Markers, Relationship to Neuromotor Performance in Female Children

Background: Mechanisms that influence muscle strength can interfere with neuromotor performance and overall health, thus hormone markers and maturation can interact in this process. Objective: The present study aimed to verify the relationship of hormonal markers and biological maturation on neuromotor abilities in young people. Methods: This is a cross-sectional study with 44 female participants (11.5 ± 1.5 years). Hormones were analyzed biochemically. Skeletal and somatic maturation were analyzed using anthropometry. The muscular power of the upper and lower limbs, body speed with change of direction, and speed of the upper limbs were verified. Results: Bone age was correlated with hormonal markers (estradiol: r = 0.58; p = 0.0007), (testosterone: r = 0.51; p = 0.005). Peak growth velocity correlated with estradiol (r = 0.51; p = 0.004). The power of the lower limbs (estradiol: r = 0.52; p = 0.006; testosterone: r = 0.42; p = 0.03) and of the upper limbs (estradiol: r = 0.51; p = 0.007; testosterone: r = 0.42; p = 0.02) had a positive correlation with hormone levels and had similar results with maturation. The analysis by artificial neural networks indicated that the maturation can predict the neuromotor performance between 57.4% and 76%, while the hormonal markers showed a potential of more than 95% for the foreshadowing of the neuromotor performance of the upper limbs. Conclusion: It was possible to conclude that the hormones had a relationship with maturational development and bone age in female subjects.

The relationship between pubertal hormones and brain plasticity: Implications for cognitive training in adolescence

Adolescence may mark a sensitive period for the development of higher-order cognition through enhanced plasticity of cortical circuits. At the same time, animal research indicates that pubertal hormones may represent one key mechanism for closing sensitive periods in the associative neocortex, thereby resulting in decreased plasticity of cortical circuits in adolescence. In the present review, we set out to solve some of the existing ambiguity and examine how hormonal changes associated with pubertal onset may modulate plasticity in higher-order cognition during adolescence. We build on existing age-comparative cognitive training studies to explore how the potential for change in neural resources and behavioral repertoire differs across age groups. We review animal and human brain imaging studies, which demonstrate a link between brain development, neurochemical mechanisms of plasticity, and pubertal hormones. Overall, the existent literature indicates that pubertal hormones play a pivotal role in regulating the mechanisms of experience-dependent plasticity during adolescence. However, the extent to which hormonal changes associated with pubertal onset increase or decrease brain plasticity may depend on the specific cognitive domain, the sex, and associated brain networks. We discuss implications for future research and suggest that systematical longitudinal assessments of pubertal change together with cognitive training interventions may be a fruitful way toward a better understanding of adolescent plasticity. As the age of pubertal onset is decreasing across developed societies, this may also have important educational and clinical implications, especially with respect to the effects that earlier puberty has on learning.

Sex Hormone Phenotypes in Young Girls and the Age at Pubertal Milestones

CONTEXT

The age of pubertal onset is influenced by many variables in young girls. Previous studies have not examined sex hormones longitudinally around the time of breast development and their relationship to pubertal onset.

OBJECTIVE

We sought to use an unbiased statistical approach to identify phenotypes of sex hormones in young girls and examine their relationship with pubertal milestones.

DESIGN AND SETTING

Longitudinal observational study.

PARTICIPANTS AND MAIN OUTCOME MEASURES

In 269 girls, serum concentrations of steroid sex hormones [estradiol (E2), estrone, testosterone, and dehydroepiandrosterone sulfate] were measured by HPLC-mass spectrometry at time points before, at, and after thelarche. Girls were classified into four hormone phenotypes using objective principal components and cluster analyses of longitudinal hormone data. The association between the identified phenotypes and age of pubertal milestones was estimated using Cox proportional hazards modeling.

RESULTS

Mean ages at thelarche, pubarche, and menarche were 9.02, 9.85, and 12.30 years, respectively. Girls with low levels of all four hormones, phenotype 3b, were youngest at thelarche (8.67 years); those in phenotype 2, with the highest E2 levels and E2 surge 6 months after thelarche, were youngest at menarche (11.87 years) with shortest pubertal tempo. When controlling for race, maternal age of menarche, caregiver education, and body mass, different phenotypes were associated with the age of pubertal events.

CONCLUSIONS

Hormone phenotypic clustering can identify clinically relevant subgroups with differing ages of thelarche, pubarche, and menarche. These findings may enhance the understanding of timing of pubertal milestones and risk of adult disease.

Impact of Pubertal Maturation and Chronologic Age on Sex Steroids in Peripubertal Girls

CONTEXT

There is a 4- to 5-year variation in age of breast maturation in girls.

OBJECTIVE

To examine longitudinal changes in sex hormone values relative to chronologic age and time relative to breast maturation.

SETTING AND DESIGN

Longitudinal observational study into which girls were recruited at 6 to 7 years of age and followed up every 6 months.

MAIN OUTCOME MEASURES

Maturation status, chronologic age, race, and fasting blood specimen data were obtained. Hormones were analyzed at 6-month intervals between 2 years before and 1 year after breast maturation, using HPLC tandem mass spectroscopy.

RESULTS

Estradiol and estrone levels correlated with chronologic age (R = 0.350 and 0.444, respectively); time was correlated relative to breast maturation (R = 0.222 and 0.323, respectively; all correlations, P < 0.0001). In generalized estimating equation (GEE) models, chronologic age and time relative to pubertal onset were significantly associated with serum estradiol, with similar results for estrone. Local estimated scatterplot smoothing for estradiol and estrone, by chronologic age, demonstrated differences between black and white girls, especially between 8.5 and 11 years of age, but not by race in time relative to breast maturation. Testosterone level was correlated to chronologic age (R = 0.362) and time relative to breast maturation (R = 0.259); in the GEE model, only chronologic age was significant.

CONCLUSION

Chronologic age as well as time relative to onset of puberty provided unique information regarding estradiol and estrone concentrations in peripubertal girls. Serum estrogen concentrations should be evaluated with reference to chronologic age and race.

Dynamic DNA methylation of ovaries during pubertal transition in gilts

Background

In female mammals, the initiation of puberty, coupling with the dramatically morphological changes in ovaries, indicates the sexual and follicular maturation. Previous studies have suggested that the disrupted DNA methylation results in the delayed puberty. However, to date, the changes in ovarian methylomes during pubertal transition have not been investigated. In this study, using gilts as a pubertal model, the genome-wide DNA methylation were profiled to explore their dynamics during pubertal transition across Pre-, In- and Post-puberty.

Results

During pubertal transition, the follicles underwent maturation and luteinization, coupled with the significant changes in the mRNA expression of DNMT1 and DNMT3a. DNA methylation levels of In-puberty were higher than that of Pre- and Post-puberty at the locations of genes and CpG islands (CGIs). Analysis of the DNA methylation changes identified 12,313, 20,960 and 17,694 differentially methylated CpGs (DMCs) for the comparisons of Pre- vs. In-, In vs. Post-, and Pre- vs. Post-puberty, respectively. Moreover, the CGIs, upstream and exonic regions showed a significant underrepresentation of DMCs, but the CGI shores, CGI shelves, intronic, downstream and intergenic regions showed a significant overrepresentation of DMCs. Furthermore, biological functions of these methylation changes enriched in PI3K-Akt signaling pathway, GnRH signaling pathway, and Insulin secretion, and the mRNA expressions of several genes of these signaling pathway, including MMP2, ESR1, GSK3B, FGF21, IGF1R, and TAC3, were significantly changed across Pre-, In- and Post-puberty in ovaries.

Conclusions

During pubertal transition in gilts, the DNA methylation changes of ovaries were likely to affect the transcription of genes related to PI3K-Akt signaling pathway, GnRH signaling pathway, and Insulin secretion. These observations can provide new insight into the epigenetic mechanism of follicular and sexual maturation during pubertal transition in mammals.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5884-x) contains supplementary material, which is available to authorized users.

Puberty: Normal physiology (brief overview)

Puberty is a defining phase of human development where growth ends and the ability to reproduce begins. An understanding of the events leading up to puberty highlights the fact that this is the culmination of a process of skeletal and gonadal activity that has been ongoing since conception. Although there is natural variation in the timing of events in and around puberty the basic underlying processes are common to all healthy human beings. This chapter is intended to outline the mechanisms underlying normal growth and development before and during puberty. By understanding normality the pathological processes that give rise to abnormalities of pubertal development can be understood more easily.

Neural systems underlying reward cue processing in early adolescence: The role of puberty and pubertal hormones

Affective neuroscience research suggests that maturational changes in reward circuitry during adolescence present opportunities for new learning, but likely also contribute to increases in vulnerability for psychiatric disorders such as depression and substance abuse. Basic research in animal models and human neuroimaging has made progress in understanding the normal development of reward circuitry in adolescence, yet, few functional neuroimaging studies have examined puberty-related influences on the functioning of this circuitry. The goal of this study was to address this gap by examining the extent to which striatal activation and cortico-striatal functional connectivity to cues predicting upcoming rewards would be positively associated with pubertal status and levels of pubertal hormones (dehydroepiandrosterone, testosterone, estradiol). Participants included 79 adolescents (10-13 year olds; 47 girls) varying in pubertal status who performed a novel reward cue processing task during fMRI. Pubertal maturation was assessed using sex-specific standardized composite measures based on Tanner staging (self-report and clinical assessment) and scores from the Pubertal Development Scale. These composite measures were computed to index overall pubertal maturation as well as maturation of the adrenal and gonadal axes separately for boys and girls. Basal levels of circulating pubertal hormones were measured using immunoassays from three samples collected weekly upon awakening across a three-week period. Results indicated greater striatal activation and functional connectivity between nucleus accumbens (NAcc) and medial prefrontal cortex (mPFC) to reward cue (vs. no reward cue) on this task. Also, girls with higher levels of estradiol showed reduced activation in left and right caudate and greater NAcc-putamen connectivity. Girls with higher levels of testosterone showed greater NAcc connectivity with the anterior cingulate cortex and the insula. There were no significant associations in boys. Findings suggest that patterns of activation and connectivity in cortico-striatal regions are associated with reward cue processing, particularly in girls. Longitudinal follow-up neuroimaging studies are needed to fully characterize puberty-specific effects on the development of these neural regions and how such changes may contribute to pathways of risk or resilience in adolescence.

Association of Prepubertal and Adolescent Androgen Concentrations With Timing of Breast Development and Family History of Breast Cancer

IMPORTANCE

Early breast development is a risk factor for breast cancer, and girls with a breast cancer family history (BCFH) experience breast development earlier than girls without a BCFH.

OBJECTIVES

To assess whether prepubertal androgen concentrations are associated with timing of breast development (analysis 1) and to compare serum androgen concentrations in girls with and without a BCFH (analysis 2).

DESIGN, SETTING, AND PARTICIPANTS

Prospective cohort study of 104 girls aged 6 to 13 years at baseline using data collected between August 16, 2011, and March 24, 2016, from the Lessons in Epidemiology and Genetics of Adult Cancer From Youth (LEGACY) Girls Study, New York site.

EXPOSURES

Analysis 1 included serum concentrations of dehydroepiandrosterone sulfate, androstenedione, and testosterone (free and total) measured before breast development and divided at the median into high and low categories. Analysis 2 included the degree of BCFH: first-degree was defined as having a mother with breast cancer and second-degree was defined as having a grandmother or aunt with breast cancer.

MAIN OUTCOMES AND MEASURES

Analysis 1 included age at onset of breast development measured using the Pubertal Development Scale (scores range from 1-4; scores ≥2 indicate breast development), and analysis 2 included serum androgen concentrations. We also assessed breast cancer-specific distress using the 8-item Child Impact of Events Scale.

RESULTS

Our analyses included 36 girls for the prospective model, 92 girls for the cross-sectional model, and 104 girls for the longitudinal model. Of the 104 girls, the mean (SD) age at baseline was 10.3 (2.5) years, and 41 (39.4%) were non-Hispanic white, 41 (39.4%) were Hispanic, 13 (12.5%) were non-Hispanic black, and 9 (8.7%) were other race/ethnicity. Forty-two girls (40.4%) had a positive BCFH. Girls with prepubertal androstenedione concentrations above the median began breast development 1.5 years earlier than girls with concentrations below the median (Weibull survival model-estimated median age, 9.4 [95% CI, 9.0-9.8] years vs 10.9 [95% CI, 10.4-11.5] years; P = .001). Similar patterns were observed for dehydroepiandrosterone sulfate (1.1 years earlier: age, 9.6 [95% CI, 9.1-10.1] years vs 10.7 [95% CI, 10.2-11.3] years; P = .009), total testosterone (1.4 years earlier: age, 9.5 [95% CI, 9.1-9.9] years vs 10.9 [95% CI, 10.4-11.5] years; P = .001), and free testosterone (1.1 years earlier: age, 9.7 [95% CI, 9.2-10.1] years vs 10.8 [95% CI, 10.2-11.4] years; P = .01). Compared with girls without BCFH, girls with a first-degree BCFH, but not a second-degree BCFH, had 240% higher androstenedione concentrations (geometric means: no BCFH, 0.49 ng/mL vs first-degree BCFH, 1.8 ng/mL vs second-degree, 1.6 ng/mL; P = .01), 10% higher total testosterone concentrations (12.7 ng/dL vs 14.0 ng/dL vs 13.7 ng/dL; P = .01), and 92% higher free testosterone concentrations (1.3 pg/mL vs 2.5 pg/mL vs 0.3 pg/mL; P = .14). The dehydroepiandrosterone sulfate concentration did not differ between BCFH-positive and BCFH-negative girls but was elevated in girls with breast cancer-specific distress.

CONCLUSIONS AND RELEVANCE

Our findings suggest that androgen concentrations may differ between girls with and without a BCFH and that elevated hormone concentrations during adolescence may be another factor to help explain the familial clustering of breast cancer.

Menstrual Patterns in the First Gynecological Year: A Systematic Review

STUDY OBJECTIVE

Understanding what constitutes a normal menstrual cycle during the first gynecological year (GY1) is a common concern of adolescents and clinicians. However, limited high-quality evidence exists. We aimed to summarize published literature regarding menstrual and ovulatory patterns in GY1. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: Electronic databases (MEDLINE, Pre-MEDLINE, Embase, Web of Science, CINAHL, Cochrane Library) were systematically searched from database inception to 2018. Eligible studies described menstrual cycles, symptoms, or validated ovulatory data in healthy adolescents in GY1. Two authors independently screened studies, extracted data, and assessed methodological quality.

RESULTS

Twenty-two studies involving more than 2000 adolescents were included. Thirteen recorded menstrual cycle and/or symptom data and 14 measured ovulation. Mean cycle length ranged from 32 to 61 days and decreased throughout GY1. Mean menses length was 4.9 to 5.4 days. Frequent menstrual bleeding was reported in up to 23% of participants, infrequent menstrual bleeding in up to one-third, and "irregular menstrual bleeding" in up to 43%. Dysmenorrhea was reported by 30%-89% of participants. Prevalence of ovulatory cycles identified using luteal phase serum or salivary progesterone or urinary pregnanediol was 0 to 45% and increased throughout GY1. However, all used definitions that would be considered subovulatory in clinical practice.

CONCLUSION

Menstrual and ovulatory patterns in GY1 are diverse and differ from those of adults. A transitional phase of menstrual and ovulatory immaturity is common. However, ovulation, irregular cycles, and dysmenorrhea are not uncommon. As such, safe sexual practice should be advocated and prompt medical management should be accessible.

Outcomes of pubertal development in girls as a function of pubertal onset age

BACKGROUND

The relationship between pubertal onset and tempo and pubertal growth is controversial. We hypothesized that the age at onset of girls' puberty predicts pubertal tempo and the rate of pubertal progression.

METHODS

We analysed the data of 380 girls from the prospective Study of Early Child Care and Youth Development (SECCYD), who were recruited in the USA from 1991-2006 and followed from birth to age 15.5 years. We used the following indicators: thelarche age (Tanner stage B2), pubarche age (P2), menarche age (M), the age when breast (B5) and pubic hair (P5) became fully mature, pubertal growth, pubertal duration (time from B2 to B5), pubertal progression (time from B2 to M). We clustered the girls according to B2 age into early onset (EO;<9.4 years), intermediate (IO;9.4-10.5 years), late onset (LO;>10.5 years).

RESULTS

All indicators of pubertal onset and conclusion occurred earlier in the EOs than in the LO; yet, the differences in the age at main pubertal milestones lessened as puberty progressed: two years for B2; -1.4 years for M; - one year for B5. In EO, puberty was one year (average) longer than in LO. Although EO grew 7 cm (average) more than LO, their heights at B5 were comparable. There was a significant relationship between the thelarche age and puberty tempo (r=0.23, P<0.0001).

CONCLUSIONS

The study highlights the predictive nature of variation in the onset age of puberty on its progression and duration. These results are reassuring in this context and will add to clinicians' and parental understanding of the expected milestones of puberty.