Worldwide Secular Trends in Age at Pubertal Onset Assessed by Breast Development Among Girls: A Systematic Review and Meta-analysis

The effects of pharmacologic estradiol on anxiety-related behavior in adolescent and adult female mice

Early pubertal onset during adolescence is consistently linked with increased risk of anxiety and depression in girls. Although estradiol tends to have anxiolytic effects on behavior in adulthood, whether estradiol's anxiolytic actions change pre- to post-adolescent development is not clear. Using a rodent model, the current study tested whether anxiety-like responses to estradiol differ before and after adolescence in female mice. Prepubertal and adult C57BL/6 mice were ovariectomized, implanted with vehicle- or estradiol-filled silastic capsules, and behavioral tested 6 days later in the open field and elevated zero maze. A pharmacologic dose of estradiol was administered in silastic capsules (0.72 μg/0.02 mL) to maximize behavioral responses at both ages. In the open field, estradiol implants decreased anxiety-like behavior in adolescent females (relative to vehicle) and had negligible effects on anxiety-related behavior in adult females. These data suggest that adolescence is associated with changes in behavioral responsiveness to estradiol. In the elevated zero maze, adolescent females displayed higher levels of anxiety-like behavior than adults, irrespective of estradiol treatment. These findings demonstrate that substantial changes in anxiety-related behavior occur during adolescence, including an assay-dependent shift in behavioral responsiveness to estradiol.

Differentiating true precocious puberty and puberty variants in consecutive 275 girls: a single center experience

OBJECTIVES

This study aimed to identify clinical features of girls referred to a pediatric endocrinology clinic for suspected precocious puberty, differentiate true precocious puberty from other variants, evaluate treatment status, and identify distinguishing factors between patient groups.

METHODS

We retrospectively evaluated the records of 275 consecutive girls aged 0-10 years referred for suspected precocious puberty.

RESULTS

Among the patients, 30 (10.9 %) were diagnosed with precocious puberty, 35 (12.7 %) with premature adrenarche, 22 (8 %) with premature thelarche, 33 (12 %) with rapidly progressing early puberty, 108 (39.3 %) with early puberty, and 47 (17.1 %) had a normal diagnosis. Precocious puberty was associated with higher rates of overweight/obesity (p=0.002), advanced bone age (p<0.001), height SD, and mid-parental height SD difference (p<0.001), as well as a history of preterm birth (p=0.041). Patients with rapidly progressing early puberty had mothers with a lower age at menarche (p=0.040). No significant differences were found for being born small for gestational age, maternal polycystic ovary syndrome, screen time, and junk food consumption (p>0.05). Treatment was recommended for 32 patients (11.6 %), including 11 with precocious puberty and 21 with rapidly progressing early puberty.

CONCLUSIONS

Most patients referred for early pubertal development are diagnosed with normal puberty or its variants. Assessing preterm birth, early maternal menarche age, and advanced bone age helps identify true precocious puberty and rapidly progressing early puberty, aiding timely treatment.

Maternal asthma in pregnancy and pubertal timing in daughters and sons: a population-based cohort study

PURPOSE

We investigated the impact of maternal asthma on children's pubertal timing as it remains underexplored.

METHODS

The Danish National Birth Cohort (DNBC) provided information on maternal asthma during pregnancy, supplemented with diagnosis codes from the Danish National Patient Register. The DNBC sub-cohort the Puberty Cohort gave half-yearly information on pubertal timing from 11 years. We estimated adjusted mean age differences in months for reaching Tanner Stages 1-5 for breast, genital and pubic hair development, axillary hair, acne, and voice break, and menarche for daughters, and first ejaculation for sons. Further, a negative control analysis explored confounding, and two mediation analyses explored mediation through birthweight and childhood asthma.

RESULTS

In total, 15,819 children and their mothers participated and 6.6% of the children had mothers with asthma. Results indicated slightly later pubertal development in sons of mothers with asthma (average difference: 1.0 months (95% confidence intervals -0.4, 2.4)). This association was not mediated by birthweight or childhood asthma. We did not observe any associations among daughters. The negative control analysis suggested some confounding towards the null.

CONCLUSION

Sons of mothers with asthma during pregnancy had slightly later pubertal timing, though the result could also indicate no association.

Difference in precocious puberty between pre-COVID-19 and COVID-19 periods: a meta-analysis

We conducted this systematic review and meta-analysis to clarify the trend of precocious puberty (PP) incidence after the COVID-19 outbreak and explore potential contributing factors, such as age at presentation and body mass index (BMI) SD score (SDS). Children visiting pediatric endocrinology clinics for the first time for suspected PP were included. We searched databases until February 28, 2023, for studies reporting various indicators of PP incidence before and during the pandemic. Total numbers of events and observations were recorded. A meta-analysis was performed to compare the odds of PP, BMI SDS, and age at presentation between the 2 periods. The dose-response relationships between time points (by number of years away from the pandemic) and PP risk were explored. In summary, a total of 32 studies including 24 200 participants were recruited. The COVID-19 pandemic was associated with the increasing odds of PP among children referred for a suspicious condition (odds ratio = 1.96; 95% CI, 1.56-2.47; I2 = 54%; P < .001). Sensitivity analysis confirmed the robustness of the findings. The BMI SDS did not vary between the 2 periods, whereas age at presentation was lower after the pandemic. Precocious puberty incidence increased more rapidly during the pandemic period than during the prepandemic period. Trial registration: International Prospective Register of Systematic Reviews (PROSPERO; identifier: CRD42023402212).

Broadening the Healthy Aging Paradigm: Inclusion of Gestation, Development, and Reproductive Health

The prevailing focus of lifespan health research has predominantly centered on "healthy aging". This oversight may hinder the understanding of health across the lifespan, as disorders in earlier stages can substantially impact overall health and longevity. Aging, conceptually, begins at gestation. The trajectory of an individual's health is influenced from the earliest stages of life, where adverse conditions can set a foundation for lifelong health challenges. For example, suboptimal conditions during gestation leading to premature birth can predispose individuals to various health issues later in life. Additionally, precocious puberty defined as the onset of sexual maturity before eight years of age or early menopause-occurring before 50 years of age requires medical intervention and is indicative of atypical aging processes. To address these critical gaps in lifespan health research, the expansion of medical lexicons and research categorizations is advocated to include "healthy gestation," "healthy development," and "healthy reproduction" alongside "healthy aging." This broader terminology will enable a more comprehensive investigation of disorders at all life stages. An integrative approach underscores the interconnectedness of all life stages and the continuous nature of aging, advocating for a seamless continuum in health research and interventions from gestation through late adulthood.

Age at Menarche and Its Potential Role in Early Detection of Hyperandrogenic Polycystic Ovary Syndrome

OBJECTIVES

Polycystic ovary syndrome (PCOS) is a multifaceted heritable endocrine disorder that affects 4%-20% of females worldwide. Characterized by symptoms such as polycystic ovaries, anovulation, and hyperandrogenism, PCOS remains challenging to diagnose, particularly in its early stages. Research suggests that women with PCOS may experience earlier onset of menarche, but the mechanisms behind this association are not well understood. This study explores whether early menarche could serve as an effective diagnostic marker for PCOS.

MATERIALS AND METHODS

A survey was conducted with 95 adult women (ages 19-62), divided into two groups: women diagnosed with PCOS (49%, n = 47) and women without PCOS (51%, n = 48). Participants with PCOS self-identified and were required to meet the Rotterdam Criteria for diagnosis. Notably, all self-identified participants with PCOS exhibited the hyperandrogenic phenotype. Independent samples t-tests and linear regression were used for data analysis.

RESULTS

Women with PCOS reached menarche an average of 1.8 years earlier than those without the condition (mean age 11.4 ± 1.6 years vs. 13.2 ± 1.2 years).

DISCUSSION

These findings suggest that early menarche may be a promising, underexplored indicator of PCOS, offering a potential new avenue for earlier diagnosis of the condition. This could be particularly valuable, as PCOS is often not diagnosed until more classic symptoms, such as anovulation or hirsutism, emerge. Further research is needed to confirm these results and investigate the underlying mechanisms.

Abdominal imaging in precocious puberty in girls: can imaging determine onset of puberty?

Precocious puberty in girls is defined by the appearance of secondary sex characteristics before the age of 8 years. Precocious puberty is either peripheral or central. In most cases, the cause of central precocious puberty is unknown. Rapidly progressive forms of central precocious puberty may benefit from puberty suppression to prevent compromised final height and psychosocial problems related to the physical changes. Idiopathic central precocious puberty in girls can be a challenging diagnosis. Clinical examination, evaluation of growth charts, bone age, and hormonal tests are part of the workup. The role of pelvic ultrasound to evaluate pubertal features of the internal genitalia in this context is controversial. In this paper, we have reviewed the literature to find the scientific bases for several proposed ultrasound parameters and cutoff values for the determination of onset of puberty in girls with suspected central precocious puberty. There are no reliable cutoffs for the measurements of uterus and ovaries for the diagnosis of central precocious puberty and there is overlap in the appearance of the organs in both prepubertal and pubertal girls. The interpretation of the findings on pelvic ultrasound must be done with caution and always in close communication with the referring clinicians.

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.

Reassessing the association between age at menarche and cardiovascular disease: observational and Mendelian randomization analyses

AIMS

Observational studies have shown a U-shaped association between age at menarche (AAM) and cardiovascular disease (CVD). We assessed non-linearity of the observational association and the potential causal relationship between AAM and CVD using data from the European Prospective Investigation into Cancer and Nutrition-Cardiovascular Disease (EPIC-CVD) study and the UK Biobank.

METHODS AND RESULTS

We included women without pre-existing myocardial infarction (MI) or stroke at baseline. We estimated hazard ratios for incident MI, ischaemic and haemorrhagic stroke later in life using Cox regression in observational analyses and conducted non-linear Mendelian randomization (MR) based on fractional polynomials and linear MR based on inverse-variance weighted regression. We analysed 283 210 women with a median AAM of 13 (IQR 12-14) years in both EPIC-CVD and the UK Biobank, of which 8468 experienced a MI, 5501 an ischaemic and 1887 a haemorrhagic stroke. The association between AAM and MI and ischaemic stroke was U-shaped with higher risks in women aged ≤12 and ≥16 compared with those aged 13 years at menarche. Our MR analyses found no evidence for non-linearity between genetically proxied AAM and any CVD endpoint later in life, but each year higher genetically proxied AAM was related to a lower risk of MI (hazard ratio 0.92 [95% CI 0.86-0.99]), but not to ischaemic and haemorrhagic stroke.

CONCLUSION

This study supported non-linear observational associations between AAM and MI and ischaemic stroke. MR analyses suggested a causal relationship between higher AAM and risk of MI without an indication for non-linearity. There was no support for a potential causal link with ischaemic and haemorrhagic stroke.

Psychosocial Stress Trajectories Are Associated With Puberty Timing: Findings From a 7-Year Cohort in Chongqing, China

CONTEXT

Evidence for the associations between psychosocial stress PS related exposures and puberty timing are inconclusive. The PS of children has rarely been evaluated through repeated measurements.

OBJECTIVE

To evaluate the associations between PS trajectories and pubertal outcomes of girls and boys in a Chinese cohort (2015-2022).

METHODS

Pubertal outcomes of 732 girls and 688 boys were physically examined every 6 months. Stressful life events were repeatedly assessed 7 times. A group-based trajectory model was fitted for the optimum trajectories of total PS and PS from 5 sources. A Cox model adjusted for age, body mass index, and socioeconomic factors was used to evaluate the association.

RESULTS

Compared with the "low, gradual decline" trajectory, the "moderate, gradual decline" trajectory of total PS was associated with late menarche (hazard ratio [HR] 0.816, 95% CI 0.677-0.983), late pubic hair development (HR 0.729, 95% CI 0.609-0.872), and late axillary hair development (HR 0.803, 95% CI 0.661-0.975) in girls. Girls following the "high, rise then decline" trajectory of PS from family life demonstrated delayed axillary hair development (HR 0.752, 95% CI 0.571-0.990). For boys, the "high, rise then decline" trajectory of PS from academic adaptation (HR 0.670, 95% CI 0.476-0.945) and life adaptation (HR 0.642, 95% CI 0.445-0.925) was associated with late axillary hair development. Boys in the "moderate, gradual decline" trajectory of PS from peer relationships was at risk of early testicular development (HR 1.353, 95% CI 1.108-1.653).

CONCLUSION

Chronic PS may be associated with delayed onset of several pubertal signs in both girls and boys. It may also accelerate testicular development of boys, indicating its varying impact on pubertal timing during early and later stages.

Research on Body Composition and Lifestyle Behaviors During Pubertal Development in 6-12-Year-Old Children with Obesity

Objective: The objective of this study was to investigate the pubertal development in school-age children with obesity and to explore the body composition and lifestyle behaviors influencing its onset. Method: We enrolled 217 children, aged 6-12 years, who visited the Pediatrics Department at Beijing Jishuitan Hospital, Capital Medical University. All participants underwent a series of examinations. These assessments included body composition analysis, measurement of blood glucose and fasting insulin levels, and evaluation of secondary sexual characteristics. Statistical analysis was conducted using R4.0.3 software. Results: Of the 152 male participants, 83 (54.6%) were in the adolescent-undeveloped group, and 69 (45.4%) were in the adolescent-developed group. Of the 119 female students, 30 (25.2%) were in the adolescent-undeveloped group, and 89 (74.8%) were in the adolescent-developed group. In a comparative analysis of children, those in the adolescent development group exhibited significantly higher values for age, height, weight, body mass index (BMI), BMI-z score, body fat, muscle mass, fat-free weight, fat-free body mass index, and waist/hip ratio compared to the adolescent-undeveloped group (p < 0.05). Additionally, fasting insulin and insulin resistance index were also higher in the development group, with statistical significance observed. BMI emerged as an independent factor affecting the adolescent development of school-age girls with obesity (p < 0.05). Among boys in the adolescent development group, the consumption of sugary drinks and fried food was higher than in the undeveloped group, and moderate-intensity exercise was significantly lower, with statistical significance (p < 0.05). In girls, the adolescent development group reported longer daily sitting times and higher intakes of sugary drinks and fried foods compared to the undeveloped group, with these differences being statistically significant (p < 0.05). The consumption of fried food was positively correlated with adolescent development in children with obesity and was identified as an independent influencing factor of adolescent development (p < 0.05). Conclusions: A high body mass index (BMI) in girls with obesity and high intake of fried foods in both genders are strong predictors of early puberty in school-age children.

Maternal Factors During Pregnancy and Pubertal Timing in Offspring: A Systematic Review of the Literature

PURPOSE

This systematic review aims to identify, assess the quality of, and synthesize evidence on nongenetic maternal factors, such as psychological factors, lifestyle, nutrition, and endocrine conditions that may be associated with pubertal timing in male and female offspring.

METHODS

The search was conducted in Medline, Embase, PsycInfo and Web of Science. The reference lists of retrieved articles were checked to avoid missing relevant studies. There were no restrictions on publication year or language. The quality of the studies was assessed using the Newcastle-Ottawa Scale. This review has been registered on PROSPERO (CRD42023394102). A best-evidence approach was applied to qualitatively summarize the findings and draw conclusions on the level of evidence.

RESULTS

The search yielded 4199 studies, of which 73 were included in this systematic review. In both boys and girls, there is strong evidence of a positive association between maternal gestational weight gain and an earlier pubertal timing, while no association was found with maternal substance use, thyroid dysfunction, or gestational hypertension. In addition, there is insufficient evidence of an association with maternal psychological factors, smoking, diet, physical activity, prepregnancy weight/body mass index, diabetes, menstruation-related disorders, and steroid medication use.

CONCLUSION

This review provides a comprehensive overview of the quality and consistency of existing evidence regarding maternal factors during pregnancy that may be associated with the pubertal timing in their offspring. This review may serve as an orientation for future research initiatives, with a particular focus on exploring these associations among male offspring and in low- and middle-income countries.

The role of gynecologic sonography in sexual development assessment of girls and adolescents

INTRODUCTION AND OBJECTIVES

Transabdominal ultrasonography (US) is the technique of choice for pelvis evaluation in paediatric population. The results of studies regarding US findings show a wide variation. The objectives of our study were: to estimate and correlate uterine and ovarian ultrasound measures (longitudinal diameter and volume) with chronological age, breast Tanner stage (TS) and gynaecological age (GA); to evaluate presence and size of follicles in patients according to their pubertal stage; and to determine the endometrial length in prepubertal and pubertal girls.

MATERIAL AND METHODS

Unicentric, observational, retrospective, analytical study, conducted between 2010 and 2019. Healthy girls between 8.0 and 16.0 years, attended in the deparment of radiology were evaluated. Breast Tanner's stage (TS) was evaluated and gynaecological age was determined. Ultrasounds were performed by a paediatric diagnostic radiospecialist. Uterus length (UL) and ovarian length (OL) were measured; uterus and ovarian volume were calculated (UV and OV). Diameter of the largest follicle and endometrial thickness were measured.

RESULTS

292 patients were analyzed, mean age was 12.5 years (SD: 2.1). A significant correlation was observed between uterine and ovarian measurements with chronological age (CA), TS and GA (p < 0.0001). A significant increase in DLU and VU is described as the CA intervals increase, also in ovarian measurements. No significant differences in measurements were observed between TS I and II. An increase was evidenced at menarche. In 30.9% of pubertal patients and 11.8% of prepubertal patients showed ovarian follicles. The endometrium was not measurable in 88.24% of the pre-pubertal population and was always measurable in patients with TS IV and V.

CONCLUSIONS

Uterine and ovarian measurements increased with CE and ET (except ETI and II). The greatest increase occurred with menarche. Ovarian follicles and endometrium thickness less than or equal to 1 mm were presented in prepubertal patients.

Associations between birth characteristics, pubertal timing and adult height

AIM

This study investigated the association between gestational age and birth size with pubertal timing, measured as peak height velocity, and adult height.

METHODS

This retrospective, population-based study was conducted in Sweden in 2023. A sub-group of the 1974 and 1990 GrowUp Gothenburg cohorts was used (n = 4700, 50% males). The subgroup consisted of healthy individuals with Nordic ethnicity, known parental heights and measured adult heights. Data on birth characteristics (gestational age, birth length, birth weight) were collected. Pubertal timing was assessed as age at peak height velocity. Univariable linear regression analysis and bivariate correlations were conducted to answer the research questions.

RESULTS

Gestational age was not associated with age at peak height velocity or adult height. Birth length and weight could explain 12% and 8% (p ≤ 0.001) respectively of attained adult height. However, birth length and birth weight could only explain the variation in age at peak height velocity to a small degree.

CONCLUSION

This study showed that gestational age is not associated with age at peak height velocity or adult height. A positive relationship was found between birth size, particularly birth length, and adult height. No strong associations were found between birth size and age at peak height velocity.

Environmental factors trigger pubertal development

PURPOSE OF REVIEW

We provide an overview of the secular trend of earlier pubertal development, why there is a growing concern that environmental factors may be to blame, and how these factors may influence the developing reproductive axis.

RECENT FINDINGS

We highlight recent work suggesting that, in addition to activating sex steroid receptors, environmental compounds may influence neuropeptide receptors and/or epigenetic regulators. We describe recent studies linking air pollution, metals, endocrine disrupting compounds (EDCs), short sleep duration, early life adversity, and stress to pubertal timing.

SUMMARY

Pubertal timing is tightly controlled by genetic, epigenetic, and environmental factors. While animal and epidemiological studies have pointed to several potential environmental factors, additional work is necessary to identify the critical levels and developmental windows of exposure as well as the mechanistic underpinnings.

Early life growth is related to pubertal growth and adult height - a QEPS-model analysis

BACKGROUND

The early life growth period, from conception to ~2 years of age, has proven crucial for later health. We hypothesized that early life growth could explain variations in pubertal growth and timing, and adult height.

METHODS

This retrospective, population-based study was conducted in Sweden. A subgroup, including individuals of all gestational ages and birth sizes (n = 4700, 50% males), from the longitudinal GrowUp1974&1990Gothenburg cohorts was used. QEPS variables were analyzed in univariate and multivariate linear regression models, separately per sex; Q-function throughout all growth periods, and specific E- and P-functions, for early life growth and pubertal growth, respectively.

RESULTS

In multivariate models, early life growth explained 37-38% of the variability in specific pubertal growth, but less so the variability in pubertal timing. Variability in adult height was explained by birth size (57-62%), early growth (66-67%), childhood growth (65-69%), and to a lesser degree by mid-parental height (35-39%). The change in height during puberty explained 8-9% of the variation in adult height.

CONCLUSION

This study indicates that early life growth is strongly associated with the variability in pubertal growth, and adult height, but not with the timing of pubertal growth.

IMPACT

Early life growth is important as it can serve as a marker for future growth, development, and health. The association between length growth during fetal life and infancy and pubertal growth and timing, and adult height, is only partly understood. Using the QEPS growth model, specific early life growth (E-function) and specific pubertal growth (P-function), including individual variations in tempo and amplitude, can be studied separately from ongoing basic growth (Q-function). This study showed that early life growth is strongly associated with and explains specific pubertal height gain and adult height but less so the timing of pubertal growth.

Research on the height of primary school students in Zhuzhou and analysis of influencing factors of short stature

Objective

To construct a growth curve for children aged 6-12 years residing in Zhuzhou, assess the height distribution among local elementary school students, and analyze the factors contributing to short stature.

Methods

We measured the heights of children from 110 elementary schools in Zhuzhou using cluster sampling. A total of 106,864 samples of children aged 6-12 years were collected and divided into 25 age groups, each spanning three months. The Lambda-Mu-Sigma (LMS) method was employed to calculate the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles of height for each age group. Children below the 3rd percentile according to the national growth curve made in 2005 were considered to be short stature. The heights of boys and girls in Zhuzhou were compared with the national average heights from 2005. The height growth curve was constructed using the curve estimation function of SPSS software and the influencing factors for the prevalence of short stature were identified using logistic regression analysis based on data obtained from parental questionnaires.

Results

The prevalence of short stature among children aged 6-12 years in Zhuzhou was found to be 3.97%. Boys exhibited a significantly higher incidence of short stature at 4.53% compared to girls at 3.37%. Children residing in suburban areas showed a notably higher prevalence of short stature (5.80%) compared to their urban counterparts (3.67%), with these disparities proving statistically significant. Logistic regression analysis identified several contributing factors for short stature in this population, including low birth weight, inadequate daily physical activity (less than 0.5 h), father's educational qualification of junior college level or below, short stature of parents, insufficient sleep duration, and male gender.

Conclusion

To improve children's height in Zhuzhou, it's important for them to exercise for over 30 min daily and sleep for more than 10 h each night. Regular monitoring of growth and nutrition is crucial. Health education for families with less educated fathers and early intervention for children with short-statured parents are also key strategies.

Menstrual Health Education: School Health Curriculum Topics by Grade Level Recommended by Specialized Medical Professionals in Menstrual Health Clinics

STUDY OBJECTIVE

Evidence-based menstrual health education is not mandated in any US state or territory. Aspects of normal and abnormal menstruation impact quality of life and educational engagement, but many youths are not prepared to know when to seek medical help. We sought to determine which topics should be included in a third- through eighth-grade school-based menstrual health curriculum.

METHODS

We conducted a cross-sectional online survey of medical professionals who care for patients with menstrual problems. We asked participants to indicate the top 3 menstrual health topics by grade, and we compared the most common responses by year. We also solicited general comments about the curriculum content.

RESULTS

Surveys from 55 medical professionals met the criteria for analysis. The topics selected most frequently were normal and abnormal menstruation, reproductive anatomy, puberty timeline, and menstrual products. Most recommended the topics of puberty timeline (38, 69.1%) and reproductive anatomy (34, 61.8%) for third grade, introducing normal menstruation (31, 56.4%) and menstrual products (24, 46.3%) in fourth grade, and abnormal menstruation (27, 49.1%) in sixth grade. More complex topics, such as world cultures around menstruation (14, 25.5%) and period poverty (11, 20.0%), were preferred for eighth grade. Many providers emphasized the importance of teaching normal vs abnormal menstruation in a school health curriculum.

CONCLUSION

Medical professionals provided recommendations for a school-based menstrual health curriculum that introduces topics at developmentally appropriate ages from a medical perspective, teaches basic menstrual symptom management, and instructs on warning signs for abnormal menstruation.

Clinical and epidemiological insights into early puberty in Thai girls: a 5-year study

PURPOSE

There is growing global concern about the shift to earlier onset of puberty among girls; however, the prevalences of precocious and normal variant puberty among Thai girls are uncertain. We conducted a study at King Chulalongkorn Memorial Hospital in Bangkok from 2018 to 2022 (amid the coronavirus disease 2019 pandemic) to investigate the prevalence, characteristics, and treatment of early puberty in a large cohort of Thai girls.

METHODS

The medical records of 583 girls who had been evaluated for early puberty were reviewed. Demographic and clinical characteristics, and treatment approaches were analyzed.

RESULTS

The analyses found a significant annual increase in evaluations for early signs of puberty (P-value for trend 0.04). The majority (71.2%) of cases were categorized as gonadotropin-releasing-hormone (GnRH)-dependent or central precocious puberty (CPP), with 16 cases showing abnormal brain magnetic resonance imaging findings. Among girls with normal variant puberty, early normal puberty was the most common category (10.5%), followed by premature thelarche (9.5%), slow-progressive precocious puberty (6.6%), and premature adrenarche (2.2%). Median age at presentation, basal luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and bone age differed significantly among groups. Importantly, 97% of girls with CPP received GnRH agonists. Girls with CPP exhibited higher body mass index z-scores and basal LH and FSH compared with those with slow-progressive precocious puberty.

CONCLUSION

Our analyses of the prevalence, characteristics, and treatment of early puberty in Thai girls highlighted the impact of obesity on pubertal timing. The findings underscore the need for preventive weight management and country-specific guideline updates to enhance healthcare strategies for young girls.

Twenty-year changes of adolescent mental health and substance use: a Finnish population-based time-trend study

This time-trend study assesses changes in mental health and substance use among Finnish adolescents from 1998 to 2018. Representative samples of adolescents (N = 6,600) aged 13-16 years participated in school-based, almost identical cross-sectional studies in 1998 (n = 1,446), 2008 (n = 2,009), 2014 (n = 1,800) and 2018 (n = 1,345), respectively. The Strengths and Difficulties Questionnaire was used to assess mental health. When comparing mental health in the clinical range between 1998 and 2018, the main finding was the significant increase of emotional symptoms among females. The percentage of females in the clinical range increased from 17.5 to 30.1% during the twenty-year period. When psychopathology measures were analyzed as continuous variables, the finding of increased emotional problems was confirmed. The study clearly illustrates a linear trend, with a consistent increase in emotional problems among females and decrease in substance use among both genders. An alarming finding of steady increase of self-reported emotional problems indicates the importance of early detection and evidence-based interventions for adolescent with anxiety and depression to prevent adversities associated with these disorders.

Editorial: Studying child development in a changing world

In this editorial, I reflect on the implications of social, technological and cultural change for children and young people. Whilst we have a reasonably good understanding of trends in certain aspects of child development (e.g. height, weight, cognitive attainment), there are many unanswered questions. We do not know what explains the steep rise in mental health problems among young people, nor are we in position to evaluate and predict the consequences of different societal trends for current and future generations of young people. This is in part due to a reliance on older life course cohorts without adequate measurement of important aspects of children's lives (e.g. their online experiences). There are also some broader questions which require attention - what does it mean to be a child today? How is childhood changing? I consider possible implications and priorities for developmental research; in particular, the importance of listening to young people's perspectives, innovation in measurement in future life course cohorts, and developing more efficient real time monitoring of mental health at a population level.

Exposure to polyethylene and polyvinylchloride microplastics caused advanced puberty onset in females through promoting hypothalamic GnRH expression

Precocious puberty (PP) is a common pediatric endocrine disorder that affects children's growth and sexual development. Environmental pollutants, especially microplastics (MPs), may be an important triggering factors in PP. MPs were widely found in children's living environment, while the impact of MPs on pubertal development remains unknown. In this study, 14 serum samples were collected from central precocious puberty (CPP) girls and healthy controls. The concentration of total MPs in CPP girls (68.19 ± 26.49 mg/kg) showed significant increase than healthy controls (36.94 ± 13.22 mg/kg). 5 of 11 types of MPs were detected, among which PE (CPP, 28.22 %; Control, 31.62 %) and PVC (CPP, 62.67 %; Control, 58.14 %) being the dominant ones. Correlation analysis between MPs and sex hormone revealed that total MPs were negatively correlated with progesterone and positively correlated with dehydroepiandrosterone (DHEAS). In order to investigate the toxic effects of MPs on pubertal onset, young female mice at 21 days were orally administered various concentrations of MPs for two weeks. Female mice exposed to MPs (PE, 3 mg/day; PVC, 6 mg/day) had an advanced vaginal opening, while none significant changes in body weight. Immunohistochemical staining demonstrated that MPs exposure during puberty could activate microglia, astrocytes and promote GnRH expression in the hypothalamus, which leading to an earlier pubertal onset. These data suggested that MPs can be absorbed and accumulated in brain and gonad after gavage, and accelerate female pubertal initiation. This study provided valuable evidence that MPs threatened the normal progression of female pubertal development.

The study of pubertal stage and age of menarche in girls in Isfahan province, Iran

BACKGROUND

The onset age of pubertal changes varies widely among girls and has undergone changes over time around the world. This study aimed to determine the age of onset of puberty in healthy Iranian girls living in Isfahan province.

METHODS

This cross- sectional study was conducted among 13,886 students aged 6-18 years. They were selected by multistage random cluster sampling from urban and rural areas of Isfahan province of Iran. Pubertal stage was determined according the 5-level Tanner stages proposed by Marshall and Tanner. Trained physicians determined the breast development through both visual inspection and palpation, in addition, mothers assessed their daughter's pubic hair growth using Tanner's Sexual Maturation Scale (SMS) by comparison to standard pictures. The data were analyzed by the status quo method. Probit regression analysis was used to evaluate the median age of onset for each characteristic including menarche, breast and pubic hair.

RESULTS

A total of 13,886 healthy girls with mean age (SD) of 11.97 (2.9) were studied. Overall 6968 (50.2%) girls experienced menstruation with a median (95%CI) age of 12.05(11.88-12.21) years at its onset. The median age for onset of breast development was 9.89 (95% CI: 9.77 - 10.02) years and for onset of pubic hair development was 10.14 (95% CI: 9.88- 10.39) years. The 3rd percentile for breast stage 2 (B2) and pubic hair stage 2 (PH2) was 6.85 and 6.75 years, respectively, and the 97th percentile for B2 and PH2 was 12.94and 13.54 years, respectively.

CONCLUSION

According to our findings, the onset of puberty before 6.85 years should be considered as precocious puberty for Iranian girls. Our study indicated the secular trend toward earlier menarche in girls. Nationally representative surveys and longitudinal studies are necessary to determine the exact age of puberty for future international comparisons.

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.

Timing, velocity, and magnitude of pubertal changes in body composition: a longitudinal study

BACKGROUND

Pubertal changes in body composition significantly influence future health, with links to various diseases. This study aimed to evaluate the weight changes, fat-free mass (FFM), and body fat mass (BFM) during pubertal growth in Korean children and adolescents.

METHODS

We utilized mixed longitudinal data, employing bioelectrical impedance analysis for 4641 height measurements (2204 boys, 2437 girls) from 361 individuals (170 boys, 191 girls) aged 7-18 years. Utilizing the Superimposition by Translation and Rotation (SITAR) model, a shape-invariant growth curve model, reference curves for height, weight, and body composition change velocities were estimated.

RESULTS

Korean boys experience peak weight velocity (PWV) at an average age of 12.41 years, with a rate of 8.19 kg/year, peak fat-free mass velocity (PFFV) at 12.70 years (7.60 kg/year), and peak body fat mass velocity (PBFV) at 9.69 years (2.67 kg/year). Korean girls show PWV at 11.28 years (6.33 kg/year), PFFV at 11.13 years (4.86 kg/year), and PBFV at 12.33 years (2.72 kg/year). Positive correlations exist among the ages of peak height velocity, PWV, PFFV, and PBFV.

CONCLUSIONS

This research represents the groundbreaking application of the SITAR model in analyzing changes in body composition during pubertal growth in Korean children and adolescents.

IMPACT

This study utilized the SITAR model to analyze longitudinal changes in the body composition of the general pediatric population in Korea across pre- and post-pubertal stages, addressing overlooked aspects in cross-sectional studies. Examining growth parameters, including size (mean mass), tempo (timing), and velocity (compression and expansion) for each body component, revealed positive correlations among ages at peak velocities for various body composition parameters. This study can be employed for further investigations that compare the tempo, size, and velocity of various body composition parameters in pediatric disease cohorts and the general population.

Influence of exposure to endocrine disruptors and other environmental chemicals on breast development in girls: A systematic review of human studies

BACKGROUND

Age at thelarche has decreased over recent decades. This change in female puberty timing may be influenced by exposure to endocrine disrupting chemicals (EDCs) during critical periods of development.

OBJECTIVE

To review the scientific literature for evidence on the association of exposure to EDCs and other environmental chemicals with the timing of thelarche in girls.

METHODS

A systematic search for original peer-reviewed articles published up to July 2023 was conducted in three databases (Medline/PubMed, Scopus, and Web of Science), following the PECO strategy and PRISMA guidelines. The quality of evidence and reporting and the risk of bias were evaluated using GRADE, STROBE, and ROBINS-E tools.

RESULTS

Out of 3094 articles retrieved in the search, 67 met the review inclusion criteria. Data from 10 out of the 14 studies offering high-quality suggest that in utero and/or childhood exposure to certain synthetic and natural chemicals is associated with earlier breast development in girls; 8 of these 10 studies described a relationship with exposure to organohalogenated compounds in utero and to phthalates in childhood.

CONCLUSIONS

This systematic review provides the first overview of available human data on the association of EDCs/environmental chemicals with the timing of thelarche. Further high-quality research is urgently needed to fully elucidate the influence of this exposure on breast development timing in girls.

New French height velocity growth charts: An innovative big-data approach based on routine measurements

AIM

Height velocity is considered a key auxological tool to monitor growth, but updated height velocity growth charts are lacking. We aimed to derive new French height velocity growth charts by using a big-data approach based on routine measurements.

METHODS

We extracted all growth data of children aged 1 month-18 years from the electronic medical records of 42 primary care physicians, between 1 January 1990 and 8 February 2018, throughout the French metropolitan territory. We derived annual and biannual height velocity growth charts until age 15 years by using the Lambda-Mu-Sigma method. These new growth charts were compared to the 1979 French and 2009 World Health Organisation (WHO) ones.

RESULTS

New height velocity growth charts were generated with 193 124 and 209 221 annual and biannual values from 80 204 and 87 260 children, respectively, and showed good internal fit. Median curves were close to the 1979 French or 2009 WHO ones, but SD curves displayed important differences. Similar results were found with the biannual height velocity growth charts.

CONCLUSION

We produced new height velocity growth charts until age 15 years by using a big-data approach applied to measurements routinely collected in clinical practice. These updated growth charts could help optimise growth-monitoring performance.

The role of body composition and appetite-regulating hormones in idiopathic central precocious puberty and their changes during GnRH analog therapy

PURPOSE

It was aimed to compare circulating levels of ghrelin, leptin, peptide YY (PYY), and neuropeptide (NPY) between girls with idiopathic central precocious puberty (ICPP) and prepubertal girls, as well as to evaluate alterations in these hormone levels and body composition during leuprolide acetate treatment in girls with ICPP.

METHODS

This prospective study was conducted on girls with isolated premature thelarche (IPT), girls with ICPP, and age-matched prepubertal controls. Anthropometric measurements, body composition analysis and appetite-regulating hormone level measurements were performed in each group and also at the 6th and 12th months of the leuprolide acetate treatment for the girls with ICPP.

RESULTS

Seventy-three girls participated in the study (24 girls with ICPP, 28 with IPT, and 21 prepubertal controls). No significant differences were observed in ghrelin, leptin, PYY, and NPY levels among the three groups. Leuprolide acetate treatment resulted in increased leptin, decreased PYY and NPY levels, and no significant changes in ghrelin. Despite no significant change in body mass index standard deviation score (BMI SDS), body fat percentage increased during treatment.

CONCLUSION

While appetite-regulating hormones do not seem to directly contribute to precocious puberty pathogenesis, puberty blockade was shown to lead to altered levels of these hormones along with changes in body composition.

Prenatal and childhood exposure to endocrine-disrupting chemicals and early thelarche in 8-year-old girls: A prospective study using Bayesian kernel regression

BACKGROUND

Studies on the combined effects of persistent and non-persistent endocrine-disrupting chemicals (EDCs) on puberty are insufficient. To date, no studies have analyzed breast development at age 8 years, a key criterion for determining precocious puberty. We investigated the relationship between prenatal or childhood exposure to EDC mixtures and early thelarche, defined as breast development before age 8 years in girls.

METHODS

This prospective study included 211 girls with data on prenatal and 8-year-old exposure of cadmium (Cd), lead, mercury, bisphenol-A (BPA), 3-phenoxybenzoic acid, and three phthalate metabolites from the Environment and Development of Children cohort. Prenatal exposure was assessed through samples from pregnant women at 14-27th weeks of gestation. Tanner staging was assessed by a pediatric endocrinologist. The relationship between single and mixed chemical exposures and outcomes was assessed using logistic regression, generalized additive models (GAM), and Bayesian kernel machine regression (BKMR) models.

RESULTS

Early thelarche was observed in 42 (19.9%) girls at age 8 years. In the logistic regression models, the risk of early thelarche increased with increased exposure to Cd in their mothers (adjusted odds ratio [aOR] per interquartile range [IQR] = 1.80, 95% confidence interval [CI] 1.23-2.65) but decreased with prenatal BPA exposure (aOR per IQR = 0.57, 95% CI 0.35-0.92). None of the 8-year-old chemical exposures was associated with early thelarche. In the GAM, early thelarche was positively correlated with prenatal Cd and inversely associated with prenatal BPA exposure (p = 0.004 for Cd and p = 0.036 for BPA). In the BKMR models, an increase in log-transformed prenatal Cd concentrations from the 25th to 75th percentile was associated with an increase in the estimated probability of early thelarche at age 8 years (risk difference: 0.46 [95% credible interval: 0.04-0.88]) when other chemicals were set at their median values.

CONCLUSIONS

Considering the combined effects of persistent and non-persistent chemical mixtures, maternal Cd exposure during the second trimester may be associated with early thelarche in 8-year-old girls.

Adult height in girls with idiopathic central precocious puberty treated with triptorelin

Objective

Idiopathic central precocious puberty (CPP) precipitates epiphyseal fusion of growth plates in long bones, leading to reduced adult stature. Gonadotropin-releasing hormone analogues (GnRHa) are the treatment of choice for idiopathic CPP, but their benefit on height gain is unclear. We aimed to elucidate the effects of GnRHa treatment on adult height in girls with idiopathic CPP.

Design

This prospective observational descriptive study analyzed data of girls with idiopathic CPP diagnosed at 55 centers in Spain between January 1, 1998 and December 31, 2012 included in the Spanish Society for Pediatric Endocrinology's national registry.

Methods

We included girls with idiopathic CPP (thelarche < 8 years, positive LHRH stimulation test, bone age > 1 year older than chronological age, and normal brain imaging) treated with triptorelin (3.75 mg monthly, adjusted according to LHRH test results and clinical findings). We assessed weight, height, BMI, and secondary sexual characteristics every 6 months and bone age every 12 months until adult height (AH) was attained. The primary outcome was the difference between AH and target height (TH).

Results

A total of 465 girls (18.90% adopted) were included; we analyzed data recorded at treatment end in 358 girls and at AH in 216. Mean difference between AH and TH was -1.5 (95%CI: -2.56- -0.45) cm and between AH and PAH 2,57 (95%CI:-3.56- -1.58) cm.

Conclusions

GnRHa treatment helps preserve genetic growth potential in girls with idiopathic CPP.

Precocious puberty, pandemic and beyond

WHO declared SARS-COVID19 a pandemic in March 2020. Most governments declared health emergency states and implemented various measures. Since then, changes in the reasons for medical consultations were observed in healthcare institutions. Pediatric endocrinologists perceived an increase in the number of consultations related to early or accelerated CPP during the months following the lockdown that different governments had established. Several papers reported the increment in incidence in Central Precocious Puberty, especially in girls. Reports from different parts of the world highlighted a two to threefold rise in the number of cases of precocious puberty treated in Pediatric Endocrinology Centers. This trend of CPP incidence strongly suggests that changes in habits and the environment in which boys and girls were immersed during the lockdown, have played a significant role in triggering the early onset of the gonadotrophic axis.

Whole mount preparation and analysis of rabbit mammary gland

The mammary gland undergoes dynamic structural and compositional changes throughout life, influenced significantly by hormonal fluctuations and environmental factors. From embryonic development through menopause, this tissue adapts to accommodate phases such as postnatal expansion, pregnancy-induced lactation, and post-weaning involution. Hormones, growth factors, cytokines, and exogenous factors regulate these innate processes, affecting mammary epithelial cell proliferation and sensitivity, particularly in terminal end buds (TEB) and lobules, which are highly susceptible to endocrine disruption. Rodent models have provided invaluable insights into mammary gland biology, yet differences exist compared to human development, prompting the exploration of alternative models like rabbits. Additionally, there is momentum to move away from the use of nonhuman primates in safety assessments, increasing the need for evaluation tools for all tissues in the rabbit model. Rabbit mammary glands exhibit similarities to humans, making them promising for studying breast biology and pathology. However, protocols for whole-mount analysis of rabbit mammary glands are lacking due to the technical challenges of working with thicker tissue than rodent mammary glands. Here, we developed a methodology modified from rodent studies for preparing and analyzing rabbit mammary gland whole mounts, which is essential for advancing research in mammary gland biology and understanding the effects of hormonal and toxicant-induced disruption of mammary gland growth and function.

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.

Higher peak height velocity in early maturing girls depends on insulin rather than fat mass or IGF-I

OBJECTIVE

Age at pubertal onset has decreased over the recent decades. Early maturing girls have longer puberty duration, and higher peak height velocity (PHV) than late maturing girls. To what extent this is generated by increased insulin-like growth factor-I (IGF-I), fat mass, or fasting insulin levels is currently unknown.

DESIGN, SETTING, PARTICIPANTS

A population-based study-part of the COPENHAGEN puberty study-longitudinal part. Eighty-one girls evaluated biannually for a median of 10 (2-15) visits for a total of 815 evaluations.

METHODS

Pubertal staging, anthropometric measures, PHV, skin fold thickness (SFT), and IGF-I and fasting insulin levels were measured.

RESULTS

Early maturing girls achieved similar final height compared to late maturing girls (166.1 vs 167.1 cm, P = .36). Early pubertal onset was associated with significantly greater PHV (8.7 vs 7.4 cm/year, P < .001) and a longer puberty duration (age at onset of breast development to age at PHV [1.8 vs 1.1 years, P < .001]) compared with late maturation. After correcting for age at pubertal onset, neither body mass index, SFT, nor IGF-I levels differed between early vs late maturing girls. By contrast, fasting insulin levels were significantly higher in early compared with late maturing girls 1.5, 2.0, and 3.0 years after pubertal onset (all P = .039).

CONCLUSION

Growth velocity was higher and more prolonged in early compared with late maturing girls and associated with higher insulin levels. Thus, the higher insulin levels may compensate for the shorter total growth period by intensifying the pubertal growth period.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01411527.

Association of screen exposure/sedentary behavior and precocious puberty/early puberty

Background

In recent years, with the development of society, children's daily exposure to screen time has gradually increased. Screen exposure and sedentary behavior have brought a host of harms to children's lives. The aim of this study was to explore the effects of screen exposure and sedentary behavior on precocious puberty and early development.

Methods

This is a cross-sectional study in the school-based population. A total of 3,560 children were recruited from Qufu City, Shandong province using multistage stratified cluster random sampling. All study subjects had a physical examination by professional pediatricians in October 2019, and were investigated with health questionnaires. Precocious puberty is defined as development of secondary sexual signs in boys before 9 years or in girls before 8 years. Screen time was calculated as the average of screen time on weekdays and weekend days, and sedentary time was calculated as the average of sedentary time on weekdays and weekend days. After adjusting for potential confounders, logistic regression was used to examine the association between screen exposure and sedentary behavior and early puberty and precocious puberty.

Results

Sedentary time was a risk factor for precocious puberty and early development (OR = 1.428, 95% CI = 1.087-1.876) in girls without adjustment. No significant association was found between screen exposure and early puberty and early development both in girls and boys.

Conclusions

Excessive sedentary behavior was associated with an increased risk of early puberty, especially in girls, while there was no significant association between screen exposure and early puberty and early development. In addition, further longitudinal investigations are needed to determine the causal relationship between screen exposure, sedentary behavior and precocious puberty.

Looking Beyond the Number of Repetitions: An Observational Cross-Sectional Study on Calf Raise Test Outcomes in Children Aged 10-17 Years

AIMS

The calf raise test (CRT) assesses plantarflexor strength and endurance, but normative data for children are scarce. Furthermore, contradictions exist on which factors are associated with total repetitions, with repetitions being the only metric considered. We quantified three of the main CRT outcomes (repetitions, total work, and peak height) in children 10-17 years and explored their relationship with various factors.

METHODS

Healthy children (n = 165, 50.3% female) completed single-legged calf raises on a 10° incline, once on each leg. Test outcomes were extracted using the valid and reliable Calf Raise application.

RESULTS

CRT outcomes were not significantly different between legs (p ≥ .19). The only covariates significantly associated with outcomes based on stepwise quantile regressions were body mass index centile for repetitions, meeting physical activity recommendations for total work and peak height, and age for total work. Outcomes did not significantly differ based on sex or maturation. Median values were around 26 for repetitions, 640-1460 J for total work (age dependent), and 10.1 cm for peak height for children meeting physical activity recommendations.

CONCLUSION

Children who were older, had lower body mass indices, and were more active exhibited superior CRT outcomes. Meeting physical activity recommendations appears beneficial for plantarflexor function and should continue to be prioritized in children.

The estimation of pubertal growth spurt parameters using the superimposition by translation and rotation model in Korean children and adolescents: a longitudinal cohort study

Objectives

Understanding the characteristics of the pubertal growth spurt in Korean children and adolescents can serve as crucial foundational data for researching puberty and growth-related disorders. This study aims to estimate the key parameters of pubertal growth, specifically the age and magnitude of the pubertal growth spurt, utilizing longitudinal data from a cohort of Korean children and adolescents.

Methods

This study used mixed longitudinal height data from a cohort of Korean elementary, middle, and high school students aged 7-18 years. The Superimposition by Translation and Rotation (SITAR) model, a shape-invariant growth curve model, was utilized to estimate a reference height velocity curve for the entire dataset and individual curves via random effects to evaluate pubertal growth parameters. Altogether, 3,339 height measurements (1,519 for boys and 1,820 for girls) from 270 individuals (123 boys and 147 girls) were analyzed.

Results

The average age of growth spurt onset in Korean boys was 10.17 ± 0.61 years (mean ± SE), with peak height velocity occurring at 12.46 ± 0.69 years of age (9.61 ± 1.26 cm/year). Korean girls, contrarily, experience their growth spurt at an earlier age (8.57 ± 0.68 years), with peak height velocity occurring at 10.99 ± 0.74 years of age (8.32 ± 1.09 cm/year). An earlier onset of puberty in both sexes is associated with a shorter growth spurt duration (0.63 years for boys and 0.58 years for girls) and a higher peak height velocity (1.82 cm/year for boys and 1.39 cm/year for girls). These associations were statistically significant for both sexes (all p < 0.0001).

Conclusion

This study is the first to use the height velocity curve from the SITAR model to examine the pubertal growth spurt of Korean children and adolescents. The estimated timing and magnitude of the pubertal growth spurt, and their relationships can be useful data for clinicians and researchers.

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.

Indications of younger age at menarche in Greek adolescents but with no relation to body mass index

PURPOSE

This study aimed to present recent trends in the pubertal timing of a Greek female sample.

METHODS

Data were collected retrospectively from medical records of healthy females aged 6-18 years who attended a tertiary Adolescent Friendly Health Center over a 5-year period (2016-2020) and included gestational age, birth anthropometrics, and age of thelarche and/or pubarche and/or menarche, along with corresponding anthropometric, hormonal, and biochemical measurements.

RESULTS

Data from 298 girls' medical records were included in the analysis. Median age at menarche, thelarche, and pubarche was 12, 9, and 9 years, respectively. The mean interval between pubertal onset and menarche was 1.99 years. The mean body mass index (BMI) at menarche and thelarche was 20.99 kg/m2 and 18.90 kg/m2, respectively. The mean weight at menarche was 49.6 kg, whereas the mean height difference between thelarche and menarche was 19.17 cm. Among participants, 6.3% had premature menarche, while 24.0% had premature thelarche. Birth weight was moderately correlated with BMI at thelarche/pubarche (rs=0.334, p = 0.005). Birth weight and BMI at thelarche/pubarche were not predictive of premature menarche or premature thelarche. Median (interquartile range, IQR) levels at menarche vs. thelarche were significantly higher for insulin-like growth factor-1 [358.00 (140.50) vs. 176.00 (55.00) ng/ml], follicle stimulation hormone [5.65 (3.14) vs. 3.10 (4.23) mIU/ml], testosterone [25.50 (31.00) vs. 13.00 (21.00) ng/dl], dehydroepiandrosterone sulfate [117.00 (112.50) vs. 46.40 (51.90) µg/dl], and insulin [17.40 (15.05) vs. 8.47 (4.97) µIU/ml].

CONCLUSION

The timing of pubertal stages in the Greek female sample studied followed the recent international downward trends. Younger age at menarche was not related to BMI.

Trends in incidence, prevalence, and survival of breast cancer in the United Kingdom from 2000 to 2021

Breast cancer is the most frequently diagnosed cancer in females globally. However, we know relatively little about trends in males. This study describes United Kingdom (UK) secular trends in breast cancer from 2000 to 2021 for both sexes. We describe a population-based cohort study using UK primary care Clinical Practice Research Datalink (CPRD) GOLD and Aurum databases. There were 5,848,436 eligible females and 5,539,681 males aged 18+ years, with ≥ one year of prior data availability in the study period. We estimated crude breast cancer incidence rates (IR), prevalence and survival probability at one-, five- and 10-years after diagnosis using the Kaplan-Meier method. Analyses were further stratified by age. Crude IR of breast cancer from 2000 to 2021 was 194.4 per 100,000 person-years for females and 1.16 for males. Crude prevalence in 2021 was 2.1% for females and 0.009% for males. Both sexes have seen around a 2.5-fold increase in prevalence across time. Incidence increased with age for both sexes, peaking in females aged 60-69 years and males 90+ . There was a drop in incidence for females aged 70-79 years. From 2003-2019, incidence increased > twofold in younger females (aged 18-29: IR 2.12 in 2003 vs. 4.58 in 2018); decreased in females aged 50-69 years; and further declined from 2015 onwards in females aged 70-89 years. Survival probability for females after one-, five-, and ten-years after diagnosis was 95.1%, 80.2%, and 68.4%, and for males 92.9%, 69.0%, and 51.3%. Survival probability at one-year increased by 2.08% points, and survival at five years increased by 5.39% from 2000-2004 to 2015-2019 for females, particularly those aged 50-70 years. For males, there were no clear time-trends for short-term and long-term survival probability. Changes in incidence of breast cancer in females largely reflect the success of screening programmes, as rates rise and fall in synchronicity with ages of eligibility for such programmes. Overall survival from breast cancer for females has improved from 2000 to 2021, again reflecting the success of screening programmes, early diagnosis, and improvements in treatments. Male breast cancer patients have worse survival outcomes compared to females, highlighting the need to develop male-specific diagnosis and treatment strategies to improve long-term survival in line with females.

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.

Menstrual Cycle Characteristics of U. S. Adolescents According to Gynecologic Age and Age at Menarche

STUDY OBJECTIVE

To characterize typical menstrual cycle characteristics in adolescents and determine how these differ with age at menarche or years since menarche (gynecologic age).

METHODS

We surveyed 13 to 18-year-old U.S. users of the Clue app (N = 6,486) and linked their responses to app-recorded cycle data (N=38,916 cycles). We analyzed cycle characteristics including cycle length, cycle variability, period length, experience of heavy flow, and dysmenorrhea in relation to gynecologic age and menarcheal age using mixed effects models.

RESULTS

With increasing gynecologic age, we observed dose-dependent associations of lower odds of cycle irregularity (defined as cycles that were highly variable, short, or long) and higher odds of reporting ≥1 day of heavy flow. Individuals <1 year post-menarche had lower odds of heavy flow (Odds Ratio (OR) = 0.3; 95% confidence interval (CI): 0.1, 0.6), and increased odds of having a highly variable cycle (OR = 2.6; 95% CI: 1.3, 5.2) or short cycles (OR = 5.0; 95% CI: 2.3, 11.0) compared to those who were 6+ years post-menarche. We also found associations with early and late age at menarche. Compared to menarcheal age of 14+ years, menarcheal age ≤10 years was associated with shorter cycle length (β = -1.63 days; 95% CI: -2.51, -0.75), increased odds of dysmenorrhea (OR = 3.2; 95% CI: 2.3, 4.6), and decreased odds of high cycle variability (OR = 0.8; 95% CI: 0.6, 1.0).

CONCLUSION

Cycle characteristics in adolescence are associated with menarcheal age and gynecologic age. Notably, highly variable cycles are common, especially among those with younger gynecologic age or older menarcheal age.

Association of prenatal exposure to phthalates and synthetic phenols with pubertal development in three European cohorts

BACKGROUND

There is limited epidemiological evidence on the association of prenatal exposure to phthalates and synthetic phenols with altered pubertal timing.

OBJECTIVE

To examine the association of prenatal exposure to phthalates, bisphenol A (BPA), parabens, benzophenone 3 (BP-3), and triclosan (TCS) with pubertal development in girls and boys from three European cohorts.

METHODS

Urinary metabolites of six different phthalate diesters (DEP, DiBP, DnBP, BBzP, DEHP, and DiNP), BPA, methyl- (MePB), ethyl- (EtPB), propyl- (PrPB), and butyl-paraben (BuPB), BP-3, and TCS were quantified in one or two (1st and 3rd trimester) urine samples collected during pregnancy (1999-2008) from mothers in three birth cohorts: INMA (Spain), EDEN (France), and MoBa (Norway). Pubertal development of their children was assessed at a single visit at age 7-12 years (579 girls, 644 boys) using the parent-reported Pubertal Development Scale (PDS). Mixed-effect Poisson and g-computation and Bayesian Kernel Machine Regression (BKMR) were employed to examine associations of individual and combined prenatal chemical exposure, respectively, with the probability of overall pubertal onset, adrenarche, and gonadarche (stage 2+) in girls and boys. Effect modification by child body mass index (BMI) was also assessed.

RESULTS

Maternal concentrations of the molar sum of DEHP and of DiNP metabolites were associated with a slightly higher probability of having started puberty in boys (relative risk, RR [95% CI] = 1.13 [0.98-1.30] and 1.20 [1.06-1.34], respectively, for a two-fold increase in concentrations), with a stronger association for DiNP in boys with overweight or obesity. In contrast, BPA, BuPB, EtPB, and PrPB were associated with a lower probability of pubertal onset, adrenarche, and/or gonadarche in all boys (e.g. overall puberty, BPA: RR [95% CI] = 0.93 [0.85-1.01] and BuPB: 0.95 [0.90-1.00], respectively), and the association with BPA was stronger in boys with underweight/normal weight. In girls, MEHP and BPA were associated with delayed gonadarche in those with underweight/normal weight (RR [95% CI] = 0.86 [0.77-0.95] and 0.90 [0.84-0.97], respectively). Most of these associations were trimester specific. However, the chemical mixture was not associated with any pubertal outcome in boys or girls.

CONCLUSIONS

Prenatal exposure to certain phthalates and synthetic phenols such as BPA may impact the pubertal development of boys, and weight status may modify this effect. BPA may also alter the pubertal development of girls.

Depressive Symptoms in Adolescence and Young Adulthood

Importance

Depressive symptoms have increased among US adolescents since 2010. It remains unclear as to what extent this increase will persist into young adulthood, potentially turning the youth mental health crisis into a young adult mental health crisis.

Objective

To test the association between birth cohort and adolescent depressive symptoms at ages 18, 19 to 20, and 21 to 22 years and changes in these symptoms by cohort.

Design, Setting, and Participants

This panel cohort study analyzed data from the Monitoring the Future longitudinal survey from 1990 to 2019, including birth cohorts from 1972 to 2001. Survey respondents were recruited from US high schools in 12th grade and were approximately aged 18 years (at baseline) through age 21 to 22 years (during mail and web follow-up). Data analysis was conducted from April to October 2023.

Exposure

Depressive symptoms score (>12 vs ≤12, with >12 representing top-decile scores) on a scale examining affective items (eg, "Life often seems meaningless").

Main Outcomes and Measures

High (vs lower) depressive symptoms at ages 19 to 20 years and 21 to 22 years.

Results

The 36 552 respondents included 18 597 females (50.5%), and most reported having a parent who graduated from college (44.8%). Among females, 19.1% (95% CI, 16.7%-21.4%) of the most recent birth cohort (born: 1997-2001) had high depressive symptoms at age 18 years, higher than any previous birth cohort. While prevalence declined by age 21 to 22 years, it remained higher than previous cohorts at that age. Among males, 13.4% (95% CI, 11.2%-15.6%) of the most recent birth cohort had high depressive symptoms at age 18 years, and prevalence increased through young adulthood. Males with high baseline depressive symptoms had 10.24 (95% CI, 7.01-14.97) times the odds of symptoms at age 19 to 20 years and 6.20 (95% CI, 3.93-9.78) times the odds of symptoms at age 21 to 22 years. Females with high baseline depressive symptoms had 9.16 (95% CI, 6.57-12.76) times the odds of symptoms at age 19 to 20 years and 7.28 (95% CI, 4.92-10.78) times the odds of symptoms at age 21 to 22 years. The magnitude of the associations did not vary over time. Population attributable fractions indicated that the total proportion of young adult symptoms associated with depressive symptoms at age 18 years among females has increased; in the most recent birth cohort, 55.25% (95% CI, 38.11%-65.13%) of depressive symptoms at age 21 to 22 years were associated with symptoms at age 18 years.

Conclusions and Relevance

This panel cohort study found that increases in depressive symptoms in adolescence persisted into young adulthood, suggesting the need for primary prevention and mental health resources during the adolescent years.

Prenatal, newborn and childhood factors and the timing of puberty in boys and girls

BACKGROUND

Our aim was to determine if prenatal factors, gestational age, birth weight and length, and childhood body mass index (BMI) are associated with the timing of puberty.

METHODS

Our population-based study comprised 4826 girls and 5112 boys born between 1997 and 2002. Multiple linear regression modeled the relationships between the maternal and child predictors and the age at peak height velocity (PHV).

RESULTS

Maternal smoking throughout pregnancy was associated with earlier age at PHV (-1.8 months in girls, 95%CI = -3.2 to -0.3, p = 0.015 and -1.7 months in boys, 95%CI = -3.1 to -0.3, p = 0.016). Older gestational age predicted later age at PHV in boys. One SDS increase in birth weight led to 1.7 months later age at PHV in girls (95%CI = 1.2 to 2.2, p < 0.001) and 0.8 months in boys (95%CI = 0.2 to 1.3, p = 0.005). At the age of 9 years, each increment of BMI by 1 kg/m2 was associated with 1.7 months (95%CI = -1.9 to -1.6, p < 0.001) and 1.3 months (95%CI = -1.4 to -1.1, p < 0.001) earlier age at PHV in girls and boys, respectively.

CONCLUSIONS

Fetal exposure to smoking can potentially exert enduring effects on pubertal timing. Birth weight and childhood nutritional status are significant determinants of pubertal timing in both sexes.

IMPACT

Maternal smoking was associated with earlier timing of puberty and greater birth weight with later timing of puberty in both girls and boys. Most previous studies have focused on girls and used surveys to assess pubertal development, but we studied both sexes and used the same objective measure (age at peak height velocity) for the timing of puberty. Our study increases knowledge especially regarding factors associated with the timing of puberty among boys.

Changes in the Bile Acid Pool and Timing of Female Puberty: Potential Novel Role of Hypothalamic TGR5

CONTEXT

The regulation of pubertal timing and reproductive axis maturation is influenced by a myriad of physiologic and environmental inputs yet remains incompletely understood.

OBJECTIVE

To contrast differences in bile acid isoform profiles across defined stages of reproductive maturity in humans and a rat model of puberty and to characterize the role of bile acid signaling via hypothalamic expression of bile acid receptor populations in the rodent model.

METHODS

Secondary analysis and pilot studies of clinical cohorts, rodent models, ex vivo analyses of rodent hypothalamic tissues. Bile acid concentrations is the main outcome measure.

RESULTS

Lower circulatory conjugated:deconjugated bile acid concentrations and higher total secondary bile acids were observed in postmenarcheal vs pre-/early pubertal adolescents, with similar shifts observed in infantile (postnatal day [PN]14) vs early juvenile (PN21) rats alongside increased tgr5 receptor mRNA expression within the mediobasal hypothalamus of female rats. 16S rRNA gene sequencing of the rodent gut microbiome across postnatal life revealed changes in the gut microbial composition predicted to have bile salt hydrolase activity, which was observed in parallel with the increased deconjugated and increased concentrations of secondary bile acids. We show that TGR5-stimulated GnRH release from hypothalamic explants is mediated through kisspeptin receptors and that early overexpression of human-TGR5 within the arcuate nucleus accelerates pubertal onset in female rats.

CONCLUSION

Bile acid isoform shifts along stages of reproductive maturation are conserved across rodents and humans, with preclinical models providing mechanistic insight for the neuroendocrine-hepatic-gut microbiome axis as a potential moderator of pubertal timing in females.

Validity of self-assessment pubertal Tanner stages by realistic color images and Pubertal Development Scale in a longitudinal cohort study

Introduction

To date, the reliability of pubertal development self-assessment tools is questioned, and very few studies have explored the comparison between these tools in longitudinal studies. Hence, this study aimed to examine the reliability of pubertal development self-assessment using realistic color images (RCIs) and the Pubertal Development Scale (PDS) in a longitudinal cohort study.

Methods

Our longitudinal study recruited 1,429 participants (695 boys and 734 girls), aged 5.8-12.2 years old, in Chongqing, China. We conducted two surveys, 6 months apart. Tanner stages were examined by trained medical students at each visit. RCIs and PDS scores were used to self-assess puberty at each visit. Agreement between physical examination and self-assessment was determined using weighted kappa (wk), accuracy, and Kendall rank correlation.

Results

The concordance of puberty self-assessment using RCIs at baseline and the first follow-up was almost perfect in girls and boys, wk >0.800 (p < 0.001). At baseline, the concordance of genital development self-assessment using RCIs was fair in boys, wk = 0.285 (p < 0.001), and that of boys' pubic hair development self-assessment using RCIs was poor, wk = 0.311 [95% confidence interval (CI) -0.157 to 0.818]. The wk of the PDS was less than 0.300, except for breast development. The reliability and validity of the PDS in this study population were low, and the consistency of the PDS was not good.

Conclusions

The concordance of RCIs is better than that of the PDS. Pubertal development self-assessment using RCIs is reliable, while the reliability and validity of the PDS are unacceptable. Therefore, RCIs are recommended as a reliable pubertal development self-assessment tool to measure pubertal development for large-scale epidemiological investigations and long-term longitudinal studies in China.

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.