Pubertal development and regulation

Developmental changes in lower limb joint ranges of motion in Japanese children aged 6-15 years

Background

Assessing lower limb ranges of motion (ROMs) is crucial for diagnosing and treating musculoskeletal and neurological disorders in children. Although prior studies examining decline in flexibility among school-age children suggest potential age-related changes in lower limb ROMs, this hypothesis remains unproven. Therefore, in this study, we aim to examine age-related differences in lower limb ROMs among school-age children.

Methods

The passive ROMs in the lower limbs of 572 typically developing children aged 6-15 years were measured by physiotherapists using goniometers. To examine developmental changes in lower limb ROMs, participants were categorized into four groups: 6-7 years (189 participants), 8-9 years (147 participants), 10-11 years (124 participants), and 12-15 years (112 participants).

Results

We observed a consistent trend of decreasing ROMs with age across all measures (hip flexion, popliteal angle, knee flexion, knee extension, ankle dorsiflexion, and ankle plantar flexion), excluding hip extension. Notably, only the popliteal angle exhibited values indicating clinically significant sex differences.

Conclusions

Lower limb ROMs in school-age children generally decrease with age, with notable sex differences observed in the popliteal angle. The lower limb ROM values presented herein can serve as reference values to identify disease- and injury-related changes in lower limb ROMs during this developmental stage.

Effect of a GnRH injection on kisspeptin levels in girls with suspected precocious puberty: a randomized-controlled pilot study

OBJECTIVES

Kisspeptin plays a major role in the onset of puberty by stimulating the gonadotropin-releasing hormone (GnRH) neurons. The aim of this study was to investigate whether GnRH inhibits kisspeptin secretion via a negative feedback mechanism and potential associations between kisspeptin levels and other hormones of importance for pubertal onset.

METHODS

Thirteen girls with suspected central precocious puberty underwent a GnRH stimulation test twice in a randomized, placebo-controlled manner. Blood was sampled up to 150 min after an IV injection of either Relefact LHRH® or saline. The levels of kisspeptin, acylated ghrelin, ultrasensitive oestradiol, luteinizing hormone (LH), follicle-stimulating hormone (FSH), insulin and glucose were analysed.

RESULTS

Baseline kisspeptin levels ranged from 9.9 to 201.6 pg/mL. Neither area under the curve for kisspeptin levels nor peaks were significantly lower after the GnRH injection compared to placebo. Baseline kisspeptin and glucose levels tended to be associated (rho=0.55, p=0.051) but no other associations were found between kisspeptin and other hormones.

CONCLUSIONS

Basal levels of kisspeptin vary widely in young girls. We found no evidence of a negative feedback mechanism of GnRH on kisspeptin in this small pilot study. The suggested association between kisspeptin and glucose levels needs further investigations.

Study of the Association Between Menarche and Disease Course in Pediatric Multiple Sclerosis

BACKGROUND AND OBJECTIVES

Sex steroid hormones have been demonstrated to affect the immune system in multiple sclerosis (MS), and puberty may trigger MS activity. We aimed to evaluate the association between menarche and disease course in pediatric MS through comparison of relapse rates across premenarche, perimenarche, and postmenarche periods.

METHODS

This is a retrospective analysis of a prospectively followed female cohort with pediatric-onset MS in the US Network of Pediatric MS Centers database. Perimenarche was considered the period from 1 year before to 1 year after the estimated menarche date based on menarche integer age. Relapses were collected prospectively. Negative binomial and repeated-measures Cox regression models were used to assess the association of pubertal development stage with relapse rate, adjusted for race, body mass index, and disease-modifying therapy (DMT).

RESULTS

Of 736 participants (all female; mean onset age 14.4 ± 2.8 years; mean menarche age 11.6 ± 1.4 years), onset was in premenarche in 73, perimenarche in 112 (± 1 year of menarche), and postmenarche in 551. The median time of MS onset was 2.8 years after menarche. Most (86%) were exposed to DMT in follow-up. In adjusted negative binomial analysis, the annualized relapse rate during premenarche was 0.43, perimenarche was 0.65, and postmenarche was 0.43 (premenarche rate ratio [RR] 1.00 (95% CI 0.70-1.43) and perimenarche RR 1.52 (95% CI 1.16-1.99), compared with reference of postmenarche, p = 0.0049. In adjusted repeated-events Cox regression analysis, there was increased hazard to relapse in perimenarche and postmenarche compared with premenarche (perimenarche hazard ratio [HR] 1.78 [95% CI 1.17-2.70] and postmenarche HR 1.67 [95% CI 1.12-2.50], compared with reference of premenarche, p = 0.025). In this analysis, use of oral and infusion DMTs significantly lowered the relapse hazard compared with periods of no DMT use (injectable HR 0.98 [95% CI 0.83-1.15], oral HR 0.48 [95% CI 0.37-0.61], and infusion HR 0.24 [95% CI 0.18-0.31], compared with no DMT, p < 0.001).

DISCUSSION

Onset of puberty may be a time of increase in disease activity and may require consideration of a change in therapeutic approach. Menarche age was used as a surrogate for puberty, and future studies measuring sex steroid hormones may be informative.

SHBG Gene Polymorphisms and Their Influence on Serum SHBG, Total and Free Testosterone Concentrations in Men

CONTEXT

Genetic variation in SHBG structure may affect estimates of sex steroid exposure by altering the affinity of the protein for its ligand. Consequently, free hormone calculations assuming constant binding affinity may, for certain genetic variations, lead to incorrect diagnoses if genetic variation is not taken into consideration.

OBJECTIVE

To investigate the effects of genetic variation in SHBG on calculated and measured serum free testosterone (T) in men.

DESIGN, SETTING AND PARTICIPANTS

Population-based sibling-pair study in 999 healthy men aged 25 to 45 (mean, 34.5) years.

MAIN OUTCOME MEASURES

Genotyping using microarray (Illumina) for single-nucleotide polymorphism (SNPs) suggested to affect binding affinity and/or concentration of SHBG or T. SHBG concentrations were measured using immunoassay and in a subset (n = 32) by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Total T was measured using LC-MS/MS. Free T was calculated and in a subset (n = 314) measured directly using LC-MS/MS after equilibrium dialysis.

RESULTS

Allelic frequencies of analyzed SNPs ranged from 0.5% to 58.2%. Compared to wild-type, SHBG concentrations were lower in rs6258 heterozygotes (-24.7%; P < .05) and higher in rs6259 heterozygotes, rs727428 homozygotes, and carriers of rs1799941 (+10.8 to 23.1%; all P < .05). Total T was higher in rs727428 homozygotes and carriers of rs5934505, rs1799941and rs6259 (+3.9 to 21.4%; all P < .05). No clear effects on measured free T were found, except for a trend toward higher values in rs6259 homozygotes, significant for calculated free T (+18.7%; P < .05) in the larger global study population.

CONCLUSION

In these men, analyzed SNPs were relatively prevalent and affected serum concentrations of total T and SHBG but not calculated or measured free T except for a higher trend in rs6259 homozygotes.

Effect of maternal previous pregnancy on children's pubertal development: an 8-year pubertal cohort

STUDY QUESTION

Does the maternal pregnancy history affect the course of their offspring's pubertal development?

SUMMARY ANSWER

Maternal pregnancy history, particularly adverse outcomes, significantly influences the timing of menarche and the tempo of breast development in girls.

WHAT IS KNOWN ALREADY

Preliminary evidence indicates that parity may affect the onset of puberty, mainly as reflected by changes in the timing of pubic and axillary hair development.

STUDY DESIGN, SIZE, DURATION

This 8-year cohort, conducted semi-annually, was recruited from four primary schools. The average follow-up duration was 6.09 years (range: 2-8 years).

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study cohort comprised 1390 children, including 710 girls and 680 boys, with age ranges of 6.58-19.26 years and 5.81-19.28 years, respectively, over an 8-year follow-up period. The primary exposure was whether the mother has a history of pregnancy prior to the birth of the child, including childbearing, miscarriage, and other adverse pregnancy outcomes. Pubertal milestones as assessed by a professional, including breast and genital development, were modeled using logistic regression, and the age of menarche was documented for girls. Associations between maternal pregnancy history and pubertal progression in both genders were analyzed using generalized linear regression models.

MAIN RESULTS AND THE ROLE OF CHANCE

Girls from non-first pregnancies experienced a delayed age at menarche by 0.22 years (95% CI: 0.05, 0.38) and a more rapid tempo of breast development (0.06; 95% CI: 0.01, 0.11) compared to those from first pregnancies, particularly among girls with a history of maternal adverse pregnancy outcomes. The effect of maternal pregnancy history on pubertal development was less pronounced in boys than in girls.

LIMITATIONS, REASONS FOR CAUTION

The sample was relatively small, and the cohort also lacks sufficient data due to missing data points and some study participants still maturing. While model fitting aids in describing incomplete pubertal development, the logistic growth mixed-effects model's assumptions about growth curves may not fully reflect reality.

WIDER IMPLICATIONS OF THE FINDINGS

Maternal pregnancy history, particularly adverse outcomes, can markedly influence pubertal progression in girls. Previous studies have shown that the timing and tempo of pubertal development impact adolescent psychological and behavioral health, and have implications for reproductive health and diseases in adulthood. Optimal pregnancy planning by mothers is essential for enhancing the well-being of both mother and offspring.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by Chongqing Natural Science Foundation project (CSTB2023NSCQ-MSX0133), National Natural Science Foundation of China (81973067), National Youth Science Fund Project (81502825), and Program for Youth Innovation in Future Medicine, Chongqing Medical University (W0054). This study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Ethics Committee of Chongqing Medical University (Reference Number: 2023003). Informed consent was obtained from all participants and their guardians involved in the study. The authors declared that they have no conflicts of interest to disclose.

TRIAL REGISTRATION NUMBER

N/A.

Developmental programming: preconceptional and gestational exposure of sheep to biosolids on offspring ovarian dynamics†

Developmental exposure to environmental chemicals perturbs establishment and maintenance of the ovarian reserve across the reproductive lifetime, leading to premature follicle depletion and ovarian aging. Considering humans are exposed to a complex mixture of environmental chemicals, real-life models assessing their cumulative impact on the ovarian reserve are needed. Biosolids are a source of a real-life mixture of environmental chemicals. While earlier studies demonstrated that grazing pregnant sheep on biosolids-treated pastures did not influence establishment of the ovarian reserve in fetal life, its impact on subsequent depletion of ovarian reserve during reproductive life of offspring is unknown. We hypothesized that developmental exposure to biosolids accelerates depletion of ovarian reserve. Ovaries were collected from F1 juveniles (9.5 weeks) and adults (2.5 years) born to F0 ewes grazed on control inorganic fertilizer pastures or biosolids-treated pastures from before conception and throughout gestation. The impact on follicular density, activation rate, and anti-Müllerian hormone (mediator of activation) expression by immunohistochemistry was determined. Activation rate was increased in F1 biosolids-treated pastures juveniles with a corresponding reduction in primordial follicle density. In contrast, activation rate and ovarian reserve were similar between control and F1 biosolids-treated pastures adults. The density of anti-Müllerian hormone-positive antral follicles was lower in biosolids-treated pastures juveniles, whereas anti-Müllerian hormone expression tended to be higher in antral follicles of biosolids-treated pastures adults, consistent with the changes in the ovarian reserve. These findings of detrimental effects of developmental exposure to biosolids during juvenile life that normalizes in adults is supportive of a shift in activation rate likely related to peripubertal hormonal changes.

Associations of fetal and infant growth with pubertal timing

OBJECTIVE

Impaired fetal and infant growth may cause alterations in developmental programming of the hypothalamic-pituitary-gonadal axis and subsequently pubertal development. We aimed to assess associations between fetal and infant growth and pubertal development.

DESIGN

Population-based prospective birth cohort.

SETTING

Rotterdam, the Netherlands.

PATIENTS

5830 singleton born children.

INTERVENTIONS

We estimated fetal weight in second and third trimester by ultrasound. Infant growth measures were gestational age and weight at birth and infant weight at 6, 12 and 24 months.

MAIN OUTCOME MEASURES

Pubertal timing outcomes included difference between chronological and skeletal age assessed using dual-energy X-ray absorptiometry, testicular or ovarian volumes assessed using MRI at 10 years, age at menarche and Tanner staging at 13 years.

RESULTS

Among girls, 1-SD scores birth weight increase was associated with larger ovarian volume at 10 years (0.07 SD (95% CI 0.02 to 0.12) and later age at menarche (0.06 (0.02 to 0.11)). Among girls, increased infant growth was associated with an older skeletal age at 10 years (difference 2.67 (95% CI 2.26 to 3.08) months), earlier menarche (difference 0.10 (95% CI -0.14 to -0.06) years) and more advance breast and pubic hair development at 13 years (difference in Tanner stages 0.09 (0.05 to 0.13) and 0.07 (0.03 to 0.12)). In boys, increased infant growth was associated with an older skeletal age (3.13 (95% CI 2.58 to 3.69) months) and a larger testicular volume (0.07 (95% 0.02 to 0.12) SD) at 10 years, and with more advance pubic hair development (0.09 (95% CI 0.05 to 0.14) at 13 years).

CONCLUSION

Birth anthropometrics and early-life growth patterns are associated with altered pubertal development in a sex-specific manner.

A novel model of central precocious puberty disease: Paternal MKRN3 gene-modified rabbit

BACKGROUND

Makorin ring finger protein 3 gene (MKRN3) gene mutation is the most common genetic cause of central precocious puberty (CPP) in children. Due to the lack of ideal MKRN3-modified animal model (MKRN3-modified mice enter puberty only 4-5 days earlier than normal mice), the related research is limited.

METHODS

Therefore, the MKRN3-modified rabbit was developed using CRISPR (clustered regularly interspaced short palindromic repeats) gene editing technology. The genotype identification and phenotype evaluation of MKRN3-modified rabbits were carried out.

RESULTS

The first estrus of MKRN3-modified female rabbits was observed ~27 days earlier than that of wild-type female rabbits, with a typical CPP phenotype. This study found increased gonadotropin releasing hormone (GnRH) and decreased gonadotropin inhibiting hormone (GnIH) in the hypothalamus of the CPP rabbit model with MKRN3 gene mutation. Although this study failed to fully clarify the pathogenesis of CPP caused by MKRN3 mutation, it found some differentially expressed genes and potential pathways through transcriptome sequencing.

CONCLUSIONS

This study established a novel CPP model: paternal MKRN3 gene-modified rabbit. It is hoped that the establishment of this model will help researchers better understand, treat, and prevent CPP in the future.

Critical appraisal of diagnostic laboratory tests in the evaluation of central precocious puberty

Pubertal onset is characterized by reactivation of the hypothalamic-pituitary-gonadal axis resulting in pulsatile gonadotropin secretion and subsequent sex steroid production. Accurate measurements of the gonadotropins and sex steroids are essential to ensure timely diagnosis of precocious puberty, so as to determine optimal management. This review summarizes the available laboratory testing for the diagnosis of puberty, discussing the different assays used while reviewing the limitations of such testing.

Vulvar Developmental Stages During Puberty: A Systematic Review

STUDY OBJECTIVE

Puberty is associated with important changes in secondary sexual characteristics, but the changes occurring in female external genitalia are not thoroughly described. The aim of this systematic review is to summarize and assess the current scientific knowledge regarding vulvar changes and development during puberty.

METHODS

PubMed, Embase, Web of Science, and Cochrane were searched using keywords related to "puberty," "vulva," and "morphology." The inclusion criteria were observational studies describing vulvar development in individuals between the ages of 8 and 16 years. The outcomes of interest were quantitative and/or qualitative descriptions of the vulva, including anatomic, physiological, and histological changes.

RESULTS

Of the 1658 articles screened, 10 were included. The mean clitoral glans diameter increases during puberty, as does the length of the clitoral hood. The clitoral hood changes to become more retractile and rugose. The inner labia width and length increase throughout puberty, and the development of the inner labia varies between individuals, with labial asymmetry being a common characteristic. The most frequent hymenal configuration found during puberty is the crescentic form, and features such as hymenal mounds, longitudinal intravaginal ridges, and most notches are physiological.

CONCLUSION

Reliable data on pubertal development of the external female genital organs are scarce. Future research is needed to provide more precise data to help categorize vulvar development into stages. A detailed description of vulvar maturation into sequential stages throughout puberty (as done by the Tanner scale for the male homologous structures) can increase knowledge of its morphologic diversity and help reach clinical consensus on the nature of pathologic variants. In addition, better knowledge of vulvar diversity is important to both health care professionals and individuals and may empower and promote self-esteem.

Endocrine Disruptors in Child Obesity and Related Disorders: Early Critical Windows of Exposure

PURPOSE OF REVIEW

Endocrine disruptors (EDs) can mimic or interfere with hormones in the body, leading to non-communicable diseases, such as obesity, diabetes, and metabolic syndrome. Susceptibility to EDs increases during prenatal and postnatal life, a critical time window. This review aims to summarize the latest evidence on the relation of early life exposure to some EDs with obesity and the other metabolic disorders.  RECENT FINDINGS: There is increasing evidence that early life exposure to EDs may impair adipogenesis by increasing the number and size of adipocytes, thereby increasing susceptibility to obesity in childhood. It is stated that exposure to EDs during the prenatal and postnatal period may raise the risk of type 2 diabetes in adulthood by disrupting glucose, lipid, and insulin homeostasis in the offspring. They can also accelerate the development of type 1 diabetes through various mechanisms, like immunomodulation, gut microbiota, and vitamin D pathways. There is a growing understanding that ED exposure during critical stages of life could play an important role in the development of obesity and metabolic disorders. We suggest setting national goals, global standards, and policies to reduce environmental exposure to pregnant and lactating women, and babies, considered sensitive populations.

Genetics and Epigenetics of Human Pubertal Timing: The Contribution of Genes Associated With Central Precocious Puberty

Human puberty is a dynamic biological process determined by the increase in the pulsatile secretion of GnRH triggered by distinct factors not fully understood. Current knowledge reveals fine tuning between an increase in stimulatory factors and a decrease in inhibitory factors, where genetic and epigenetic factors have been indicated as key players in the regulation of puberty onset by distinct lines of evidence. Central precocious puberty (CPP) results from the premature reactivation of pulsatile secretion of GnRH. In the past decade, the identification of genetic causes of CPP has largely expanded, revealing hypothalamic regulatory factors of pubertal timing. Among them, 3 genes associated with CPP are linked to mechanisms involving DNA methylation, reinforcing the strong role of epigenetics underlying this disorder. Loss-of-function mutations in Makorin Ring-Finger Protein 3 (MKRN3) and Delta-Like Non-Canonical Notch Ligand 1 (DLK1), 2 autosomal maternally imprinted genes, have been described as relevant monogenic causes of CPP with the phenotype exclusively associated with paternal transmission. MKRN3 has proven to be a key component of the hypothalamic inhibitory input on GnRH neurons through different mechanisms. Additionally, rare heterozygous variants in the Methyl-CpG-Binding Protein 2 (MECP2), an X-linked gene that is a key factor of DNA methylation machinery, were identified in girls with sporadic CPP with or without neurodevelopmental disorders. In this mini-review, we focus on how the identification of genetic causes of CPP has revealed epigenetic regulators of human pubertal timing, summarizing the latest knowledge on the associations of puberty with MKRN3, DLK1, and MECP2.

NAGK regulates the onset of puberty in female mice

This study examines the role of N-acetylglucosamine kinase (NAGK) in initiating puberty in female mice. We employed real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and immunofluorescence to measure NAGK expression in the hypothalamic-pituitary-ovarian axis across various developmental stages: infant, prepuberty, puberty, and adult. We further investigated the impact of Nagk gene knockdown on puberty in female mice. This included assessing the expression of puberty-related genes both in vivo and in vitro, GT1-7 cells proliferation and apoptosis, concentrations of GnRH and Kisspeptin, puberty onset timing, serum levels of progesterone (P4) and estradiol (E2), and ovarian morphology. Results revealed that Nagk mRNA is present in the hypothalamus, pituitary, and ovaries throughout different developmental stages in female mice. In the hypothalamus, Nagk mRNA levels were comparable during infant and prepuberty, lowest during puberty, and highest in adult. In the pituitary, Nagk mRNA peaked in adult, with no significant variation between infant, prepuberty, and puberty. In the ovaries, Nagk mRNA levels increased during puberty and peaked in adult. NAGK is predominantly located in the arcuate nucleus (ARC), periventricular nucleus (PeN), dorsomedial hypothalamic nucleus (DMH), paraventricular nucleus (PVN), adenohypophysis, and in the ovarian oocytes, interstitium, and granulosa cells across all developmental stages in female mice. Nagk knockdown in GT1-7 cells decreased the transcriptional level of Gnrh, Kiss1, Gpr54, Igf1 and Mapk14 mRNA and cell proliferation but increased the level of β-catenin mRNA and cell apoptosis, while reducing GnRH secretion. Following ICV injection, Nagk gene knockdown mice exhibited delayed the timing of vaginal opening (VO) and reduced hypothalamic levels of Gnrh, Kiss1, Gpr54, Igf1, Mapk14, and β-catenin mRNA. Additionally, serum concentrations of E2 in Nagk gene knockdown mice were significantly lower compared to the control group. These findings indicate that Nagk regulates the expression of Gnrh and Kiss1 mRNA in GT1-7 cells, affects hypothalamus Gnrh mRNA levels and serum E2 concentration, and that its knockdown can delay puberty onset in female mice.

The effects of anemia on the timing of pubertal onset in female rats

Attainment of vaginal patency is an endpoint for the onset of puberty in female animals in toxicity studies. It is widely acknowledged that certain substances with endocrine-modulating effects can influence the timing of puberty in female rats and that factors unrelated to endocrine mechanisms, such as malnutrition and stress, can also affect pubertal onset. Some epidemiological studies have also suggested a link between anemia and delay in pubertal onset in women, however, little is known regarding the relation between hematological changes and female pubertal onset in experimental animals. The purpose of this study was to examine the effects of anemia during the prepubertal period on pubertal onset and reproductive organs in female rats. In this study, anemia was induced by drawing a certain amount of blood from the jugular vein or by intraperitoneal administration of phenylhydrazine, a well-known inducer of hemolytic anemia. As a result, both treatment groups showed a transient anemia characterized by an approximately 20-35% decrease in hemoglobin levels compared to the control group. Anemia in these female rats produced no obvious changes in body weight on each postnatal day and had no effect on the weights and histopathology of reproductive organs after sexual differentiation, but the age at vaginal opening (VO) was delayed and the body weight at VO was higher than the same parameters in the control group. These results suggest that anemia in prepubertal females could cause a delay in pubertal onset.

"Estrogens and human brain networks: A systematic review of structural and functional neuroimaging studies"

Estrogen fluctuations during the menstrual cycle, puberty, postpartum, or in the menopausal transition are associated with cognitive, affective, and behavioral effects. Additionally, estrogens are essential in hormonal contraception, menopausal hormone therapy, or gender-affirming hormone therapy. This systematic review summarizes findings on the role of estrogens for structure, function, and connectivity of human brain networks. We searched PubMed, Web of Science, and ScienceDirect for neuroimaging articles assessing estrogens published since 2008. We included 54 studies (N = 2,494 participants) on endogenous estrogen, and 28 studies (N = 1,740 participants) on exogenous estrogen conditions. Estrogen-related changes were reported for emotion, reward, memory, and resting-state networks, and in regional white and gray matter, with a particular neural plasticity in the hippocampus and amygdala. By examining study designs, imaging measures, and analysis methods, this review highlights the role of neuroimaging in advancing neuroendocrine and neurocognitive research, particularly promoting brain health for women and individuals with ovaries.

Potential Role of Sleep Disturbance in the Development of Early Puberty: Past Clinical Evidence for Future Management

The incidence of early puberty in children has been increasing. It has been suspected that both genetic and various environmental factors such as nutrition and hormonal exposure could influence the mechanisms underlying the earlier onset of puberty. Interestingly, several previous studies have reported a strong connection between sleep and puberty. Specifically, it was discovered that luteinizing hormone (LH), a potential marker for the onset of puberty, was increased during the deep sleep period. Furthermore, a high prevalence of early puberty was observed in patients with sleep disorders, especially in those experiencing narcolepsy. In this review article, findings related to the association between sleep disturbance and early puberty have been comprehensively summarized. Any contrary findings are also included and discussed. Advances in the knowledge surrounding sleep disturbance have led to a greater understanding of a correlation between early puberty and sleep disorder and provide alternative therapeutic options for the treatment of central precocious puberty in the future.

Pharmacogenomics and pediatric drug development: science and political power. A narrative review

INTRODUCTION

Pharmacogenomics (PGx) investigates how genomes control enzyme expression. Developmental pharmacology (DP) describes the temporal sequence of enzymes impacting absorption, distribution, metabolism, and excretion (ADME) of food and drugs.

AREAS COVERED

US and European Union (EU) legislation facilitate and/or enforce pediatric studies for all new drugs, called overall 'pediatric drug development' (PDD). DP and PDD look at patients' chronological age, but oscillate between legal and physiological meanings of the term 'child.' Children's bodies become mature with puberty.

EXPERT OPINION

Decades after first DP observations in babies, PGx offers a better understanding of the variability of safety and efficacy of drugs, of the process of aging, and of shifting enzyme patterns across aging. We should rethink and revise outdated interpretations of ADME changes in minors. The Declaration of Helsinki forbids pointless studies that some pediatric researchers and regulatory agencies, more so the EMA than the FDA, demand pointless pediatric studies is regrettable. Medicine needs to differentiate between legal and physiological meanings of the term 'child' and should use objective measures of maturity.

Emerging Trend of Central Precocious Puberty: A Retrospective Study of Cases Diagnosed Before and During the COVID-19 Pandemic in a Portuguese Tertiary-Level Hospital

INTRODUCTION

In light of the recent evidence suggesting an increase in idiopathic central precocious puberty (ICPP) during the COVID-19 pandemic, this study aimed to assess the incidence of newly diagnosed ICPP cases and compare differences in demographic, anthropometric, and clinical characteristics pre-pandemic and during the pandemic.

METHODS

We conducted a retrospective study at a national reference pediatric endocrinology unit in Portugal to evaluate the proportion of referrals for precocious puberty (PP) and, within this group, the number of ICPP cases diagnosed before (group 1: January 2018 to March 2020) and during the pandemic (group 2: April 2020 to June 2022). Additionally, we compared the demographic, anthropometric, and clinical characteristics of ICPP patients between the two groups.

RESULTS

Out of 258 patients referred for PP, 20 were diagnosed with ICPP (19 girls and one boy). Sixteen cases were diagnosed during the pandemic, marking a significant increase (16 vs. 4, p = 0.023), especially among girls. Additionally, thelarche onset occurred earlier during the pandemic (6.9 vs. 7.3, decimal age (DA) in years, p = 0.035). Despite pandemic challenges, a prompt medical response was observed, with a shorter time from first visit to treatment (DA at the onset of treatment - DA at first visit: 0.19 vs. 0.79 years; p = 0.015). No other parameters showed significant differences. Referrals for PP during the pandemic were not significantly higher than pre-pandemic (144 of 904 vs. 114 of 758, p > 0.05).

CONCLUSION

This study revealed a significant four-fold increase in the diagnosis of ICPP during the pandemic, particularly among girls. Furthermore, in the pandemic group, thelarche onset was earlier, raising the question of whether increased parental presence at home contributed to heightened awareness of pubertal changes. Despite the challenges posed by the pandemic in terms of referrals and follow-up, these results point to efficient work that led to prompt treatment initiation without delays, unlike in other pathologies, as mainly observed in adults. Surprisingly, no significant increase in body mass index was observed, suggesting that other factors may be involved. To substantiate these findings and uncover additional potential contributing factors for the development of ICPP, a more extensive research effort is warranted.

Impact of Small-Quantity Lipid-Based Nutrient Supplements on Pubertal Status of 9-13-Year Olds: A Follow-Up Study of the iLiNS-DYAD-Ghana Trial

Background

Early and delayed puberty are both associated with adverse health and psychosocial outcomes.

Objectives

We assessed the impact of provision of small-quantity lipid-based nutrient supplement (SQ-LNS) to mothers during pregnancy and 6 mo postpartum and to their children aged 6-18 mo, on pubertal status.

Methods

This study was a follow-up to a partially double-blind randomized controlled trial. At ≤20 wk, 1320 females were randomly assigned to receive daily: iron and folic acid during pregnancy and placebo 0-6 mo postpartum; or multiple micronutrients during pregnancy and 0-6 mo postpartum; or SQ-LNS during pregnancy and 0-6 mo postpartum and to their children from 6 to 18 mo. We re-enrolled 966 and 919 children at 9-11 y and 11-13 y, respectively. We calculated a total pubertal status score based on the Petersen Pubertal Development Scale (PDS) to assess growth spurt, skin changes, body hair, facial hair, voice break, breast development, and menstruation. Pubertal status was regressed on child's age to generate age-adjusted PDS z-scores (aPDSZ); we performed interaction and mediation analyses.

Results

Mean ± standard deviation aPDSZ did not differ between the SQ-LNS and non-LNS groups at 9-11 y (0.01 ± 0.95 compared with -0.01 ± 0.98; P = 0.958) but was more advanced in the SQ-LNS group at 11-13 y (0.07 ± 1.04 compared with -0.04 ± 0.98; P = 0.049) in the adjusted model. The effect of SQ-LNS varied by sex (P-interaction = 0.003) and household asset index z-score (P-interaction = 0.002): Puberty was more advanced in the SQ-LNS compared with non-LNS group among females (P = 0.007) but not males (P = 0.877), and within lower (P = 0.002) than average (P = 0.436) and higher (P = 0.332) socioeconomic households.

Conclusion

Provision of SQ-LNS during the first 1000 d of life advanced pubertal status among females.

Trial registration number

This trial was registered at clinicaltrials.gov as NCT00970866 (https://clinicaltrials.gov/ct2/show/record/NCT00970866).

The Regulatory Effect of Insulin-Like Growth Factor-2 on Hypothalamic Gonadotropin-Releasing Hormone Neurons during the Pubertal Period

BACKGROUND

The insulin-like growth factor (IGF) system plays a vital role in regulating gonadotropin-releasing hormone (GnRH), whether the IGF2 can act on the GnRH neurons during the pubertal period is unclear.

METHODS

Central precocious puberty (CPP) rats were induced by danazol, and when the rats met the first diestrus, they were euthanized and tissues were collected. GT1-7 cells were cultured and treated with 0, 1, 10 ng/mL IGF2 for 4 hours and the changes in GnRH were measured. Mice were injected intracerebroventricularly with IGF2 (15 ng/g, 5 μL) or with the same dose of phosphate buffered saline (PBS), after eight hours, they were euthanized and tissues collected.

RESULTS

CPP rats had increased expression of IGF2 and GnRH mRNA and their respective proteins in the preoptic area (POA) of the hypothalamus. Treatment of GT1-7 cells with 10 ng/mL of IGF2 increased GnRH mRNA and protein expression, and GnRH concentration in the culture medium. Injection of IGF2 protein into the lateral ventricle of mice increased the expression of GnRH mRNA and protein in the POA.

CONCLUSIONS

IGF2 may upregulate the synthesis of GnRH during the pubertal period, and may also take part in the pathology of CPP.

piRNA array analysis provide insight into the mechanism of DEHP-induced testicular toxicology in pubertal male rats

Di-(2-ethylhexyl) phthalate (DEHP), a widely used plasticizer, could cause male reproductive toxicity by disrupting spermatogenesis. Piwi-interacting RNAs (piRNAs) are a small non-coding RNAs specifically highly expressed in the germline and interact with PIWI proteins to regulate spermatogenesis. Accumulating studies have confirmed that environmental poisons could induce male reproductive injury via altering piRNA expression. However, it remains unclear whether DEHP causes male reproductive dysfunction by perturbing piRNA expression levels. In this study, we conducted piRNA microarray expression analyses on testes of DEHP-exposed and control male rats and performed some in vitro and in vivo studies to explore the role of piRNA on DEHP-induced male reproductive toxicity. Our results showed that DEHP exposure leaded to changed expression profiles of piRNAs in pubertal male rat testes. And bioinformatics analyses revealed that down-regulated piR-rno-26751 probably targeted Insr mRNA expression regulation. Results from gene and protein expression tests demonstrated that DEHP caused decreased expression level of INSR mainly in spermatogonia. Moreover, MEHP, the main metabolite of DEHP resulted in cell apoptosis and down-regulation of INSR and its downstream p-IRS1, p-PI3K, p-AKT and p-FOXO1 in GC-1spg cells. Conversely, overexpression of INSR restored cell apoptosis and the down-regulation of the above proteins in GC-1spg cells. In conclusion, these findings suggest that DEHP-induced down-regulation of piR-rno-26751 targets the suppression of INSR, leading to apoptosis of spermatogonia in pubertal male rats.

[Application of urinary luteinizing hormone in the prediction of central precocious puberty in girls]

OBJECTIVE

To evaluate the level of first morning voided (FMV) urinary luteinizing hormone (LH) in girls with breast development, and to determine the value of FMV urine LH in the evaluation of central precocious puberty (CPP).

METHODS

From September 2018 to April 2021, among the patients who were admitted to the Department of Pediatrics of Peking University Third Hospital for "precocious puberty" and underwent gonadotropin-releasing hormone (GnRH) stimulation test, a total of 108 girls were enrolled. According to CPP diagnostic criteria, they were divided into CPP group (n=45) and non-CPP group (n=63). The clinical characteristics and hormone levels of the two groups were compared. Receiver operating characteristic (ROC) curve was used to analyze the cut-off value of FMV urinary LH in the diagnosis of CPP in girls. Further analyses were done to evaluate the value of FMV urinary LH in the diagnosis of CPP using correlation analysis between urinary LH level and common clinical cha-racteristics.

RESULTS

ROC curve analysis showed that FMV urine LH level was significant for the diagnosis of CPP. The cut-off value of FMV urine LH was 0.69 IU/L (specificity 56.9%, sensitivity 85.0%, area under curve 0.804, P < 0.001). The basic clinical characteristics without GnRH stimulation test were analyzed by binary Logistic regression analysis, indicating that the level of FMV urine LH, uterine volume, ovarian volume and advanced T-bone age had predictive significance for CPP diagnosis in girls (OR values were 2.125, 1.961, 1.564 and 2.672, respectively). The prediction model was established and the area under the ROC curve was 0.904, P < 0.001. The level of FMV urine LH was positively correlated with the levels of serum LH, FSH and estrogen before GnRH stimulation test, the peak value of blood LH after GnRH stimulation test, T bone age and uterine volume, with r values of 0.462, 0.373, 0.242, 0.360, 0.373 and 0.263, respectively, and P values were < 0.001, < 0.001, 0.013, < 0.001, < 0.001 and 0.007, respectively.

CONCLUSION

FMV urine LH can provide a good indication for the diagnosis of CPP. Combining with bone age advanced level and pelvic ultrasound measurement, the predictive value of FMV urine LH can be further improved for the diagnosis of CPP in girls.

ADHD and Risk of Precocious Puberty: Considering the Impact of MPH

BACKGROUND/OBJECTIVES

The complex association between attention-deficit/hyperactivity disorder (ADHD) and methylphenidate (MPH) with precocious puberty (PP) is still unclear. This study aims to investigate the association between ADHD, MPH, and PP.

METHODS

This is a nationwide cohort study including a total of 3,342,077 individuals, 186,681 with ADHD and 3,155,396 without. First, we compared the risk of PP between ADHD cases and non-ADHD cases. Second, we compared the risk of PP between MPH users and non-MPH users in patients with ADHD.

RESULTS

Patients with ADHD were at a greater risk of PP (adjusted hazard ratio [aHR], 2.01 [95% CI, 1.91-2.11]). In our moderation analyses, the female gender was a positive additive effect modifier of the association between ADHD and PP, whereas tics and intellectual disability were negative effect modifiers. In patients with ADHD, MPH users had a significantly lower risk of PP (aHR, 0.63 [95% CI 0.57-0.70]), and females had a negative effect modification on the association between MPH and PP.

CONCLUSIONS

Our study found that children with ADHD were at a greater risk of PP. Girls with ADHD were a group particularly vulnerable to PP. Comorbid tics or intellectual disability was associated with a lower risk of PP. Among patients with ADHD, MPH was protective against PP, especially in girls. However, these preliminary results need further validation due to the nature of them being from an electronic database study. Unmeasured confounding factors might affect the association between MPH and PP.

The enduring effects of antimicrobials and lipopolysaccharide on the cellular mechanisms and behaviours associated with neurodegeneration in pubertal male and female CD1 mice

Puberty is a sensitive developmental period during which stressors can cause lasting brain and behavioural deficits. While the acute effects of pubertal lipopolysaccharide (LPS) and antimicrobial (AMNS) treatments are known, their enduring impacts on neurodegeneration-related mechanisms and behaviours remain unclear. This study examined these effects in male and female mice. At five weeks old, mice received 200ul of either broad-spectrum antimicrobials or water through oral gavage twice daily for seven days. At six weeks of age, they received an intraperitoneal injection of either saline or LPS. Four weeks later, adult mice underwent neurodegeneration-related behavioural tests, including the rotarod, forepaw stride length, reversed grid hang, open field, and buried pellet tests. Two days after the final test, brain and ileal samples were collected. Results showed that female mice treated with both AMNS and LPS exhibited deficits in neuromuscular strength, while males treated with LPS alone showed increased anxiety-like behaviours. Males treated with AMNS alone had decreased sigma-1 receptor (S1R) expression in the cornu ammonis 1 (CA1) and dentate gyrus (DG), while females treated with both AMNS and LPS had decreased S1R expression. Additionally, males treated with either LPS or AMNS had lower glial-derived neurotrophic factor receptor alpha-1 (GFRA1) expression in the primary motor cortex (M1) than females. Mice treated with LPS alone had decreased GFRA1 expression in the DG and decreased S1R expression in the secondary motor cortex (M2). These findings suggest that pubertal AMNS and LPS treatments may lead to enduring changes in biomarkers and behaviours related to neurodegeneration.

Associations between birthweight and preterm birth and the ages at menarche and menopause

BACKGROUND

Women who reach menarche and menopause at earlier ages have been shown to be at increased risk for numerous conditions including cardiovascular disease, cancer, depression, and obesity; however, risk factors for earlier ages of menarche and menopause are not fully understood. Therefore, we aimed to perform a retrospective investigation of the associations between a personal birthweight and/or being born preterm and the age of and menarche and menopause and related events in the Women's Health Initiative, a large, racially and ethnically diverse cohort of postmenopausal women.

METHODS

At study entry, women reported their birthweight by category (< 6 lbs., 6-7 lbs. 15 oz, 8-9 lbs. 15 oz, or ≥ 10 lbs.) and preterm birth status (4 or more weeks premature). Ages at events related to menarche and menopause were also self-reported. Linear regression and logistic regression models were used to estimate unadjusted and adjusted effect estimates (β) and odds ratios (OR), respectively (n ≤ 86,857). Individuals born preterm were excluded from all birthweight analyses.

RESULTS

After adjustments, individuals born weighing < 6lbs. were more likely to reach natural menopause at an earlier age (adjusted β=-0.361, SE = 0.09, P = < 0.001) and have a shorter reproductive window (adjusted β = -0.287, SE = 0.10, p < 0.004) compared to individuals weighing 6-7 lbs. 15 oz. Individuals born preterm were also more likely to reach natural menopause at an earlier age (adjusted β=-0.506, SE = 0.16, P = 0.001) and have a shorter reproductive window (adjusted β = -0.418, SE = 0.17, p < 0.006).

CONCLUSIONS

These findings raise concerns that, as more preterm and low birthweight individuals survive to adulthood, the prevalence of earlier-onset menarche and menopause may increase. Clinical counseling and interventions aimed at reducing the incidence of preterm and low birthweight births, as well as intensification of lifestyle modifications to reduce CVD risk among women with these early-life risk factors, should be prioritized.

Central Precocious Puberty During the COVID-19 Pandemic Period: A Systematic Review of Literature

Central precocious puberty (CPP) is a condition where the hypothalamus-pituitary-gonadal axis is activated earlier than normal, leading to premature development of secondary sexual characteristics before eight years of age in girls and nine years of age in boys. The purpose of this study was to critically and systematically evaluate the literature regarding CPP rise during the COVID-19 pandemic. We searched PubMed and Google Scholar for relevant articles using the following MeSH terms: "COVID-19, "precocious puberty," "early puberty," "pediatric endocrinology," and "pandemic effects." We included studies calculating the risk of CPP before and during the COVID-19 pandemic. We excluded studies looking at patients with an identifiable cause for CPP or with peripheral precocious puberty. The primary outcome was the prevalence of central precocious puberty during the pandemic compared to the pre-pandemic period. We analyzed data regarding anthropometric, biochemical, and pelvic ultrasound data between the two groups. Overall, 16 studies with 2.175 subjects were included, of which 1.818 were diagnosed with CPP. There was a rise in the number of new diagnoses of CPP during the COVID-19 pandemic (985 subjects) compared with the pre-pandemic period (833 subjects). The mean age of diagnosis in the first group was 7.42 years versus 7.54 years in the second group. Notably, CPP during the pandemic was associated with a higher body mass index (BMI) compared with the group of the pre-pandemic period (17.50 versus 17.08). The pandemic and lockdowns led to changes in lifestyle habits, social isolation, sleep disturbance, excess screen time, and increased stress levels. We hypothesize that these alterations influenced the increase in CPP frequency.

Maternal stress in pregnancy and pubertal timing in girls and boys: a cohort study

OBJECTIVE

To investigate whether maternal stress in pregnancy is associated with pubertal timing in girls and boys and to explore potential mediation by childhood body mass index (BMI) and childhood psychosocial stress.

DESIGN

Cohort study.

SETTING

Not applicable.

PATIENTS

In total, 14,702 girls and boys from the Puberty Cohort, nested within the Danish National Birth Cohort.

INTERVENTION

Maternal stress was obtained from a computer-assisted telephone interview in gestational weeks 30-32 as maternal life stress and emotional distress in pregnancy using questions on the basis of validated screening tools. Maternal life stress and emotional distress in pregnancy were analyzed separately and in an interaction analysis.

MAIN OUTCOME MEASURES

Pubertal timing was measured half-yearly from age 11 years and throughout pubertal development and assessed as Tanner stages 1-5 (breast and pubic hair development in girls and genital and pubic hair development in boys), menarche in girls, voice break and first ejaculation in boys, and occurrence of acne and axillary hair in both girls and boys. A combined estimate for overall pubertal timing was derived using Huber-White robust variance estimation. Mean differences in age at attaining the pubertal milestones according to prenatal exposure to no (reference), low-, moderate-, or high-maternal stress in pregnancy were estimated using a multivariable censored regression model. Potential mediation by childhood BMI and childhood psychosocial stress was investigated in separate models.

RESULTS

After adjustment for potential confounding factors, prenatal exposure to high-maternal life stress (combined estimate: -1.8 months [95% CI, -2.7 to -0.8] and -0.9 months [95% CI, -1.8 to 0.0]), high maternal emotional distress (combined estimate: -1.5 months [95% CI, -2.5 to -0.5] and -1.7 months [95% CI, -2.8 to -0.7]), and both high-maternal life stress and emotional distress (combined estimate: -2.8 months [95% CI, -4.2, to -1.4] and -1.7 months [95% CI, -3.1 to -0.2]) were associated with earlier pubertal timing in girls and boys, respectively. The associations were not mediated by childhood BMI or childhood psychosocial stress.

CONCLUSIONS

Prenatal exposure to maternal stress in pregnancy was associated with earlier pubertal timing in girls and boys in a dose-dependent manner. The associations were not mediated by childhood BMI or childhood psychosocial stress.

Sibling relatedness and pubertal development in girls and boys: A population-based cohort study

PURPOSE

To investigate the association between sibling relatedness and pubertal development in girls and boys.

METHODS

This cohort study consisted of 10,657 children from the Puberty Cohort, Denmark. Information on sibling relatedness was obtained by self-report. Information on pubertal markers was obtained half yearly from age 11 and throughout puberty. Mean age difference at attaining pubertal markers was estimated using interval-censored regression models according to sibling relatedness (full, half and/or step siblings; half and/or step siblings; no siblings; relative to full siblings).

RESULTS

Girls with both full, half and/or step siblings (-1.2 (CI 95 %: -2.5; 0.1) months), only half- and/or stepsiblings (-2.2 (CI 95 %: -3.7; -0.7) months), and no siblings (-5.5 (CI 95 %: -8.5; -2.5) months) entered puberty earlier than girls with full siblings. Boys with full, half and/or step siblings (-1.4 (CI 95 %: -2.7; -0.1) months), only half and/or step siblings (-1.2 (CI 95 %: -3.0; 0.6) months), and no siblings (-4.5 (CI 95 %: -8.8; -0.3) months) entered puberty earlier than boys with full siblings.

CONCLUSIONS

Children with sibling relatedness other than full siblings entered puberty earlier than their peers with full siblings even after adjustment for parental cohabitation status, childhood body mass index and childhood internalizing and externalizing symptoms.

The Dynamic Interplay Between Puberty and Structural Brain Development as a Predictor of Mental Health Difficulties in Adolescence: A Systematic Review

Puberty is a time of intense reorganization of brain structure and a high-risk period for the onset of mental health problems, with variations in pubertal timing and tempo intensifying this risk. We conducted 2 systematic reviews of articles published up to February 1, 2024, focusing on 1) the role of brain structure in the relationship between puberty and mental health, and 2) precision psychiatry research evaluating the utility of puberty in making individualized predictions of mental health outcomes in young people. The first review provides inconsistent evidence about whether and how pubertal and psychopathological processes may interact in relation to brain development. While most studies found an association between early puberty and mental health difficulties in adolescents, evidence on whether brain structure mediates this relationship is mixed. The pituitary gland was found to be associated with mental health status during this time, possibly through its central role in regulating puberty and its function in the hypothalamic-pituitary-gonadal and hypothalamic-pituitary-adrenal axes. In the second review, the design of studies that have explored puberty in predictive models did not allow for a quantification of its predictive power. However, when puberty was evaluated through physically observable characteristics rather than hormonal measures, it was more commonly identified as a predictor of depression, anxiety, and suicidality in adolescence. Social processes may be more relevant than biological ones to the link between puberty and mental health problems and represent an important target for educational strategies.

Geneenvironment interaction between phthalate exposure and pubertal genetic polymorphisms on blood pressure variability in children: Exploring the moderating effects of lifestyle behaviours

Phthalates (PAEs) are synthetic compounds extensively employed in consumer products. Blood pressure (BP) in children can vary, the degree of visit-to-visit BP variability (VVV) is at least partially independent of BP. The interactions between PAEs exposure, pubertal-related genetic susceptibility and lifestyles on childhood VVV are not investigated. This study utilized data from a cohort collected from Oct 2017-2020 in Xiamen, China. Seven urine PAE metabolites were measured. The long-term VVV was characterized employing the standard deviation (SD) and average real variability. We constructed a genetic risk score (GRS) of pubertal-related genes and healthy lifestyle scores. Exposed to high levels of mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP) (OR=1.43, 95 %CI=1.07, 1.92) and mono-2-ethyl-5-oxohexyl phthalate (OR=1.36, 95 % CI=1.01, 1.83) was related to increased SBP-SD, and the OR for high SBP-SD related to high GRS was 1.38 (95 % CI=1.02, 1.85). Compared to participants who had low GRS and low MEHHP exposure, participants exhibiting high GRS and MEHHP levels were more likely to experience high SBP-SD (OR=2.00, P<0.05). Individuals exhibiting low GRS, low MEHHP levels, and adhering to healthy lifestyles were associated with the least probability of experiencing high SBP-SD (OR=0.31, P<0.05). Increased PAEs exposure could elevate childhood systolic VVV, and exacerbated the adverse impact of pubertal-related genetic susceptibility on the high VVV of SBP; however, healthy lifestyles might alleviate these adverse effects. Promoting healthy lifestyles and reducing PAEs exposure for preventing elevated BP variability among children is important, especially for individuals with greater genetic susceptibility to early pubertal onset. ENVIRONMENTAL IMPLICATION: Blood pressure (BP) in children can vary, as a noninvasive, inexpensive and applicable method, the extent of visit-to-visit variability (VVV) is at least partially independent of BP. The interactions between phthalates (PAEs) exposure, variants of puberty-related genes and lifestyles on VVV are not investigated. Increased childhood systolic VVV might be associated with PAEs exposure, with the associations more pronounced combined with pubertal genetic susceptibility. Yet, healthy habits could partly eliminate such adverse effects. Our study underscores the importance of advocating for healthy lifestyles and reducing exposure to PAEs, especially among individuals with high genetic susceptibility to early puberty onset.

Early puberty: a review on its role as a risk factor for metabolic and mental disorders

Accumulating evidence indicates that there is a trend of early puberty onset in humans. The early timing of puberty has raised concerns due to its association with significant negative health outcomes. However, overall impact and potential risk of early puberty remain uncertain. In this study, we conducted a comprehensive review of existing epidemiological studies to gain insights into the long-term adverse health effects associated with early puberty. Our objective was to provide a consolidated summary of these outcomes at a population level by considering studies that encompass various indicators of puberty. In all, early puberty has been identified as a potential risk factor for various metabolic diseases, such as obesity, diabetes, cardiovascular diseases (CVD). Children who experience early puberty are more likely to have a higher body mass index (BMI) during adulthood, increasing their risk of obesity. Early puberty also has been found to be an independent risk factor for diabetes mellitus, including gestational diabetes mellitus (GDM) and type 2 diabetes mellitus (T2DM), as earlier onset of menarche in girls and voice breaking in boys is associated with a higher prevalence of T2DM. Furthermore, evidence suggests that early puberty may contribute to an elevated risk of CVD, including conditions like coronary heart disease (CHD), stroke, angina, and hypertension. In addition, adolescents who experience early puberty, particularly girls, are more likely to suffer from mental problems, such as behavioral dysfunction and depression. Notably, early puberty has a more significant impact on girls than boys. Further research should consider the underlying mechanisms and potential preventive measures.

Effects of Heat Stress-Induced Sex Hormone Dysregulation on Reproduction and Growth in Male Adolescents and Beneficial Foods

Heat stress due to climate warming can significantly affect the synthesis of sex hormones in male adolescents, which can impair the ability of the hypothalamus to secrete gonadotropin-releasing hormone on the hypothalamic-pituitary-gonadal axis, which leads to a decrease in luteinizing hormone and follicle-stimulating hormone, which ultimately negatively affects spermatogenesis and testosterone synthesis. For optimal spermatogenesis, the testicular temperature should be 2-6 °C lower than body temperature. Heat stress directly affects the testes, damaging them and reducing testosterone synthesis. Additionally, chronic heat stress abnormally increases the level of aromatase in Leydig cells, which increases estradiol synthesis while decreasing testosterone, leading to an imbalance of sex hormones and spermatogenesis failure. Low levels of testosterone in male adolescents lead to delayed puberty and incomplete sexual maturation, negatively affect height growth and bone mineral density, and can lead to a decrease in lean body mass and an increase in fat mass. In order for male adolescents to acquire healthy reproductive capacity, it is recommended to provide sufficient nutrition and energy, avoid exposure to heat stress, and provide foods and supplements to prevent or repair testosterone reduction, germ cell damage, and sperm count reduction caused by heat stress so that they can enter a healthy adulthood.

Menstrual Dysfunction in Adolescent Female Athletes

Despite the benefits of exercise on mental and physical health, excessive training loads can lead to health problems in the long term, including a wide spectrum of menstrual dysfunction (MD). This narrative review aims to analyze the relationship between physical exercise and MD in adolescent female athletes to support regular menstrual health monitoring and promote educational programs on reproductive risks. When dealing with MD in young athletes, several factors entangled with maturation of the hypothalamus-pituitary-ovarian axis should be considered. Firstly, some disciplines seem to have a higher prevalence of MD due to the high loads of training regimes and the early introduction of athletes to a competitive career. Moreover, low energy intake and a low body mass index appear to exacerbate existing MD. Lastly, disordered eating behaviors and psychological stress can contribute to MD in female athletes. The type of sport, influencing the intensity and duration of exercise, as well as individual psycho-physiological and environmental factors, may influence the role of physical activity in the manifestation of MD. Early recognition and management of MD, along with collaboration between sports organizations and health professionals, are crucial to minimize risks, ensure proper nutrition, and balance training with recovery. Keeping an open discussion on the topic may prospectively improve awareness, early diagnosis, and treatment strategies, as well as reduce injury risk and enhance sports performance.

Transcriptome analysis reveals miRNA expression profiles in hypothalamus tissues during the sexual development of Jining grey goats

BACKGROUND

Exploring the physiological and molecular mechanisms underlying goat sexual maturation can enhance breeding practices and optimize reproductive efficiency and is therefore substantially important for practical breeding purposes. As an essential neuroendocrine organ in animals, the hypothalamus is involved in sexual development and other reproductive processes in female animals. Although microRNAs (miRNAs) have been identified as significant regulators of goat reproduction, there is a lack of research on the molecular regulatory mechanisms of hypothalamic miRNAs that are involved in the sexual development of goats. Therefore, we examined the dynamic changes in serum hormone profiles and hypothalamic miRNA expression profiles at four developmental stages (1 day (neonatal, D1, n = 5), 2 months (prepubertal, M2, n = 5), 4 months (sexual maturity, M4, n = 5), and 6 months (breeding period, M6, n = 5)) during sexual development in Jining grey goats.

RESULTS

Transcriptome analysis revealed 95 differentially expressed miRNAs (DEMs) in the hypothalamus of goats across the four developmental stages. The target genes of these miRNAs were significantly enriched in the GnRH signalling pathway, the PI3K-Akt signalling pathway, and the Ras signalling pathway (P < 0.05). Additionally, 16 DEMs are common among the M2 vs. D1, M4 vs. D1, and M6 vs. D1 comparisons, indicating that the transition from D1 to M2 represents a potentially critical period for sexual development in Jining grey goats. The bioinformatics analysis results indicate that miR-193a/miR-193b-3p-Annexin A7 (ANXA7), miR-324-5p-Adhesion G protein-coupled receptor A1 (ADGRA1), miR-324-3p-Erbb2 receptor tyrosine kinase 2 (ERBB2), and miR-324-3p-Rap guanine nucleotide exchange factor 3 (RAPGEF3) are potentially involved in biological processes such as hormone secretion, energy metabolism, and signal transduction. In addition, we further confirmed that miR-324-3p targets the regulatory gene RAPGEF3.

CONCLUSION

These results further enrich the expression profile of hypothalamic miRNAs in goats and provide important insights for studying the regulatory effects of hypothalamic miRNAs on the sexual development of goats after birth.

Effects of chronic exposure to a high fat diet, nutritive or non-nutritive sweeteners on hypothalamic-pituitary-adrenal (HPA) and -gonadal (HPG) axes of male Sprague-Dawley rats

PURPOSE

Diet-related factors are of great significance in the regulation of hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonad (HPG) axes. In this study, we aimed to investigate the effects of chronic exposure to a high fat diet (HFD), fructose or sucralose on the endocrine functions.

METHODS

Male, Sprague-Dawley rats received a normal chow diet, HFD, 10% fructose or 0.02% sucralose for 10 weeks. Behavioral changes were assessed by open field (OFT) and elevated plus-maze (EPM) tests at week 8. H&E staining was used to observe pathological changes in adrenal cortex, testis and perirenal adipose tissue. Serum hormone concentrations were quantified via enzyme-linked immunosorbent assay (ELISA). The mRNA expression levels of genes along the HPA and HPG axes were determined using real-time PCR.

RESULTS

All types of dietary interventions increased body weight and disturbed metabolic homeostasis, with anxiogenic phenotype in behavioral tests and damage to cell morphology of adrenal cortex and testis being observed. Along the HPA axis, significantly increased corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and corticosterone (CORT) concentrations were observed in the HFD or 0.02% sucralose group. For HPG axis, gonadotropin-releasing hormone (GnRH) and estradiol (E2) concentrations were significantly increased in all dietary intervention groups, while decreased concentrations of follicle-stimulating hormone (FSH) and testosterone (T) were also detected. Moreover, transcriptional profiles of genes involved in the synthesis of hormones and corresponding hormone receptors were significantly altered.

CONCLUSION

Long-term consumption of HFD, fructose or sucralose manifested deleterious effects on endocrine system and resulted in the dysregulation of HPA and HPG axes.

Parabens effects on female reproductive health - Review of evidence from epidemiological and rodent-based studies

Parabens have been used as antimicrobial preservatives since the 1920s. The prevalent use of parabens increases their detection in the environment and in women's biological samples including reproductive tissues. Recent studies suggest parabens may alter endocrine function and thus female reproductive health may be affected. In this literature review, we summarize findings on parabens and female reproduction while focusing on epidemiological and rodent-based studies. The topics reviewed include paraben effects on cyclicity, pregnancy, newborn and pubertal development, reproductive hormones, and ovarian and uterine specific outcomes. Overall, the scientific literature on paraben effects on female reproduction is limited and with some conflicting results. Yet, some epidemiological and/or rodent-based experimental studies report significant findings in relation to paraben effects on cyclicity, fertility, gestation length, birth weight, postnatal development and pubertal onset, hormone levels, and hormone signaling in reproductive tissues. Future epidemiological and experimental studies are needed to better understand paraben effects on female reproduction while focusing on human related exposures including mixtures, physiologic concentrations of parabens, and multi-generational studies.

Association of obesity and menarche SNPs and interaction with environmental factors on precocious puberty

BACKGROUND

Obesity is an important cause for the precocious or early puberty. However, the association between obesity-related loci and the risk of precocious puberty as well as the effect of gene-environment interaction are unclear, especially in the Chinese children population.

METHODS

This was a case-control study using baseline data from two cohorts and hospital cases in China. 15 SNPs loci and several environmental factors were included in the analysis of 1201 participants. Chi-square test and logistic regression were used to analyze the association between SNPs and precocious puberty. Additionally, exploratory factor analysis was conducted on 13 environmental variables, and then to explore their interaction with genes on precocious puberty.

RESULTS

The effect allele C of rs571312, and G of rs12970134 MC4R were associated with precocious puberty in girls with obesity. Regarding the gene-environment interaction, we found that when girls were in the high socioeconomic status, the rs571312 (OR: 3.996; 95% CI: 1.694-9.423) and rs12970134 (OR: 3.529; 95% CI: 1.452-8.573) risk genotypes had a greater effect on precocious puberty.

CONCLUSIONS

The obesity risk gene polymorphisms MC4R rs571312 and rs12970134 were associated with precocious puberty in Chinese girls with obesity, and girls with risk genotypes and high socioeconomic status should be given extra attention.

IMPACT

This is the first study that identified the association between rs571312 and rs12970134 of MC4R gene and precocious puberty in Chinese children. We found that when girls were in the high socioeconomic status, the risk genotypes of rs571312 and rs12970134 had a greater effect on precocious puberty. The results of this study have great public health implications. It is recommended that girls who are in high socioeconomic status and have a high genetic risk for early sexual maturity should closely monitor their pubertal development and consider early intervention strategies.

Identification of Environmental Compounds That May Trigger Early Female Puberty by Activating Human GnRHR and KISS1R

There has been an alarming trend toward earlier puberty in girls, suggesting the influence of an environmental factor(s). As the reactivation of the reproductive axis during puberty is thought to be mediated by the hypothalamic neuropeptides kisspeptin and gonadotropin-releasing hormone (GnRH), we asked whether an environmental compound might activate the kisspeptin (KISS1R) or GnRH receptor (GnRHR). We used GnRHR or KISS1R-expressing HEK293 cells to screen the Tox21 10K compound library, a compendium of pharmaceuticals and environmental compounds, for GnRHR and KISS1R activation. Agonists were identified using Ca2+ flux and phosphorylated extracellularly regulated kinase (p-ERK) detection assays. Follow-up studies included measurement of genes known to be upregulated upon receptor activation using relevant murine or human cell lines and molecular docking simulation. Musk ambrette was identified as a KISS1R agonist, and treatment with musk ambrette led to increased expression of Gnrh1 in murine and human hypothalamic cells and expansion of GnRH neuronal area in developing zebrafish larvae. Molecular docking demonstrated that musk ambrette interacts with the His309, Gln122, and Gln123 residues of the KISS1R. A group of cholinergic agonists with structures similar to methacholine was identified as GnRHR agonists. When applied to murine gonadotrope cells, these agonists upregulated Fos, Jun, and/or Egr1. Molecular docking revealed a potential interaction between GnRHR and 5 agonists, with Asn305 constituting the most conservative GnRHR binding site. In summary, using a Tox21 10K compound library screen combined with cellular, molecular, and structural biology techniques, we have identified novel environmental agents that may activate the human KISS1R or GnRHR.

Evaluating Phthalates and Bisphenol in Foods: Risks for Precocious Puberty and Early-Onset Obesity

Recent scientific results indicate that diet is the primary source of exposure to endocrine-disrupting chemicals (EDCs) due to their use in food processing, pesticides, fertilizers, and migration from packaging to food, particularly in plastic or canned foods. Although EDCs are not listed on nutrition labels, their migration from packaging to food could inadvertently lead to food contamination, affecting individuals by inhalation, ingestion, and direct contact. The aim of our narrative review is to investigate the role of phthalates and bisphenol A (BPA) in foods, assessing their risks for precocious puberty (PP) and early-onset obesity, which are two clinical entities that are often associated and that share common pathogenetic mechanisms. The diverse outcomes observed across different studies highlight the complexity of phthalates and BPA effects on the human body, both in terms of early puberty, particularly in girls, and obesity with its metabolic disruptions. Moreover, obesity, which is independently linked to early puberty, might confound the relationship between exposure to these EDCs and pubertal timing. Given the potential public health implications, it is crucial to adopt a precautionary approach, minimizing exposure to these EDCs, especially in vulnerable populations such as children.

Evaluation and comparison of nine growth and development-based measures of pubertal timing

BACKGROUND

Pubertal timing is heritable, varies between individuals, and has implications for life-course health. There are many different indicators of pubertal timing, and how they relate to each other is unclear. Our aim was to quantitatively compare nine indicators of pubertal timing.

METHODS

We used data from questionnaires and height, weight, and bone measurements from ages 7-17 y in a population-based cohort of 4267 females and 4251 males to compare nine growth and development-based indicators of pubertal timing. We summarise age of each indicator, their phenotypic and genetic correlations, and how they relate to established genetic risk score (GRS) for puberty timing, and phenotypic childhood body composition measures.

RESULTS

We show that pubic hair in males (mean: 12.6 y) and breasts in females (11.5 y) are early indicators of puberty, and voice breaking (14.2 y) and menarche (12.7 y) are late indicators however, there is substantial variation between individuals in pubertal age. All indicators show evidence of positive phenotypic intercorrelations (e.g., r = 0.49: male genitalia and pubic hair ages), and positive genetic intercorrelations. An age at menarche GRS positively associates with all other pubertal age indicators (e.g., difference in female age at peak height velocity per SD higher GRS: 0.24 y, 95%CI: 0.21 to 0.26), as does an age at voice breaking GRS (e.g., difference in age at male axillary hair: 0.11 y, 0.07 to 0.15). Higher childhood fat mass and lean mass associated with earlier puberty timing.

CONCLUSIONS

Our findings provide insights into the measurements of the timing of pubertal growth and development and illustrate value of various pubertal timing indicators in life-course research.

Novel variants ensued genomic imprinting in familial central precocious puberty

INTRODUCTION

Central precocious puberty (CPP) is characterized by the early onset of puberty and is associated with the critical processes involved in the pubertal switch. The puberty-related gene pool in the human genome is considerably large though few have been described in CPP. Within those genes, the genomic imprinting features of the MKRN3 and DLK1 genes add additional complexity to the understanding of the pathologic pathways. This study aimed to investigate the molecular etiology in the CPP cohort.

METHODS

Eighteen familial CPP cases were investigated by Sanger sequencing for five CPP-related genes; DLK1, KISS1, KISS1R, MKRN3, and PROKR2. Segregation analysis was performed in all patients with pathogenic variants. Using an ELISA test, the functional pathogenicity of novel variants was also investigated in conjunction with serum delta-like 1 homolog (DLK1) concentrations.

RESULTS

In three probands, a known variant in the MKRN3 gene (c.982C>T/p.(Arg328Cys)) and two novel variants in the DLK1 gene (c.357C>G/p.(Tyr119Ter) and c.67+78C>T) were identified. All three were inherited from the paternal allele. The individuals carrying the DLK1 variants had low detectable DLK1 levels in their serum.

CONCLUSIONS

The frequencies were 5.5% (1/18) for MKRN3 11% (2/18) for DLK1, and none for either KISS1, KISS1R, and PROKR2. Low serum DLK1 levels in affected individuals supported the relationship between here described novel DLK1 gene variants with CPP. Nonsense nature of c.357C>G/p.(Tyr119Ter) and an alteration in the evolutionarily conserved nucleotide c.67+78C>T suggested the disruptive nature of the variant's compatibility with CPP.

Adolescent gut microbiome imbalance and its association with immune response in inflammatory bowel diseases and obesity

BACKGROUND

Recently, there has been an increase in the number of studies focusing on the association between the gut microbiome and obesity or inflammatory diseases, especially in adults. However, there is a lack of studies investigating the association between gut microbiome and gastrointestinal (GI) diseases in adolescents.

METHOD

We obtained 16S rRNA-seq datasets for gut microbiome analysis from 202 adolescents, comprising ulcerative colitis (UC), Crohn's disease (CD), obesity (Ob), and healthy controls (HC). We utilized Quantitative Insights Into Microbial Ecology (QIIME) and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) to acquire Operational Taxonomic Units (OTUs). Subsequently, we analyzed Kyoto Encyclopedia of Genes and Genomes (KEGG) Orthology (KO) terms and pathway enrichment for the identified OTUs.

RESULTS

In this study, we investigated the difference between the gut microbiomes in adolescents with GI diseases and those in healthy adolescents using 202 samples of 16S rRNA sequencing data. The distribution of the six main gut microbiota (i.e., unclassified Dorea, unclassified Lachnospiraceae, unclassified Ruminococcus, Faecalibacterium prausnitzii, Prevotella copri, unclassified Sutterella) was different based on the status of obesity and inflammatory diseases. Dysbiosis was observed within Lachnospiraceae in adolescents with inflammatory diseases (i.e., UC and CD), and in adolescents with obesity within Prevotella and Sutterella. More specifically, our results showed that the relative abundance of Faecalibacterium prausnitzii and unclassified Lachnospiraceae was more than 10% and 8% higher, respectively, in the UC group compared to the CD, Ob, and HC groups. Additionally, the Ob group had over 20% and over 3% higher levels of Prevotella copri and unclassified Sutterella, respectively, compared to the UC, CD, and HC groups. Also, inspecting associations between the six specific microbiota and KO terms, we found that the six microbiota -relating KO terms were associated with NOD-like receptor signaling. These six taxa differences may affect the immune system and inflammatory response by affecting NOD-like receptor signaling in the host during critical adolescence.

CONCLUSION

In this study, we discovered that dysbiosis of the microbial community had varying degrees of influence on the inflammatory and immune response pathways in adolescents with inflammatory diseases and obesity.

Mini-Puberty, Physiological and Disordered: Consequences, and Potential for Therapeutic Replacement

There are 3 physiological waves of central hypothalamic-pituitary-gonadal (HPG) axis activity over the lifetime. The first occurs during fetal life, the second-termed "mini-puberty"-in the first months after birth, and the third at puberty. After adolescence, the axis remains active all through adulthood. Congenital hypogonadotropic hypogonadism (CHH) is a rare genetic disorder characterized by a deficiency in hypothalamic gonadotropin-releasing hormone (GnRH) secretion or action. In cases of severe CHH, all 3 waves of GnRH pulsatility are absent. The absence of fetal HPG axis activation manifests in around 50% of male newborns with micropenis and/or undescended testes (cryptorchidism). In these boys, the lack of the mini-puberty phase accentuates testicular immaturity. This is characterized by a low number of Sertoli cells, which are important for future reproductive capacity. Thus, absent mini-puberty will have detrimental effects on later fertility in these males. The diagnosis of CHH is often missed in infants, and even if recognized, there is no consensus on optimal therapeutic management. Here we review physiological mini-puberty and consequences of central HPG axis disorders; provide a diagnostic approach to allow for early identification of these conditions; and review current treatment options for replacement of mini-puberty in male infants with CHH. There is evidence from small case series that replacement with gonadotropins to mimic "mini-puberty" in males could have beneficial outcomes not only regarding testis descent, but also normalization of testis and penile sizes. Moreover, such therapeutic replacement regimens in disordered mini-puberty could address both reproductive and nonreproductive implications.

Long-term exposure to air pollution and precocious puberty in South Korea

BACKGROUND AND AIM

The increasing prevalence of precocious puberty (PP) has emerged as a significant medical and social problem worldwide. However, research on the relationship between long-term air pollution exposure and PP has been relatively limited. We thus investigated the association between long-term air pollution exposure and the onset of PP in South Korea.

METHODS

We investigated a retrospective cohort using the Korea National Health Insurance Database. Six-year-old children born from 2007 to 2009 were examined (2013-2015). We included boys ≤10 years and girls aged ≤9 years who visited hospitals for early pubertal development, were diagnosed with PP per the ICD-10 (E228, E301, and E309), and received gonadotropin-releasing hormone agonist treatment. We analyzed data for boys up until 10 years old (60-month follow-up) and for girls up to 9 years old (48-month follow-up). We assessed the association between long-term air pollution exposure and the onset of PP using a Cox proportional hazard model. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) per 1 μg/m3 increase in fine particulate matter (PM2.5) and particulate matter (PM10) and per 1 ppb increase in sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3).

RESULTS

This study included 1,205,784 children aged six years old between 2013 and 2015. A positive association was found between the 48-month moving average PM2.5 (HR: 1.019; 95% CI: 1.012, 1.027), PM10 (HR: 1.009; 95% CI: 1.006, 1.013), SO2 (HR: 1.037; 95% CI: 1.018, 1.055), and O3 (HR: 1.006; 95% CI: 1.001, 1.010) exposure and PP in girls but not boys.

CONCLUSIONS

This study provides valuable insights into the harmful effects of air pollution during childhood and adolescence, emphasizing that air pollution is a risk factor that should be managed and reduced.

Nasal application of kisspeptin-54 mitigates motor deficits by reducing nigrostriatal dopamine loss in hemiparkinsonian rats

Parkinson's Disease is a progressive neurodegenerative disorder characterized by motor symptoms resulting from the loss of nigrostriatal dopaminergic neurons. Kisspeptins (KPs) are a family of neuropeptides that are encoded by the Kiss-1 gene, which exert their physiological effects through interaction with the GPR54 receptor. In the current investigation, we investigated the prospective protective effects of central KP-54 treatments on nigrostriatal dopaminergic neurons and consequent motor performance correlates in 6-hydroxydopamine (6-OHDA)-lesioned rats. Male adult Sprague Dawley rats underwent stereotaxic injection of 6-OHDA into the right medial forebrain bundle to induce hemiparkinsonism. Following surgery, rats received chronic central treatments of nasal or intracerebroventricular KP-54 (logarithmically increasing doses) for seven consecutive days. Motor performance was evaluated seven days post-surgery utilizing the open field test and catalepsy test. The levels of dopamine in the striatum were determined with mass spectrometry. Immunohistochemical analysis was conducted to assess the immunoreactivities of tyrosine hydroxylase (TH) and the GPR54 in the substantia nigra. The dose-response curve revealed a median effective dose value of ≈3 nmol/kg for both central injections. Due to its non-invasive and effective nature, nasal administration was utilized in the second phase of our study. Chronic administration of KP-54 (3nmol/kg, nasally) significantly protected 6-OHDA-induced motor deficits. Nasal KP-54 attenuated the loss of nigrostriatal dopaminergic neurons induced by 6-OHDA. Additionally, significant correlations were observed between motor performance and nigrostriatal dopamine levels. Immunohistochemical analysis demonstrated the localization of the GPR54 within TH-positive nigral cells. These findings suggest the potential efficacy of central KP-54 on motor impairments in hemiparkinsonism.

Methylome analysis in girls with idiopathic central precocious puberty

BACKGROUND

Genetic and environmental factors are implicated in many developmental processes. Recent evidence, however, has suggested that epigenetic changes may also influence the onset of puberty or the susceptibility to a wide range of diseases later in life. The present study aims to investigate changes in genomic DNA methylation profiles associated with pubertal onset analyzing human peripheral blood leukocytes from three different groups of subjects: 19 girls with central precocious puberty (CPP), 14 healthy prepubertal girls matched by age and 13 healthy pubertal girls matched by pubertal stage. For this purpose, the comparisons were performed between pre- and pubertal controls to identify changes in normal pubertal transition and CPP versus pre- and pubertal controls.

RESULTS

Analysis of methylation changes associated with normal pubertal transition identified 1006 differentially methylated CpG sites, 86% of them were found to be hypermethylated in prepubertal controls. Some of these CpG sites reside in genes associated with the age of menarche or transcription factors involved in the process of pubertal development. Analysis of methylome profiles in CPP patients showed 65% and 55% hypomethylated CpG sites compared with prepubertal and pubertal controls, respectively. In addition, interestingly, our results revealed the presence of 43 differentially methylated genes coding for zinc finger (ZNF) proteins. Gene ontology and IPA analysis performed in the three groups studied revealed significant enrichment of them in some pathways related to neuronal communication (semaphorin and gustation pathways), estrogens action, some cancers (particularly breast and ovarian) or metabolism (particularly sirtuin).

CONCLUSIONS

The different methylation profiles of girls with normal and precocious puberty indicate that regulation of the pubertal process in humans is associated with specific epigenetic changes. Differentially methylated genes include ZNF genes that may play a role in developmental control. In addition, our data highlight changes in the methylation status of genes involved in signaling pathways that determine the migration and function of GnRH neurons and the onset of metabolic and neoplastic diseases that may be associated with CPP in later life.

The Association between Autism Spectrum Disorder and Precocious Puberty: Considering Effect Modification by Sex and Neuropsychiatric Comorbidities

Limited knowledge is available about the association between autistic spectrum disorder (ASD) and precocious puberty. Our study examined the association between the two medical conditions and effect modification by sex and neuropsychiatric comorbidities in a nationwide population. To compare the risk of precocious puberty between ASD and non-ASD cases, we conducted a Cox regression analysis using ASD as the exposure and time to precocious puberty as the outcome. We adjusted for sex, attention-deficit/hyperactivity disorder (ADHD), tic disorder, obsessive-compulsive disorder (OCD), anxiety disorder, intellectual disability, and epilepsy. We performed a moderation analysis to examine the potential moderating effects of sex and comorbidities. Patients with ASD were prone to have precocious puberty, with an adjusted hazard ratio (aHR) of 1.80 (95% CI: 1.61-2.01). For effect modification, sex, specifically females, moderated the association between ASD and precocious puberty, with a relative excess risk due to interaction (RERI) of 7.35 (95% CI 4.90-9.80). No significant effect modification was found for any of the comorbidities within the scope of additive effect modification. We found that patients with ASD were prone to precocious puberty, regardless of sex or comorbid neuropsychiatric disorders. Girls with ASD are at a particularly higher risk of developing precocious puberty.

Temporal trend of age at menarche in Korean females born between 1927 and 2004: a population-based study

Backgrounds

The age at menarche has decreased worldwide. Previous studies on Korean adolescents have reported a downward trend in age at menarche. This study aimed to investigate the current trends in age at menarche among Korean adolescents using nationally representative data.

Materials and methods

The study used data from the Korea National Health and Nutrition Examination Survey 2007-2021. A total of 50,730 females born between 1927 and 2004 with information on age at menarche were included. The trend in age at menarche was analyzed according to 15 birth-year groups (with 5-year intervals) using quantile regression analysis.

Results

The mean age at menarche decreased from 16.92 ± 0.06 years for females born before 1935 to 12.45 ± 0.04 years for females born between 2000 and 2004 (p <.001). According to the percentile group of age at menarche, mean menarche age decreased by -0.071 years per year (95% confidence interval [CI], -0.072 to -0.070) in total, -0.050 years per year (95% CI, -0.052 to -0.048) in the 3rd percentile group, -0.088 years per year (95% CI, -0.091 to -0.085) in the 97th percentile group (p <.001 for all). A decreasing trend of age at menarche was more prominent in the obesity group (-0.080 years per year, 95% CI, -0.082 to -0.078) compared to the non-obesity group (-0.069 years per year, 95% CI, -0.071 to -0.068) (p <.001 for both).

Conclusion

Ongoing downward trend in age at menarche was observed in Korean females born until 2004, decreasing by 0.71 years per decade. The downward trend was faster in individuals with a higher percentile of age at menarche and in those with obesity.

Menarche-a journey into womanhood: age at menarche and health-related outcomes in East Asians

STUDY QUESTION

Are there associations of age at menarche (AAM) with health-related outcomes in East Asians?

SUMMARY ANSWER

AAM is associated with osteoporosis, Type 2 diabetes (T2D), glaucoma, and uterine fibroids, as demonstrated through observational studies, polygenic risk scores, genetic correlations, and Mendelian randomization (MR), with additional findings indicating a causal effect of BMI and T2D on earlier AAM.

WHAT IS KNOWN ALREADY

Puberty timing is linked to adult disease risk, but research predominantly focuses on European populations, with limited studies in other groups.

STUDY DESIGN, SIZE, DURATION

We performed an AAM genome-wide association study (GWAS) with 57 890 Han Taiwanese females and examined the association between AAM and 154 disease outcomes using the Taiwanese database. Additionally, we examined genetic correlations between AAM and 113 diseases and 67 phenotypes using Japanese GWAS summary statistics.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We performed AAM GWAS and gene-based GWAS studies to obtain summary statistics and identify potential AAM-related genes. We applied phenotype, polygenic risk scores, and genetic correlation analyses of AAM to explore health-related outcomes, using multivariate regression and linkage disequilibrium score regression analyses. We also explored potential bidirectional causal relationships between AAM and related outcomes through univariable and multivariable MR analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

Fifteen lead single-nucleotide polymorphisms and 24 distinct genes were associated with AAM in Taiwan. AAM was genetically associated with later menarche and menopause, greater height, increased osteoporosis risk, but lower BMI, and reduced risks of T2D, glaucoma, and uterine fibroids in East Asians. Bidirectional MR analyses indicated that higher BMI/T2D causally leads to earlier AAM.

LIMITATIONS, REASONS FOR CAUTION

Our findings were specific to Han Taiwanese individuals, with genetic correlation analyses conducted in East Asians. Further research in other ethnic groups is necessary.

WIDER IMPLICATIONS OF THE FINDINGS

Our study provides insights into the genetic architecture of AAM and its health-related outcomes in East Asians, highlighting causal links between BMI/T2D and earlier AAM, which may suggest potential prevention strategies for early puberty.

STUDY FUNDING/COMPETING INTEREST(S)

The work was supported by China Medical University, Taiwan (CMU110-S-17, CMU110-S-24, CMU110-MF-49, CMU111-SR-158, CMU111-MF-105, CMU111-MF-21, CMU111-S-35, CMU112-SR-30, and CMU112-MF-101), the China Medical University Hospital, Taiwan (DMR-111-062, DMR-111-153, DMR-112-042, DMR-113-038, and DMR-113-103), and the Ministry of Science and Technology, Taiwan (MOST 111-2314-B-039-063-MY3, MOST 111-2314-B-039-064-MY3, MOST 111-2410-H-039-002-MY3, and NSTC 112-2813-C-039-036-B). The funders had no influence on the data collection, analyses, or conclusions of the study. No conflict of interests to declare.

TRIAL REGISTRATION NUMBER

N/A.

Normal Puberty

Puberty is characterized by gonadarche and adrenarche. Gonadarche represents the reactivation of the hypothalamic-pituitary-gonadal axis with increased gonadotropin-releasing hormone, luteinizing hormone, and follicle-stimulating hormone secretion following the quiescence during childhood. Pubarche is the development of pubic hair, axillary hair, apocrine odor reflecting the onset of pubertal adrenal maturation known as adrenarche. A detailed understanding of these pubertal processes will help clarify relationships between the timing of the onset of puberty and cardiovascular, metabolic, and reproductive outcomes in adulthood. The onset of gonadarche is influenced by neuroendocrine signals, genetic variants, metabolic factors, and environmental elements.