Determinants of menarche

Estimated timing of the first menstrual period and dietary and nutritional correlates of menarche among urban school-going adolescents in four sub-Saharan African sites

Characterizing the timing of menarche and the factors that are associated with it is important for understanding a population's reproductive health needs and long-term health trajectories. We estimated the age at the menstrual onset among adolescent girls and the association between dietary and nutritional factors and menarche in four sub-Saharan African urban sites. We used cross-sectional school-based data from 2307 female adolescents aged 10-14 years collected by the Africa Research, Implementation Science, and Education (ARISE) Network in Ouagadougou, Burkina Faso; Addis Ababa, Ethiopia; Khartoum, Sudan; and Dar es Salaam, Tanzania. Logit models were used to estimate the median age at menarche at each site. Associations between menarche and BMI-for-age, stunting, dietary quality and food insecurity across settings were assessed using Poisson regression models adjusted for country and school levels. The estimated median age at menarche was 13.1 years (95% confidence interval: 12.7, 13.5) in Ouagadougou; 12.9 (12.6, 13.2) in Addis Ababa; 13.3 (12.7, 13.6) in Khartoum; and 13.2 (12.3, 14.0) in Dar es Salaam. Between 18% and 49% of the girls in each setting had already menstruated. Based on the pooled multivariable models, underweight participants were 42% less likely (adjusted prevalence ratio [PR] 0.58 [0.44, 0.77]) to have experienced menarche in comparison to normal-weight individuals. The likelihood of experiencing menarche increased for overweight [PR 1.47 (1.30,1.66)] and obese [PR 1.57 (1.35,1.82)] in comparison to normal-weight girls. Those stunted were 47% less likely to have experienced menarche [PR 0.53 (0.41, 0.69)] than their nonstunted counterparts. A lower likelihood of menarche among those experiencing moderate/severe hunger when compared to those with no/little hunger was also observed (PR 0.78 [0.63,0.96]). No evidence of association with dietary quality was found. Further research is needed to strengthen the body of evidence and inform evidence-based initiatives in low- and middle-income settings.

Early age at menarche is associated with an increased risk of preeclampsia and adverse neonatal outcomes: a 6‑year retrospective study

PURPOSE

Preeclampsia affects between 2 to 8% of pregnancies worldwide and is associated with significant adverse outcomes for both mothers and their offspring. The present study aims to investigate whether there is a correlation between early age at menarche and an increased risk of developing preeclampsia and experiencing adverse neonatal outcomes.

METHODS

The study involved a review of medical records of 4227 pregnant women who gave birth at The First Affiliated Hospital of Chengdu Medical College between January 2017 and December 2022. The collected data included demographic characteristics, clinical manifestations of preeclampsia, laboratory indicators, gestational complications, and neonatal outcomes. Pregnant women were categorized into four groups based on their age at menarche (≤ 12, 13, 14, and ≥ 15 years). Logistic regression analysis was conducted to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for the association between different menarche age groups and the risk of preeclampsia and adverse neonatal outcomes.

RESULTS

Pregnant women who had an age at menarche of ≤ 12 years had a higher risk of preeclampsia than women who had their menarche at 13, 14, and ≥ 15 years of age, with adjusted ORs (95% CIs) for preeclampsia of 1.00 (reference), 0.78 (0.45-0.91), 0.76 (0.59-0.88), and 0.73 (0.56-0.94), respectively. The predictive efficacy of age at menarche for preeclampsia was assessed with a sensitivity and specificity of 85.2% and 76.4%, respectively, and an AUC of 0.82. Moreover, infants born to women with an age at menarche of ≤ 12 years had a higher risk of adverse neonatal outcomes, including small for gestational age, preterm birth, low birth weight, neonatal respiratory distress syndrome, and neonatal intensive care unit admission.

CONCLUSION

Our findings suggest that an early age at menarche is associated with an increased risk of preeclampsia and adverse neonatal outcomes. This information could be useful for obstetricians to identify women at risk for preeclampsia early on and implement timely interventions to reduce the incidence of preeclampsia and associated adverse neonatal outcomes.

Strong evidence supports the use of estradiol therapy for the treatment of vaginal inflammation: a two-way Mendelian randomization study

OBJECTIVE

Nowadays, there has been limited Mendelian randomization (MR) research focusing on the causal relationship between estradiol and vaginitis. Therefore, this study conducted a two-way MR study to clarify the causal effect and related influencing factors between them.

METHODS

All genetic datasets were obtained using publicly available summary statistics based on individuals of European ancestry from the IEU GWAS database. MR analysis was performed using MR-Egger, weighted median (WM) and inverse variance weighted (IVW) methods to assess the causal relationship between exposure and outcome and to validate the findings by comprehensively evaluating the effects of pleiotropic effects and outliers.

RESULTS

MR analysis revealed no significant causal relationship between estradiol and vaginitis risk. There was a negative correlation between estradiol and age at menarche (IVW, OR: 0.9996, 95% CI: 0.9992-1.0000, P = 0.0295; WM, OR: 0.9995, 95% CI: 0.9993-0.9998, P = 0.0003), and there was a positive correlation between age at menarche and vaginitis (IVW, OR: 1.5108, 95% CI: 1.1474-2.0930, P = 0.0043; MR-Egger, OR: 2.5575, 95% CI: 1.7664-9.6580, P = 0.0013). Estradiol was negatively correlated with age at menopause (IVW, OR: 0.9872, 95% CI: 0.9786-0.9959, P = 0.0041). However, there was no causal relationship between age at menopause and vaginitis (P > 0.05). In addition, HPV E7 Type 16, HPV E7 Type 18, and Lactobacillus had no direct causal effects on estradiol and vaginitis (P > 0.05). Sensitivity analyses revealed no heterogeneity and horizontal pleiotropy.

CONCLUSION

When estrogen levels drop, it will lead to a later age of menarche, and a later age of menarche may increase the risk of vaginitis, highlighting that the longer the female reproductive tract receives estrogen stimulation, the stronger the defense ability is formed, and the prevalence of vaginitis is reduced. In conclusion, this study indirectly supports an association between reduced level of estrogen or short time of estrogen stimulation and increased risk of vaginitis.

Evidence of weight loss in junior female judo athletes affects their development

Purpose

The facile manipulation of body weight in junior athletes has the potential to pose significant risks to their lifelong health. In judo, which is a weight class sport, pre-competition weight loss is widespread even among juniors, but information on the current situation is scarce, especially for female athletes, for whom it is important to provide adequate nutrition and enhance bone mass during the growth period, and the details of the current situation are not clear. Therefore, the purpose of this study was to determine the actual weight loss during the growth period in junior female judo athletes and its subsequent impact on their health.

Methods

The survey was a cross-sectional survey of junior female judo athletes in Japan using a questionnaire. Participants were asked to respond via an online questionnaire about their weight, height, weight loss experience, menstruation, competition results, and other lifestyle.

Results

51.8% of subjects experienced weight loss for competition during their junior high school years (ages 12-15). Those who experienced weight loss during secondary sexual characteristics were found to be significantly shorter in current height than those who did not (p < 0.05). Weight loss during secondary sexual characteristics did not affect current menstrual cycle. There was no significant difference in competition results due to the experience of weight loss during junior high school (χ 2 = 4.485, df = 3, n.s.).

Conclusions

These findings suggest that weight loss during the growth spurt phase may adversely impact normal development. It also suggested that weight loss during the junior high school years may not be a strategy to bring about better competition results. These observations indicate the need for education on appropriate class selection and weight control for junior athletes in weight class competitions.

Earlier Menarche in Greek Girls Born by Caesarean Section: A Case-Control Study

Objectives: The purpose of this study was to report on the menarcheal age in girls of Greek origin and assess its potential associations with their demographic and perinatal data, as well as their maternal menarcheal age. Methods: In this case-control study, adolescent girls were recruited between September 2021 and September 2022 from two Pediatric Endocrinology Units, Aristotle University of Thessaloniki, Greece. Eligible participants included Greek girls up to the age of 18 years, with menarche and the absence of chronic disease or chronic medication use. Participants were divided into two groups, the early menarche group and the control group (menarche before or after 11 years of age, respectively). Data included participants' maternal menarcheal age, their chronological age, place of residence, anthropometric data (at recruitment) and perinatal data (birth order, gestational age, type of delivery, birth weight/length). Results: A total of 100 girls aged 7-17 years (mean age ± SD 12.51 ± 2.59 years) were included in this study. The mean ± SD menarcheal age of the total sample was 11.47 ± 1.55 years (median 11.20 years; range 7.50-16.25 years); 43% had early menarche (median menarcheal age 10.50 years; range 7.50-10.91 years), and 57% had menarche after age 11 (median menarcheal age 12.08 years; range 11.00-16.25 years). The caesarean section rate was significantly (p < 0.001) higher in girls with early menarche (83.7%) than controls, whereas other variables did not differ significantly between groups. Conclusions: This Greek sample demonstrated a relatively young age at menarche with a significant proportion of girls with early menarche; in the latter group, the rate of caesarian sections was significantly higher than controls.

Morphological changes and their associations with clinical parameters in children with nephropathic cystinosis and chronic kidney disease prior to kidney replacement therapy over 25 years

BACKGROUND

Infantile nephropathic cystinosis (INC) is a rare lysosomal storage disorder, mostly and often firstly affecting the kidneys, together with impaired disharmonious growth and rickets, eventually resulting in progressive chronic kidney disease (CKD). With the introduction of cysteamine therapy, most pediatric patients reach adulthood with no need for kidney replacement therapy. Still, detailed changes in INC patients' clinical and morphological presentation over the past decades have not yet been thoroughly investigated.

METHODS

Two groups with a respective total of 64 children with INC and 302 children with CKD, both treated conservatively and aged 2 to 18 years, were prospectively observed in the time span from 1998 to 2022 with 1186 combined annual clinical and morphological examinations clustered into two measurement periods (1998 to 2015 and ≥ 2016).

RESULTS

In INC patients, thoracic proportion indices remained markedly increased, whereas body fat stores remained decreased over the past 25 years (+ 1 vs. below ± 0 z-score, respectively). Their CKD peers presented with overall improved growth, general harmonization of body proportions, and improved body fat stores, while INC patients only presented with an isolated significant increase in leg length over time (∆0.36 z-score). eGFR adjusted for age did not significantly change over the past 25 years in both groups. Alkaline phosphatase (ALP) showed a significant decrease in CKD patients over time, while remaining above normal levels in INC patients.

CONCLUSIONS

Disproportionate thoracic shape and impaired body fat stores remain the most characteristic morphological traits in INC patients over the past 25 years, while causal mechanisms remain unclear.

Factors influencing menstrual regularity among female workers: a cross-sectional analysis study

BACKGROUND

Regularity of menstrual cycles is an important indicator of women's health and fertility, and female workers are exposed to several factors, such as sleep disorders, stress, and shift work, that affect their menstrual regularity. This makes it necessary to comprehensively identify the determinants of menstrual regularity. Therefore, this study identified the factors affecting menstrual regularity among female workers from physiological, psychological, and situational dimensions based on the theory of unpleasant symptoms.

METHODS

This was a secondary analysis of the 2010-2012 Korea National Health and Nutrition Examination Survey and utilized the data of 2418 female workers. Based on the theory of unpleasant symptoms, physiological factors included age, age at menarche, childbirth experience, body mass index, and sleep duration. Psychological factors included stress level, depressive mood, and suicidal ideation. Situational factors included education level, household income, consumption of alcohol, engagement in smoking, and work schedule. The χ²-test and hierarchical logistic regression analysis were performed, reflecting the complex sample design.

RESULTS

Age at menarche, childbirth experience, and body mass index among physiological factors and education level and work schedule among situational factors were found to be related to menstrual regularity. A higher risk of menstrual irregularities was found among those who had given birth (versus those who had not), had a high age at menarche (versus those with a low age at menarche), were obese (versus those who had a normal body mass index), had elementary school-level or lesser educational achievements (versus those with college graduate-level or higher educational achievements), and who had a shift work schedule (versus those with a fixed schedule).

CONCLUSIONS

Intervention is needed for female workers who have these risk factors, and special attention must be paid to female workers who have a shift work schedule. Additionally, since body mass index can be controlled, intervention concerning body mass index is necessary to reduce menstrual irregularity.

Association between BMI and age at menarche or spermarche among both sexes: Findings from six successive national surveys in China

Background

To explore trends of the association between body mass index (BMI) and age at menarche or spermarche and its urban-rural disparities from 1995 to 2019.

Methods

A total of 912 753 children and adolescents - including 519 940 9-18 years old girls and 392 813 11-18 years old boys - were involved in six successive cross-sectional surveys conducted across 30 provinces in China from 1995 to 2019. Data on menarche and spermarche was collected using the status quo method, where same-gender physicians conducted face-to-face interviews to determine if children and adolescents had experienced their first menstrual cycle or ejaculation (yes/no). The median age at menarche or spermarche was estimated by probit analysis. Anthropometric measurements measured the height and weight of the study subjects. Children and adolescents were classified into thinness, normal range of weight, overweight, and obesity. t test was used to compare the differences in BMI between premenarchal and postmenarchal girls or prespermarcheal and postspermarcheal boys. Logistic regression was used to explore the associations between BMI/nutritional status and menarche or spermarche stratified by urban or rural residency status.

Results

From 1995 to 2019, BMI in all age groups growth over time, and the values of BMI among children and adolescents under 15 who had menarche or spermarche were more significant than those without menarche or spermarche. In 2019, for girls, thinness was associated with delayed menarche (odds ratio (OR) = 0.26; 95% confidence interval (CI) = 0.24-0.28), while overweight (OR = 1.99; 95% CI = 1.85-2.14) and obesity (OR = 2.20; 95% CI = 1.92-2.53) was associated with advanced menarche. For boys, thinness was associated with delayed spermarche (OR = 0.71; 95% CI = 0.65-0.78), overweight was associated with advanced spermarche (OR = 1.08; 95% CI = 1.01-1.15) while obesity had no association with spermarche. The OR between BMI and menarche in 1995 was 1.35 (95% CI = 1.33-1.37), which decreased to 1.19 (95% CI = 1.18-1.20) by 2019. The OR between BMI and spermarche in 1995 was 1.10 (95% CI = 1.09-1.11), which decreased to 1.02 (95% CI = 1.02-1.03) by 2019. The trends by urban-rural stratification were consistent with the total sample.

Conclusions

We have established a dose-response relationship between BMI and menarche in girls, whereas the association appears to be nonlinear in boys, and the associations were diminishing. Similar findings were observed in both urban and rural areas. Considering the dual adverse effects of obesity and early puberty on health, the results of this study suggest that sexual health education should be strengthened, especially among obese girls. Further research on the influencing factors and biological mechanisms of early puberty will be beneficial.

Reproductive factors and cardiometabolic disease among middle-aged and older women: a nationwide study from CHARLS

Background

Cardiometabolic disease is skyrocketing to epidemic proportions due to the high prevalence of its components and the aging of the worldwide population. More efforts are needed to improve cardiometabolic health. The aim of this nationally representative study based on the China Health and Retirement Longitudinal Study (CHARLS, 2014-2018) was to examine the association between reproductive factors and cardiometabolic disease among Chinese women aged ≥45 years.

Methods

The CHARLS is an ongoing longitudinal study initiated in 2011, and the latest follow-up was completed in 2018. In total, 6,407 participants were analyzed. Effect-sizes are expressed as odds ratios (OR) and 95% confidence intervals (CI). Confounding was considered from statistical adjustment, subsidiary exploration, and unmeasured confounding assessment aspects.

Results

Of 6,407 accessible participants, 60.9% were recorded as having one or more of five predefined cardiovascular or metabolic disorders. Compared to those with two children, participants who had 0-1 child were found to have a lower risk of cardiometabolic disease (OR = 0.844, 95% CI: 0.714-0.998), and those who had ≥3 children had a greater risk (OR = 1.181, 95% CI: 1.027-1.357). Age at menarche of 16-18 years was a protective factor compared with ≤16 years of age (OR = 0.858, 95% CI: 0.749-0.982). In contrast, participants with a history of abortion were 1.212 times more likely to have cardiometabolic disorders (OR = 1.212, 95% CI: 1.006-1.465). The likelihood for the presence of unmeasured confounding was low, as reflected by E-values.

Conclusions

Our findings demonstrate that number of children, age at menarche, and history of abortion were associated with a significant risk of cardiometabolic disease among Chinese women aged ≥45 years.

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.

Anastrozole monotherapy further improves near-adult height after the initial combined treatment with leuprorelin and anastrozole in early-maturing girls with compromised growth prediction: results from the second phase of the GAIL study

Background

The first phase of the GAIL study ("Girls treated with an Aromatase Inhibitor and Leuprorelin," ISRCTN11469487) has shown that the combination of anastrozole and leuprorelin for 24 months is safe and effective in improving the predicted adult height (PAH) in girls with early puberty and compromised growth prediction by +1.21 standard deviation score (SDS; +7.51 cm) compared to inhibition of puberty alone, +0.31 SDS (+1.92 cm).

Objectives and hypotheses

In the second phase of the GAIL study, we assessed the adult height (AH)/near-adult height (NAH) at the end of the first phase and, in addition, the efficacy of anastrozole monotherapy thereafter in further improving NAH.

Methods

We measured the AH (age 16.5 years)/NAH [bone age (BA), 15 years] of the 40 girls included, divided into two matched groups: group A (20 girls on anastrozole + leuprorelin) and group B (20 girls on leuprorelin alone). Group A was further randomized into two subgroups: A1 and A2. Group A1 (n = 10), after completion of the combined therapy, received anastrozole 1 mg/day as monotherapy until BA 14 years, with a 6-month follow-up. Group A2 (n = 10) and group B (n = 20), who received only the combined treatment and leuprorelin alone, respectively, were recalled for evaluation of AH/NAH.

Results

AH or NAH exceeded the PAH at the completion of the 2-year initial phase of the GAIL study in all groups, but the results were statistically significant only in group A1: NAH-PAH group A1, +3.85 cm (+0.62 SDS, p = 0.01); group A2, +1.6 cm (+0.26 SDS, p = 0.26); and group B, +1.7 cm (+0.3 SDS, p = 0.08). The gain in group A1 was significantly greater than that in group A2 (p = 0.04) and in group B (p = 0.03). Anastrozole was determined to be safe even as monotherapy in Group A1.

Conclusions

In early-maturing girls with compromised growth potential, the combined treatment with leuprorelin and anastrozole for 2 years or until the age of 11 years resulted in a total gain in height of +9.7 cm when continuing anastrozole monotherapy until the attainment of NAH, as opposed to +7.4 cm if they do not continue with the anastrozole monotherapy and +3.6 cm when treated with leuprorelin alone. Thus, the combined intervention ends at the shortest distance from the target height if continued with anastrozole monotherapy until BA 14 years.

Repeatability of measures of behavioral organization over two years in captive infant rhesus macaques, Macaca mulatta

Individual differences of infant temperament have been associated with future health outcomes that provide explanatory power beyond adult personality. Despite the importance of such a metric, our developmental understanding of personality-like traits is poor. Therefore, we examined whether young primates show consistency in personality traits throughout development. We replicated a Biobehavioral Assessment (BBA) at three time periods: 3-4 months, 1 year, and 2 years of age in 47 rhesus macaque (Macaca mulatta) subjects from large mixed-sex outdoor social housing units at the California National Primate Research Center. We report results for tests focused on responses and adaptation to the temporary separation and relocation, responses to a threatening stimulus, and ratings of overall temperament. We found consistently repeatable associations in measures of Emotionality; these associations were stronger in males, but also present in females, and broadly consistent between Years 1 and 2. We also explored whether behavioral responses to this experimental relocation might be influenced by their experience being relocated for other reasons (i.e., hospitalizations) as individuals' responses might be influenced by similar experiences to the BBA procedure. Only locomotion, during one of the assessments, was associated with past hospitalization events. Overall, repeatability in Emotionality-associated behaviors was evident across the 2 years, in both sexes. We did, however, find evidence of the emergence of sex differences via differentiated expression of behavioral responses during the BBA. We emphasize that there is likely contextual nuance in the use of these BBA factor-associated behaviors. Further research is required to determine whether and how shifts occur in underlying factor structure and the expression of associated behaviors.

Age and menstrual cycle may be important in establishing pregnancy in female athletes after retirement from competition

BACKGROUND

Although it has been shown that amenorrhea associated with low energy availability or relative energy deficiency in sport affects body physiology in female athletes, the association between menstrual dysfunction during active sports careers and reproductive function after retirement is not clear.

OBJECTIVE

To investigate the association between menstrual dysfunction during their active sports career and post-retirement infertility in female athletes.

METHODS

A voluntary web-based survey was aimed at former female athletes who had become pregnant and gave birth to their first child after retirement. Nine multiple-choice questions were included, on maternal age, competition levels and menstrual cycles during active sports careers, time from retirement to pregnancy, the time of resumption of spontaneous menstruation after retirement, conception method, and mode of delivery, etc. Regarding cases of primary and secondary amenorrhea among the abnormal menstrual cycle group, only those whose spontaneous menstruation had not recovered from retirement to the time of pregnancy were included in the study. The association between the presence of abnormal menstrual cycles from active sports careers to post-retirement pregnancy and the implementation of infertility treatment was evaluated.

RESULTS

The study population included 613 female athletes who became pregnant and gave birth to their first child after retiring from competitive sports. Of the 613 former athletes, the infertility treatment rate was 11.9%. The rate of infertility treatment was significantly higher in athletes with abnormal than normal menstrual cycles (17.1% vs. 10.2%, p = 0.0225). Multivariable logistic regression analysis showed that maternal age (adjusted odds ratio [OR] 1.194; 95% confidence interval [CI] 1.129, 1.262) and abnormal menstrual cycles (OR and 1.903; adjusted OR 1.105, 3.278) were the relevant factors for infertility treatment.

CONCLUSION

It was suggested that menstrual dysfunction that persist from active sports careers to post-retirement may be a factor in infertility when trying to conceive after retirement.

Early age at menarche and the risk of gestational diabetes mellitus: a cohort study

PURPOSE

To evaluate whether there is an association between age at menarche (AAM) and the risk of gestational diabetes mellitus (GDM).

METHODS

A retrospective cohort study was conducted, including 5390 pregnant women who were screened for GDM at Alexandra Hospital in Athens, Greece over a 15-year period (2000-2014). Maternal age, pre-pregnancy body mass index (BMI), height, family history of type 2 diabetes mellitus, parity, educational and smoking status, and AAM were recorded. The results were expressed as odds ratios (OR) with a 95% confidence interval (95% CI).

RESULTS

Pregnant women with GDM experienced earlier menarche compared to normoglycemic women (12.9 ± 1.5 vs 13.1 ± 1.6, p < 0.001, respectively). The OR for a woman with AAM <12 years to develop GDM was 1.08 (95% CI 1.03-1.14), while the OR to be obese was 1.70 (95% CI 1.50-1.90). The multivariate logistic regression analysis showed that AAM is a risk factor for GDM. However, that effect was lost after adjusting for BMI.

CONCLUSION

Early AAM may be associated with an increased risk of GDM. Therefore, it can be used to identify high-risk women and implement preconception interventions for GDM prevention. Future studies should be conducted to confirm these findings.

Long-term exposure to ambient PM2.5 and its components on menarche timing among Chinese adolescents: evidence from a representative nationwide cohort

BACKGROUND

Ambient air pollutants have been suggested to affect pubertal development. Nevertheless, current studies indicate inconsistent effects of these pollutants, causing precocious or delayed puberty onset. This study aimed to explore the associations between long-term exposure to particulate matter with aerodynamic diameters ≤ 2.5 μm (PM2.5) along with its components and menarche timing among Chinese girls.

METHOD

Self-reported age at menarche was collected among 855 girls from China Health and Nutrition Survey 2004 to 2015. The pre-menarche annual average concentrations of PM2.5 and its components were calculated on the basis of a long-term (2000-2014) high-resolution PM2.5 components dataset. Generalized linear models (GLM) and logistic regression models were used to analyze the associations of exposure to a single pollutant (PM2.5, sulfate, nitrate, ammonium, black carbon and organic matter) with age at menarche and early menarche (< 12 years), respectively. Weighted quantile sum methods were applied to examine the impacts of joint exposure on menarche timing.

RESULTS

In the adjusted GLM, per 1 µg/m3 increase of annual average concentrations of nitrate and ammonium decreased age at menarche by 0.098 years and 0.127 years, respectively (all P < 0.05). Every 1 µg/m3 increase of annual average concentrations of PM2.5 (OR: 1.04, 95% CI: 1.00-1.08), sulfate (OR: 1.23, 95% CI: 1.01-1.50), nitrate (OR: 1.23, 95% CI: 1.06-1.43) and ammonium (OR: 1.32, 95% CI: 1.06-1.66) were significantly positively associated with early menarche. Higher level of joint exposure to PM2.5 and its components was associated with 11% higher odds of early menarche (P = 0.04). Additionally, the estimated weight of sulfate was the largest among the mixed pollutants.

CONCLUSIONS

Long-term exposure to PM2.5 and its components could increase the risk of early menarche among Chinese girls. Moreover, sulfate might be the most critical components responsible for this relationship. Our study provides foundation for targeted prevention of PM2.5 components.

Secular trend in age at menarche among Indian women

Age at menarche is not only a parameter that signifies biological characteristics for women but is also considered as an indicator to measure the quality of life of a population. Moreover, menarche has significant implications on women's health and information about menarcheal age is crucial for health policymakers. However, little is known about the trends in menarcheal age in India. Thus, in order to fill this research gap, the present study aimed to explore the age at menarche, its trend and regional heterogeneity among Indian women. A birth cohort approach was used by polling data from the 1st (1992-93), 4th (2015-16) and 5th (2019-21) rounds of NFHS. Descriptive statistics and bivariate analyses were performed to present the distribution of age at menarche and mean age at menarche across birth cohorts and each category of covariates. A multiple linear regression model was fitted to examine the trend in age at menarche and further to investigate the association of covariates with menarcheal age among Indian women. The analysis demonstrated that a majority of women (66.2%) attained menarche between the ages of 13-14 years. Moreover, about 17.2% of women experienced an early age at menarche, whereas 16.7% of women had a late age at menarche. The mean age at menarche for the sampled women was 13.49 years. The analysis also observed a secular declining trend in menarcheal age among Indian women and a significant variation in the mean age at menarche across birth cohorts. It also highlighted significant socio-economic patterning in menarcheal age among women.

Association of blood metal exposure with age at menarche in Korean women: KNHANES (2008-2017)

Humans are exposed to metals in their daily lives and this metal exposure is responsible for various adverse health effects. Delayed pubertal development has been suggested as an adverse outcome of metal exposure; however, evidence in nationally representative populations, especially in Asia, is limited. We evaluated the association of blood cadmium (Cd), lead (Pb), and mercury (Hg) levels with the age at menarche in Korean females whose blood heavy metals were measured as part of the Korean National Health and Nutrition Examination Survey (KNHANES) 2008-2017. Among the females 16 years of age or older, all measured heavy metals in blood, i.e., Cd, Pb, and Hg, were positively associated with age at menarche. These associations remained significant in a model adjusted for age, survey year, income, education, body mass index, smoking history, and menopausal status as covariates (β: 0.10, 95% confidence interval (CI): 0.03-0.18 for Cd; β: 0.17, 95%CI: 0.06-0.27 for Pb; β: 0.12, 95%CI: 0.05-0.19 for Hg). When the population was separated by age group at the time of the survey, the significance between heavy metal levels and age at menarche became inconsistent, but the general trends were similar. Among those in their 20s and 40s, blood Cd showed a significant association, while Pb was significant among those in their 40s and 50s. A similar trend was observed in the sensitivity analysis in the girls aged 10-15 years at the time of the survey. Blood Cd levels were associated with decreased odds of precocious menarche (OR: 0.57, 95%CI: 0.31-1.03). Delayed menarche is a risk factor for cardiovascular and chronic kidney diseases in later life; hence, public health implication of heavy metal exposure warrants a public health attention.

Menstrual characteristics and associations with sociodemographic factors and self-rated health in Spain: a cross-sectional study

BACKGROUND

Evidence on how menstrual characteristics may differ based on socioeconomic factors and self-rated health is significantly scarce. The main aim of this study was to investigate the associations between menstrual characteristics, sociodemographic factors and self-rated health among women and people who menstruate (PWM) aged 18-55 in Spain.

METHODS

This cross-sectional study includes data from an online survey collected in March-July 2021 across Spain. Descriptive statistical analyses and multivariate logistic regression models were performed.

RESULTS

The analyses included a total of 19,358 women and PWM. Mean age at menarche was 12.4 (SD = 1.5). While 20.3% of our participants experienced a menstrual abundance over 80 ml, 64.1% reported having menstrual blood clots; 6.4% menstruated for longer than 7 days. 17.0% had menstrual cycles that were shorter than 21 days or longer than 35 days. Reports of moderate (46.3%) and high (22.7%) intensity menstrual pain were common. 68.2% of our participants experienced premenstrual symptoms in all or most cycles. The odds for lighter menstrual flow, shorter bleeding days and menstrual cycles were higher as age increased, and amongst participants with less educational attainment. Caregivers presented higher odds for abundant menstrual flow and longer menstruations. Reporting financial constraints and a poorer self-rated health were risk factors for abundant menstrual flow, menstrual blood clots, shorter/longer menstruations and menstrual cycles, premenstrual symptoms, moderate and intense menstrual pain.

CONCLUSIONS

This study suggests that age, educational attainment, caregiving, experiencing financial hardship and a poorer self-rated health may shape or mediate menstrual characteristics. It thus highlights the need to investigate and address social inequities of health in menstrual research.

Shared Genetics between Age at Menarche and Type 2 Diabetes Mellitus: Genome-Wide Genetic Correlation Study

Background: Age at menarche (AAM) has been associated with type 2 diabetes mellitus (T2DM). However, little is known about their shared heritability. Methods: Our data comes from the Taiwan Biobank. Genome-wide association studies (GWASs) were conducted to identify single-nucleotide polymorphisms (SNPs) related to AAM-, T2DM-, and T2DM-related phenotypes, such as body fat percentage (BFP), fasting blood glucose (FBG), and hemoglobin A1C (HbA1C). Further, the conditional false discovery rate (cFDR) method was applied to examine the shared genetic signals. Results: Conditioning on AAM, Quantile-quantile plots showed an earlier departure from the diagonal line among SNPs associated with BFP and FBG, indicating pleiotropic enrichments among AAM and these traits. Further, the cFDR analysis found 39 independent pleiotropic loci that may underlie the AAM-T2DM association. Among them, FN3KRP rs1046896 (cFDR = 6.84 × 10-49), CDKAL1 rs2206734 (cFDR = 6.48 × 10-10), B3GNTL1 rs58431774 (cFDR = 2.95 × 10-10), G6PC2 rs1402837 (cFDR = 1.82 × 10-8), and KCNQ1 rs60808706 (cFDR = 9.49 × 10-8) were highlighted for their significant genetic enrichment. The protein-protein interaction analysis revealed a significantly enriched network among novel discovered genes that were mostly found to be involved in the insulin and glucagon signaling pathways. Conclusions: Our study highlights potential pleiotropic effects across AAM and T2DM. This may shed light on identifying the genetic causes of T2DM.

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.

Unraveling the Link: A Comprehensive Literature Review of Type 2 Diabetes and Menopause Onset

Women with diabetes mellitus (DM), a metabolic endocrine illness, may experience a variety of reproductive problems. The age at menopause onset has been extensively studied as a major predictor of women's health in the future; however, its relationship to diabetes in Indian women has received less attention. This literature review looked at the consequences of diabetes in women as well as the association between diabetes and the age at which menopause begins. The average age at menopause onset among women with type 2 diabetes mellitus (T2DM) has decreased globally. According to one Indian study, the average menopause age dropped to 45 years for 26% of women with T2DM. In the current review, 10 studies indicated that women with T2DM displayed an imbalanced hormonal profile resulting in an extended anovulatory period. Two investigations highlighted the significance of altered body composition of women with T2DM, thereby suggesting obesity as the primary risk factor of ovarian aging and early climacteric symptoms. T2DM may lower the average age at menopause onset; however, further research on Indian women is necessary. There is a need of studies on T2DM in premenopausal women are needed to demonstrate how the changes in body composition impact the age at which menopause begins. Delaying the onset of menopause in women with T2DM necessitates diet and lifestyle interventions to minimize ovarian aging and hormonal imbalance.

Menopause age, reproductive span and hormone therapy duration predict the volume of medial temporal lobe brain structures in postmenopausal women

Medial temporal lobe (MTL) atrophy is correlated with risk and severity of Alzheimer disease (AD) pathology and cognitive decline. Increasing evidence suggest that oestrogens affect the aging of MTL structures. Here we investigate the relationship between reproductive hormone exposure, polygenic scores for AD risk and oestradiol concentration, MTL anatomy and cognitive performance in postmenopausal women. To this end, we used data from 10,924 female participants in the UK Biobank from whom brain MRI and genetic data were available. We fitted linear regression models to test whether the volume of structures comprising the MTL were predicted by a) timing related to menopause, b) the use and timing of hormone replacement therapy (HRT) and c) polygenic scores for AD risk and oestradiol concentration. Results showed that longer use of HRT was associated with larger parahippocampal volumes (2.53 mm3/year, p = 0.042). A later age of natural menopause, and a longer reproductive span, was associated with larger hippocampal (6.08 and 5.72 mm3/year, p = 0.0006 and 0.0005), parahippocampal (4.17 mm3 and 4.19 mm3/year, p = 0.00006 and 0.00001), amygdala (2.10 and 2.22 mm3/year, p = 0.028 and 0.01) and perirhinal cortical (2.56 and 2.95 mm3/year, p = 0.028 and 0.008) volumes. Superior prospective memory performance was associated with later age at natural menopause, and a longer reproductive span (ß = 0.05 and 0.05 respectively, p = 0.019 and 0.019). Polygenic scores for AD risk and for oestradiol concentration were not associated with MTL volume and did not interact with menopause-related factors to affect MTL structure. Our results suggest that HRT use did not have any detrimental effects on cognition or brain structure, whilst greater exposure to reproductive hormones across time is associated both with slightly larger volumes of specific MTL structures and marginally superior memory performance, independent of genetic risk for AD and genetic predisposition for higher oestradiol levels. However, the clinical utility of maintenance of oestrogens post-menopause for brain health and protection against cognitive decline is curtailed by the small effect sizes observed.

Incessant ovulation: a review of its importance in predicting cancer risk

Estrous cycles are recurring changes in therian mammals induced by estrogen, progesterone, and other hormones culminating in endometrial proliferation, ovulation, and implantation if fertilization occurred. In women, the estrous cycle is the menstrual cycle; but, unlike most mammals, the end of an infertile cycle is marked by endometrial sloughing and the start of another without an anestrous phase. Women stop cycling at menopause, while in most mammals, cycles continue until death. Epidemiologic studies identified menarche, menopause, births, lactation, and oral contraceptive (OC) use as key risk factors for ovarian, breast, and endometrial cancers. A composite variable was created to estimate the number of cycles not interrupted by events that stop ovulation. Captured by the phrase "incessant ovulation", repetitive cycles were first postulated to affect ovarian cancer risk and later extended to breast and endometrial cancers. These associations could be explained by cumulative effects of repetitive tissue changes within reproductive organs, immune consequences of repetitive ovulation through the glycoprotein mucin 1, and residual effects of past ovulations that enhance ovarian production of testosterone. The latter two pathways could affect the risk for cancers in other organs not considered "reproductive".

A Prospective Study of the Age at Menarche in North Indian Girls, Its Association With the Tanner Stage, and the Secular Trend

Background Menarche is an important event in a female's reproductive health. However, the age at menarche is variable and has implications on the future health of the girl. The purpose of this study was to estimate the mean age at menarche of North Indian adolescent girls and its association with the Tanner stage and to study the trend of menarcheal age in India in the 21st century. Materials & methods A longitudinal descriptive study was conducted on 470 healthy girls aged nine to 16 years in expectant menarche (Tanner stage II). They were followed for six months to check for the attainment of menarche. Those who achieved menarche were grouped in Group I and the rest in Group II. The data were analyzed using the independent t-test. Results Menarche was achieved by 263 girls in the six-month follow-up period. The mean (SD) age of menarche was 13.13 (1.23) years. Group I girls were mostly in Tanner stage IV and above. Group II girls had a mean (SD) age of 11.53 (1.1) years and were mostly in Tanner stage III or below. The estimated decline in the age of menarche in the 21st century was about 0.41 years per decade. Conclusion The girls who achieved menarche had a significantly higher age and Tanner stage of sexual maturity than girls who did not achieve menarche in the study period. Tanner stage is a better measure to estimate the pubertal onset than age. The studies on the age of menarche in the current century reveal that the declining trend in the menarcheal age is continuing in India.

Age at Menarche, Menopause Status and Metabolic Syndrome and its Components: Findings from the Henan Rural Cohort Study

INTRODUCTION

To evaluate the effect of age at menarche on metabolic syndrome (Mets) and its components and explore the impact of menopause status on the association between age at menarche and Mets in rural Chinese women.

METHODS

This cross-sectional study enrolled 23382 women from the Henan Rural Cohort study. The relationship between age at menarche and Mets was assessed using logistic regression and restricted cubic spline. Interaction plots were used to describe interactive effects of age at menarche and menopause status on Mets.

RESULTS

Age at menarche was inversely associated with the risk of Mets with the adjusted OR of 1.16, 0.98, 1.00, 0.82, and 0.77, respectively, for those with age at menarche≤13, 14, 15-16 (reference), 17, and≥18 years. Each year of delay in menarche age correlated with a 6.2% (P<0.001) lower risk of Mets. Among the components of Mets, an inverse association was observed between age at menarche and central obesity (OR (95% CI): 0.92 (0.90, 0.94)), abnormal FPG (OR (95% CI): 0.96 (0.94, 0.97)), abnormal BP (OR (95% CI): 0.967 (0.95, 0.98)), abnormal TG (OR (95% CI): 0.96 (0.94, 0.97)), and abnormal HDL-C (OR (95% CI): 0.96 (0.95, 0.98)). Significant interactions were discovered between age at menarche, menopause status, and the risk of Mets, central obesity, abnormal FPG, abnormal BP, and abnormal TG (all P interaction<0.001). The adverse effect of menopausal status on Mets, central obesity, abnormal FPG, abnormal BP, and abnormal TG decreased with delayed age at menarche.

CONCLUSIONS

Later menarche was associated with a lower risk of Mets. More importantly, the deleterious effect of menopause status on Mets decreased with the increase in age at menarche.

PFAS and Phthalate/DINCH Exposure in Association with Age at Menarche in Teenagers of the HBM4EU Aligned Studies

Early puberty has been found to be associated with adverse health outcomes such as metabolic and cardiovascular diseases and hormone-dependent cancers. The decrease in age at menarche observed during the past decades has been linked to an increased exposure to endocrine-disrupting compounds (EDCs). Evidence for the association between PFAS and phthalate exposure and menarche onset, however, is inconsistent. We studied the association between PFAS and phthalate/DINCH exposure and age at menarche using data of 514 teenagers (12 to 18 years) from four aligned studies of the Human Biomonitoring for Europe initiative (HBM4EU): Riksmaten Adolescents 2016-2017 (Sweden), PCB cohort (follow-up; Slovakia), GerES V-sub (Germany), and FLEHS IV (Belgium). PFAS concentrations were measured in blood, and phthalate/DINCH concentrations in urine. We assessed the role of each individual pollutant within the context of the others, by using different multi-pollutant approaches, adjusting for age, age- and sex-standardized body mass index z-score and household educational level. Exposure to di(2-ethylhexyl) phthalate (DEHP), especially mono(2-ethyl-5-hydroxyhexyl) phthalate (5OH-MEHP), was associated with an earlier age at menarche, with estimates per interquartile fold change in 5OH-MEHP ranging from -0.34 to -0.12 years in the different models. Findings from this study indicated associations between age at menarche and some specific EDCs at concentrations detected in the general European population, but due to the study design (menarche onset preceded the chemical measurements), caution is needed in the interpretation of causality.

Application of ADAPT-ITT: adapting an evidence-based HIV/STI mother-daughter prevention intervention for Black male caregivers and girls

BACKGROUND

Black girls are disproportionately impacted by HIV and sexually transmitted infections (STIs), underscoring the urgent need for innovative strategies to enhance the adoption and maintenance of HIV/STI prevention efforts. Historically, Black male caregivers have been left out of girls' programming, and little guidance exists to inform intervention development for Black girls and their male caregivers. Engaging Black male caregivers in Black girls' sexual and reproductive health may reduce sexual risk-taking and improve the sustainability of preventative behaviors.

OBJECTIVE

This paper describes the formative phases, processes, and methods used to adapt an evidence-based mother-daughter sexual and reproductive health intervention for Black girls 9-18 years old and their male caregivers.

METHODS

We used the ADAPT-ITT model to tailor IMARA for Black girls and their male caregivers. Diverse qualitative methods (interviews, focus groups, and theater testing) were used throughout the adaption process.

RESULTS

Findings support using the ADAPT-ITT model to tailor an evidence-based HIV/STI intervention for Black girls and their Black male caregivers. Findings highlight the importance of community engagement and the use of qualitative methods to demonstrate the acceptability and feasibility of the adapted intervention. Key lessons learned are reviewed.

CONCLUSIONS

Adapting evidence-based interventions to incorporate Black girls and their Black male caregivers should be driven by a relevant theoretical framework that aligns with the target population(s). Adapting the intervention in partnership with the community has been shown to improve acceptability and feasibility as it is responsive to community needs. Using a systematic process like the ADAPT-ITT model will ensure that the new program is ready for efficacy trials.

Contraception, female cycle disorders and injuries in Swiss female elite athletes-a cross sectional study

Aim: The national Olympic committee of Switzerland has conducted an online survey among female elite athletes with a focus on cycle disorders, contraception, and injuries in 2021. Methods: A total of 1,092 female elite athletes from 107 different sports were asked to answer the questionnaire. A descriptive analysis was carried out to determine location parameters and create frequency tables. Results: The questionnaire was completed by 408 athletes (37.4%) from 92 different sports. 43.4% participated in a lean sport. 57.1% reported no injuries, 32.6% one injury, and 10.2% two or more injuries per year. A considerable proportion reported being affected by primary amenorrhoea (10.8%). Primary amenorrhoea occurred significantly more often in female athletes with a BMI lower than 21.7 kg/m2 (15.2%) than in athletes with a BMI above 21.7 kg/m2 (7.4%, p = 0.021). Considering contraception, 25.8% of female athletes were currently using an oral contraceptive pill. The proportion of female athletes not using contraception at all or using non-hormonal contraceptive methods was high at 54.4%. In lean sports, significantly more athletes used no or non-hormonal contraceptives (p < 0.05). Conclusion: Among top Swiss female athletes, a considerable proportion used non-hormonal or no contraceptives. This trend was more evident in lean sports. Delayed menarche and cycle irregularities were common among female athletes, especially among athletes with high training volumes as well as a BMI below 21.7 kg/m2. This orienting survey underlines the importance of specialized gynecological care for elite female athletes.

Identification of Adolescent Menarche Status Using Biplanar X-ray Images: A Deep Learning-Based Method

The purpose of this study is to develop an automated method for identifying the menarche status of adolescents based on EOS radiographs. We designed a deep-learning-based algorithm that contains a region of interest detection network and a classification network. The algorithm was trained and tested on a retrospective dataset of 738 adolescent EOS cases using a five-fold cross-validation strategy and was subsequently tested on a clinical validation set of 259 adolescent EOS cases. On the clinical validation set, our algorithm achieved accuracy of 0.942, macro precision of 0.933, macro recall of 0.938, and a macro F1-score of 0.935. The algorithm showed almost perfect performance in distinguishing between males and females, with the main classification errors found in females aged 12 to 14 years. Specifically for females, the algorithm had accuracy of 0.910, sensitivity of 0.943, and specificity of 0.855 in estimating menarche status, with an area under the curve of 0.959. The kappa value of the algorithm, in comparison to the actual situation, was 0.806, indicating strong agreement between the algorithm and the real-world scenario. This method can efficiently analyze EOS radiographs and identify the menarche status of adolescents. It is expected to become a routine clinical tool and provide references for doctors' decisions under specific clinical conditions.

The Role of the Strong Black Woman in Black Female Sexual Development

Black girls and women are disproportionately impacted by sexual health disparities, including an increased risk of HIV and sexually transmitted infections (STI). Early sexual development among Black females heightens their risk of HIV/STI. Utilizing the Becoming a Sexual Black Woman (SBW) framework, this study sought to understand how early sexual development and stereotype messages may underpin HIV/STI risk, building on and furthering the discussion of the consequences of the SBW schema. To better understand this phenomenon, we conducted a secondary thematic data analysis from two previously completed grounded theory studies with Black girls and women ranging in age from 11 to 62 (N = 40). Findings revealed that Black women have been socialized to be strong and independent and yet are highly vulnerable to HIV/STI. This clash between Black girl's and women's ideals of strength and heightened vulnerability to HIV/STI presents a paradox that may help explain disparities in HIV/STI risk. Four themes emerged among both Black girls and women: complex construction of the SBW schema, burden and consequences of strength, pressure to be strong, and being strong and sexual. Findings also highlight how becoming both a strong and sexual Black woman occurs over the life course and is inherent to Black female sexual development. We discuss the implications of these findings for parents, healthcare providers, educators, and researchers with the aim to improve sexual health outcomes for Black females across the life course.

Adherence to the Mediterranean Diet in Women and Reproductive Health across the Lifespan: A Narrative Review

The Mediterranean diet (MD) has been previously proven to have various health-related benefits; however, its effect on women's reproductive health over a lifespan is yet to be summarized. This study aimed to summarize the evidence-based knowledge regarding the association between the MD and selected reproductive health outcomes. By searching PubMed, ScienceDirect, and Google Scholar databases, as well as reference lists, 21 studies were included in this narrative review. The available evidence was very limited; however, there is some suggestion that higher adherence to the MD may be positively associated with a lower risk of early age menarche (1 study) and shorter menstrual cycles (1 study), but is unrelated to dysmenorrhea (1 study). Moreover, no study to date has examined the relationship between the MD and the onset age of natural menopause. Considering reproductive health diseases, there was limited evidence that a higher adherence to the MD was associated with a lower risk of premenstrual syndrome (1 study), an improvement in sexual health and a lower prevalence of sexual dysfunction (3 studies), and an improvement in the general condition of with endometriosis and the pain they can experience (1 study). The largest number of studies were found for polycystic ovarian syndrome (PCOS; 7 studies) and infertility (6 studies). Results showed that a higher adherence to the MD was associated with a lower risk of infertility, while results for PCOS were unclear, but mostly indicated a beneficial trend. Further investigations are necessary to establish the role of adherence to the MD in reproductive health maintenance and its possible role in the prevention and treatment of reproductive health diseases in women.

Investigating the Link between Early Life and Breast Anomalies

Several factors during childhood and adolescence are thought to be associated with the development of proliferative benign breast diseases and breast cancer in adulthood. In order to identify them, the authors conducted an extensive review of the literature up to October 2022, searching for clinical studies, reports, and guidelines in English. A thorough Medline/Pubmed and Google scholar database research was performed, investigating the link between diet, exercise, age of menarche, body mass index, ionizing radiation exposure during childhood and adolescence, and proliferative breast diseases and breast cancer in adulthood. A list of keywords, including breast disorders, adolescence, childhood, and breast cancer was included in our search algorithm. Numerous studies concede that the development of breast disease in adulthood is influenced by various risk factors, whose influence begins during early childhood and adolescence.

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.

Light on Shedding: A Review of Sex and Menstrual Cycle Differences in the Physiological Effects of Light in Humans

The human circadian system responds to light as low as 30 photopic lux. Furthermore, recent evidence shows that there are huge individual differences in light sensitivity, which may help to explain why some people are more susceptible to sleep and circadian disruption than others. The biological mechanisms underlying the differences in light sensitivity remain largely unknown. A key variable of interest in understanding these individual differences in light sensitivity is biological sex. It is possible that in humans, males and females differ in their sensitivity to light, but the evidence is inconclusive. This is in part due to the historic exclusion of women in biomedical research. Hormonal fluctuations across the menstrual cycle in women has often been cited as a confound by researchers. Attitudes, however, are changing with funding and publication agencies advocating for more inclusive research frameworks and mandating that women and minorities participate in scientific research studies. In this article, we distill the existing knowledge regarding the relationship between light and the menstrual cycle. There is some evidence of a relationship between light and the menstrual cycle, but the nature of this relationship seems dependent on the timing of the light source (sunlight, moonlight, and electric light at night). Light sensitivity may be influenced by biological sex and menstrual phase but there might not be any effect at all. To better understand the relationship between light, the circadian system, and the menstrual cycle, future research needs to be designed thoughtfully, conducted rigorously, and reported transparently.

Exploring adolescence as a key life history stage in bioarchaeology

Adolescence is a unique period in the life history of an individual. It is characterized by a myriad of changes that bioarchaeologists are only just coming to appreciate, related to sexual maturation, linear growth, immunological transformation, and emotional and cognitive development. New methods allow us to measure this age of transition through the stages of the adolescent growth, as a proxy for the physical development associated with sexual maturation (puberty). This review outlines ways bioarchaeologists may draw on research developments from the fields of human biology, evolutionary theory and neurobiology to advance a more holistic approach to the study of adolescence in the past. It considers current theoretical and analytical approaches to highlight the research potential of this critical stage of life history. This synthesis integrates the most recent research in the medical sciences concerned with body and brain development, and outlines the biological processes involved with sexual and physical maturation of the adolescent. The goal of this review is to help inform potentially rewarding areas of research that bioarchaeologists can contribute to and draw from, as well as the challenges and limitations, theoretical and methodological questions, and ways in which we can develop the study of adolescence in the discipline going forward.

Linking Puberty and the Gut Microbiome to the Pathogenesis of Neurodegenerative Disorders

Puberty is a critical period of development marked by the maturation of the central nervous system, immune system, and hypothalamic-pituitary-adrenal axis. Due to the maturation of these fundamental systems, this is a period of development that is particularly sensitive to stressors, increasing susceptibility to neurodevelopmental and neurodegenerative disorders later in life. The gut microbiome plays a critical role in the regulation of stress and immune responses, and gut dysbiosis has been implicated in the development of neurodevelopmental and neurodegenerative disorders. The purpose of this review is to summarize the current knowledge about puberty, neurodegeneration, and the gut microbiome. We also examine the consequences of pubertal exposure to stress and gut dysbiosis on the development of neurodevelopmental and neurodegenerative disorders. Understanding how alterations to the gut microbiome, particularly during critical periods of development (i.e., puberty), influence the pathogenesis of these disorders may allow for the development of therapeutic strategies to prevent them.

Secular Changes in the Age of Menarche of Rural and Urban Girls from an Industrial Region of Poland in Relation to Family Structure

Purpose: The consequence of better living conditions for every subsequent generation is the phenomenon of change in the rate of maturation and body dimensions. The aim of this study was to evaluate the intergenerational changes in the age of menarche of girls living in rural and urban communities in the industrial region of Poland using samples from two different centuries and to determine the relationship between family structure (two-parent and single-parent) and sexual maturation of the girls in both environments. Methods: The study included 3643 rural and urban girls aged 7–16 from southwestern Poland (Copper Basin). The research was cross-sectional in each environment around 2000 and 2010, and it was carried out twice. Two types of family structure were taken into account: two-parent and single-parent families. The median age of menarche and odds ratio (OR) of menarche depending on the place of residence and family structure were calculated. The status quo method was used when assessing the age of menarche. Results: In both groups, the age of menarche significantly decreased during the decade. The median age of menarche in the urban girls was lower compared with their rural peers, but a significant difference was found only during the second examination (a decade after the first examination). There were no significant changes in menarche during the decade regarding family structure (neither in girls from two-parent families nor those from single-parent families), except in rural girls from two-parent families. Comparing the median age of menarche of girls from two-parent families with girls from single-parent families (urban and rural) showed lower median values in the girls from two-parent families, but no differences were significant. Conclusions: The acceleration of the maturation rate over the last decade has been observed among both rural and urban girls. Environmental differences in maturation rates between rural and urban girls increased over the course of the decade, and the difference between the rural and urban girls’ age of menarche was statistically significant in the second examination (around 2010).The living conditions related to family structure did not significantly affect the timing of menarche.

Heritability of Age at Menarche in Nigerian Adolescent Twins

Heritability of age at menarche (AAM) in African populations remains largely unknown. A question on AAM was given to 1803 [454 monozygotic (MZ), 823 same-sex dizygotic (DZ), and 526 female members of opposite sex] adolescent twins attending public schools in Lagos State, Nigeria. The age range of the sample was 12-18 years, with a mean (SD) of 14.57 (±1.70) years. The data included 905 missing cases consisting of those who had not experienced menarche and did not recall AAM. Missing values were imputed using the Expectation-Maximization algorithm. Kaplan-Meier analysis based on the imputed data yielded 13.23 years [95% CI [13.18, 13.28] for the mean and 13.00 years [95% CI [12.96, 13.04] for the median of AAM. Twin correlation and model-fitting analyses were performed on the basis of those who reported AAM (MZ = 82 complete pairs and 38 cotwin missing cases; DZ = 157 complete pairs and 99 cotwin missing cases). Maximum likelihood MZ and DZ twin correlations for AAM were .63 (95% CI [.48, .74]) and .33 (95% CI [.19, .45]) respectively. Model-fitting analyses indicated that 58% (95% CI [46, 67]) of the variance of AAM was associated with additive genetic influences with the remaining variance, 42% (33-54) being due to nonshared environmental influences including measurement error. The heritability estimate found in this study was within the range of those found in Asian and Western twin samples.

Age at Menarche in Urban Girls Exposed to Lead in the Copper Basin, Poland

Lead negatively affects human growth and development. In this research, we aimed to assess the effect of elevated blood lead level on age at menarche (AM), controlling for body mass index (BMI) and estimated fatness. The sample included 490 girls aged 7−16 examined in Polkowice town (Copper Basin, Poland) in 2008. Measurements included height, weight, skinfold thicknesses and estimated percentage of body fat. AM was assessed using the status quo method. Blood samples were taken for lead level assessment. Two groups were defined based on the median blood lead level for the total sample of children (3.7 µg/dL). Logistic regression models were used to assess the association between AM and independent variables. The results indicated that menarche in the higher blood lead level group was significantly later compared to the lower blood lead level group (p < 0.01). This relationship remained only marginally significant when BMI (p < 0.10), sum of skinfolds (p < 0.09) or percentage of fat (p < 0.08) were controlled. The results revealed that a lower blood lead level (3.7 µg/dL) than the currently acceptable threshold (5 µg/dL) is related to a later AM; however, this relationship is moderated by body fatness, which may decrease its significance.

Effect of air pollution on age at menarche in polish females, born 1993-1998

The aim of the study was to analyse the association between the degree of air pollution (suspended particulate matter, sulphur dioxide, benzopyrene levels) in the location of residence during childhood and adolescence and the age at menarche. The research was carried out in the period from 2015 to 2018 in Poland. Anthropometric measurements were performed, and questionnaire data were collected from 1,257 women, aged 19-25 years. The average levels of subjects' exposure to analysed air pollutants, i.e., particulate matter, sulphur dioxide, nitric oxide and benzene during childhood-adolescence was assessed from the data acquired by the Polish Chief Inspectorate for Environmental Protection. Negative relationships between age at menarche and suspended particulate matter as well as nitrogen levels were found. A similar trend was observed in an analysis of the relationship between age at menarche and the complex air pollution index. The tendency for age at menarche to decrease together with worsening air quality was also visible after adjusted for socioeconomic status. Girls exposed to high suspended particulate matter levels were characterised by higher risk of early age at menarche. High levels of air pollution are related to younger age at menarche and the risk of the menstruation onset below 11 years.

Being fast or cautious? Sociocultural conditions influencing the sexual pathways of Black females in the United States

BACKGROUND

Black females in the United States face unique sociocultural conditions that impact their sexual development and increase their risk for sexually transmitted infections (STI), including but not limited to chlamydia, gonorrhea, and HIV. Research has not adequately explained how sociocultural conditions contribute to this increased risk. The purpose of our investigation was to explore the sociocultural conditions that influence Black cisgender females risk for STI.

METHODS

This grounded theory study involved in-depth audio-recorded interviews with 20, primarily heterosexual, Black females ages 19-62.

RESULTS

Findings informed a conceptual model that builds on previous theory about the sexual development of Black females and explains how sociocultural conditions impact two, participant identified, sexual pathways: Fast and Cautious. Movement on these sexual pathways was not always a linear trajectory; some participants shifted between pathways as their sociocultural contexts changed (i.e., sexual assault, STI, and level of protection). The Fast sexual pathway often led to greater STI risk.

CONCLUSIONS

This model may inform future research designed to prevent STI/HIV and promote the sexual health of Black females across the life course.

The effect of peer education based on adolescent health education on the resilience of children and adolescents: A cluster randomized controlled trial

BACKGROUND

An increasing number of children and adolescents have reported mental health problems, and resilience is a protective factor against these problems. Therefore, the aim of the study is to verify the effect of peer education based on adolescent health education on adolescent resilience.

METHOD

A cluster randomized controlled trial was conducted including 1,613 students who were divided into an intervention group (19 classes, 732 participants) and a control group (24 classes, 881 participants). One-year peer education was performed in the intervention group, and the control group had no interventions. The Resilience Scale for Chinese Adolescents by Yueqin Hu and a self-designed basic information questionnaire were used to collect data. Chi-square test and rank-sum test were used to compare the differences of demographic characteristics between the two groups. A linear mixed model was used to compare the changes of resilience between the two groups after intervention, and the intra-cluster correlation coefficient (ICC) was calculated. A generalized linear mixed model (GLMM) was used to verify the effect of peer education on adolescent resilience. The significance was set at P < 0.05.

RESULTS

After intervention, compared with the control group, the intervention group showed significant improvement in target focus, emotion adjustment, interpersonal assistance and total resilience (P < 0.05). The ICC range was 0.003 to 0.034. The GLMM results indicated that peer education based on adolescent health education had significant effects on adolescents' target focus (β = 0.893, P = 0.002), emotional adjustment (β = 1.766, P < 0.001), interpersonal assistance (β = 1.722, P = 0.016) and total mental resilience (β = 5.391, P < 0.001), and the effect was greater for boys than for girls.

CONCLUSIONS

Peer education based on adolescent health education is effective for improving adolescents' target focus, emotional adjustment, interpersonal assistance, and total resilience, especially for males. Future research should devote more attention to positive cognition and family support as well as gender differences.

The Impact of COVID-19 Among Black Girls: A Social-Ecological Perspective

Objective

To explore the impact of the COVID-19 pandemic on Black adolescent girls’ physical, psychological, and sexual development.

Methods

Semistructured interviews were conducted with 25 girls (9–18 years old) primarily across the Midwestern United States. Interviews were conducted until theoretical saturation was reached. We conducted a conventional content analysis by reviewing transcripts, coding data, and developing themes.

Results

Utilizing the social-ecological model findings revealed themes related to the individual-, interpersonal-, institutional-, and community-level changes that Black girls experienced during the COVID-19 pandemic.

Conclusions

Black adolescent girls need opportunities to discuss the changes, receive relevant resources, and have spaces to support their physical, psychological, and sexual development. Systems such as families, schools, and clinics should implement programming to facilitate discussions around the impact of COVID-19 on Black girls.

Teachers' Perceptions and Experiences of Menstrual Cycle Education and Support in UK Schools

The purpose of this study was 2-fold, to (1) explore current education provision in UK schools including barriers to menstrual cycle education and (2) assess the perceived support teachers received to deliver menstrual cycle education. Seven hundred eighty-nine teachers (91% female) from all stages of school education in England (48%), Scotland (24%), Wales (22%) and Northern Ireland (6%) completed an online survey. The survey captured information on menstrual education in schools, teacher's knowledge and confidence of the menstrual cycle, support provided to teachers, provision of menstrual products in school and perceived impact of the menstrual cycle on young people in school. Four hundred ninety-eight teachers reported lessons were provided on the menstrual cycle (63%), predominantly delivered within personal, social, health and economic or science subjects, with over half of the lessons focusing on the biology (56%) or provision of menstrual products (40%) rather than lived experiences (14%). Teachers perceived the menstrual cycle affected participation in PE (88%), pupil confidence (88%), school attendance (82%) and attitude and behavior (82%). Overall, 80% of teachers felt receiving training would be beneficial to improve menstrual education. The results highlight education is scientifically focused, with less education on management of symptoms or lived experiences. Teachers also perceive the menstrual cycle to influence multiple aspects of school attendance and personal performance. There is a need to address menstrual education provided in schools across the UK to help empower girls to manage their menstrual cycle, preventing a negative impact on health and school performance.

Family environmental antecedents of pubertal timing in girls and boys: A review and open questions

Across nonhuman species, pubertal timing is affected by the social environment, with consequences for reproductive success and behavior. In human beings, variations in pubertal timing have not been systematically examined in relation to social environmental antecedents, although their psychological consequences are well documented. This paper focuses on links in human beings between pubertal timing and the childhood social environment, with several sections: A review of studies relating pubertal timing to the family context, a key aspect of the social environment; challenges in studying the issue; and opportunities for future work that takes advantage of and creates links with evidence in other species. The review shows that pubertal timing in girls is accelerated by adversity in aspects of the early family social context, with effects small in size; data in boys are not sufficient to enable conclusions. Inferences from existing studies are limited by variations in conceptualizations and measurement of relevant aspects of puberty and of the family social environment, and by methodological issues (e.g., reliance on existing data, use of retrospective reports, nonrandom missing data). Open questions remain about the nature, mechanisms, and specificity of the links between early family social environment and pubertal timing (e.g., form of associations, consideration of absence of positive experiences, role of timing of exposure). Animal studies provide a useful guide for addressing these questions, by delineating potential hormonal mechanisms that underlie links among social context, pubertal timing, and behavior, and encouraging attention to aspects of the social environment outside the family, especially peers.