Secular Trend of Age at Menarche in Chinese Adolescents Born From 1973 to 2004

Socioeconomic Status and Age at Menarche in Türkiye

OBJECTIVES

The trend in declining age at menarche (AAM) largely continues while body size increases globally. The aim was to investigate trends in AAM, menstrual characteristics, and post-menarcheal anthropometric parameters in adolescents living in an urban area in Türkiye between 1999 and 2018.

METHODS

Female adolescent high school students in the Manisa region were asked about menarche and socioeconomic status (SES). There were 1017 girls in the first study (1999-2001) and 1304 (2016-2018) in the second study. Height and weight were measured. Body mass index (BMI) was calculated. Adolescent girls were grouped into three socioeconomic status (SES) groups based on parental education and occupation, and all parameters were evaluated using SES.

RESULTS

The mean ± standard deviation for AAM in the first period was 12.82 ± 1.07 years and 12.83 ± 0.9 years in the second. AAM did not differ between the two periods nor between SES groups in either period. Post-menarcheal height, weight, and BMI increased in the second period compared to the first study and across all SES groups (p < 0.05). The whole group AAM was similar in both periods, only 3 months earlier in the second period than in the first period. However, the AAM in girls with a post-menarcheal BMI indicating being overweight or obese was significantly earlier than that of those with a normal post-menarcheal BMI in both periods (p < 0.05).

CONCLUSIONS

Despite changing sociodemographic characteristics and an increasing trend in height, weight, and BMI in all socioeconomic groups, no change was observed in mean AAM in an urban region of Western Türkiye over 18 years. While the inverse relationship between BMI and postmenarcheal BMI continued in both periods, the decline in AAM became more pronounced over the years in the presence of high postmenarcheal BMI.

Preliminary comparison of net gain in final adult height of girls with early menarche treated with or without gonadotropin-releasing hormone agonist

Background

Early menarche is associated with both physical and psychosocial problems. Based on psychological and physical health considerations, for girls with early menarche, some parents and physicians may elect to use gonadotropin-releasing hormone agonists (GnRHa) to delay menstruation. This study aimed to explore the effects of GnRHa treatment on the final height of girls with early menarche and build the models to predict the final adult height (FAH).

Methods

Girls who experienced menarche between the ages of 8 and 10 years and were diagnosed with idiopathic central precocious puberty (ICPP) at Tianjin Medical University General Hospital between July 2017 and August 2023 were included in this study. Participants were divided into two groups based on treatment strategy: GnRHa-treated and GnRHa-untreated groups. Laboratory parameters including growth factors and basal gonadotropins were tested at diagnosis. The heights and weights of the participants were measured every three months. Bone radiographs of the left hand and wrist were assessed by professional appraisers to determine the bone age (BA), which was measured every 6 months after diagnosis.

Results

Clinical data of 176 girls who experienced early menarche were retrospectively analyzed. For participants in the GnRHa-treated group (n=87), growth velocity (GV) showed significant differences between the first 6 months and second 6 months of treatment (P=0.01; 5.82±2.3 vs. 4.79±2.31 cm, respectively). The height standard deviation score (SDS) and BA (P<0.001) decreased during treatment. The predicted adult height was higher at the end of treatment, but was not statistically different from that at diagnosis (P=0.73). In the linear regression analysis, no significant relationships were observed between GnRHa treatment and net gain (NG) in final height [Model A, adjusted for BA and chronological age (CA) at baseline: P=0.43; Model B, adjusted for Model A plus HtSDS-BA, HtSDS, and BMISDS: P=0.65; Model C, adjusted for Model B plus LH, FSH, and IGF-1: P=0.82]. The generalized additive model (GAM) for NG in final height in GnRHa-treated participants included three independent risk factors: LH/FSH [estimated degrees of freedom (edf) =5.36, P=0.02], GV (edf =4.11, P=0.007), and the bone maturation ratio (BMR) (edf =4.79, P=0.02). GAM performed better than multivariate linear (stepwise) regression in predicting the FAH in GnRHa-treated girls with early menarche.

Conclusions

For girls who experienced menarche between the ages of 8 and 10 years, GnRHa treatment suppressed GV and skeletal maturity. The GAM provides a theoretical basis for pediatric endocrinologists in deciding whether to apply GnRHa treatment, determining the time to withdraw GnRHa treatment, and predicting the FAH of girls with early menarche.

Endocrine-Disrupting Chemicals, Hypothalamic Inflammation and Reproductive Outcomes: A Review of the Literature

Endocrine-disrupting chemicals (EDCs) are environmental and industrial agents that interfere with hormonal functions. EDC exposure is linked to various endocrine diseases, especially in reproduction, although the mechanisms remain unclear and effects vary among individuals. Neuroinflammation, particularly hypothalamic inflammation, is an emerging research area with implications for endocrine-related diseases like obesity. The hypothalamus plays a crucial role in regulating reproduction, and its inflammation can adversely affect reproductive health. EDCs can cross the blood-brain barrier, potentially causing hypothalamic inflammation and disrupting the reproductive axis. This review examines the existing literature on EDC-mediated hypothalamic inflammation. Our findings suggest that exposure to 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD), polychlorinated biphenyl (PCB), tributyltin (TBT), phthalates, bisphenol A (BPA), and chlorpyrifos (CPF) in animals is linked to hypothalamic inflammation, specifically affecting the hypothalamic centers of the gonadotropic axis. To our knowledge, this is the first comprehensive review on this topic, indicating hypothalamic inflammation as a possible mediator between EDC exposure and reproductive dysfunction. Further human studies are needed to develop effective prevention and treatment strategies against EDC exposure.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

IMPACT

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

Health condition and socioeconomic status mediate the causal effect of reproductive traits on nonalcoholic fatty liver disease: evidence from Mendelian randomization study

Background

Observational data posits a correlation between reproductive traits and nonalcoholic fatty liver disease (NAFLD), but their causal inference is still unclear. This investigation seeks to elucidate the causal influence of reproductive traits on NAFLD and determine the intervening role of health condition and socioeconomic status in these connections.

Methods

Utilizing a Mendelian Randomization (MR) approach, this research leveraged a comprehensive dataset from the Genome-wide Association Study (GWAS) database. The study incorporated body mass index, major depression, educational level, household income and Townsend deprivation index as intermediary variables. Initially, a bidirectional two-sample MR study was conducted to explore the genetic associations between reproductive traits and NAFLD. Then, two-step MR analyses were implemented to quantify the extent of mediation by these indicators. The weighted inverse variance method was the primary analytical approach, complemented by several sensitivity analyses to affirm the robustness of the MR assumptions. Finally, these findings were validated in the FinnGen research.

Results

The bidirectional MR analysis indicated that earlier reproductive traits (age at menarche, age at first sexual intercourse, and age at first birth) were associated with an elevated risk of NAFLD, absent any evidence of the reverse relationship. Body mass index accounted for 35.64% of the association between premature menarche and NAFLD. Additionally, body mass index, major depression, educational level and household income mediated 41.65%, 14.35%, 37.88%, and 18.59% of the connection between early sexual intercourse and NAFLD, respectively. Similarly, these same variables elucidated 36.36%, 15.58%, 41.56%, and 22.73% of the correlation between younger age at first birth and NAFLD.

Conclusion

Our study elucidated the causal relationships between reproductive traits and NAFLD. Potential underlying mechanisms may involve factors such as body mass index, major depression, educational attainment and household income.

A Century of Change: Unraveling the Impact of Socioeconomic/Historical Milestones on Age at Menarche and Other Female Reproductive Factors in Japan

BACKGROUND

Reproductive factors, such as age at menarche, are known to be associated with disease risk, but data on trends in these factors in Japan are limited. In this study, we investigated secular trends in reproductive factors and explored their potential association with socioeconomic and historical events.

METHODS

We conducted a retrospective analysis of 62,005 Japanese women born between 1890 and 1991 using a survey conducted over 25 years. Trends in reproductive factors were analyzed using linear and joinpoint regression models, and their associations with major historical events involving Japan were evaluated.

RESULTS

We found that the age at menarche showed a significant downward trend (P < 0.001) over the century. Three joinpoints were identified, in 1932 (15.23 years old), 1946 (13.48 years old), and 1959 (12.71 years old), which indicated that average age at menarche decreased by approximately 0.8% per year between 1932 and 1946, and then by 0.4% per year between 1946 and 1959, both of which were statistically significant. However, after 1959, age of menarche remained stable. Analyses of other reproductive factors found significant changes, including a decrease in parity and the number of babies breastfed, and an increase in age at first birth.

CONCLUSION

Age at menarche showed a long-term downward trend in Japan, with significant change points in annual percent change. Other factors showed secular changes in trends as well. These change points were observed at the same time as historical events, namely wars and economic development, suggesting that socioeconomic and environmental changes at the population level affect reproductive factors in females.

The Association Between Prolactin Levels and Cognitive Function in Female Patients With Severe Mental Disorders

OBJECTIVE

Cognition impairments are considered as a fundamental characteristic of severe mental disorders (SMD). Recent studies suggest that hyperprolactinemia may exert a detrimental influence on cognitive performance in patients with SMD. The objective of this study was to investigate the correlation between serum prolactin levels and cognitive function in female individuals diagnosed with SMD.

METHODS

We conducted a study on 294 patients with SMD and 195 healthy controls, aged between 14 to 55 years old. Cognitive function was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), while prolactin levels were measured in serum. Descriptive analysis and comparative analysis were performed to compare cognitive function and prolactin levels between groups, and linear regression models were used to explore the relationship between prolactin and cognitive function.

RESULTS

Compared to the healthy control, individuals with SMD exhibited significantly higher levels of prolactin, while scoring lower on RBANS total and every index scores. Furthermore, a negative association between prolactin levels and cognitive function (RBANS total index score, attention, and delayed memory) was observed in SMD patients. Importantly, this inverse correlation between prolactin and cognition function (RBANS total index score, total scale score, and attention) persisted in patients who were not taking medications that could potentially influence serum prolactin levels.

CONCLUSION

Our study reveals a significant correlation between elevated prolactin levels and cognitive impairment in female patients with SMD, underscoring the importance of monitoring prolactin levels in order to prevent cognitive deterioration among female SMD patients.

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

Backgrounds

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

Materials and methods

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

Results

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

Conclusion

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

Research in China about the biological mechanisms that potentially link socioenvironmental changes and mental health: a scoping review

China's rapid socioeconomic development since 1990 makes it a fitting location to summarise research about how biological changes associated with socioenvironmental changes affect population mental health and, thus, lay the groundwork for subsequent, more focused studies. An initial search identified 308 review articles in the international literature about biomarkers associated with 12 common mental health disorders. We then searched for studies conducted in China that assessed the association of the identified mental health related-biomarkers with socioenvironmental factors in English-language and Chinese-language databases. We located 1330 articles published between 1 January 1990 and 1 August 2021 that reported a total of 3567 associations between 56 specific biomarkers and 11 socioenvironmental factors: 3156 (88·5%) about six types of environmental pollution, 381 (10·7%) about four health-related behaviours (diet, physical inactivity, internet misuse, and other lifestyle factors), and 30 (0·8%) about socioeconomic inequity. Only 245 (18·4%) of the papers simultaneously considered the possible effect of the biomarkers on mental health conditions; moreover, most of these studies assessed biomarkers in animal models of mental disorders, not human subjects. Among the 245 papers, mental health conditions were linked with biomarkers of environmental pollution in 188 (76·7%), with biomarkers of health-related behaviours in 48 (19·6%), and with biomarkers of socioeconomic inequality in 9 (3·7%). The 604 biomarker-mental health condition associations reported (107 in human subjects and 497 in animal models) included 379 (62·7%) about cognitive functioning, 117 (19·4%) about anxiety, 56 (9·3%) about depression, 21 (3·5%) about neurodevelopmental conditions, and 31 (5·1%) about neurobehavioural symptoms. Improved understanding of the biological mechanisms linking socioenvironmental changes to community mental health will require expanding the range of socioenvironmental factors considered, including mental health outcomes in more of the studies about the association of biomarkers with socioenvironmental factors, and increasing the proportion of studies that assess mental health outcomes in humans.

Association between age at menarche and cardiometabolic risk among Samoan adults

OBJECTIVES

Recent studies suggest that early menarche may increase cardiometabolic morbidity and mortality. Yet few studies have examined this association in the Pacific Islands, where obesity prevalence is among the highest globally. We sought to examine associations between age at menarche and cardiometabolic risk in Samoa.

METHODS

Participants were from the Soifua Manuia study (n = 285, age 32-72 years) conducted in Samoa from 2017 to 2019. Logistic regressions were conducted to estimate odds of obesity, hypertension, diabetes, dyslipidemia, and metabolic syndrome per one-year increase in age at menarche. Linear regressions were conducted to examine associations between age at menarche and continuous measures of adiposity, blood pressure, insulin resistance, and serum lipids.

RESULTS

Median age at menarche was 14 years (IQR = 2). After controlling for relevant covariates, each one-year increase in age at menarche was associated with a 15% decrease (OR = 0.85, 95% CI: 0.72-1.01, p = .067) in odds of hypertension, but a 21% increase (OR = 1.21, 95% CI: 1.01-1.45, p = .044) in odds of diabetes and 18% increase (OR = 1.18, 95% CI: 0.98-1.42, p = .081) in odds of high total cholesterol. Each additional year in age at menarche was associated with a 1.60 ± 0.52 kg (p = .002) decrease in lean mass and 1.56 ± 0.51 kg (p = .003) decrease in fat-free mass.

CONCLUSIONS

Associations between age at menarche and cardiometabolic risk may be population-specific and are likely influenced by both current and historical nutritional and epidemiological contexts. Prospective studies are needed to clarify the role of childhood adiposity and other early life exposures on age at menarche and subsequent cardiometabolic risk.

Secular trends and urban-rural disparities in the median age at menarche among Chinese han girls from 1985 to 2019

BACKGROUND

Menarche is a substantial milestone of female puberty. Timing of age at menarche is considered the key to understanding the potential linkages with women's health outcomes later in life. This study aimed to explore the secular trends and urban‒rural disparities in the median age at menarche among Chinese Han girls from 1985 to 2019.

METHODS

Data were extracted from the 1985, 1995, 2005, 2014, and 2019 Chinese National Surveys on Students' Constitution and Health, which were nationally representative cross-sectional studies, and a total of 173,535 Han girls aged 9-18 years were examined. Girls were asked whether menarche had occurred. The median age at menarche was estimated by probit analysis. Z tests were used to compare the differences between survey years and between urban and rural areas.

RESULTS

The median age at menarche among Chinese Han girls decreased from 13.37 years in 1985 to 12.00 years in 2019, and the overall decrease was more significant in rural areas (1.77 years) than in urban areas (0.99 years). The average five-year change in the decrease in the median age at menarche showed an accelerating and then slowing pace; and it was observed similarly in both urban and rural areas. The urban‒rural disparities shrank from 0.64 years in 1985 to 0.44 years in 1995, then to 0.27 years in 2005, 0.24 years in 2014, and finally to - 0.14 years in 2019.

CONCLUSIONS

The median age at menarche among Chinese Han girls continued to decline from 1985 to 2019 but at a slowing pace in the last five years. Urban‒rural disparities gradually narrowed. Sexual and reproductive health education and interventions to prevent the decline in the age of menarche are needed, especially in rural areas.

Alterations in Appetite-Regulating Hormones in Girls with Central Early or Precocious Puberty

The prevalence of central precocious puberty (CPP) in girls has increased worldwide and is often associated with obesity in childhood as well as high fat/high glycemic index diets. Evidence suggests that subjects with obesity present with alterations in appetite-regulating hormones. The arcuate and paraventricular nuclei of the hypothalamus are the centers of action of appetite hormones, as well as the location of gonadotropin-releasing hormone (GnRH) neurons, the activation of which results in the onset of puberty. This anatomical proximity raises the question of possible alterations in appetite-regulating hormones in patients with CPP. Furthermore, diet-induced hypothalamic inflammation constitutes a probable mechanism of the pathophysiology of CPP, as well as alterations in appetite-regulating hormones in young children. In this article, we summarize the evidence investigating whether girls with CPP present with alterations in appetite-regulating hormones. We present evidence that leptin concentrations are elevated in girls with CPP, ghrelin concentrations are lower in girls with CPP, nesfatin-1 and orexin-A concentrations are elevated among girls with premature thelarche, and insulin concentrations are increased in girls with early menarche.

[Secular trends of age at menarche and age at menopause in women born since 1951 from a county of Shandong Province, China]

OBJECTIVE

To describe the secular trends of age at menarche and age at natural menopause of women from a county of Shandong Province.

METHODS

Based on the data of the Premarital Medical Examination and the Cervical Cancer and Breast Cancer Screening of the county, the secular trends of age at menarche in women born in 1951 to 1998 and age at menopause in women born in 1951 to 1975 were studied. Joinpoint regression was used to identify potential inflection points regarding the trend of age at menarche. Average hazard ratios (AHR) of early menopause among women born in different generations were estimated by performing multivariate weighted Cox regression.

RESULTS

The average age at menarche was (16.43±1.89) years for women born in 1951 and (13.99±1.22) years for women born in 1998. The average age at menarche was lower for urban women than that for rural women, and the higher the education level, the lower the average age at menarche. Joinpoint regression analysis identified three inflection points: 1959, 1973 and 1993. The average age at menarche decreased annually by 0.03 (P < 0.001), 0.08 (P < 0.001), and 0.03 (P < 0.001) years respectively for women born during 1951-1959, 1960-1973, and 1974-1993, while it remained stable for those born during 1994-1998 (P=0.968). As for age at menopause, compared with women born during 1951-1960, those born during 1961-1965, 1966-1970 and 1971-1975 showed a gradual decrease in the risk of early menopause and a tendency to delay the age at menopause. The stratified analysis presented that the risk of early menopause gradually decreased and the age of menopause showed a significant delay among those with education level of junior high school and below, but this trend was not obvious among those with education level of senior high school and above, where the risk of early menopause decreased and then increased among those with education level of college and above, and the corresponding AHRs were 0.90 (0.66-1.22), 1.07 (0.79-1.44) and 1.14 (0.79-1.66).

CONCLUSION

The age at menarche for women born since 1951 gradually declined until 1994 and leveled off, with a decrease of nearly 2.5 years in these years. The age at menopause for women born between 1951 and 1975 was generally delayed over time, but the trend of first increase and then decrease was observed among those with relatively higher education levels. In the context of the increasing delay in age at marriage and childbearing and the decline of fertility, this study highlights the necessity of the assessment and monitoring of women' s basic reproductive health status, especially the risk of early menopause.

Associations of Obesity With Growth and Puberty in Children: A Cross-Sectional Study in Fuzhou, China

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.

Age at menarche of adolescent girls and the neighbourhood socioeconomic status of their school area

PURPOSE

To assess the association between abnormal timing of menarche among adolescent girls and neighbourhood socioeconomic status of their school area.

MATERIALS AND METHODS

Our analysis included 187,024 girls aged 15-18 years from the Korea Youth Risk Behaviour Web-Based Survey (KYRBS) from 2007 to 2015. Early and late menarche were defined as menarche before 11 years and no menarche by age 14 years, respectively. The deprivation index values for the areas where the schools were located were used as an indicator of neighbourhood socioeconomic status based on the 2005 national census data. We calculated odds ratios (OR) for early and late menarche using a multinomial logistic regression model. Covariates included body mass index, parental education, single or stepparents, siblings, household wealth, year of birth, survey year, and urbanisation.

RESULTS

Mean age at menarche was 12 years. The overall proportions of early and late menarche were 11.3% and 3.3%, respectively. When divided into four quartile groups based on the socioeconomic deprivation index, 11.3% of girls in the most deprived quartile and 10.6% in the least deprived area showed early menarche. The prevalence of late menarche did not differ across the deprivation index quartiles of school area. Attendance at schools located in highly deprived areas was associated with up to 10% higher risk of early menarche. This positive association was not evident for late menarche.

CONCLUSION

Among contemporary Korean girls, socioeconomic deprivation of the school area was associated with earlier puberty. This finding highlights the potential role of the socioeconomic environment of schools in women's lifetime health.

Causal relationships between birth weight, childhood obesity and age at menarche: A two-sample Mendelian randomization analysis

OBJECTIVES

Observational studies suggest birth weight and childhood obesity are closely associated with age at menarche. However, the relationships between them are currently inconsistent and it remains elusive whether such associations are causal. Therefore, the aim of the study was to investigate whether there existed causal relationships between birth weight, childhood obesity and age at menarche.

DESIGN, PATIENTS AND MEASUREMENTS

A two-sample Mendelian randomization (MR) study. The standard inverse variance weighted MR analyses were adopted to evaluate the causal effects of birth weight (n = 143,677), childhood body mass index (BMI) (n = 39,620) on age at menarche (n = 182,416) with summary statistics from large-scale genome-wide association studies (GWASs). Meanwhile, we validated our MR results with some sensitivity analyses including maximum likelihood, weighted-median and MR pleiotropy residual sum and outlier methods.

RESULTS

The present study showed that each one standard deviation (1-SD) lower birth weight was predicted to result in a 0.1479 years earlier of age at menarche (β = .1479, 95% confidence interval [CI] = 0.0422-0.2535; p = 0.0061). We also found that genetically predicted 1-SD increase in childhood BMI was causally associated with early age at menarche (β = -.3966, 95% CI = -0.5294 to -0.2639; p = 4.73E-09).

CONCLUSIONS

Our MR study suggests the causal effect of lower birth weight and higher childhood BMI on the increased risk of earlier menarche. It may be the opportune time to carry out weight control intervention in prenatal and early childhood development periods to prevent early menarche onset, thus decreasing the future adverse consequences.

Diet and Nutrients Intakes during Infancy and Childhood in Relation to Early Puberty: A Systematic Review and Meta-Analysis

The onset of puberty has become earlier over the decades, and nutrients and diet are related to the timing of puberty onset. Hence, we aimed to investigate the association between diet or nutrients in infancy, childhood and early puberty. PubMed, Embase, and Cochrane library were searched systematically up to 15 April 2022. The pooled relative risks (RRs) or regression coefficients (beta) were estimated using the random-effect model or fixed-effect model according to the heterogeneity between studies. Twenty-two articles on diet or nutrients in childhood and six about breastfeeding in infancy were included. The prolonged breastfeeding duration in infancy could reduce the risk of early menarche (beta 0.31, 95% CI: 0.01, 0.60, p = 0.045). The high intake of yogurt was associated with a 35% reduction in the risk of earlier menarche (RR 0.65, 95% CI: 0.47, 0.89, p = 0.008). Girls with severe food insecurity experienced later menarche (RR 0.81, 95% CI: 0.67, 0.98, p = 0.027). Conversely, due to the high intake of protein, the risk of early menarche increased by 8% (RR 1.08, 95% CI: 1.01, 1.16, p = 0.016). High intake of yogurt, longer duration of breastfeeding, and food insecurity decreased the possibility of earlier menarche, while high intake of protein increased that risk. As a modifiable factor, diet and nutrients in infancy and childhood provide new insights into the future prevention of early puberty.

Association between Age at Menarche and Hyperhomocysteinemia among Women in Hunan, China: A Cross-Sectional Study

Background

We aim to examine the relationship between age at menarche and hyperhomocysteinemia in women in Hunan Province.

Methods

Participants were required to complete a questionnaire that included age at menarche, lifestyle habits, other baseline information, and blood biochemical parameters in a cross-sectional study. The association between hyperhomocysteinemia and age at menarche was examined by Multivariable adjusted logistic regression.

Results

A cohort of 2008 women with a mean age of 60.11 years (aged from 18.0 to 88.0 years) was included in this study. After adjustment for confounding factors such as age, the results showed that the risk of hyperhomocysteinemia among women whose age at menarche were over 16 years was 2.543 (1.849, 3.469) times higher than the risk among women whose age at atmenarche were less than 14 years, and 2.656 (1.882, 3.748) times more likely to have hypertension than women with menarche at 14 years. Besides, the odds ratios of diabetes, hyperlipidemia, and obesity were elevated in women older than 16 years of age at menarche (OR = 1.924, p < 0.001; OR = 1.491, p = 0.014; OR = 1.670, p = 0.022).

Conclusions

Our findings suggest that late menarche tends to be associated with a high risk of hyperhomocysteinemia and its associated set of diseases such as hypertension, diabetes, hyperlipidemia, and obesity in women in Hunan, China. This association tends to differ across birth cohorts. Therefore, adequate attention of menarcheal age may be able to predict diseases in elderly females.

Obesity-related genetic polymorphisms are associated with the risk of early puberty in Han Chinese girls

OBJECTIVE

To explore the association between obesity and precocious puberty from the perspective of genetic polymorphism.

DESIGN

Two hundred and ninety-eight pairs of girls in early puberty and age-matched controls (±3 months) were recruited. The genotypes of four obesity-related single-nucleotide polymorphism (SNP) loci (rs10968576, rs12935153, rs4674340 and rs7635103) were determined and the effect of variation on early puberty in Chinese Han girls was evaluated. The unstimulated luteinizing hormone (LH), follicle-stimulating hormone and estradiol levels were also measured to determine the relationship with SNP polymorphisms.

RESULTS

The effect allele A of rs12935153 was associated with early puberty (odds ratio [OR] = 1.256, 95% confidence interval [CI]: 1.010-1.585), but the significance disappeared after multiple comparisons. After adjusting for body mass index, rs12935153 variation increased the risk of early puberty in additive (OR = 1.589, 95% CI: 1.222-2.066), dominant (OR = 1.788, 95% CI: 1.210-2.642) and recessive (OR = 1.915, 95% CI: 1.207-3.038) models of inheritance. Individuals harbouring AA genotype in rs12935153 had a risk of higher LH levels than that of wild type (OR = 1.668, 95% CI: 1.093-2.546).

CONCLUSIONS

The association between obesity and precocity can be explained from a genetic perspective. Our study suggests that variations in rs12935153 increase the risk of early puberty in Chinese girls. Further studies are needed to verify our findings.

Secular trends of age at menarche and the effect of famine exposure on age at menarche in rural Chinese women

BACKGROUND

Over the past few decades, more studies have suggested that the age at menarche (AAM) has continued to decline. However, the AAM for women in resource-constrained areas is not clear. Moreover, the association between the China famine and AAM is still unclear in rural regions.

AIM

The study aimed to investigate the secular trends of AAM for women born between 1935 and 2000 and to further explore the effect of famine on AAM in rural China.

SUBJECTS AND METHODS

The study included 23444 women participants from the baseline study of Henan Rural Cohort study. Changing AAM over time was analysed using linear regressions. Multinomial logistic regression was conducted to analyse the association between famine exposure and AAM subgroups.

RESULTS

The age-standardized mean AAM was 14.74 years. The average AAM declined from 16.98 years for those born in 1935 to 13.87 years for those born in 2000, a decline of 0.077 years per 1 year and 0.729 years per decade. Compared to the reference group, women exposed to famine during fetal, early childhood, middle childhood, and late childhood were 1.376 (95% CI, 1.071 - 1.769), 1.848(95% CI, 1.512 - 2.259), 2.084(95% CI, 1.725 - 2.518), and 2.146 (95% CI, 1.788 - 2.576) times more likely to be ≥18 years of AAM than unexposed famine women, respectively.

CONCLUSION

AAM showed a decreasing trend in rural China. Furthermore, both fetal and childhood famine exposure, especially in late childhood, were positively associated with increased AAM compared to unexposed famine.

Assessing the Opinion of Mothers about School-Based Sexual Education in Romania, the Country with the Highest Rate of Teenage Pregnancy in Europe

Background and Objectives: Without mandatory school-based education, Romania is a leading European country in teen pregnancy. This survey aimed at assessing the level of knowledge and the opinions about sexual education and sexual-related issues among mothers of female teenagers aged 13–18 years old. Material and Methods: The survey was conducted between 2015 and 2017 and had four parts, collecting data about sociodemographic variables, the level of knowledge about sexuality, sexually transmitted diseases, and contraception. The respondents were mothers of female teenagers hospitalized in a tertiary pediatric clinic. Data were analyzed using IBM Statistical Package for Social Sciences (SPSS) Statistics for Windows, version 25 (Inc., Chicago, IL, USA). Results: One hundred and thirty-five mothers (42.46 ± 6.81 years old) were included in the research. Most of them were from rural areas, had graduated secondary school, were Christian-orthodox, married, and with a stable job. More than half of the mothers (61.42%) declared that they personally knew adolescents that were already mothers. In great proportion, mothers proved good knowledge about sexual education, contraception, and STDs. They considered that the minimum age for becoming married, in general, is about M = 18.62 ± 2.09 years old but in the case of their daughters, mothers appreciated that the best age would be 23.56 ± 9.37. Mothers considered that they had good communication with their daughters (M = 4.28 ± 0.99) and two-thirds sustained that they had discussed with them about sexual activity, pregnancy, sexually transmitted diseases, and contraception. In case of unwanted pregnancy of their daughters, one-third of the mothers (38.50%) would advise their girls to continue the pregnancy and 7.40% mentioned the termination of pregnancy. Two-thirds of them (74.10%) agreed to school-based sexual education. In the order of preferred sources for sexual education, mothers mentioned parents (85.90%), teachers (33.30%), and family doctors (24.40%). Comparative results regarding their own sex life and that of their daughters are presented. Conclusions: School-based programs should meet parental beliefs about sexuality and sexual education. School, as a creator of values and models, should find the golden ratio to better shape the personal, familial, and social needs for the healthy sexual behavior of the new generation.

Reproductive and environmental exposures and the breast cancer risk in Taiwanese women

Breast cancer (BC) incidence is increasing around the globe, including in Taiwan, though the cause of the increasing incidence is less clear. We followed up 11,296 Taiwanese females who did not have BC at baseline, and ascertained new invasive BC (N = 351) through data linkage to the National Cancer Registry from 1991 to 2018 to examine whether reproductive, lifestyle and environmental risk factors including polycyclic aromatic hydrocarbons (PAH) were associated with BC risk. We conducted a nested case-control study using baseline blood available from a total of 305 women with BC and 598 women without BC matched on time in cohort. We examined the association of PAH-albumin adducts and BC risk using conditional logistic regression models. Age at menarche (HR 0.6 (95% CI 0.5-0.9) for ≥ 15 vs. < 13 years) and multiparity were associated with BC risk (HR 2.0 (95% CI 1.4-2.8), 2.8 (1.9-4.2), and 2.4 (1.0-5.0) for 3-4, 1-2 and 0 live birth, compared with women ≥ 5 births). PAH-albumin adducts were not associated with BC risk. Given the increasing BC incidence in Taiwan, there is a need to identify environmental factors that are important to this population.

The overall diet quality in childhood is prospectively associated with the timing of puberty

PURPOSE

The influences of nutrition in childhood on puberty onset could have sustained consequences for health and wellbeing later in life. The aim of this study was to investigate the prospective association of diet quality prior to puberty with the timing of puberty onset.

METHODS

We considered data from 3983 SCCNG (Southwest China Childhood Nutrition and Growth) study participants with dietary data, anthropometric measurement, and information on potential confounders at their baseline assessment (mean age: 7.1 years for girls and 7.3 years for boys; mean length of follow-up was 4.2 years). Cox proportional hazard regression estimating hazard ratios (HRs) and 95% confidence intervals (CIs) were used to examine the relationship between diet quality and puberty onset. Dietary intake at baseline was assessed using a validated food frequency questionnaire. Diet quality was determined using the Chinese Children Dietary Index (CCDI) which measures adherence to current dietary recommendations (theoretical range: 0-160 points). Age at Tanner stage 2 for breast/genital development (B2/G2), menarche or voice break (M/VB) were used as pubertal markers.

RESULTS

The CCDI score ranged from 56.2 to 136.3 for girls and 46.1-131.5 for boys. Pubertal markers consistently indicate that girls and boys with higher diet quality were more likely to enter their puberty later than their counterparts with lower CCDI scores (higher vs. lower CCDI tertiles: adjusted HR for age at B2: 0.85 (95% CI, 0.81-0.94), p for trend = 0.02; G2: 0.86 (95% CI,0.80-0.96), p for trend = 0.02; M: 0.86 (95% CI,0.80-0.95), p for trend = 0.02; VB: 0.86 (95% CI,0.79-0.98), p for trend = 0.03), after adjustment for paternal education level, baseline energy intake, and pre-pubertal body fat.

CONCLUSIONS

Our data suggested a later puberty onset and later timing of progressed puberty stages in children with a high diet quality, which were independent of pre-pubertal body fat.

Temporal trends in age at menarche and age at menopause: a population study of 312 656 women in Norway

STUDY QUESTION

Have mean age at menarche or mean age at natural menopause changed from the 1939 birth cohort to the 1964 birth cohort?

SUMMARY ANSWER

We estimated a minor decrease in mean age at menarche and an increase by nearly 3 years in mean age at natural menopause.

WHAT IS KNOWN ALREADY

In the Western world, age at menarche decreased across birth cohorts from the early 1800s until the 1950s. Whether mean age at menarche has continued to decrease in birth cohorts after the 1950s remains uncertain. It is also uncertain whether mean age at natural menopause has changed across birth cohorts.

STUDY DESIGN, SIZE, DURATION

We performed a retrospective population study of 312 656 women who were born in Norway during the years 1936–1964.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The data were obtained by two self-administered questionnaires from women who participated in the Norwegian breast cancer screening program (BreastScreen Norway) during the years 2006–2014. We used flexible parametric survival models with restricted cubic splines to estimate mean age at menarche, mean age at menopause and mean number of years between menarche and menopause according to the women’s year of birth. The women who were still having menstrual periods contributed with follow-up time until the time of data collection, and the women who had reported surgical removal of the uterus and/or both ovaries prior to natural menopause contributed with follow-up time until the time of surgery.

MAIN RESULTS AND THE ROLE OF CHANCE

The mean age at menarche was 13.42 years (95% CI: 13.40–13.44 years) among women born during 1936–1939, and it was 13.24 years (95% CI: 13.22–13.25 years) among women born during 1960–1964. The mean age at natural menopause increased from 50.31 years (95% CI: 50.25–50.37 years) among women born during 1936–1939 to 52.73 years (95% CI: 52.64–52.82 years) among women born during 1960–1964. The mean number of years between menarche and menopause increased from 36.83 years (95% CI: 36.77–36.89 years) to 40.22 years (95% CI: 40.11–40.34 years).

LIMITATIONS, REASONS FOR CAUTION

Information about age at menarche and age at menopause was based on self-reports.

WIDER IMPLICATIONS OF THE FINDINGS

Late menopause is associated with increased risk of breast cancer but also with increased life expectancy. Thus, higher mean age at menopause may partly explain the increase in breast cancer incidence after menopause and the increase in life expectancy in recent time. Also, a longer interval between menarche and menopause could suggest that the number of years of female fecundity has increased.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by the South-Eastern Norway Regional Health Authority [grant number 2016112 to M.S.G.] and by the Norwegian Cancer Society [grant number 6863294-2015 to E.K.B.]. The authors declare no conflicts of interest.

Causal relationship between the timing of menarche and young adult body mass index with consideration to a trend of consistently decreasing age at menarche

Younger age at menarche (AAM) is associated with higher body mass index (BMI) for young women. Considering that continuous trends in decreasing AAM and increasing BMI are found in many countries, we attempted to assess whether the observed negative association between AAM and young adult BMI is causal. We included 4,093 women from the Korean Genome and Epidemiology Study (KoGES) and Healthy twin Study (HTS) with relevant epidemiologic data and genome-wide marker information. To mitigate the remarkable differences in AAM across generations, we converted the AAM to a generation-standardized AAM (gsAAM). To test causality, we applied the Mendelian randomization (MR) approach, using a genetic risk score (GRS) based on 14 AAM-associated single nucleotide polymorphisms (SNPs). We constructed MR models adjusting for education level and validated the results using the inverse-variance weighted (IVW), weighted median (WM), MR-pleiotropy residual sum and outliers test (MR-PRESSO), and MR-Egger regression methods. We found a null association using observed AAM and BMI level (conventional regression; -0.05 [95% CIs -0.10-0.00] per 1-year higher AAM). This null association was replicated when gsAAM was applied instead of AAM. Using the two-stage least squares (2SLS) approach employing a univariate GRS, the association was also negated for both AAM and gsAAM, regardless of model specifications. All the MR diagnostics suggested statistically insignificant associations, but weakly negative trends, without evidence of confounding from pleiotropy. We did not observe a causal association between AAM and young adult BMI whether we considered the birth cohort effect or not. Our study alone does not exclude the possibility of existing a weak negative association, considering the modest power of our study design.

Growth and Maturity Status of Female Soccer Players: A Narrative Review

Reported mean ages, heights and weights of female soccer players aged <19 years in 161 studies spanning the years 1992-2020 were extracted from the literature or calculated from data available to the authors; 35 studies spanning the years 1981-2020 also included an indicator of biological maturation. Heights and weights were plotted relative to U.S. reference data. Preece-Baines Model 1 was fitted to moving averages to estimate ages at peak velocity. Maturity indicators included skeletal age, pubertal status, age at menarche, percentage of predicted adult height and predicted maturity offset. Heights and weights showed negligible secular variation across the time interval. Heights were slightly above or approximated the reference medians through 14 years old and then varied between the medians and 75th percentiles through 18 years old. Weights were above the reference medians from 9 to 18 years old. Mean ages at menarche ranged from 12.7 to 13.0 years. The trend in heights and weights suggested the persistence and/or selection of taller and heavier players during adolescence, while estimated age at peak height velocity (PHV) and ages at menarche were within the range of mean ages in European and North American samples. Data for skeletal and sexual maturity status were limited; predicted maturity offset increased linearly with mean ages and heights at prediction.

The mean age of menarche among Chinese schoolgirls declined by 6 months from 2005 to 2014

AIM

This study assessed the trends in the age at menarche in Chinese schoolgirls from the majority Han group and 21 ethnic minorities from 2005 to 2014. We also compared the group differences during the study period.

METHODS

A total of 344 230 girls aged 9-18 years were extracted from the 2005, 2010 and 2014 Chinese National Survey on Students' Constitution and Health. The age at menarche for each subgroup was estimated by probit analysis. The chi-square test and Z-test were used to compare the differences between the groups.

RESULTS

The overall average age at menarche in Chinese schoolgirls decreased from 12.8 years in 2005 to 12.3 years in 2014. The Han girls and girls from 17 ethnic minorities showed decreasing trends in the age at menarche, while four ethnic minorities demonstrated fluctuating increasing trends over time. The gaps in age at menarche between the Han group and 14 of the ethnic minorities became smaller over the study period and were similar by 2014.

CONCLUSION

The overall findings were a decrease in the age at menarche in China and smaller gaps between the majority Han group and ethnic minority groups. Ethnic-specific public health policies are urgently needed on issues such as contraception.

Exogenous Oestrogen Impacts Cell Fate Decision in the Developing Gonads: A Potential Cause of Declining Human Reproductive Health

The increasing incidence of testicular dysgenesis syndrome-related conditions and overall decline in human fertility has been linked to the prevalence of oestrogenic endocrine disrupting chemicals (EDCs) in the environment. Ectopic activation of oestrogen signalling by EDCs in the gonad can impact testis and ovary function and development. Oestrogen is the critical driver of ovarian differentiation in non-mammalian vertebrates, and in its absence a testis will form. In contrast, oestrogen is not required for mammalian ovarian differentiation, but it is essential for its maintenance, illustrating it is necessary for reinforcing ovarian fate. Interestingly, exposure of the bi-potential gonad to exogenous oestrogen can cause XY sex reversal in marsupials and this is mediated by the cytoplasmic retention of the testis-determining factor SOX9 (sex-determining region Y box transcription factor 9). Oestrogen can similarly suppress SOX9 and activate ovarian genes in both humans and mice, demonstrating it plays an essential role in all mammals in mediating gonad somatic cell fate. Here, we review the molecular control of gonad differentiation and explore the mechanisms through which exogenous oestrogen can influence somatic cell fate to disrupt gonad development and function. Understanding these mechanisms is essential for defining the effects of oestrogenic EDCs on the developing gonads and ultimately their impacts on human reproductive health.

Associations between reproductive factors and biliary tract cancers in women from the Biliary Tract Cancers Pooling Project

BACKGROUND & AIMS

Gallbladder cancer (GBC) is known to have a female predominance while other biliary tract cancers (BTCs) have a male predominance. However, the role of female reproductive factors in BTC etiology remains unclear.

METHODS

We pooled data from 19 studies of >1.5 million women participating in the Biliary Tract Cancers Pooling Project to examine the associations of parity, age at menarche, reproductive years, and age at menopause with BTC. Associations for age at menarche and reproductive years with BTC were analyzed separately for Asian and non-Asian women. Hazard ratios (HRs) and 95% CIs were estimated using Cox proportional hazards models, stratified by study.

RESULTS

During 21,681,798 person-years of follow-up, 875 cases of GBC, 379 of intrahepatic bile duct cancer (IHBDC), 450 of extrahepatic bile duct cancer (EHBDC), and 261 of ampulla of Vater cancer (AVC) occurred. High parity was associated with risk of GBC (HR ≥5 vs. 0 births 1.72; 95% CI 1.25-2.38). Age at menarche (HR per year increase 1.15; 95% CI 1.06-1.24) was associated with GBC risk in Asian women while reproductive years were associated with GBC risk (HR per 5 years 1.13; 95% CI 1.04-1.22) in non-Asian women. Later age at menarche was associated with IHBDC (HR 1.19; 95% CI 1.09-1.31) and EHBDC (HR 1.11; 95% CI 1.01-1.22) in Asian women only.

CONCLUSION

We observed an increased risk of GBC with increasing parity. Among Asian women, older age at menarche was associated with increased risk for GBC, IHBDC, and EHBDC, while increasing reproductive years was associated with GBC in non-Asian women. These results suggest that sex hormones have distinct effects on cancers across the biliary tract that vary by geography.

LAY SUMMARY

Our findings show that the risk of gallbladder cancer is increased among women who have given birth (especially women with 5 or more children). In women from Asian countries, later age at menarche increases the risk of gallbladder cancer, intrahepatic bile duct cancer and extrahepatic bile duct cancer. We did not see this same association in women from Western countries. Age at menopause was not associated with the risk of any biliary tract cancers.

Menarche at an Earlier Age: Results from Two National Surveys of Israeli Youth, 2003 and 2016

STUDY OBJECTIVE

To assess emergent changes in the age at menarche and investigate associated factors in Israeli adolescents in 2003 and 2016.

DESIGN

Cross-sectional study.

SETTING

Two national representative school-based surveys (first and second "Mabat Youth").

PARTICIPANTS

Both surveys included female students in 7th-12th grades (ages 11-19 years). The first (N = 3328) was conducted between the years 2003 and 2004, and the second (N = 2535) from 2015 to 2016.

INTERVENTIONS

The survey questionnaire was self-administered and anthropometric measurements were performed by trained personnel.

MAIN OUTCOME MEASURES

The current age at menarche in Israeli girls was determined and independent factors (demographic, clinical, and lifestyle) examined. Changes that occurred since the past national survey more than a decade ago were documented.

RESULTS

The estimated median age at menarche declined from 13.0 (interquartile range, 12.0-14.0) years in 2003-2004 to 12.5 (interquartile range, 12.0-13.0) years in 2015-2016 (P < .0001). Jewish girls reached menarche earlier than Arab girls, but both populations experienced a similar downward trend in the past approximately 14 years. Greater body mass index, higher socioeconomic status, and immigrant status were associated with younger menarche onset (P < .001). Age at menarche remained lower in 2015-2016 vs 2003-2004, even after adjustment for these potential confounders, with a high hazard ratio (HR), which decreased as a function of survival time (t): HR_t = 15.417 × 0.813^t.

CONCLUSION

This study confirms the decline in age at menarche in Israel. Findings were associated with body mass index and population group but also indicated that other factors are likely involved.

Modern dietary pattern is prospectively associated with earlier age at menarche: data from the CHNS 1997-2015

Background

Early age at menarche is associated with risk of several chronic diseases. Prospective study on the association between dietary pattern and timing of menarche is sparse. We examined whether dietary patterns prior to the menarche onset were prospectively associated with menarcheal age in Chinese girls.

Methods

One thousand one hundred eighteen girls aged 6–13 y in the China Health and Nutrition Survey (CHNS) with three-day 24-h recalls and information on potential confounders at baseline were included in the study. Dietary patterns were identified using principal component analysis. Age at menarche was self-reported at each survey. Cox proportional hazard regression models were performed to examine the associations of premenarcheal dietary patterns and menarcheal timing. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated.

Results

Three major dietary patterns were identified: modern dietary pattern, animal food pattern, and snack food pattern. After adjustment for age at baseline, region, ethnicity, maternal education level, energy intake at baseline, and body mass index Z-score at baseline, girls in the highest quartile of modern dietary pattern score had a 33% higher probability of experiencing menarche at an earlier age than those in the lowest quartile (HR: 1.33, 95% CI: 1.002–1.77, p for trend = 0.03). No significant association was found for the animal food pattern or snack food pattern.

Conclusions

Higher adherence to modern dietary pattern during childhood is associated with an earlier menarcheal age. This association was independent of premenarcheal body size.

Recent pubertal timing trends in Northern Taiwanese children: Comparison with skeletal maturity

BACKGROUND

International studies have reported an early age of onset of puberty in girls and boys. However, the current situation of puberty onset in Taiwanese children is unknown. In this study, the timing of menarche and pubertal change in testicular volume (TV) in Taiwanese children was examined, and bone age (BA) was used as an internal somatic maturity scale and compared with the chronological age (CA) at pubertal timing.

METHODS

Clinical data from October 1, 2010, to March 31, 2018, were retrospectively collected from a general hospital in Taipei. The data of patients who were diagnosed with endocrine/genetic disorders were excluded. Clinical data included CA, timing of menarche, and X-ray images of TV and BA. BA was determined by a senior pediatrician and a senior pediatric radiologist. The reliability and validity of BA readings were tested. Collected data were analyzed statistically.

RESULTS

Overall, TV records of 241 boys and the menarche timing data of 98 girls were collected from 1823 children. CA for menarche was 11.35 ± 1.06 years (mean ± SD), and BA for menarche was 12.95 ± 0.80 years. CA and BA at TV = 15 mL in male puberty was 12.32 ± 1.22 and 13.46 ± 0.68 years, respectively. A stronger correlation was observed between TV and BA than between TV and CA during the pubertal period.

CONCLUSION

The secular trend of earlier puberty timing continues. The decline rate of menarche timing was approximately 0.43 years per decade in the past 30 years. Among boys, an advance of more than 1 year in pubertal timing age was observed over the past 20 years. BA and TV showed high correlation during puberty.

Racial differences in prostate cancer: does timing of puberty play a role?

The burden of prostate cancer has a remarkably disproportionate distribution across racial groups. For example, in the USA, African Americans are twice as likely as individuals of European ancestry to develop or die from prostate cancer, and have a more aggressive disease nature at diagnosis. In contrast, Asian American men have the lowest incidence and mortality rates of prostate cancer. That considerable racial disparities exist even in the subclinical stage of prostate cancer among young men in their 20–30s suggests that patterns of prostate carcinogenesis start to diverge even earlier, perhaps during puberty, when the prostate matures at its most rapid rate. Mendelian randomisation studies have provided strong population-based evidence supporting the hypothesis that earlier onset of puberty increases the risk of prostate cancer—particularly of high grade—and prostate cancer-specific mortality later in life, observations which correspond to the epidemiology of the disease in African Americans. Notably, African American boys initiate genital development ~1 year earlier and thus go through longer periods of pubertal maturation compared with European American boys. In this perspective, bringing together existing evidence, we point to puberty as a potential critical window of increased susceptibility to prostate carcinogenesis that could account for the marked prevailing racial differences in the burden of prostate cancer.

Early age at menarche and its associated factors in school girls (age, 10 to 12 years) in Bangladesh: a cross-section survey in Rajshahi District, Bangladesh

Background

Early onset of menarche is one of the most important factors for breast cancer and other associated health hazards. The aim of this study was to investigate the early age at menarche and its associated factors in school girls (age, 10–12 years) in Rajshahi District, Bangladesh.

Methods

Data was collected from Rajshahi District, Bangladesh, using multistage random sampling. Independent sample t test and binary logistic regression model were used in this study. A total number of 386 school girls aged 10–12 years were considered as a sample for this study.

Results

This study revealed that more than 48% girls already attained menarche within the age of 12 years, among them 25.6%, 41.0%, and 58.3% girls experienced menarche at the age of 10, 11, and 12 years, respectively. It was observed that the menarcheal girls were significantly taller (p < 0.01) and heavier (p < 0.01) than non-menarcheal girls. The menarcheal girls’ mothers were heavier (p < 0.01), shorter (p < 0.01), had more BMI (p < 0.01), reached menarche (p < 0.05) earlier than non-menarcheal girls’ mothers. Menarcheal girls had less number of siblings (p < 0.01) and lower order of birth (p < 0.05) than non-menarcheal girls. After controlling the effect of other factors, multiple logistic regression model demonstrated that obese girls were more likely to attain menarche than under- [AOR = 0.279, CI 95% 0.075–0.986; p < 0.05] and normal [AOR = 0.248, CI 95% 0.082–0.755; p < 0.05] weight girls. Urban school girls had more chance to get menarche than rural school girls at same age (AOR = 0.012, 95% CI 0.003–0.047; p < 0.01).

Conclusions

Therefore, modern lifestyle changes may have the important factors for early age at menarche of the studied girls in Bangladesh.

Evolutionary Strategies for Body Size

Humans show marked variation in body size around the world, both within and among populations. At present, the tallest people in the world are from the Netherlands and the Balkan countries, while the shortest populations are central African Pygmies. There are genetic, genetic plasticity, developmental, and environmental bases for size variation in Homo sapiens from the recent past and the present. Early populations of Homo species also have shown considerable size variation. Populations from the present and the past are also marked by sexual dimorphism, which, itself, shows group variation. There is abundant evidence for the effects of limited food and disease on human growth and resultant adult body size. This environmental influence has been reflected in "secular trends" (over a span of years) in growth and adult size from socioeconomic prosperity or poverty (availability of resources). Selective and evolutionary advantages of small or large body size also have been documented. Heritability for human height is relatively great with current genome-wide association studies (GWAS) identifying hundreds of genes leading to causes of growth and adult size variation. There are also endocrinological pathways limiting growth. An example is the reduced tissue sensitivity to human growth hormone (HGH) and insulin-like growth factor (IGF-1) in Philippine and African hunter-gatherer populations. In several short-statured hunter-gatherer populations (Asian, African, and South American), it has been hypothesized that short life expectancy has selected for early maturity and truncated growth to enhance fertility. Some island populations of humans and other mammals are thought to have been selected for small size because of limited resources, especially protein. The high-protein content of milk as a staple food may contribute to tall stature in East African pastoral peoples. These and other evolutionary questions linked to life history, male competition, reproduction, and mobility are explored in this paper.

The relationship among the age at menarche, anthropometric characteristics, and socio-economic factors in Bengali girls from Kolkata, India

OBJECTIVES

The aim of the study was to measure the causal effect of selected socio-economic factors and anthropometrical characteristics on the menarche occurrence.

METHODS

The sample consisted of 2195 Bengali girls (aged 7-21) from middle-class families, from Kolkata city, India. The age at menarche was recorded from the retrospective data and status quo method. The causal effect of anthropometric and socio-economic variables on menarche occurrence was estimated by the nonparametrical analysis of survival probability (survival random forest).

RESULTS

In the examined cohort menarche occurred, on average, at 11.8 years of age. The probability of menarche occurrence amplified with the increasing values of factors such as body mass index, height-for-age z-scores, number of family members, household rooms, and toilets, but decreased when expenditures increased. The relation maintained a similar pattern of causal effect with girls' age.

CONCLUSIONS

A complex pattern of relationship among sexual development, physique, and socio-economic characteristics was defined. The tendency toward early menarche, along with the observed causal relationships indicate that the analyzed sample is nearing the characteristics and standards of living noted in other middle and even high-income countries in the world.

Variation in menarcheal age of school-aged female athletes engaged in different types of sport

It is widely known from the literature that the rate of physical development and sexual maturation is not only determined by genetics but is also modified by physical workload factors. Given the above, this paper aimed at comparing menarcheal age of school-aged athletes engaged in different types of sport (and their respective workloads) after controlling for physical traits such as body height and mass and slenderness ratio. The survey was conducted in 2017 in 6 sports schools in Poland’s Lubuskie Voivodeship. Body height and mass were measured and the slenderness index (body height divided by the cubic root of body weight) was used to establish body build. The age of menarche was self-reported by the study participants. In total, 232 girls aged 9–18 were included in the research, of whom 125 reported their age of menarche. The age-adjusted arithmetic means and standard deviations were calculated for the study participants’ estimates. The raw data were then transformed into standardized z-score values. The significance of differences was assessed by Mann-Whitney U test as an alternative to the t-test when a given variable was not normally distributed. Pearson’s correlation coefficient was used to evaluate linear relations between the workload and age at menarche. It was found that dancers, acrobats and swimmers reported the youngest menarcheal ages. Girls practising most demanding sport disciplines (in terms of strength and endurance) reported the oldest age at menarche. Girls practising more than 3 times per week had menarche later than those practising 3 times a week or less, and the difference was statistically significant. In conclusion it might be stated that the type of sport discipline has a significant effect on age of menarche. Sport disciplines involving heavier physical exertion usually delay the onset of menstruation.

Endocrine disrupters and possible contribution to pubertal changes

The onset of puberty strongly depends on organizational processes taking place during the fetal and early postnatal life. Therefore, exposure to environmental pollutants such as Endocrine disrupting chemicals (EDCs) during critical periods of development can result in delayed/advanced puberty and long-term reproductive consequences. Human evidence of altered pubertal timing after exposure to endocrine disrupting chemicals is equivocal. However, the age distribution of pubertal signs points to a skewed distribution towards earliness for initial pubertal stages and towards lateness for final pubertal stages. Such distortion of distribution is a recent phenomenon and suggests environmental influences including the possible role of nutrition, stress and endocrine disruptors. Rodent and ovine studies indicate a role of fetal and neonatal exposure to EDCs, along the concept of early origin of health and disease. Such effects involve neuroendocrine mechanisms at the level of the hypothalamus where homeostasis of reproduction is programmed and regulated but also peripheral effects at the level of the gonads or the mammary gland.

Early menarche and its relationship to paternal migrant work among middle-school-aged students in China

Associations have been shown between father's absence and menarcheal age, but most studies have focused on absence resulting from divorce, abandonment or death. Little research has been conducted to evaluate the effect on menarcheal age of paternal absence through migrant work. In a sample of 400 middle school students, this study examined the association between paternal migrant work and menarcheal age against a backdrop of extensive rural-to-urban migration in China. Data were collected through a self-reported questionnaire, including social-demographic characteristics, aspects of family relationships, information about father's migrant work and age at menarche. After adjusting for BMI, parent marital status and perceived relationship with mother, lower self-perceived quality of father-daughter relationship (both 'father present, relationship poor' and 'father absent, relationship poor') and lower frequency of contact with the father were associated with higher odds for early menarche. These findings suggest that the assumption that father's absence for work influences the timing of menarche needs to be examined in the context of the quality of the father-daughter relationship and paternal care, which appear to play a critical role in the timing of menarche. These findings also emphasize the importance of enhancing paternal involvement and improving father-daughter relationships in the development of appropriate reproductive strategy in daughters.

MKRN3 Mutations in Central Precocious Puberty: A Systematic Review and Meta-Analysis

MKRN3 mutations represent the most common genetic cause of central precocious puberty (CPP) but associations between genotype and clinical features have not been extensively explored. This systematic review and meta-analysis investigated genotype-phenotype associations and prevalence of MKRN3 mutations in CPP. The search was conducted in seven electronic databases (Cochrane, EMBASE, LILACS, LIVIVO, PubMed, Scopus, and Web of Science) for articles published until 4 September 2018. Studies evaluating MKRN3 mutations in patients with CPP were considered eligible. A total of 22 studies, studying 880 subjects with CPP, fulfilled the inclusion criteria. Eighty-nine subjects (76 girls) were identified as harboring MKRN3 mutations. Girls, compared with boys, exhibited earlier age at pubertal onset (median, 6.0 years; range, 3.0 to 7.0 vs 8.5 years; range, 5.9 to 9.0; P < 0.001), and higher basal FSH levels (median, 4.3 IU/L; range, 0.7 to 13.94 IU/L vs 2.45 IU/L; range, 0.8 to 13.70 IU/L; P = 0.003), and bone age advancement (ΔBA; median, 2.3 years; range, -0.9 to 5.2 vs 1.2 years; range, 0.0 to 2.3; P = 0.01). Additional dysmorphisms were uncommon. A total of 14 studies evaluating 857 patients were included for quantitative analysis, with a pooled overall mutation prevalence of 9.0% (95% CI, 0.04 to 0.15). Subgroup analysis showed that prevalence estimates were higher in males, familial cases, and in non-Asian countries. In conclusion, MKRN3 mutations are associated with nonsyndromic CPP and manifest in a sex-dimorphic manner, with girls being affected earlier. They represent a common cause of CPP in western countries, especially in boys and familial cases.

Age at menarche and prevention of hypertension through lifestyle in young Chinese adult women: result from project ELEFANT

Background

Early and late age at menarche are associated with risk of hypertension, but little is known whether modifiable lifestyle can reduce this risk.

Methods

Our study leverages 60,135 healthy young Chinese women from the Environmental and LifEstyle FActors iN metabolic health throughout life-course Trajectories (ELEFANT) study. Menarche age and lifestyle factors were assessed by self-reported questionnaires and hypertension was diagnosed by physicians. We estimated the odds ratios (ORs) of hypertension associated with menarche age using multivariable logistic regression. We further investigated whether modifiable lifestyles (body mass index, BMI; psychological stress; passive smoking; and imbalanced diet) increased risk in joint analyses.

Results

The association between age at menarche and hypertension was U-shaped, with age ≤ 12 at menarche giving the highest OR (1.46, 95% confidence interval [CI], 1.27–1.69) and ≥ 16 the second highest (OR = 1.36, 95% CI = 1.15–1.62). Simultaneous analysis of lifestyle risk factors and age of menarche showed that having one or more modifiable risk factors increased the menarche age-hypertension association. The risk of hypertension among participants with menarche age ≤ 12 decreased from OR 13.21 (95% CI = 5.17–29.36) with four high-risk lifestyle factors to 12.36 (95% CI = 9.51–16.05) with three high-risk factors, 5.24 (95% CI = 4.11–6.69) with two, and 2.76 (95% CI = 2.09–3.60) with one, in comparison to individuals with no high-risk lifestyle factors and menarche age 14.

Conclusions

Our results suggest that modification of lifestyle, including maintenance of normal weight and a balanced diet, are associated with substantially reduce the risk of hypertension in high-risk individuals.

Plain English summary

Early and late age at menarche are risk factors for the development of hypertension in Western populations, and there is limited evidence that this is also true of Chinese populations. Targeted prevention of hypertension in vulnerable populations would be highly beneficial in efforts to reduce the incidence of cardiovascular disease, but it is not currently known whether lifestyle intervention could reduce hypertension risk.

In this study, we analysed the risk of hypertension by age at menarche and four modifiable lifestyle factors (BMI, diet, psychological stress, and smoking tobacco) in a cohort of 60,135 young adult Chinese women (mean age 29).

We identified that early and late age at menarche are associated with increased risk of hypertension in young Chinese women. There was joint effects between age at menarche and lifestyles on hypertension only participants with age at menarche ≤12 and being overweight or obese. Modification of lifestyle, including maintenance of normal weight and a balanced diet, can substantially reduce the risk of hypertension in high-risk individuals.

In conclusion, our study has revealed that early and late menarche age are associated with the development of hypertension in young Chinese women, and that this risk is modified by healthy lifestyle traits.

Electronic supplementary material

The online version of this article (10.1186/s12905-018-0677-y) contains supplementary material, which is available to authorized users.

Individualized evaluation of lumbar bone mineral density and bone mineral apparent density in children and adolescents

Lumbar spine bone mineral density (LS-BMD) assessed by dual-energy X-ray absorptiometry (DXA) is used in children to evaluate bone health. LS-BMD results in children are influenced significantly by height and BMI. An adjustment for these parameters may improve the clinical use of the method.

PURPOSE/INTRODUCTION

DXA evaluation is considered useful in children to assess bone health. For this purpose, lumbar spine bone mineral density (LS-BMD) and bone mineral apparent density (LS-BMAD) are often used. The aim of the study was to estimate the effect of height and BMI on LS-BMD and LS-BMAD in children and adolescents and to develop a method to adjust individual results for these factors.

METHODS

As part of the National Health and Nutrition Examination Survey (NHANES) study, between the years 2005 and 2010 lumbar DXA scans on randomly selected Americans from 8 to 20 years of age were carried out. From all eligible DXA scans, three major US ethnic groups were evaluated (Non-Hispanic Whites, Non-Hispanic Blacks, and Mexican Americans) for further statistical analysis. The relationship between height as well as BMI for age Z-scores and age-adjusted LS-BMD and LS-BMAD Z-scores was analyzed.

RESULTS

For the statistical analysis, the DXA scans of 1799 non-Hispanic White children (823 females), of 1696 non-Hispanic Black children (817 females), and of 1839 Mexican American children (884 females) were eligible. The statistical analysis showed that taller and heavier children had significantly (p < 0.001) higher age-adjusted LS-BMD Z-scores than shorter and lighter children. But on LS-BMAD, only BMI and not height had a significant influence.

CONCLUSIONS

LS-BMD results in children were influenced significantly by their height and BMI, the LS-BMAD results were only influenced by their BMI. For the first time, the proposed method adjusts LS-BMD and LS-BMAD to BMI. An adjustment of the LS-BMD and LS-BMAD results to these factors might improve the clinical significance of an individual result.

Declining age at menarche in Indonesia: a systematic review and meta-analysis

BACKGROUND

There has been much research on the average age at menarche onset. In higher income countries the lowering in average age at menarche is earlier than in middle-income countries and lower income countries. Indonesia as a middle-income country also has some research experience related to the average age at menarche for girls.

OBJECTIVES

This study aimed to review the lowering of the average age at menarche in Indonesia and to predict changes in average age at menarche.

METHODS

This study provides a systematic review and meta-analysis using references from Google Scholar, PubMed and Popline databases on the trend of age at menarche in Indonesia and other data sources from local and national survey reports. Metaprop command in STATA was used to do the meta-analysis of proportion of early age at menarche and time series with auto-regressive integrated moving average (ARIMA) models were used in analyzing the trend and predicting the age at menarche.

RESULTS

The results show that in Indonesia the timing of age at menarche onset has significantly lowered during the 40 years before 2010. There was meaningful decrease of age at menarche, which changed from 14.43 years [confident interval (CI) 95%: 14.42, 14.44] to 13.63 years (CI95%: 13.63, 13.64). Using the ARIMA model, mean age at menarche onset for the next year predicted that the coefficient regression would be -0.0245 (CI95%: -0.0275, -0.0215). The predicted average age at menarche shows a decrease of 0.0245 years (8-9 days) each year.

CONCLUSION

The findings indicate a significant lowering of age at menarche in Indonesian girls that has continued as a predictable trend through time until the present, paralleling recent socioeconomic changes. These predictions provide key indicators of a girl's future healthy transition from childhood into young adulthood.

Adolescence and the next generation

Adolescent growth and social development shape the early development of offspring from preconception through to the post-partum period through distinct processes in males and females. At a time of great change in the forces shaping adolescence, including the timing of parenthood, investments in today's adolescents, the largest cohort in human history, will yield great dividends for future generations.