Secular trends for age at spermarche among Chinese boys from 11 ethnic minorities, 1995-2010: a multiple cross-sectional study

Matching actions to needs: shifting policy responses to the changing health needs of Chinese children and adolescents

China is home to the second largest population of children and adolescents in the world. Yet demographic shifts mean that the government must manage the challenge of fewer children with the needs of an ageing population, while considering the delicate tension between economic growth and environmental sustainability. We mapped the health problems and risks of contemporary school-aged children and adolescents in China against current national health policies. We involved multidisciplinary experts, including young people, with the aim of identifying actionable strategies and specific recommendations to promote child and adolescent health and wellbeing. Notwithstanding major improvements in their health over the past few decades, contemporary Chinese children and adolescents face distinct social challenges, including high academic pressures and youth unemployment, and new health concerns including obesity, mental health issues, and sexually transmitted infections. Inequality by gender, geography, and ethnicity remains a feature of health risks and outcomes. We identified a mismatch between current health determinants, risks and outcomes, and government policies. To promote the health of children and adolescents in China, we recommend a set of strategies that target government-led initiatives across the health, education, and community sectors, which aim to build supportive and responsive families, safe communities, and engaging and respectful learning environments. TRANSLATION: For the Chinese translation of the abstract see Supplementary Materials section.

Association between sex hormones and bone age in boys aged 9-18 years from China

This study aimed to analyse the association between sex hormones and bone age (BA) in boys aged 9-18 years, both individually and interactively, and further to explore whether nutritional status may influence this association. A retrospective analysis was performed among 1382 Chinese boys with physical measurements, sexual characteristics, BA radiographs and sex hormone indicators from February 2015 to February 2022. A total of 470 (34.0%) boys had advanced BA. BA was positively associated with estradiol, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone in both advanced and normal BA groups after adjusting for age, genetic height and body mass index. Multiple logistic regression showed that after adjusting for covariates, estradiol (odds ratio [OR] = 1.66, 95% confidence interval [CI]: 1.14-2.12), LH (OR = 1.43, 95% CI: 1.04-1.96), and testosterone (OR = 1.58, 95% CI: 1.17-2.13) were significantly associated with the increased risk of advanced BA in boys, and the association was reinforced when these hormones were interactively explored. Stratified by nutritional status, the interaction between estradiol, LH, and testosterone showed a strong association with advanced BA in boys with normal weight.

Prepubertal BMI, pubertal growth patterns, and long-term BMI: Results from a longitudinal analysis in Chinese children and adolescents from 2005 to 2016

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.

Impact of Insulin Resistance on Cardiometabolic Risk Factors and an Anthropometry-Based Predictive Nomogram for Insulin Resistance Among Adolescents in China

OBJECTIVE

We aimed to investigate the impact of insulin resistance (IR), as determined by the homeostasis model assessment of insulin resistance (HOMA-IR), on cardiometabolic risk factors (CMRFs), and develop an anthropometry-based predictive nomogram for IR among adolescents in China.

DESIGN

Data were acquired from a cross-sectional study with a stratified cluster sampling method, conducted among adolescents in Northeast China.

PARTICIPANTS

A total of 882 adolescents (aged 12-16 years, 468 boys) were included.

MEASUREMENTS

All participants underwent anthropometric and biochemical examinations. The thresholds of IR included the 90th percentile of the HOMA-IR for adolescents with a normal body mass index (BMI) and fasting plasma glucose (FPG) level within each sex group (Cutoff A), and the 75th percentile for all participants of the same sex (Cutoff B).

RESULTS

The HOMA-IR was associated with CMRFs. IR, as defined by both cutoffs A and B, was significantly associated with most CMRFs, except decreased HDL-C levels. Excellent concordance (κ = 0.825) was found between these two criteria in diagnosing IR. However, IR using cutoff A, was more closely associated with cardiometabolic risk. The incidence of IR, as defined by cutoff A, was 18.93% and increased from 10.99% to 43.87% based on the different BMI categories. Further, an anthropometry-based predictive model for IR, incorporating sex, age, waist-to-hip ratio, weight and BMI, was developed and presented as a nomogram.

CONCLUSIONS

IR among adolescents is strongly related to cardiometabolic risk. We developed an anthropometry-based predictive nomogram for IR among adolescents, which may facilitate health counselling and self-risk assessments.

The First Ejaculation: A Male Pubertal Milestone Comparable to Menarche?

Boys experience their first ejaculation (thorarche) during adolescence, but this event is often overlooked as a milestone in male adolescent development. The purpose of this article is to draw attention to thorarche and consider it in comparison with the female milestone of menarche. A critical analysis is provided of how thorarche has been interpreted to date and the complexities in construing thorarche from a biological perspective are outlined. Despite potential tenability of characterizing thorarche as a comparable milestone to menarche, two particular points challenge this notion: (a) While thorarche may befall the boy involuntarily, it may also be induced by the boy's own will; and (b) Thorarche occurs concomitantly with (pubertal) orgasmarche and has an innate connection with sexuality. The answer to the title question remains contentious, but open topics for future research are noted throughout the article as essential steps towards attaining a better understanding of thorarche.

20-year trends in prevalence of overweight and obesity among children aged 0-6 in Harbin, China: A multiple cross-sectional study

To examine the 20-year trends in the combined prevalence of overweight and obesity among children aged 0-6 years between 1995 and 2015 in Harbin, China, we selected altogether 49,553 children aged 0-6 years old by using a multistage stratified cluster sampling methods in Harbin, one provincial capital city in northeast China in 1995, 2005 and 2015. Height and weight information of the children were collected. We used the child growth standards of World Health Organization to calculate the Z-scores for body mass index (BMI). Cut-offs recommended by World Health Organization and International Obesity Task Force were used to define overweight and obesity for each children. We found there is no difference between boys' BMI and girls' among newborns in each survey point (p>0.05), but in older age groups, the BMI of boys was higher than that of girls (p<0.05). From 1995 to 2015, the average BMI was increasing continuously among boys older than 42 months and girls older than 48 months (p<0.01 for linear trend across year) in Harbin. The combined prevalence of overweight and obesity increased from 2.6% in 1995 to 7.6% in 2015. For every 10-year the risk of combined overweight and obesity in children aged 0-6 years increased by 167% (95%CI: 146%, 188%, p<0.01). The combined prevalence of overweight and obesity in most age subgroups showed an increasing trend over time (p<0.01 for trend test across survey year). The age when the combined prevalence of overweight and obesity dramatically increased was earlier in 2015 than that in 2005 and 1995. In conclusion, there was an increasing trend of the combined prevalence of overweight and obesity during the past 20 years in Harbin and the age when the prevalence dramatically increased became earlier. Comprehensive intervention should be undertaken among younger children to prevent and control children's overweight and obesity.

Early pubertal timing is associated with lower sperm concentration in college students

To study the associations between pubertal timing and semen quality and reproductive hormones, 680 volunteers were recruited from universities in Chongqing, China. Pubertal timing was obtained using a questionnaire. The main measurements were five routine semen parameters and six reproductive hormones. After adjusting for potential confounders, we found that early pubertal timing was associated with lower sperm concentration. An one-year increase in age of peak height velocity was associated with a 4.7% (95% confidence interval [CI] = 1.0 to 8.6) increase in sperm concentration. An one-year increase in age of first spermatorrhea was associated with a 6.4% increase in sperm concentration and a 2.9% decrease in semen volume (95% CI = 1.7 to 11.3, -5.5 to -0.3; respectively). Regarding reproductive hormones, an one-year increase in age of height spurt and peak height velocity was associated with a 6.5% and a 6.7% decrease in estrogen (95% CI = -9.8 to -3.0, -10.4 to -2.8; respectively). While an one-year increase in age of height spurt was associated with higher follicle-stimulating hormone (% change = 2.6, 95% CI = 0.2 to 4.7). This was the first report that has suggested that early pubertal timing is associated with lower sperm concentration. However, further study is still needed to validate this association and fully elucidate the mechanism behind it.

The association between digit ratio (2D:4D) and the first spermatorrhea among Chinese boys

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.

Timing of spermarche and menarche among urban students in Guangzhou, China: trends from 2005 to 2012 and association with Obesity

In Guangzhou, China, whether the trend of a decreasing pubertal age has continued in recent years remained unknown, and the association between obesity and early puberty was still controversial. Herein, we conducted a serial cross-sectional study using data from physical fitness surveillance (2005–2012), to determine the recent trends in age at spermarche and menarche among students in Guangzhou, and to investigate whether elevated BMI modified timing of spermarche and menarche. This study included 1,278,258 urban students. In boys, no significant differences were observed in median ages of spermarche (MAS) from 2005 to 2012, with overlapping 95% CIs. Similar results were observed for median ages of menarche (MAM) in girls. The Cox-Stuart trend test showed neither upward nor downward shift in MAS and MAM over time (P = 0.625; 1.000). Each year, both MAS and MAM decreased with increasing BMI. Furthermore, a higher BMI was associated with early age at spermarche and menarche, with ORs of 1.052 (95% CI = 1.045–1.059) and 1.233 (95% CI = 1.220–1.247) in 2012 for boys and girls, respectively. In conclusion, the pubertal timing has been stable in urban students from 2005 to 2012. Furthermore, obesity was associated with early timing of spermarche and menarche.

Prevalence and Correlates of Metabolic Syndrome in Chinese Children: The China Health and Nutrition Survey

Metabolic syndrome (MetS) is generally defined as a cluster of metabolically related cardiovascular risk factors which are often associated with the condition of insulin resistance, elevated blood pressure, and abdominal obesity. During the past decades, MetS has become a major public health issue worldwide in both adults and children. In this study, data from the China Health and Nutrition Surveys (CHNS) was used to assess the prevalence of MetS based on both the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATPIII) guidelines and the International Diabetes Federation (IDF) criteria, and to evaluate its possible correlates. A total of 831 children aged 7–18 years were included in this study, and 28 children were classified as having MetS as defined by the modified NCEP-ATPIII definition, which yielded an overall prevalence of 3.37%. Elevated blood pressure was the most frequent MetS component. The results of logistic regression models revealed that increased body mass index (BMI), hyperuricemia, and insulin resistance (IR) were all associated with the presence of MetS. To conclude, our study revealed the prevalence of MetS in Chinese children at the national level. Further large-scale studies are still needed to identify better MetS criteria in the general paediatric population in China.