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To elucidate the processes underlying the cultural construction of adolescence, this research examined youth's stereotypes about teens in Hong Kong and Chongqing, a relatively less developed city in Mainland China. Youth (N = 1,269) reported on their teen stereotypes and problem behavior in the fall and spring of 7th grade. Youth in Hong Kong (vs. Chongqing) saw adolescence as a time of dampened family obligation as well as heightened individuation from parents, disengagement from school, and orientation toward peers. The tendency for youth in Hong Kong (vs. Chongqing) to see teens as less obligated to their family and more disengaged from school undergirded their greater problem behavior over the 7th grade, with problem behavior appearing to contribute to the maintenance of the two stereotypes.

Objective: To investigate overweight prevalence and socio-demographic and economic correlates in Chinese adolescents. Methods: Weight, height, waist circumference, and socio-demographic and economic variables of 6863 middle and high school students were measured. Results: 10% of girls and 17% of boys were overweight. Waist circumference and overweight risk were significantly associated with pubertal status (P less than 0.05). High levels of parental education and family income were significant risk factors for overweight (P less than 0.05). Discussion: Our findings underscore the need for development of evidence-based and culturally appropriate public health programs to prevent and treat pediatric obesity in China.

Purpose: Sex education in China has been promoted for many years, but limited data are available regarding the sources from which adolescents receive sex-related knowledge. The present study was designed to examine the sources from which Chinese adolescents obtain their information on puberty, sexuality and STI/HIV/AIDS, and whether there are any differences in sources of sex knowledge according to adolescents' demographic characteristics and sexual status. Design/methodology/approach: The data were collected in 2001 in Changchun City, China. Unmarried adolescents 15-19 years of age (322 males and 360 females) were included in a cross-sectional survey using self-administered questionnaires. Findings: Schoolteachers and mass media were identified as the two most important sources of sex knowledge. Sources of sex knowledge among adolescents on various topics (puberty, sexuality, and STI/HIV/AIDS) differed by the level of taboo associated with these topics in Chinese culture. The percentage of adolescents obtaining knowledge for puberty, sexuality, and STI/HIV/AIDS from teachers declined by topic (45.4, 30.7 and 18.4 percent, respectively), while the percentage of adolescents obtaining knowledge from television/movie increased by topic (6.7, 12.2 and 27.5 percent, respectively). Adolescents obtained knowledge on topics with less taboo (e.g. puberty) from teachers and obtained knowledge on topics with more taboo (e.g. sexuality, STI/HIV/AIDS) from mass media. However, this differs by having been sexually experienced or not. Parents were the primary source for sex knowledge on less taboo subjects. Doctors were the primary source for STI/HIV/AIDS knowledge. Sexually active adolescents obtained sex knowledge mainly from peers or mass media, while those adolescents who were not sexually experienced identified teachers and parents as the main sources of sex knowledge. Originality/value: The current study illustrates that it is necessary to improve and enhance current sex education programs in China by recognizing and strengthening the role of parents, teachers, and health care professionals in adolescent sex education. (Contains 4 tables and 1 figure.)

Reports the results of a broad-scale survey of the sexual knowledge and development of Chinese middle school youth. Includes information on sources of sexual knowledge, age of onset for specific sexual acts, psychological characteristics, and the goals of the sex education curriculum in Chinese middle schools. (JDH)

STUDY QUESTION Does fetal genetically determined birth weight associate with the timing of puberty? SUMMARY ANSWER Lower fetal genetically determined birth weight was causally associated with an earlier onset of puberty, independent of the indirect effects of the maternal intrauterine environment. WHAT IS KNOWN ALREADY Previous Mendelian randomization (MR) studies have indicated a potential causal link between birth weight, childhood BMI, and the onset of puberty. However, they did not distinguish between genetic variants that have a direct impact on birth weight through the fetal genome (referred to as fetal genetic effects) and those that influence birth weight indirectly by affecting the intrauterine environment (known as maternal genetic effects). It is crucial to emphasize that previous studies were limited because they did not account for the potential bias caused by unaddressed correlations between maternal and fetal genetic effects. Additionally, the proportion of birth weight variation explained by the fetal genome is considerably larger than that of the maternal genome. STUDY DESIGN, SIZE, DURATION We performed two-sample MR analyses to investigate the causal effect of fetal genetically determined birth weight on puberty timing using summary data from large-scale genome-wide association studies (GWASs) in individuals of European ancestry. PARTICIPANTS/MATERIALS, SETTING, METHODS From the two most recent GWASs specifically centered on birth weight, which included 406 063 individuals and 423 683 individuals (63 365 trios) respectively, we identified genetic variants associated with fetal genetically determined birth weight, while adjusting for maternal genetic effects. We identified genetic variants associated with childhood BMI from an independent GWAS involving 21 309 European participants. On this basis, we employed two-sample MR techniques to examine the possible causal effects of fetal genetically determined birth weight on puberty timing using a large-scale GWAS of puberty timing (including 179 117 females of European ancestry). Furthermore, we employed advanced analytical methods, specifically MR mediation and MR-Cluster, to enhance our comprehension of the causal relationship between birth weight determined by fetal genetics and the timing of puberty. We also explored the pathways through which childhood BMI might act as a mediator in this relationship. MAIN RESULTS AND THE ROLE OF CHANCE In the univariable MR analysis, a one SD decrease in fetal genetically determined birth weight (∼ 418 g) was associated with a 0.16 (95% CI [0.07–0.26]) years earlier onset of puberty. The multivariable MR analysis including fetal genetically determined birth weight and childhood BMI in relation to puberty timing provided compelling evidence that birth weight had a direct influence on the timing of puberty. Lower birth weight (one SD) was associated with an earlier onset of puberty, with a difference of 0.23 (95% CI [0.05–0.42]) years. We found little evidence to support a mediating role of childhood BMI between birth weight and puberty timing (−0.07 years, 95% CI [−0.20 to 0.06]). LIMITATIONS, REASONS FOR CAUTION Our data came from European ancestry populations, which may restrict the generalizability of our results to other populations. Moreover, our analysis could not investigate potential non-linear relationships between birth weight and puberty timing due to limitations in genetic summary data. WIDER IMPLICATIONS OF THE FINDINGS Findings from this study suggested that low birth weight, determined by the fetal genome, contributes to early puberty, and offered supporting evidence to enhance comprehension of the fetal origins of disease hypothesis. STUDY FUNDING/COMPETING INTEREST(S) C.Z. was funded by the Sichuan Province Science and Technology Program [grant number 2021JDR0189]. J.Z. was supported by grants from the National Natural Science Foundation of China [grant number 82373588]. No other authors declare any sources of funding. The authors have no conflicts of interest. TRIAL REGISTRATION NUMBER N/A. [ABSTRACT FROM AUTHOR]

Introduction: Pineal cysts have long been considered a benign intracranial variation. However, in our clinical practice, it has been observed that some children with central precocious puberty (CPP) who have pineal cysts experience rapid progression in adolescent development. In recent years, there has been a significant increase in the prevalence of CPP in girls, leading to more diagnoses of CPP among children with pineal cysts. Despite this, there is no consensus regarding whether pineal cysts contribute to CPP as one of its organic factors. This study aimed to analyze the clinical characteristics of pineal cysts in children with CPP and explore the potential effects of pineal cysts on puberty development. Methods: This single-center study retrospectively analyzed clinical data from girls aged 3 to 10 years who underwent head/pituitary magnetic resonance imaging at the Children's Hospital Affiliated to Zhengzhou University between 2019 and 2022. The study categorized the detection rates of pineal cysts based on systematic disease classification and compared the rates of cyst detection between girls diagnosed with CPP and those without CPP. Subsequently, CPPdiagnosed girls with pineal cysts were examined. Among CPP-diagnosed girls meeting the study's criteria, those with pineal cysts formed the 'cyst group,' while those without cysts were matched in a 1:1 ratio based on age and body mass index to form the 'non-cyst group.' Comparative analyses were conducted to assess the clinical characteristics between these two groups. CPP-diagnosed girls with cysts were further subdivided into three groups according to cyst size (≤5 mm, 5.1-9.9 mm, and ≥10 mm) to investigate potential differences in clinical characteristics among these subgroups. The study involved an analysis of clinical data from girls diagnosed with CPP and included imaging follow-ups to explore the progression of pineal cysts over time. Results: Among the 23,245 girls who underwent head/pituitary magnetic resonance imaging scans, the detection rate of pineal cysts was 3.6% (837/23,245), with most cases being associated with endocrine diseases. The detection rate of pineal cysts in CPP patients was 6.4% (262/4099), which was significantly higher than the 3.0% (575/19,146) in patients without CPP. In comparison to the non-cyst group, the cyst group exhibited statistically significant increases in estradiol levels, peak luteinizing hormone (LH) levels, peak LH/follicle-stimulating hormone (FSH) ratios, uterine body length, and cervix length (P < 0.001). As cyst size increased, there were significant rises in LH peak, peak LH/FSH ratio, uterine body length, and cervical length (P < 0.01). Estradiol levels and left ovarian volume also showed an increasing trend (P < 0.05). Among girls who underwent follow-up imaging, 26.3% (5/19) exhibited an increase in cyst size. Conclusion: Pineal cysts are relatively common in children with CPP. They may affect the pubertal development process, with larger cysts correlating to faster pubertal development. Therefore, the authors hypothesize that pineal cysts may trigger CPP in some cases, especially when the cysts are larger than 5mmin size, as indicated by our data. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to determine the clinical characteristics of obese pediatric non-alcoholic fatty liver disease (NAFLD) in central China and verify the applicability of some known risk factors for pediatric NAFLD before late puberty. Methods: This was a retrospective case-control study. A total of 1,029 inpatients at Wuhan Children's Hospital before the late puberty stage were enrolled in the study, including 815 children with obesity (non-NAFLD group) and 214 children with obesity and NAFLD (NAFLD group) diagnosed by liver ultrasound. Subgroup analyses were performed according to sex and puberty. The anthropometric indices and laboratory test data of these 1,029 children were sorted. After intergroup comparison, a logistic regression model was used to determine the risk factors for pediatric NAFLD. Significant risk factors for NAFLD were further tested using receiver operating characteristic (ROC) curves to evaluate their ability to predict an early diagnosis of NAFLD. Results: The NAFLD group had a mean age of 11.03 ± 1.66, with 11.18 ± 1.66 and 10.27 ± 1.45 years for male and female children, respectively (p < 0.05 and p < 0.01, respectively). Even subdivided by both sex and puberty, raised body mass index (BMI), homeostatic model-insulin resistance, triglycerides, alanine transaminase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transferase (γ-GT) were still found in the non-NAFLD and NAFLD groups (p < 0.05 and p < 0.01, respectively). The results of logistic regression analysis showed that BMI (odds ratio [OR], 1.468;95% confidence interval [CI], 1.356-1.590; p<0.001) and ALT (OR, 1.073;95%CI, 1.060-1.087; P<0.001) were two most independent risk factors for NAFLD. The maximal OR for BMI was 1.721 (95% CI, 1.336-2.217). In the female group, the maximal OR of ALT was found to be 1.104 (95% CI, 1.061-1.148). Age and thyroid-stimulating hormone (TSH) and γ-GT levels were also risk factors, but they appeared only in some groups. The results of the ROC analysis showed that ALT was a better predictor of pediatric NAFLD than BMI. The maximum area under the ROC curve in six of the nine groups belongs to ALT. Conclusions: BMI, ALT, and age are risk factors for NAFLD in children with obesity before late puberty. BMI had the greatest exposure risk for NAFLD, and ALT had the highest predictive value for the diagnosis of NAFLD. At the stratified level, for exposure risk, age was specific to the male sex, TSH was specific to the early puberty stage, and γ-GT was specific to the female sex plus the prepuberty stage. On a stratified level, for the female sex, even with age stratification, BMI rather than ALT has a better ability for the diagnosis of NAFLD. [ABSTRACT FROM AUTHOR]

Sex education is integral to helping protect adolescents and young adults from sexually transmitted infections, avoid unwanted pregnancies, and build healthy intimate relationships. The aim of this study was to examine gender differences in sex-related knowledge, attitudes, and behaviors, and to identify factors that may contribute to these differences. A cross-sectional survey was distributed to 190 adolescents from three middle schools and one senior high school in Fuzhou, China. Multivariable logistic regression analyses were used to determine the associations between individual factors and students' attitudes or behaviors. Parents were more likely to answer girls' questions about sex than boys' questions (p < 0.001), and sex education courses were delivered later to boys (p = 0.003) than to girls. Accordingly, girls were more positive than boys when they encountered issues related to puberty (p < 0.001) and when participating in friends' discussions about puberty and adolescence (p = 0.004). Girls were less likely to accept intimate behavior (sexual touch/intercourse) than boys (p = 0.011). In the multivariable logistic regression model, gender and parents' reactions to the students' questions were independent factors in their styles of coping with puberty-related issues. However, gender was not associated with students' reactions to friends' discussions about puberty or their acceptance of intimate behavior in the adjusted model, while other variables, such as knowledge score and need score, were identified as independent factors. Our study found that several individual factors may explain gender differences in adolescents' attitudes and behaviors about sex. Designation of targeted sex education programs should consider these individual factors in the future. [ABSTRACT FROM AUTHOR]

Background: The applicability and accuracy of artificial intelligence (AI)-assisted bone age assessment and adult height prediction methods in girls with early puberty are unknown. Objective: To analyze the performance of AI-assisted bone age assessment methods by comparing the corresponding methods for predicted adult height with actual adult height. Materials and methods: This retrospective review included 726 girls with early puberty, 87 of whom had reached adult height at last follow-up. Bone age was evaluated using the Greulich–Pyle (GP), Tanner–Whitehouse (TW3–RUS) and China 05 RUS–CHN (RUS-CHN) methods. Predicted adult height was calculated using the China 05 (CH05), TW3 and Bayley–Pinneau (BP) methods. Results: We analyzed 1,663 left-hand radiographs, including 155 from girls who had reached adult height. In the 6–8- and 9–11-years age groups, bone age differences were smaller than those in the 12–14-years group; however, the differences between predicted adult height and actual adult height were larger than those in the 12–14-years group. TW3 overestimated adult height by 0.4±2.8 cm, while CH05 and BP significantly underestimated adult height by 2.9±3.6 cm and 1.3±3.8 cm, respectively. TW3 yielded the highest proportion of predicted adult height within ±5 cm of actual adult height (92.9%), with the highest correlation between predicted and actual adult heights. Conclusion: The differences in measured bone ages increased with increasing bone age. However, the corresponding method for predicting adult height was more accurate when the bone age was older. TW3 might be more suitable than CH05 and BP for predicting adult height in girls with early puberty. Methods for predicting adult height should be optimized for populations of the same ethnicity and disease. [ABSTRACT FROM AUTHOR]

Background: Central precocious puberty (CPP) is a precocious puberty due to premature activation of the hypothalamic–pituitary‐gonadal axis (HPG). MKRN3 defects are well‐known causes of CPP, while DLK1 mutations were recently identified in a few patients with CPP. Methods: The study was approved by the Institutional Review and the scientific committee of the hospital. The clinical data were collected. Whole‐exome sequencing (WES) was performed to detect causative variants. Key words 'DLK1', 'MKRN3', and "central precocious puberty" were used for literature search in PubMed, Google Scholar, HGMD, and OMIM databases. Results: The patient, a male, whose puberty began before age nine, had significant metabolic abnormalities including overweight, hyperlipidemia, and hyperuricemia. WES detected a recurrent frame‐shift mutation, NM_003836.5:c.479delC(p.P160fs*50) in DLK1 in the patient and his father. Conclusion: The familial DLK1‐CPP was identified in China for the first time, which supported that short stature is predicted in patients with CPP without GnRHa treatment. Therefore, we recommend that children with DLK1‐CPP should be treated as early as possible to improve adult height. The patient in this study had persistent hyperuricemia, further suggests that this antiadipogenic factor represents a link between reproduction and metabolism. [ABSTRACT FROM AUTHOR]

Background: cblC deficiency is the most common type of methylmalonic aciduria in China. Late-onset patients present with various non-specific symptoms and are usually misdiagnosed. The purpose of this study is to investigate the clinical features of patients with late-onset cblC deficiency and explore diagnosis and management strategies around puberty.Results: This study included 56 patients (35 males and 21 females) with late-onset cblC deficiency who were admitted to our clinic between 2002 and September 2021. The diagnosis was confirmed by metabolic and genetic tests. The clinical and biochemical features, disease triggers, outcome, and associated genetic variants were examined. The onset age ranged from 10 to 20 years (median age, 12 years). Fifteen patients (26.8%) presented with symptoms after infection or sports training. Further, 46 patients (82.1%) had neuropsychiatric diseases; 11 patients (19.6%), cardiovascular diseases; and 6 patients (10.7%), pulmonary hypertension. Renal damage was observed in 6 cases (10.7%). Genetic analysis revealed 21 variants of the MMACHC gene in the 56 patients. The top five common variants detected in 112 alleles were c.482G > A (36.6%), c.609G > A (16.1%), c.658_660delAAG (9.8%), c.80A > G (8.0%), and c.567dupT (6.3%). Thirty-nine patients carried the c.482G > A variant. Among 13 patients who exhibited spastic paraplegia as the main manifestation, 11 patients carried c.482G > A variants. Six patients who presented with psychotic disorders and spastic paraplegia had compound heterozygotic c.482G > A and other variants. All the patients showed improvement after metabolic treatment with cobalamin, L-carnitine, and betaine, and 30 school-aged patients returned to school. Two female patients got married and had healthy babies.Conclusions: Patients with late-onset cblC deficiency present with a wide variety of neuropsychiatric symptoms and other presentations, including multiple organ damage. As a result, cb1C deficiency can easily be misdiagnosed as other conditions. Metabolic and genetic studies are important for accurate diagnosis, and metabolic treatment with cobalamin, L-carnitine, and betaine appears to be beneficial. [ABSTRACT FROM AUTHOR]

Introduction: The relationship between the characteristics of puberty growth and the stature (height and overweight and obesity) in late adolescence was not clear. We aimed to explore the effects of puberty growth patterns on the stature in late adolescence. Methods: A total of 13,143 children from a longitudinal cohort from 2006 to 2016 in Zhongshan city of China were included. The Preece-Baines growth curve was fitted for each individual child, and the age at peak height velocity (APHV), peak height velocity (PHV), and age at take-off (TOA) were obtained from the Preece-Baines model. To compare the difference in height in late adolescence (at 18 years old) at different pubertal height growth patterns (height spurt timing, intensity, and duration), the height at baseline was matched by using the propensity score matching. The log-binomial model was applied to assess the association between the three pubertal height growth patterns (timing, intensity, and duration) and overweight and obesity status in late adolescence, controlling the urbanity and body mass index (BMI) at baseline. Results: After matching the baseline height, boys and girls in three pubertal patterns with early timing (P < 0.01), small intensity (P < 0.01), and short duration (P < 0.01) of height spurt had the lowest final height in the late adolescence. A 16% increase and 45% increase of risk for overweight and obesity were significantly associated with the early APHV in boys and girls, respectively, relative risk (RR) in boys, 1.16(95% confidence interval, CI: 1.03-1.30), P = 0.011; RR in girls, 1.45(1.21-1.75), P < 0.001. A 21% increase and 59% increase of risk for overweight and obesity were significantly associated with small PHV in boys and girls, respectively, RR in boys, 1.21(1.07-1.36), P < 0.001; RR in girls, 1.59 (1.30-1.95), P < 0.001; and an 80% increase of risk for overweight and obesity with small spurt duration in girls (RR = 1.80; 95% CI: 1.49, 2.18; P < 0.001). Conclusion: Pubertal growth patterns, including earlier puberty onset timing, smaller puberty intensity, and shorter puberty spurt duration, had a positive association with lower height risks and higher overweight and obesity risks in late adolescence. [ABSTRACT FROM AUTHOR]

Pediatric Reference Intervals in China (PRINCE) is a nationwide initiative that aims to establish and validate harmonized reference intervals (RIs) for Chinese children and adolescents, in which 15,150 healthy volunteers aged up to 20 years were recruited from 11 centers to establish RIs and 7,557 children and adolescents were enrolled from 21 centers to validate RIs. The complete blood cell counts (CBC) of venous whole blood were measured by hematology analyzers through Sysmex systems in different centers. Age- and sex-specific RIs were calculated according to the guidelines. Unlike adults with certain levels of analyte concentrations, hematological parameters of children changed through growth and development. Red blood cell counts, hemoglobin, and hematocrit increased with age, and revealed higher concentrations in boys than girls after puberty. White blood cell counts and platelet counts showed significant higher levels than adults before 2 years of age, and then gradually decreased without distinct sex differences. In addition, lymphocyte counts decreased with age while neutrophil counts showed an opposite trend. The lower and upper limits of pediatric RIs of CBC were different from those of adults. The validation of RIs indicated that the PRINCE study provided a version of RIs suitable for most of regions in China. This first harmonized pediatric RIs of CBC across China provided a robust database to understand the dynamic changes of hematologic parameters from birth to adolescence, and will contribute to clinical diagnosis and prognosis evaluation for pediatric patients as well. [ABSTRACT FROM AUTHOR]

Context: Although gonadotropin-releasing hormone stimulation test (GnRHST) is the gold standard in diagnosing central precocious puberty (CPP), it is invasive, expensive, and time-consuming, requiring multiple blood samples to measure gonadotropin levels.Objective: We evaluated whether urinary hormones could be potential biomarkers for prepuberty or postpuberty, aiming to simplify the current diagnosis and prognosis procedure.Methods: We performed a cross-sectional study of a total of 355 girls with CPP in National Clinical Research Center for Child Health in China, including 258 girls with positive and 97 girls with negative results from GnRHST. Twenty patients received GnRH analogue (GnRHa) treatment and completed a 6-month follow up. We measured luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol, prolactin, progesterone, testosterone, and human chorionic gonadotropin in the first morning voided urine samples.Results: Their urinary LH levels and the ratios of LH to FSH increased significantly with the advancement in Tanner stages. uLH levels were positively associated with basal and peak LH levels in the serum after GnRH stimulation. A cutoff value of 1.74 IU/L for uLH reached a sensitivity of 69.4% and a specificity of 75.3% in predicting a positive GnRHST result. For the combined threshold (uLH ≥ 1.74 + uLH-to-uFSH ratio > 0.4), the specificity reached 86.6%. After 3 months of GnRHa therapy, the uLH and uFSH levels decreased accordingly.Conclusion: uLH could be a reliable biomarker for initial CPP diagnosis and screening; uLH could also be an effective marker for evaluating the efficacy of clinical treatment. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to establish a protein binding model of unbound valproic acid (VPA) based on Chinese pediatric patients with epilepsy and provide a reference for clinical medication. Methods: A total of 313 patients were included and both their total and unbound VPA concentrations (375 pairs of concentrations) were measured. NONMEM software was used for population pharmacokinetic modeling. The stepwise method was used to screen the potential covariates. Goodness-of-fit plot, bootstrap, and visual predictive check were used for model evaluation. In addition, dose recommendations for typical patients aged 0 to 16 years were proposed by Monte Carlo simulations. Results: A one-compartment model of first-order absorption and first-order elimination was used to describe the pharmacokinetic characteristics of unbound VPA, and the linear non-saturable binding equation was introduced to describe the protein binding. Body weight, age-based maturation, and co-medicated with lamotrigine could affect the CL/F of unbound and bound VPA. Model evaluation showed satisfactory robustness of the final model. The dosing regimens for children aged 0 to 16 years were proposed based on the final established model. Conclusion: We developed a population pharmacokinetic model of unbound and bound VPA that took account of protein binding. The VPA dosing regimen in pediatric patients with epilepsy needs to be optimized by the body weight, age, and co-medications. [ABSTRACT FROM AUTHOR]

Background: Thyroid volume (Tvol) is associated with many factors, but the current reference values for Tvol in children with sufficient iodine intake are inappropriate and need to be updated. Moderate changes in thyroid morphology and accentuated increases in body fat percentage occur during puberty as an adaption of the body and sexual development occurs. This study aimed to evaluate the influences of physical growth on Tvol and propose an easily applicable method for conducting Tvol assessments in pubertal girls with sufficient iodine intake. Methods: A cohort study was conducted on 481 pubertal girls in East China from 2017 to 2019. B-ultrasound was used to assess Tvol. Multiple linear regression models were used to estimate the associations of Tvol enlargement (d Tvol) with changes in height (d H), weight (d W), waist circumference (d W), body mass index (d BMI), and body surface area (d BSA). Thyroid volume indexes (TVIs), including height thyroid volume index (HVI), weight and height thyroid volume index (WHVI), body mass index thyroid index (BMIV), and body surface area thyroid index (BSAV), were calculated to explore an appropriate method for Tvol assessments by Spearman correlation analyses. Results: Tvol, height, weight, BMI, and BSA increased significantly from baseline to follow-up (P <0.001). The associations between d Tvol and physical growth were only observed in the 13 to 14-year-old group. d H, d W, d BMI, and d BSA were positively related to d Tvol, with the maximum β of 5.74 (95%CI: 2.54 to 8.94) on d BSA, while d WC was negatively related to d Tvol (β= -0.05, 95%CI: -0.08 to -0.03). Both d HVI and d BSAV were not associated with d H, d W, d BMI, or d BSA in both age groups (P >0.05). Conclusions: Thyroid volume was associated with physical growth in pubertal girls in East China, both age and anthropometric measurements must be comprehensively considered to establish the reference values for Tvol. HVI, and BSAV may be better indicators for Tvol assessments in pubertal girls. [ABSTRACT FROM AUTHOR]

Background: The onset of puberty is influenced by thyroid function, and thyroid hormones (THs) fluctuate substantially during the period of pubertal development. However, it needs to be further clarified how THs change at specific puberty stages and how it influences pubertal development in girls. So far, longitudinal data from China are scarce. Methods: A cohort study was conducted among girls during puberty in iodine-sufficient regions of East China between 2017 to 2019. Serum thyroid stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) were determined for each participant. Thyroid homeostasis structure parameters (THSPs), including the ratio of FT4 to FT3 (FT4/FT3), Jostel's TSH index (TSHI), and thyroid feedback quantile-based index (TFQI), were calculated. Puberty category scores (PCS), calculated based on the Puberty Development Scale (PDS), was used to assess the stage of puberty. Girls were grouped into three categories according to PCS changes (△PCS) and six categories according puberty stage (BPFP: pre-pubertal at both baseline and follow-up; BPFL: pre-pubertal at baseline and late-pubertal at follow-up, respectively; BPFT: pre-pubertal at baseline and post-pubertal at follow-up, respectively; BLFL: late-pubertal at both baseline and follow-up; BLFT: late-pubertal at baseline and post-pubertal at follow-up, respectively; BTFT: post-pubertal at both baseline and follow-up). Multiple linear regression analyses were used to evaluate the associations of THs changes with pubertal progress. Results: The levels of serum TSH and FT3 decreased while serum FT4 increased during the study period (P<0.001). In multiple linear regression analyses, after adjustment for covariables, FT3 decreased by an additional 0.24 pmol/L (95% CI: -0.47 to -0.01) in the higher △PCS group than the lower △PCS group. Compared with the BLFL group, the BPFT group showed an additional decline in FT3 (β= -0.39 pmol/L, 95%CI: -0.73 to -0.04), the BTFT group showed a lower decline in TSH (β=0.50 mU/L, 95% CI: 0.21 to 0.80) and a lower decline in TSHI (β=0.24, 95%CI: 0.06 to 0.41), respectively. There was no association of △FT4 or △TFQI with △PCS or the puberty pattern. Conclusions: Serum TSH and FT3 decreased while serum FT4 increased among girls during puberty. Both the initial stage and the velocity of pubertal development were related to thyroid hormone fluctuations. [ABSTRACT FROM AUTHOR]

Background: The hypothalamic-pituitary-adrenocortical (HPA) axis had been proved to calibrate to early-life adversity and puberty may reverse the calibration. This study examines the consequences of prolonged parent-child separation on HPA axis reactivity and the pubertal recalibration hypothesis.Methods: Totally of 144 participants aged 8.75 to 15.25 (mean age 12.50 years, SD: 1.32) were enrolled from rural areas of Chizhou city, Anhui Province of China in 2019. Data on parent-child separation was collected from parents. Self-reported Peterson Pubertal Development Scale was used to assess pubertal maturation and HPA axis stress reactivity was measured using the Trier Social Stress Test for Children.Results: For children at early stage of puberty, childhood parent-child separation experiences were associated with blunted HPA axis reactivity (B = -1.888, p = 0.034); while for those at later stage of puberty, HPA axis reactivity was similar between children experienced early childhood separation and those without separation (AUCi: B = -0.426, p = 0.878). In contrast, for children experienced persistent parent-child separation, blunted HPA axis reactivity was observed (all p < 0.05).Limitations: Due to the cross-sectional nature of this study, conclusions about causality remain speculative.Conclusions: The effect of parent-child separation on dysregulation of HPA axis acts in a time-dependent manner. This finding provides support for the pubertal recalibration hypothesis suggesting that a focus of improving environment in adolescence would help those individuals reared initially in non-supportive conditions. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of polycyclic aromatic hydrocarbons(PAHs) on puberty in boys., Methods: 695 subjects were selected from four primary schools in Chongqing, China. 675 urine samples from these boys were collected four PAH metabolites: 1-hydroxypyrene, 2-hydroxynaphthoic, 2-hydroxyfluorene, and 9-hydroxyphenanthrene. Pubertal development of 695 boys was assessed at follow-up visits starting in December 2015 and occurring every six months thereafter until now, data used in this article ending in June 2021. A total of 12 follow-up visits were performed. Cox proportional hazards regression models were used to analyze the relationship between PAH metabolite concentrations and indicators of pubertal timing., Results: The mean age at puberty onset of testicular volume, facial hair, pubic hair, first ejaculation, and axillary hair in boys was 11.66, 12.43, 12.51, 12.72 and 13.70 years, respectively. Cox proportional hazards regression models showed that boys with moderate level of 1-OHPyr exposure was associated with earlier testicular development (hazard ratio [HR] = 1.276, 95% confidence interval [CI]: 1.006-1.619), with moderate level of 2-OHNap were at higher risk of early testicular development (HR = 1.273, 95% CI: 1.002-1.617) and early axillary hair development (HR = 1.355, 95% CI: 1.040-1.764), with moderate level of 2-OHFlu was associated with earlier pubic hair development (HR = 1.256, 95% CI: 1.001-1.577), with high level of 9-OHPhe were at higher risk of early fisrt ejaculation (HR = 1.333, 95% CI: 1.005-1.767) and early facial hair development (HR = 1.393, 95% CI: 1.059-1.831)., Conclusion: Prepubertal exposure to PAHs may be associated with earlier pubertal development in boys., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Objectives: Although the association between thyroid stimulating hormone (TSH) and obesity in children has been investigated in several cross-sectional studies, no study evaluated this association among girls during puberty, which were in a key period closely related to the fluctuations of thyroid hormones and development of obesity. Therefore, we conducted a cohort study to investigate the association of general and abdominal obesity with TSH in girls during puberty. Setting and participants: A cohort study of 481 school-aged girls during puberty was conducted in four regions in east China, with a baseline survey in 2017 and a follow-up survey in 2019. Outcome measures: Anthropometric indexes including height, weight and waist circumference (WC) were measured, and body mass index (BMI) was then calculated. Blood samples were collected to determine TSH and free thyroxine (FT4). Results: Of the 474 girls at baseline survey, the prevalences of BMI-based general obesity and WC-based abdominal obesity were 19.8% (94/474) and 21.7% (103/474), respectively. Compared with normal weight girls, the median serum TSH level was significantly higher in general obese girls (P = 0.037), but not in central obese girls (P = 0.173). Multiple logistic regression models indicated that those in the highest tertile of serum TSH level had a significantly higher risk of BMI-based overweight/obesity (OR = 1.83, 95% CI 1.01 to 3.32) compared with the lowest tertile. Analyses from 435 girls prospectively followed-up for 2 years revealed that those with general or central obesity also had higher follow-up TSH level (P = 0.004 and P = 0.008, respectively). The TSH level for girls with general obesity at baseline but normal weight at follow-up was 0.45 mU/L (95% CI 0.11 to 0.79) higher than those with normal weight at baseline and follow-up. Conclusions: TSH was positively associated with both general and abdominal obesity among girls during puberty. [ABSTRACT FROM AUTHOR]

Summary: Background: The intake of sugar‐sweetened beverages (SSBs) has been linked to an increased risk of cardiometabolic diseases. Objectives: This study aims to examine associations between SSB intake and cardiometabolic risks among Chinese children and adolescences. Methods: Data from 3958 participants aged 6‐17 years old were obtained in Shanghai, China, from September to October 2015. A 3‐day dietary record and a food‐frequency questionnaire (FFQ) were applied to assess SSB consumption and frequency. Anthropometric and laboratory measurements were conducted to measure cardiometabolic indicators. Results: After adjusting for age, sex, daily energy intake, pubertal stage, sedentary time, maternal education, and household income, SSB consumption was positively associated with serum total cholesterol and low‐density lipoprotein‐cholesterol (LDL‐C), while it was inversely associated with systolic blood pressure (P <.05). The participants in the highest intake category (≥201.7 mL/day) of SSB consumption had 0.10 (95%CI, 0.02‐0.18) mmol/L higher total cholesterol and 0.09 (95%CI, 0.03‐0.16) mmol/L higher LDL‐C levels than the nonconsumption group (0 mL/day). There was a quasi‐U‐shaped trend in LDL‐C across the categories of >0 mL/day SSB consumption. SSB frequency was positively associated with BMI (P =.04). Conclusions: SSB intake was positively associated with serum cholesterol and was weakly associated with BMI in Chinese children and adolescents, independent of energy intake. [ABSTRACT FROM AUTHOR]

Background. A deficiency in steroid 5α-reductase type 2 is an autosomal recessive disorder. Affected individuals manifested ambiguous genitalia, which is caused by decreased dihydrotestosterone (DHT) synthesis in the fetus. Methods. We analyzed 25 patients with 5α-reductase deficiency in China. Seventeen of the 25 patients (68%) were initially raised as females. Sixteen patients changed their social gender from female to male after puberty. Results. Eighteen mutations were identified in these patients. p.Gly203Ser and p.Gln6 ∗ were found to be the most prevalent mutations. On the basis of the genotype of these patients, we divided them into different groups. There was no significant difference in hormone levels and external masculinization score (EMS) in patients with or without these prevalent mutations. Twelve common single-nucleotide polymorphisms (SNPs) near the p.Gln6 ∗ mutation were chosen for haplotype analysis. Three haplotypes were observed in 6 patients who had the p.Gln6 ∗ mutation (12 alleles). Conclusion. We analyzed mutations of the SRD5A2 gene in Chinese patients with 5α-reductase deficiency. Although hotspot mutations exist, no founder effect of prevalent mutations in the SRD5A2 gene was detected in the Chinese population. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to analyze the growth patterns of height and foot length (FL) among Chinese children aged 3-18 and examine their associations with puberty development., Methods: A cross-sectional survey was conducted in September 2022 in Beijing. Data were collected through questionnaires and on-site physical examinations. The growth patterns and velocity of height and FL in different age groups were described, and their associations with puberty development were analyzed., Results: From an age perspective, the peak FL growth occurred between 9 and 11 years (boys were 11 years and girls were 9 years), while the peak height growth occurred at 11 ~ 13 years for boys and 9 ~ 11 years for girls. Additionally, boys and girls reached 99.0% of their final FL at the ages of 14 and 13, respectively, while they reached 99.0% of their final height at the ages of 16 and 15, respectively. From the perspective of Tanner stage, the age of peak FL growth in boys coincided with the age of the G 2 stage, while in girls it occurred slightly earlier than the mean age of the B 2 stage. The peak height growth for both boys and girls occurred between Tanner stages 2 and 3., Conclusion: Boys and girls reach their peak FL growth at 11 and 9 years old, respectively, which were both 2 years earlier than their peak height growth. The peak FL growth occurred around the onset of puberty, while the peak height growth occurred between Tanner stages 2 and 3., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Wu, Zhang, Yu, Yang, Tao, Shu, Li, Huang, Hou, Chen, Liu, Li and Zong.)

Objective: To assess the association between body mass index (BMI) and physical fitness index (PFI) among children and adolescents in Xinjiang Uyghur Autonomous Region, China. Methods: In total, 17,618 children and adolescents aged 7–18 years from the selected region were enrolled in this cross-sectional study (8,800 boys and 8,818 girls). Participants were stratified by age and sex and divided into five groups by BMI percentiles: very low (BMI <5th percentile); low, (5th ≤ BMI < 15th percentile); normal (15th ≤ BMI < 85th percentile); high (85th ≤ BMI < 95th percentile); and very high (BMI ≥95th percentile). PFI was assessed by height, weight, and five health-related fitness indicators (grip strength, standing long jump, sit and reach, 50 m dash, and endurance run). Results: BMI was significantly associated with PFI during adolescence (13–18 years) in boys and pre-adolescence (7–12 years) in girls. Between the ages of 13 and 18 years, an increase in BMI had a greater impact on PFI in boys than girls. PFI showed a parabolic curvilinear relationship with BMI. Conclusion: Children and adolescents in China’s Xinjiang Uyghur Autonomous Region with a normal BMI demonstrated good physical fitness. A BMI below or above the normal range may contribute to poor physical fitness. The relationship between BMI and PFI shows an inverted U-shaped curve. [ABSTRACT FROM AUTHOR]

This paper reports the development and baseline data of a vignettes-based measure of gender equality. Methods: Vignettes were developed through 3-day long focus groups. After piloting in 13 sites and repiloting a revised version in 6 countries, responses were categorized by the construct tapped and a scoring system developed. Finalized vignettes were then tested in DR Congo, Ecuador and China. Results: Young adolescents can successfully respond to vignettes; and can differentiate self from hypothetical protagonists of same and opposite sex. Response differences by sex of respondent and protagonist were statistically significant across a range of scenarios and settings. Conclusion: This is the first vignettes-based measure for young adolescents assessing young adolescent perceptions of relationships differentiated by sex of the protagonist. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to analyse the associations of left-hand digit ratio (2D:4D), digit length and puberty characteristics to show the role of prenatal hormones in development among Chinese girls.Method: A total of 318 Chinese girls aged 8-15 years were recruited using a stratified cluster sampling method. The index finger (2D), ring finger (4D) of the left hand, oestradiol and testosterone were measured, and age at menarche (AAM), breast (high and low) and pubic hair (high and low) development were recorded.Results: Girls who had experienced menarche had longer left digits (2D and 4D) and higher oestradiol, testosterone than those who had not. The high breast group had longer digits (2D and 4D), and higher oestradiol than the low breast group. With regard to pubic hair development, the high group had high 2D:4D, longer 2D and higher oestradiol, testosterone than the low group. After adjusting for oestradiol and testosterone, 4D length was positively related to occurrence of menarche. In addition, 2D and 2D:4D were significantly correlated with pubic hair development after adjusting for oestradiol, respectively.Conclusion: Prenatal hormone level may be related to the development of puberty characteristics among Chinese girls. [ABSTRACT FROM AUTHOR]

• Early puberty affects an increasing proportion of children for reasons that remain obscure. • This study sought to apply untargeted metabolomic profiling to identify triggering mechanisms and candidate biomarkers in children with early puberty. • Metabolomic profiling for early puberty presents sex-specific manner. • Through metabolomic analysis, the present study have identified metabolic perturbations and potential biomarkers of early puberty. A trend toward earlier pubertal maturation in both sexes has been shown in many countries. Early puberty affects an increasing proportion of children for reasons that remain obscure. Novel candidate biomarkers are strongly needed. We sought to apply untargeted metabolomic profiling to identify triggering mechanisms and candidate biomarkers in children with early puberty. Participants aged 7 – 12 years old were recruited directly from two elementary schools of Bengbu, Anhui Province, China, from Feb 2021 to May 2021. Early puberty was determined by breast and testicular development at baseline (May 2021) and 6-month later. Ultra-high-performance liquid chromatography-based untargeted metabolomic profiling was performed on urine samples of children with early puberty and control subjects. Metabolomic profiling for early puberty in a sex dependent manner. For boys, we identified several perturbed pathways, including histidine metabolism, glycine, serine and threonine metabolism, and selenoamino acid metabolism, associated with early puberty. In contrast, there were differences in pyruvate metabolism, one carbon pool by folate, and D -glutamine and D -glutamate metabolism pathways in girls with early puberty compared with controls. In addition, 4-hydroxyhippuric acid and 5-methoxytryptophol were shown as potential independent diagnostic biomarker for early puberty in boys, 3-hydroxybenzoic acid and glutaminylproline were shown as early biomarker for early puberty in girls, achieving area under the ROC curve of 0.71 and 0.72 in discriminating early puberty boys, and 0.70 and 0.74 in discriminating early puberty girls from controls. Through metabolomic analysis, we have identified metabolic perturbations and potential biomarkers of early puberty. [Display omitted] We sought to apply untargeted metabolomic profiling to identify triggering mechanisms and candidate biomarkers in children with early puberty. Participants aged 7 – 12 years old were recruited directly from two elementary schools of Bengbu, Anhui Province, China, from Feb 2021 to May 2021 (N = 160, 50% girls). Metabolomic profiling for early puberty presents sex-specific manner. Through metabolomic analysis, we have identified metabolic perturbations and potential biomarkers of early puberty. [ABSTRACT FROM AUTHOR]

Early onset of puberty could have significant impacts on childhood health, but the extent to which it was affected by phthalate esters (PAEs) and sex hormone disruption was not understood. The aim of this study is to investigate the associations between exposure to PAEs and sex hormone disruption and early onset of puberty in children. A longitudinal cohort study was conducted in China from May 2017 to Oct 2020, involving 740 children during consecutive visits. The onset of puberty was evaluated using Tanner definition, and early puberty was defined as an onset age less than the first 25 %, with cut-offs of 10.33 and 8.97 years for boys and girls, respectively. Serum testosterone (TT), estradiol (E 2) and urinary PAE metabolites were measured during three visits. Generalized linear models were used to explore the associations between PAE and sex hormones with the age of puberty onset, while log-binomial regressions were applied to assess the associations of persistent exposure to PAEs and sex hormones with early pubertal onset. Approximately 86.0 % of boys and 90.2 % of girls completed puberty onset from pre-puberty, and more than 95 % of participants had PAE concentrations higher than the limit of detection. Boys showed higher exposure to PAE pollutants and higher TT levels. Persistent exposure to PAEs was positively associated with early pubertal onset in girls (ARR = 1.97, 95 %CI = 1.12, 3.46). Moreover, persistent exposure to PAEs and E 2 had synergistic associations with early pubertal onset in both boys (ARR = 4.77, 95 %CI = 1.06, 21.54) and girls (ARR = 7.07, 95 %CI = 1.51, 33.10). However, PAEs and TT had antagonistic associations only in boys (ARR = 0.44, 95 %CI = 0.07, 2.58). Long-term exposure to PAEs might increase the risk of early pubertal onset, and it appears to work in synergy with E 2 , while in antagonism with TT in boys' early pubertal onset. Reducing PAEs exposure might promote pubertal health. • Long-term phthalates exposure was related with girls' early pubertal onset. • Phthalates and estradiol had synergistic associations with early pubertal onset. • Phthalates worked in antagonism with testosterone in boys' early pubertal onset. • Determining exposure limits is critical for pubertal development. [ABSTRACT FROM AUTHOR]

Background. The factors influencing pubertal timing have gained much attention due to a secular trend toward earlier pubertal onset in many countries. However, no studies have investigated the association between the Great earthquake and early puberty. We aimed to assess whether the Wenchuan earthquake is associated with early puberty, in both boys and girls. Methods. We used data from two circles of a survey on reproductive health in China to explore the impact of the Wenchuan earthquake on early puberty, and a total of 9,785 adolescents (4,830 boys, 49.36%) aged 12-20 years from 29 schools in eight provinces were recruited. Wenchuan earthquake exposure was defined as those Sichuan students who had not experienced oigarche/menarche before May 12, 2008. Early puberty was identified as a reported onset of oigarche/menarche at 11 years or earlier. We tested the association between the Wenchuan earthquake and early puberty in boys and girls. Then, subgroup analysis stratified by the age at earthquake exposure also was performed. Results. In total, 8,883 adolescents (4,543 boys, 51.14%) with a mean (SD) age of 15.13 (1.81) were included in the final sample. In general, children exposed to the earthquake had three times greater risk of early puberty (boys, RR [95% CI] = 3.18 [2.21-4.57]; girls: RR [95%CI] = 3.16 [2.65-3.78]). Subgroup analysis showed that the adjusted RR was 1.90 [1.19-3.03] for boys and 2.22 [1.75-2.80] for girls. Earthquake exposure predicted almost a fourfold (RR [95%CI] = 3.91 [1.31-11.72]) increased risk of early puberty in preschool girls, whereas the increase was about twofold (RR [95%CI] = 2.09 [1.65-2.64]) in schoolgirls. Among boys, only older age at earthquake exposure was linked to early puberty (RR [95%CI] = 1.93 [1.18-3.16]). Conclusions. Wenchuan earthquake exposure increased the risk of early puberty in boys and girls, and preschoolers were more at risk than schoolchildren. The implications are relevant to support policies for those survivors, especially children, to better rebuild after disasters. [ABSTRACT FROM AUTHOR]

Background: The second-to-fourth digit ratio (2D:4D) is a marker of prenatal hormone exposure, which is negatively correlated with prenatal androgen and positively correlated with prenatal estrogen. The study was to analyze the association between 2D:4D and the first spermatorrhea to indirectly show the possible role of prenatal hormone during puberty development among boys.Method: The total of 367 boys aged 8-15 years were enrolled by using the stratified cluster sampling method. The variables of index finger (2D), ring finger (4D), height, weight, waist circumference (WC), skinfold thickness, testosterone and estradiol were measured, and the age at the first spermatorrhea was surveyed.Results: The average age at the first spermatorrhea was 12.15 years. The 2D:4D was not related to first spermatorrhea, circulating testosterone in boys (P > 0.05), however, was positively correlated with circulating estradiol (P < 0.05). The direct association (OR value) between 4D, average of index finger and ring finger (AIR) and first spermatorrhea were 2.79 and 2.29, and the mediating effect (OR value) of which were 1.95 and 2.01 by testosterone, accounting for 41.18% and 46.73% of the total effect, respectively. The 2D, MIDRL, lean body mass (LBM) were indirectly related to first spermatorrhea by testosterone, the mediating effects (OR value) were 2.11, 1.71 and 2.41, respectively.Conclusion: The prenatal androgen exposure may be directly and indirectly related to first spermatorrhea. In addition, the high prenatal estrogen exposure may be indirectly associated with first spermatorrhea by testosterone. [ABSTRACT FROM AUTHOR]

The histology of bone can be preserved virtually unaltered for hundreds of millions of years in fossils from all environments and all vertebrate taxa, giving rise to the flourishing field of paleohistology. 1 The shafts of long bones are formed by the apposition of periosteal bone tissue, similar to the growth of wood, and preserve, an often cyclical, record of the growth of the individual and events in its life history. One such event is sexual maturation or puberty, during which hormonal changes transform the juvenile into a sexually mature adult. Puberty has been well studied in humans and some other living vertebrates. Here, we describe puberty in Keichousaurus , a small sexually dimorphic and live-bearing marine reptile from Middle Triassic rocks of SW China, about 240 million years old. Using a combination of bone histology and morphology, we detected puberty 2 as one of the four life stages (the others being fetus, juvenile, and adult). Adult Keichousaurus males have a more robust humerus than females, with pronounced muscle attachment sites and a triangular shaft cross section. Midshaft sections of the humeri of the males show the transition from the rounded juvenile cross section to the triangular adult cross section, as reflected in the contour of the growth marks. This shape change is produced by differential bone apposition of the periosteum, presumably triggered by sex hormones, as in humans, 3 and influenced by changes in loading regime during puberty. This is the first report of puberty in a fossil amniote. [Display omitted] • Puberty is recognized in a Triassic reptile called Keichousaurus by bone histology • Shape change of male humeri in Keichousaurus starts from the onset of puberty • Sex hormones may trigger puberty in Keichousaurus • Loading regime during puberty can result in differential bone apposition in humeri Li et al. report puberty for the first time in a fossil amniote. The bone thin sections show the onset of pubertal growth and reveal the development of sexually dimorphic features in a live-bearing marine reptile called Keichousaurus from the Triassic of South China. [ABSTRACT FROM AUTHOR]

Background: To test the independent and interactive associations of physical activity (PA) and body mass index (BMI) with age at menarche among Chinese adolescence.Methods: We conducted a cross-sectional survey in two elementary schools in September 2015 in Shaoxing city, Zhejiang province, China. We used self-administered questionnaires to collect the information of the participators. Analyses were performed with logistic regression models, and the relative excess risk due to interaction (RERI), the attributable proportion because of the interaction (AP), and the synergy index (S) were used to evaluate the biological interaction.Results: A total of 1530 middle school students from grade 1-3 were selected for this study, and we collected 1505 (98.366%) valid questionnaires for the last analyses. The mean age of menarche is 11.603 (SD=0.447)years. Students with overweight/obesity and without SMPA had the highest risks of early age of menarche (OR=3.507, 95%CI: 1.929-6.376) compared with women both with a normal BMI and with SMPA, and the RERI was 1.846 (95% CI: 0.415-4.107), meaning that there was positive interaction on the additive scale.Conclusion: Insufficient PA can significantly modify the association between obesity and early menarche risk. Therefore, the government and society should pay more attention to the promotion of PA throughout childhood and adolescence. [ABSTRACT FROM AUTHOR]

Background: It is well known that excess adiposity during childhood may influence pubertal development. However, the extent to which body compositions vary in throughout puberty in boys and girls is currently unknown. The aim of this study was to investigate whether obesity and body compositions correlate with the timing of puberty in boys and girls.Methods: By random cluster sampling, our study analyzed data from 1472 students (690 girls, 782 boys) aged 6-17 years from two schools in the Chongqing area. Data were collected by physical examination of weight, height, and skinfold thicknesses. Testicular volume was measured in boys and breast development in girls. By which we got the indicators of obesity, timing of puberty and body compositions. Probit regression analysis was used to group subjects into early puberty (>P25), on-time puberty (P25 ~ P75), and delayed puberty (Results: There were significant differences in the distribution of fat levels (normal weigh, overweight, obesity) among different pubertal groups in different sex (boys:χ2 = 10.639, P = 0.031; girls:χ2 = 63.232, P = 0.000). Multivariate analysis of covariance showed that percentage of body fat, fat mass and fat-free mass in the delayed puberty girls were significantly lower than the girls in the on-time puberty and early puberty, while body density had the opposite result (all P < 0.001). Body density, percentage of body fat, fat mass and fat-free mass of boys all had no significant difference among different timing of puberty groups (all P > 0.05).Conclusions: In girls, delayed puberty was negatively correlated with Obesity, percentage of body fat, fat mass and fat-free mass, and positively correlated with body density. But in boys, delayed puberty was only negatively correlated with Obesity, the relation between puberty and body compositions was not found. [ABSTRACT FROM AUTHOR]

Background: Animal studies suggest that bisphenol A (BPA) may perturb pubertal development in females. However, evidence from human studies is limited.Methods: This was a cross-sectional study to investigate the association between BPA exposure and pubertal development in school-aged girls. A total of 655 girls aged 9-18 years were selected from three schools in Shanghai, from May to June 2011. We collected one single spot urine sample from each girl. Urine BPA concentrations were measured by modified high-performance liquid chromatography and categorized according to LOD and the median of those above LOD. Pubertal development status was assessed by using Tanner staging, and age at menarche was collected as a milestone for mid-puberty. Modified Poisson regression was used to estimate adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs).Results: After adjustment for potential confounders, girls with detected BPA were more likely to have delayed menarche, a mid-puberty event, compared with girls with undetectable BPA; the prevalence ratios (PR) were 0.73 (0.56, 0.95) for those with moderate BPA(LOD-median) and 0.72 (0.52, 0.99) for those with high BPA(>median), respectively. Girls aged 9-12 years with detected BPA were more likely to have reached pubic hair stage 2, the indicator of pubarche; while among girls aged >15 years, those with detected BPA were less likely to have reached pubic hair stage 5, the late stage of pubic hair development.Conclusions: BPA exposure was associated with alterations in the timing of pubertal development. Results in the present study should be interpreted with caution because of its cross-sectional nature and the limited sample size in each age group. [ABSTRACT FROM AUTHOR]

Organophosphate esters (OPEs), used as flame retardants and plasticizers, have been indicated to impair growth and development in toxicological studies, but current epidemiological data on their associations with body mass index (BMI) are limited and the underlying biological mechanisms remain unclear. In this study, we aim to explore the association of OPE metabolites with BMI z-score, and assess whether sex hormones mediate the relationships between OPE exposure and BMI z-score. We measured weight and height, and determined OPE metabolites in spot urine samples and sex hormones in serum samples among 1156 children and adolescents aged 6–18 years in Liuzhou city, China. The results showed that di-o-cresyl phosphate and di-pcresyl phosphate (DoCP & DpCP) levels were associated with lower BMI z-score of all participants and a similar pattern of associations were presented in prepubertal boys stratified by sex-puberty groups and male children stratified by sex-age groups. In addition, sex hormone binding globulin (SHBG) were related to reduced BMI z-score among all subgroups including prepubertal boys, prepubertal girls, pubertal boys, and pubertal girls (all P trend <0.05). We also found that DoCP & DpCP showed positive associations with SHBG among prepubertal boys. Mediation analysis further showed that SHBG mediated 35.0% of the association between DoCP & DpCP and reduced BMI z-score in prepubertal boys. Our results indicated that OPEs may impair growth and development by disrupting the sex hormones in prepubertal boys. [Display omitted] • The mediating role of sex hormones in association between OPE exposure and BMI z-score was examined. • Urinary DoCP & DpCP was associated with lower BMI z-score in prepubertal boys. • Urinary DoCP & DpCP showed positive associations with serum SHBG levels in prepubertal boys. • Serum SHBG levels were related to reduced BMI z-score in prepubertal boys. • SHBG mediated the effect of DoCP & DpCP on reduced BMI z-score in prepubertal boys. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the associations of obesity with growth and puberty in children. Methods: From November 2017 to December 2019, height, weight, and Tanner stages of 26,879 children aged 3-18 years in Fuzhou, China were assessed. Results: The obese group was significantly taller than the non-obese group after age 4 years for both genders, yet there was no significant difference in height between obese and non-obese group after 15.5 years old for boys and 12.5 years old for girls. The inflection points of significant growth deceleration in obese and non-obese groups were 14.4 and 14.6 years old for boys, and 11.8 and 12.8 years old for girls, respectively. The proportions of testicular development in boys with obesity and non-obesity were 7.96% and 5.08% at 8.5-8.9 years old, respectively, while the proportions of breast development in girls were 17.19% and 3.22% at age 7.5-7.9 years old, respectively. Conclusion: Children with obesity were taller in early childhood, earlier onset of puberty and earlier cessation of growth than children with non-obesity of the same age. However, there was sex dimorphism on the effect of obesity on the incidence of precocious puberty., Competing Interests: The authors declare that they do not have any conflicts of interest., (Copyright © 2023 Zhang, Yuan, Yang, Lin, Cai, Chen, Ai, ShangGuan, Wu and Chen.)

Aim: To examine the secular trend and the urban-rural disparity of spermarche among Chinese Han boys from 1995 to 2019., Methods: A total of 392 775 boys of Han ethnicity aged 11-18 years were extracted from the 1995, 2000, 2005, 2010, 2014 and 2019 Chinese National Surveys on Students' Constitution and Health. The median age at spermarche was estimated using the status quo data and probit analysis. The chi-square, ANOVA and LSD tests were used to compare the differences between the year-subgroups. U-test was used to compare the difference between urban and rural areas at each year., Results: The median age at spermarche in Chinese Han boys decreased from 14.6 years in 1995 to 13.9 years in 2019 (p < 0.001). The rural boys showed a faster decreasing pace with a 1-year advance of age at spermarche while the urban boys had only a 0.5-year decrement, and there was still a statistically significant difference between urban-rural areas in 2019 (p < 0.001). Similar to urban-rural disparity, the age gap at spermarche between areas with different urbanisation rates became smaller over time., Conclusions: In general, spermarche in Chinese Han boys showed a decreasing trend, but the pace was slowing down. The urban-rural disparity in puberty development still existed but was gradually narrowing., (© 2022 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.)

Background Girls adopted internationally from some states have been found to have high rates of early puberty, including early menarche. Explanations for the link between international adoption and early puberty include post-adoption catch-up growth triggering puberty, and under-recorded age. Methods We compared menarcheal age in a cohort of 814 girls adopted from China into North America against menarcheal ages in girls in China. Adoptive parents provided survey data on their daughters′ weight in 2005 and on menarcheal status and age at menarche in 2011. Results Estimated median age at menarche for adopted Chinese girls is 12.37 years (95% CI: 11.84-13.00 years). Estimated prevalence of menarcheal age ≤10.00 years for adopted girls is 3%. These findings are similar to published findings on non-adopted Chinese girls. The distribution of menarche of adopted girls and non-adopted girls at the estimated incidence rates P3-P97 are also similar. Among the 609 girls whose parents reported on their weight shortly after adoption, 148 (24.3%) were −2SD or more below the median weight in the WHO weight-for-age tables. The proportion of these girls who had attained menarche was not statistically different from other girls. Conclusions For girls adopted from China, the age of menarche, the percentage of girls attaining menarche <10 years and the distribution of menarcheal age are all similar to Chinese girls growing up in China. [ABSTRACT FROM AUTHOR]

Summary: Background: Little is known about the secular trends in age at spermarche among boys, and the association between body mass index (BMI) and male puberty is controversial. Objective: This study aimed to estimate the trend in age at spermarche in China and explore the association of spermarche with BMI. Methods: We used four cross‐sectional Chinese National Surveys on Students' Constitution and Health (CNSSCH; 1995, 2000, 2005 and 2010). Median age at spermarche was determined using probit analysis. Logistic regression was used to assess the association of spermarche with BMI. Results: Age at spermarche among Chinese boys dropped from 14.57 to 14.03 years from 1995 to 2010 with a decrease of 4.3 months per decade. Boys with BMI‐for‐age z‐score lower than −2 had the latest age at spermarche. A higher BMI or BMI‐for‐age z‐score was associated with an increased likelihood of having reached spermarche, and this association was consistently observed at all survey points. Conclusion: This study provides important evidence of a secular trend of earlier age at spermarche over the past 15 years in China, and this decrease was accompanied by a simultaneous increase in BMI. Strategies and interventions focusing on thinness may promote both their nutritional status and puberty development among Chinese boys. [ABSTRACT FROM AUTHOR]

Objective To investigate the combined impact of diet and cardiorespiratory fitness (CRF) on metabolic syndrome (MetS) among Chinese schoolchildren. Methods A cross-sectional study among 615 children (354 boys and 261 girls) aged 9.6 ± 0.6 years was conducted in Wuhan, China, from May to June 2010. Body mass index, waist circumference, CRF, blood pressure, lipids, glucose, and pubertal status were assessed. MetS was defined by the criteria proposed by De Ferranti. Based on data from a food frequency questionnaire, a diet score was created for each food item and then summed. Gender-specific median values were set as the cut-off points for the classification of high and low CRF. Results The highest prevalence of MetS (15.7 %) was observed among participants in the low tertile of diet scores and having a low level of CRF. Multivariate logistic regression showed that the odds ratio for MetS was 0.30 (95 % confidence interval 0.09-1.00) among children in the medium tertile of diet scores with low CRF, 0.24 (0.07-0.89) among those in the high tertile of diet scores with low CRF, 0.07 (0.02-0.33) among those in the low tertile of diet scores with high CRF, and 0.08 (0.01-0.58) among those in the high tertile of diet scores with medium CRF compared with those in the low tertile of diet score with low CRF. Conclusions Findings of the present study suggest that diet and CRF are synergistically associated with the risk of MetS in Chinese schoolchildren. [ABSTRACT FROM AUTHOR]

This study examined the genetic and environmental effects on variances in weight, height, and body mass index (BMI) under 18 years in a population-based sample from China. We selected 6,644 monozygotic and 5,969 dizygotic twin pairs from the Chinese National Twin Registry (CNTR) aged under 18 years (n = 12,613). Classic twin analyses with sex limitation were used to estimate the genetic and environmental components of weight, height, and BMI in six age groups. Sex-limitation of genetic and shared environmental effects was observed, especially when puberty begins. Heritability for weight, height, and BMI was low at 0–2 years old (less than 20% for both sexes) but increased over time, accounting for half or more of the variance in the 15–17 year age group for boys. For girls, heritabilities for weight, height and BMI was maintained at approximately 30% after puberty. Common environmental effects on all body measures were high for girls (59–87%) and presented a small peak during puberty. Genetics appear to play an increasingly important role in explaining the variation in weight, height, and BMI from early childhood to late adolescence, particularly in boys. Common environmental factors exert their strongest and most independent influence specifically in the pre-adolescent period and more significantly in girls. These findings emphasize the need to target family and social environmental interventions in early childhood years, especially for females. Further studies about puberty-related genes and social environment are needed to clarify the mechanism of sex differences. [ABSTRACT FROM PUBLISHER]

Abstract: Background/objective: Adequate calcium intakes may enhance bone mineral accumulation during childhood. Little is known about the optimal calcium intake in Chinese adolescents. We examined the effects of three levels of calcium intake on bone mineral accretion in adolescents. Methods: This was a 2-year randomized, double-blind, controlled trial. The subjects were randomly assigned to receive 40g of milk powder containing 300mg of calcium and 200IU of vitamin D (Low-Ca group), or same milk powder additionally fortified with 300mg of calcium (Mid-Ca group) or 600mg of calcium (High-Ca group) for 2years. The subjects' bone mineral density (BMD) and bone mineral content (BMC) at the total body, lumbar spine and left hip were determined by dual-energy X-ray absorptiometry at baseline and after the second year of treatment. Of the 111 girls and 109 boys (aged 12–14years) enrolled, 91 girls and 91 boys completed the trial. Results: The girls in the High-Ca group (1,110mg/d) had 2.3%, 2.7% and 2.6% greater BMD accretion at the total hip, femoral neck and shaft (P<0.05) but not at total body less head and spine than those in the Low-Ca group (655mg/d). A significant effect of higher calcium intake was also observed for percentage change of size-adjusted BMC at femur neck (P=0.047). Bonferroni tests indicated no significant differences in the percentage changes in BMD, BMC or size-adjusted BMC between the Mid- and Low-Ca groups and between the High- and Mid-Ca groups. Extra calcium had no observable additional effect in the boys (P>0.05). Conclusion: An intake of 1000mg/d or more might be helpful in maximizing bone mineral accretion in the hip for girls. But further large studies are required to identify its long-term effects and the optimal calcium intake for boys. [Copyright &y& Elsevier]

Abstract: Purpose: To evaluate the credibility of twin status as an instrumental variable for birth weight and infant growth and to obtain less-confounded estimates of the associations of birth weight or infant growth with adolescent blood pressure (BP). Methods: Prospective population-based “Children of 1997” birth cohort of all surviving infants born in Hong Kong, China, from April to May 1997 with sex-, age-, and height-specific BP z-score at approximately 11 years (n = 6276) and approximately 13 years (n = 5305). Results: In instrumental variable analyses, birth weight-for-gestational age z-score was not associated with z-score for systolic BP (0.01; 95% confidence interval [CI], −0.22 to 0.25) or diastolic BP (0.04; 95% CI, −0.09 to 0.18) at approximately 11 years adjusted for maternal age and migrant status (F = 38.6). Change in weight z-score at 0 to 12 months was not associated with z-score for systolic BP (−0.003; 95% CI, −0.15 to 0.15) or diastolic BP (−0.02; 95% CI, −0.10 to 0.07) at approximately 11 years (F = 54.4). Estimates were similar for BP at approximately 13 years, although the F-statistic was lower. Conclusions: Birth weight and infant growth may make little contribution to adolescent BP. Extending consideration of the effects of early life to other growth periods, such as puberty, on BP might yield public health benefits. [Copyright &y& Elsevier]

Background: Although previous studies suggested that there is a certain level of body fat mass before puberty can be initiated, most studies have focused on girls., Objective: To investigate the relationship between precocious puberty and physical growth in school-aged children in Beijing, China., Methods: 7590 Chinese children (3591 girls and 3999 boys) aged 6-11 years were recruited in Beijing, China. Body mass index (BMI) categories were defined by WHO Child Growth Standards and central obesity were defined by sex-specific waist-to-height ratio cut-offs (≥0.46 for girls, ≥0.48 for boys). Sexual development was assessed using Tanner criteria., Results: The prevalence of general obesity and central obesity among boys was higher than that in girls. Girls had a significantly higher precocious puberty rate than boys (5.93% vs. 0.87%), particularly in those aged 7 years old (9.20%). Children in the general obesity and central obesity groups have a higher prevalence of precocious puberty and earlier median ages for the attainment of Tanner B 2 /T 2 . For girls with Tanner stages≥II at 6-year-old and 7-year-old, the mean BMI was equivalent to the 50th centile of a normal 9.9-year-old and 11.9-year-old girl, respectively. The mean BMI of boys with Tanner stages≥II at 7-year-old and 8-year-old was correspondent to the 50th centile of a normal 14-year-old and 15.3-year-old boy, respectively. For girls, general obesity appears to contribute to the risk of the development of precocious puberty to a greater extent than central obesity does. For boys, central obesity, but not general obesity, was an independent risk factor for precocious puberty., Conclusions: The prevalence of childhood obesity and precocious puberty was high in China. Precocious puberty was correlated with a large BMI. Boys had a higher threshold of BMI for puberty development than girls. Children with precocious puberty, particularly those with central obesity, should be aware of adverse cardiovascular events., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Liu, Cao, Luo, Wang, Liu, Liang, Wu, Li, Su, Chen and Gong.)

Objective: To assess the effects of prepubertal BMI on pubertal growth patterns, and the influence of prepubertal BMI and pubertal growth patterns on long-term BMI among Chinese children and adolescents., Methods: A total of 9606 individuals aged between 7 and 18 years from longitudinal surveys in Zhongshan city of China from 2005 to 2016 were enrolled. Age at peak height velocity (APHV) and peak height velocity (PHV) were estimated using Super-Imposition by Translation and Rotation (SITAR) model. Associations between prepubertal BMI, APHV, PHV, and long-term overweight and obesity were assessed by linear regression and multinominal logistic regression. Scatter plots were elaborated to show the associations between prepubertal BMI and pubertal growth patterns according to prepubertal BMI categories., Results: Prepubertal BMI Z-Score was positively correlated with long-term BMI Z-Score, and negatively correlated with APHV in both sexes. In addition, there was a negative association between prepubertal BMI Z-Score and PHV in boys. With 1-year decrease in APHV, risk of long-term underweight decreased by 92%, while overweight increased by 33% in boys. Corresponding risk of long-term underweight and overweight for girls decreased by 42% and increased by 20%, respectively., Conclusion: High prepubertal BMI levels were associated with earlier APHV and lower PHV, and the early onset of pubertal development could increase the risks of long-term overweight and obesity at 17-18 years of age both in boys and girls. Such evidence emphasized the importance of reducing prepubertal obesity risks combined with appropriate pubertal development timing, including later APHV and higher PHV, so as to prevent the obesity and related cardiovascular diseases in adulthood., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Estrogen can promote the acceleration of bone maturation and phthalate esters (PAEs) have estrogen-mimicking effects. We investigated whether PAEs are associated with the acceleration of bone age (BA) in girls with early onset of puberty (EOP). This case-control study enrolled 254 girls with EOP from the Endocrinology Department at Shenzhen Children's Hospital between December 2018 and August 2019. Ultra-performance liquid chromatography and tandem mass spectrometry were used to analyze the 10 metabolites of PAEs (mPAEs) in urine samples. BA was measured using an artificial intelligence system. BA exceeding the chronological age (CA) by &gt; 2 years (BA-CA ≥ 2 years) was referred to as significant BA advancement. Participants were divided into groups A (BA-CA ≥ 2 years; case group) and B (BA-CA &lt; 2 years; control group). Propensity score matching (PSM) was performed for both groups in a 1:2 ratio with a caliper of 0.25. To identify potential dose-response relationships between PAEs exposure and BA advancement, we grouped the participants after PSM according to the tertiles of the mPAE concentrations. After PSM, 31 and 62 girls in groups A and B were selected. The concentration of Mono-ethyl phthalate (MEP) in group A was significantly higher than in group B (11.83 μg/g vs. 7.11 μg/g, P &lt; 0.05); there was no significant difference in the levels of other mPAEs between the groups. The degree of BA advancement and proportion of significantly advanced BA in the lowest, middle, and highest tertiles of the MEP sequentially increased, as well as in the lowest, middle, and highest tertiles of Mono-(2-ethyl-5-carboxypentyl) phthalate; however, these were only statistically different between the highest and lowest MEP tertiles (both P &lt; 0.05). For the remaining mPAEs, differences in the degree of BA advancement among the lowest, middle, and highest tertiles, as well as differences in the proportion of significantly advanced BA among the lowest, middle, and highest tertiles, were not significant (all P &gt; 0.05). Our findings suggested that MEP was positively associated with BA advancement in girls with EOP. Exposure to PAEs may promote accelerated bone maturation., (© 2022. The Author(s).)