Early Puberty Trend during the COVID-19 Pandemic in Singapore: A Retrospective Review in a Single Tertiary Centre.

Objectives: We aimed to study the trend of referrals for precocious puberty during the COVID-19 pandemic compared to pre-COVID years, explore the differences in the demographic and clinical features, and evaluate the contributing factors. Methodology: The cases referred for assessment of PP from 2018-2021 to our endocrine centre were grouped into pre-COVID (2018-2019) and COVID (2020-2021) years. Cases fulfilling the diagnosis of PP included the onset of thelarche <8 years in females and 4 ml testicular volume <9 years in males. The PP was further differentiated as Isolated Thelarche (IST) and Central Precocious Puberty (CPP). Early menarche was defined as menarche <10 years old. Results: There were more referrals for PP and more diagnosed as CPP during the COVID-19 pandemic, predominantly among females. There were more endocrine tests done and more cases received treatment. None of the abnormal magnetic resonance imaging (MRI) pituitary findings required surgical intervention. The body mass index (BMI) was found to be positively associated with the risk of getting CPP with a crude-odd ratio (COR) of 1.8, P <0.001, and early menarche (COR 2.1, P <0.001). Conclusion: We found a significant increase in the referrals of PP and diagnosis of CPP during the COVID-19 pandemic. Higher BMI was found to be associated with CPP and early menarche.

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.

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.

Association between depression and young-onset dementia in middle-aged women.

BACKGROUND: Dementia is associated with older adults; however, it can also affect younger individuals, known as young-onset dementia (YOD), when diagnosed before the age of 65 years. We aimed to conduct a retrospective cohort study involving middle-aged women to investigate the association between premorbid depression and YOD development. METHODS: We included 1.6 million women aged 40-60 years who underwent health checkups under the Korean National Health Insurance Service and investigated the association between depression and YOD. RESULTS: Women with depression had a significantly higher risk of developing YOD than women without depression. Among premenopausal women, those with depression had a 2.67-fold increased risk, whereas postmenopausal women with depression had a 2.50-fold increased risk. Late age at menarche (> 16 years) and young age at menopause (< 40 years) was associated with an increased risk of YOD. CONCLUSIONS: Depression in middle-aged women is a significant risk factor for the development of YOD. Understanding the role of reproductive factors can aid in the development of targeted therapeutic interventions to prevent or delay YOD.

Association of early menarche with breast tumor molecular features and recurrence.

BACKGROUND: Early menarche is an established risk factor for breast cancer but its molecular contribution to tumor biology and prognosis remains unclear. METHODS: We profiled transcriptome-wide gene expression in breast tumors (N = 846) and tumor-adjacent normal tissues (N = 666) from women in the Nurses' Health Studies (NHS) to investigate whether early menarche (age < 12) is associated with tumor molecular and prognostic features in women with breast cancer. Multivariable linear regression and pathway analyses using competitive gene set enrichment analysis were conducted in both tumor and adjacent-normal tissue and externally validated in TCGA (N = 116). Subgroup analyses stratified on ER-status based on the tumor were also performed. PAM50 signatures were used for tumor molecular subtyping and to generate proliferation and risk of recurrence scores. We created a gene expression score using LASSO regression to capture early menarche based on 28 genes from FDR-significant pathways in breast tumor tissue in NHS and tested its association with 10-year disease-free survival in both NHS (N = 836) and METABRIC (N = 952). RESULTS: Early menarche was significantly associated with 369 individual genes in adjacent-normal tissues implicated in extracellular matrix, cell adhesion, and invasion (FDR ≤ 0.1). Early menarche was associated with upregulation of cancer hallmark pathways (18 significant pathways in tumor, 23 in tumor-adjacent normal, FDR ≤ 0.1) related to proliferation (e.g. Myc, PI3K/AKT/mTOR, cell cycle), oxidative stress (e.g. oxidative phosphorylation, unfolded protein response), and inflammation (e.g. pro-inflammatory cytokines IFN α and IFN γ ). Replication in TCGA confirmed these trends. Early menarche was associated with significantly higher PAM50 proliferation scores (ß = 0.082 [0.02-0.14]), odds of aggressive molecular tumor subtypes (basal-like, OR = 1.84 [1.18-2.85] and HER2-enriched, OR = 2.32 [1.46-3.69]), and PAM50 risk of recurrence score (ß = 4.81 [1.71-7.92]). Our NHS-derived early menarche gene expression signature was significantly associated with worse 10-year disease-free survival in METABRIC (N = 952, HR = 1.58 [1.10-2.25]). CONCLUSIONS: Early menarche is associated with more aggressive molecular tumor characteristics and its gene expression signature within tumors is associated with worse 10-year disease-free survival among women with breast cancer. As the age of onset of menarche continues to decline, understanding its relationship to breast tumor characteristics and prognosis may lead to novel secondary prevention strategies.

Association between 25-hydroxyvitamin D concentrations and pubertal timing: 6-14-year-old children and adolescents in the NHANES 2015-2016.

Background: The association between 25(OH)D and pubertal timing has not been well studied. The aim of this study was to assess the relationship between 25(OH)D levels and pubertal timing in children. Methods: Participants aged 6-14 years who had available nutritional and serum sex hormone (total testosterone (TT) and estradiol (E2)) information (n =1318) were included. We conducted a cross-sectional analysis of the associations between 25(OH)D and sex steroid hormones among children in the National Health and Nutrition Examination Survey, 2015-2016. Puberty was indicated by high levels of steroid hormones (TT≥50 ng/dL in men, E2≥20 pg/ml in women) or menarche. Results: Serum 25(OH)D and pubertal status showed the same trend in both males and females. In the male population, the OR values of serum 25(OH)D between 50 and <75 and ≥75 nmol/L were 0.52 (0.25, 1.08) and 0.64 (0.23, 1.75), respectively, compared with serum 25(OH)D<50 nmol/L. The OR of serum 25(OH)D ≥50 nmol/L compared with <50 nmol/L was 0.54 (0.26, 1.10), and the P value was statistically significant (P=0.048). In the female population, when the serum 25(OH)D concentration was <50 nmol/L, the ORs corresponding to a serum 25(OH)D concentration between 50 and <75 and ≥75 nmol/L were 0.53 (0.29, 0.98) and 0.50 (0.19, 1.30), respectively. The OR of serum 25(OH)D≥50 nmol/L compared with <50 nmol/L was 0.52 (0.19, 0.96), and the P value was statistically significant (P=0.037). Conclusions: A lower 25(OH)D level was associated with earlier puberty in both girls and boys. There was a negative association between 25(OH)D concentrations and pubertal timing.

Does timing of sexual debut following menarche among female youth in Uganda matter? A discrete time analysis.

BACKGROUND: The burden of early sexual engagement among youth is enormous. It directly raises the risk of sexually transmitted infections(STIs) and indirectly contributes to unintended pregnancy, unsafe abortion, premature childbirth, and psychosocial issues. The aim of this paper was to estimate the timing of sexual debut and examine the factors influencing the timing of first sexual intercourse following menarche among female youth aged between 15 and 24 in Uganda. METHOD: Self-reported data were extracted from the 2016 Uganda Demographic and Health Survey (UDHS), with a sub-sample of 7964 female youth from the individual woman file. Kaplan-Meier survival curves, decrement life-table analysis, and the discrete-time logit model were used to examine the timing of sexual debut and associated factors. RESULTS: 67.4% of the female youth had experienced first sexual initiation. Overall, the meantime to sexual debut was 4.4 years and the median time was 4.3 years, and all the female youth had experienced first sexual initiation by the end of the twelfth year following menarche. Significant factors found to influence the timing of sexual initiation include having higher education level (OR = 0.724: 95% CI = 0.59-0.89; p = 0.003), residing in the Northern region (OR = 0.877:95% CI = 0.79-0.97, p = 0.012), being employed (OR = 1.085: 95% CI = 1.01-1.16; p = 0.021), and being literate (OR = 1.155; 95% CI = 1.07-1.25; p < 0.001). CONCLUSIONS: These findings are expected to be central in the bid to delay first sexual intercourse. Also they shed light on some of the factors associated with the timing of sexual debut which may be addressed at community level for non-school going youth and in schools, as school based prevention sexual and reproductive health programs. The findings highlight the need for future studies to collect more data to explore further the linkage between time to first debut since menarche and, mass media, religion, type of residence, and wealth index.

Maternal exposure to polycyclic aromatic hydrocarbons during pregnancy and timing of pubertal onset in a longitudinal mother-child cohort in rural Bangladesh.

BACKGROUND: In experimental studies, several polycyclic aromatic hydrocarbons (PAHs) have shown endocrine disrupting properties, but very few epidemiological studies have examined their impact on pubertal development and results have been heterogenous. OBJECTIVE: To explore if maternal PAH exposure during pregnancy was associated with the offspring's timing of pubertal onset. METHODS: We studied 582 mother-daughter dyads originating from a population-based cohort in a rural setting in Bangladesh. Maternal urinary samples, collected in early pregnancy (on average, gestational week 8), were analyzed for monohydroxylated metabolites of phenanthrene (1-OH-Phe, Σ2-,3-OH-Phe, and 4-OH-Phe), fluorene (Σ2-,3-OH-Flu), and pyrene (1-OH-Pyr) using liquid chromatography with tandem mass spectrometry (LC-MS/MS). The girls were interviewed on two separate occasions concerning date of menarche, as well as breast and pubic hair development according to Tanner. Associations were assessed using Kaplan-Meier analysis and multivariable-adjusted Cox proportional hazards regression or ordered logistic regression. RESULTS: In early pregnancy, the mothers' median urinary concentrations of Σ1-,2-,3-,4-OH-Phe, Σ2-,3-OH-Flu, and 1-OH-Pyr were 3.25 ng/mL, 2.0 ng/mL, and 2.3 ng/mL respectively. At the second follow-up, 78 % of the girls had reached menarche, and the median age of menarche was 12.7 ± 0.81 years. Girls whose mothers belonged to the second and third quintiles of ΣOH-Phe metabolites had a higher rate of menarche, indicating a younger menarcheal age (HR 1.39; 95 % CI 1.04, 1.86, and HR 1.41; 95 % CI 1.05, 1.88, respectively), than girls of mothers in the lowest quintile. This trend was not observed in relation to either breast or pubic hair development. None of the other maternal urinary PAH metabolites or the sum of all thereof in early pregnancy were associated with age at menarche or pubertal stage. CONCLUSIONS: Indications of non-monotonic associations of prenatal phenanthrene exposure with the daughters' age of menarche were found, warranting further investigation.

Early Menarche as a Protective Factor Against Cardiovascular Events: A Systematic Review and Meta-analysis.

BACKGROUND: Women are often neglected in cardiovascular health prevention. Age at menarche (AAM) has been linked to cardiovascular (CVD) disease in women and is potentially identified as one of the significant CVD risk factor. However, there is still limited comprehensive evidence addressing this issue. This systematic review and meta-analysis aimed to investigate how early menarche affects the outcome of all-cause mortality, CVD mortality, total cardiovascular disease event, stroke (ischemic, hemorrhagic, and total stroke), and coronary heart disease (CHD). METHOD: The Cochrane Library, MEDLINE, Embase, ScienceDirect, and Google Scholar databases were searched from March 2013 to March 2023 for cohorts investigating the effect of early onset of menarche on CVD events with a minimum follow-up period of 5 years. Studies that observed specific population and/or included women with a history of CVD at baseline were excluded. The Newcastle-Ottawa scale was used for risk of bias assessment for each cohort included. The data were presented as dichotomous measure using risk ratios. I2 statistics were utilized to evaluate the heterogeneity of presented data. RESULTS: Thirteen cohorts included 18 626 799 female patients with ages ranging from 43 to 62.6 years. These reported 6 estimates each for CHD (5 483 298 patients) and all-cause mortality (1 595 878 patients), 5 estimates each for total stroke (2 941 321 patients) and CVD mortality (1 706 742 patients), 4 estimates each for total CVD events (3 988 311 patients) and ischemic stroke (2 434 580 patients), and 1 estimate for hemorrhagic stroke (66 104 patients). Our study found that events of CHD were significantly lower in early menarche (RR 0.57; 95% CI 0.41-0.78; P <.00001), as well as total stroke (RR 0.51; 95% CI 0.35-0.73; P =.0003), CVD mortality (RR 0.47; 95% CI 0.22-0.98; P =.04), total CVD events (RR 0.44; 95% CI 0.25-0.76; P =.003), ischemic stroke (RR 0.31; 95% CI 0.15-0.61; P <.0008), and hemorrhagic stroke (RR 0.12; 95% CI 0.07-0.20; P <.00001); and insignificantly higher in all-cause mortality (RR 0.90, 95% CI 0.76-1.06, P =.20). CONCLUSION: In our study, cardiovascular events are lower in women with early menarche; hence, the later age of menarche is a potential risk factor to be considered when assessing CVD risk in a patient. However, our sample characteristics were heterogenous, and we did not consider other female hormonal factors that might potentially contribute to the CVD outcomes observed; thus, further studies are needed to clarify.

A comprehensive investigation of biopsychosocial determinants influencing primary dysmenorrhea among university students.

Dysmenorrhea, characterized by pain and related symptoms, significantly impacts women's quality of life in work and education, prompting a comprehensive evaluation of associated factors. The objective of this study was to utilize structural equation modeling (SEM) to analyze and assess the biopsychosocial factors influencing dysmenorrhea among university students. Three hundred and thirty-nine university students were included in this cross-sectional descriptive study. Data were collected using the Participant Information Form, the Beck Anxiety Scale (BAS), the Beck Depression Scale (BDS), the Multidimensional Scale of Perceived Social Support (MSPSS), the Adverse Childhood Experiences Scale (ACES), the Pain Catastrophizing Scale (PCS) and the Visual Analogue Scale (VAS). It was determined that the variables of pain onset (t = 3.24, p < .05) and age at menarche (t = -2.16, p < .05) showed a significant relationship with the model. The variables of the PCS (t = 16.87, p < .001), BDS (t = 3.06, p < .05), and BAS (t = 5.13, p < .001) showed a significant relationship with the model. Social factors in the model were examined, and a family history of dysmenorrhea and the ACES variables did not contribute significantly to the model (p > .05). The study indicates primary dysmenorrhea influenced by biological and psychological factors. Nurses should conduct holistic assessments and provide comprehensive care for affected women.

Reproductive factors and cardiovascular health in post-menopausal women: a special focus on natural menopause.

Female-specific reproductive factors might contribute to increased risk of cardiovascular disease, and the American Heart Association (AHA) recently proposed Life's Essential 8 (LE8) score to quantify cardiovascular health (CVH). The study aimed to examine the relationships between reproductive factors and the LE8 score among post-menopause women in the United States. We enrolled 3223 post-menopause women from National Health and Nutrition Examination Survey (NHANES). CVH groups based on LE8 score were low (0-49), moderate (50-79), and high good CVH levels (80-100). Multivariate ordinal logistic regressions were applied to estimate the associations between reproductive factors and the LE8 score. In multivariate model, early menarche (OR: 0.69, 95 percent CI: 0.51-0.93) and early menopause (OR: 0.57, 95 percent CI: 0.43-0.77) were associated with LE8 score compared with normal menarche and menopause; Meanwhile, ages at menarche and menopause were positively correlated with LE8 score. The number of pregnancies and full-term pregnancies were negatively associated with LE8 (OR for per pregnancy increase and 95 percent CI, 0.93 (0.88, 0.98), 0.93 (0.87, 0.99), separately). Overall, natural menopausal women with early age at menarche and menopause, and a higher number of pregnancies may have a high risk of lower CVH, and need to focus on their CVH.

A causal examination of the correlation between hormonal and reproductive factors and low back pain.

Background: The relationship between hormonal fluctuations in the reproductive system and the occurrence of low back pain (LBP) has been widely observed. However, the causal impact of specific variables that may be indicative of hormonal and reproductive factors, such as age at menopause (ANM), age at menarche (AAM), length of menstrual cycle (LMC), age at first birth (AFB), age at last live birth (ALB) and age first had sexual intercourse (AFS) on low back pain remains unclear. Methods: This study employed Bidirectional Mendelian randomization (MR) using publicly available summary statistics from Genome Wide Association Studies (GWAS) and FinnGen Consortium to investigate the causal links between hormonal and reproductive factors on LBP. Various MR methodologies, including inverse-variance weighted (IVW), MR-Egger regression, and weighted median, were utilized. Sensitivity analysis was conducted to ensure the robustness and validity of the findings. Subsequently, Multivariate Mendelian randomization (MVMR) was employed to assess the direct causal impact of reproductive and hormone factors on the risk of LBP. Results: After implementing the Bonferroni correction and conducting rigorous quality control, the results from MR indicated a noteworthy association between a decreased risk of LBP and AAM (OR=0.784, 95% CI: 0.689-0.891; p=3.53E-04), AFB (OR=0.558, 95% CI: 0.436-0.715; p=8.97E-06), ALB (OR=0.396, 95% CI: 0.226-0.692; p=0.002), and AFS (OR=0.602, 95% CI: 0.518-0.700; p=3.47E-10). Moreover, in the reverse MR analysis, we observed no significant causal effects of LBP on ANM, AAM, LMC and AFS. MVMR analysis demonstrated the continued significance of the causal effect of AFB on LBP after adjusting for BMI. Conclusion: Our study explored the causal relationship between ANM, AAM, LMC, AFB, AFS, ALB and the prevalence of LBP. We found that early menarche, early age at first birth, early age at last live birth and early age first had sexual intercourse may decrease the risk of LBP. These insights enhance our understanding of LBP risk factors, offering valuable guidance for screening, prevention, and treatment strategies for at-risk women.

How autistic women are aware of their body and take care of their health? Focus on menstruation cycles and gynecological care.

Objective: The combination of femininity and inequality is an increasingly studied in the field of social medicine, even more if the girls or women in question experience conditions of disability or neurodivergence. The onset of menstruation, menarche, constitutes a significant and transformative event in women's lives comprising a true and proper watershed in mental and reproductive health and sexual welfare. The onset of menstruation has a profound effect not just for girls but, in the case of disabled girls, for the whole family. In this scoping review, we have researched the literature in studies which consider the issue of menstruation and autism. The works in scientific literature have been selected which, in the last 5 years, investigated the issue of menstrua-tion for autistic girls and/or women. Results: Selected studies, although few in number, have all equally evidenced the total lack of in-depth understanding of this theme, notwithstanding the fact that females, girls and women with autism would benefit from specialized services if these existed. Families, girls and women involved, moreover, although not experiencing menstruation per se in a negative light, note a deterioration in their condition particularly in respect of sensorial perception and the intensification of anxious depressive instances. This work highlights the need to deepen the aspects concerning the period in autistic girls/women, up to now the question appears to have been little studied, investigated in an uneven way. We propose a social medical program to improve sexual-affective knowledge and body awareness in autistic people.

Genetic Prediction of Osteoporosis by Anti-Müllerian Hormone Levels and Reproductive Factors in Women: A Mendelian Randomization Study.

Previous observational studies have suggested that anti-Müllerian hormone (AMH) and reproductive factors are linked to reduced bone mineral density (BMD) and an increased risk of osteoporosis (OP) in women. However, related studies are limited, and these traditional observational studies may be subject to residual confounders and reverse causation, while also lacking a more comprehensive observation of various reproductive factors. Univariate and multivariate two-sample Mendelian randomization analyses were conducted to determine the causal associations of AMH levels and six reproductive factors with BMD and OP, using the random-effects inverse-variance weighted method. Heterogeneity was assessed using Cochran's Q-statistic, and sensitivity analyses were performed to identify causal correlations. Age at menarche (AAM) was negatively associated with total body BMD (TB-BMD) in females aged 45-60 and over 60 years, as well as with heel bone mineral density (eBMD). Conversely, age at natural menopause (ANM) was positively associated with TB-BMD in the same age ranges and with eBMD. ANM was only causally associated with self-reported OP and showed no significant correlation with definitively diagnosed OP. Neither AMH level nor other reproductive factors were significantly associated with a genetic predisposition to BMD at any age and OP. Later AAM and earlier ANM are significantly genetically causally associated with decreased BMD but not with OP. AMH levels, length of menstrual cycle, age at first birth, age at last birth, and number of live births, in terms of genetic backgrounds, are not causally related to BMD or OP.

Effects of growth hormone therapy on the onset and progression of pubertal development in girls with idiopathic short stature.

OBJECTIVE: The aim of this study was to explore the impact of growth hormone (GH) therapy on the onset and progression of puberty in girls with idiopathic short stature. METHODS: This study included 541 girls aged between 4.5 and 10.6 years who were receiving GH treatment, monitored over a 22-year follow-up period. Of these, 126 girls have been followed up to the onset of menarche. The participants were divided into two groups: a ISS control group (n = 66) and a group receiving daily GH treatment at a dose of 0.15 iu/kg (n = 60). We assessed the pubertal development and GH usage of these girls every three months. RESULTS: (1) There was no significant difference in the onset of puberty between the growth hormone (GH) treatment group and the control group; however, the average duration of puberty was longer in the treatment group compared to the control group. (2) During puberty, there were no significant differences in height growth between the treated and untreated groups. (3) The duration of GH treatment showed a significant negative correlation with the age at onset of gonadal development and the age at menarche in females within the treatment group. CONCLUSION: GH treatment does not seem to accelerate the onset of puberty but may extend its duration, without significantly impacting height growth during puberty. Additionally, longer GH treatment duration is linked to earlier gonadal development and menarche in females.

Menarche and Time to Cycle Regularity Among Individuals Born Between 1950 and 2005 in the US.

Importance: Early menarche is associated with adverse health outcomes. Trends toward earlier menarche have been observed in the US, but data remain limited on differences by sociodemographic factors and body mass index (BMI). Time from menarche to cycle regularity is another understudied early-life characteristic with health implications. Objectives: To evaluate the temporal trends and disparities in menarche and time to regularity and explore early-life BMI as a mediator. Design, Setting, and Participants: This ongoing cohort study enrolled participants from an ongoing mobile application-based US cohort from November 14, 2019, to March 20, 2023. Exposures: Birth year (categorized as 1950-1969, 1970-1979, 1980-1989, 1990-1999, and 2000-2005). Main Outcomes and Measures: Main outcomes were age at menarche and time to regularity, which were self-recalled at enrollment. In addition, early (aged <11 years), very early (aged <9 years), and late (aged ≥16 years) age at menarche was assessed. Results: Among the 71 341 female individuals who were analyzed (mean [SD] age at menarche, 12.2 [1.6] years; 2228 [3.1%] Asian, 3665 [5.1%] non-Hispanic Black, 4918 [6.9%] Hispanic, 49 518 [69.4%] non-Hispanic White, and 8461 [11.9%] other or multiple races or ethnicities), 5223 were born in 1950 to 1969, 12 226 in 1970 to 1979, 22 086 in 1980 to 1989, 23 894 in 1990 to 1999, and 7912 in 2000 to 2005. The mean (SD) age at menarche decreased from 12.5 (1.6) years in 1950 to 1969 to 11.9 (1.5) years in 2000 to 2005. The number of individuals experiencing early menarche increased from 449 (8.6%) to 1223 (15.5%), the number of individuals experiencing very early menarche increased from 31 (0.6%) to 110 (1.4%), and the number of individuals experiencing late menarche decreased from 286 (5.5%) to 137 (1.7%). For 61 932 participants with reported time to regularity, the number reaching regularity within 2 years decreased from 3463 (76.3%) to 4075 (56.0%), and the number not yet in regular cycles increased from 153 (3.4%) to 1375 (18.9%). The magnitude of the trend toward earlier menarche was greater among participants who self-identified as Asian, non-Hispanic Black, or other or multiple races (vs non-Hispanic White) (P = .003 for interaction) and among participants self-rated with low (vs high) socioeconomic status (P < .001 for interaction). Within a subset of 9865 participants with data on BMI at menarche, exploratory mediation analysis estimated that 46% (95% CI, 35%-61%) of the temporal trend in age at menarche was explained by BMI. Conclusions and Relevance: In this cohort study of 71 341 individuals in the US, as birth year increased, mean age at menarche decreased and time to regularity increased. The trends were stronger among racial and ethnic minority groups and individuals of low self-rated socioeconomic status. These trends may contribute to the increase in adverse health outcomes and disparities in the US.

Menstrual pattern in polycystic ovary syndrome and hypothalamic-pituitary-ovarian axis immaturity in adolescents: a systematic review and meta-analysis.

OBJECTIVE: To analyze differences in the menstrual pattern, age at menarche, and body mass index (BMI) in adolescents with Hypothalamic-Pituitary-Ovarian (HPO) axis immaturity and Polycystic Ovary Syndrome (PCOS) through a systematic review and meta-analysis. METHODS: The PubMed, EMBASE, Web of Science, Virtual Health Library, Scopus databases were searched using combinations of descriptors. Study quality was assessed using the Newcastle-Ottawa Scale. For data analysis, the results were grouped into PCOS group and NPCOS group (HPO axis immaturity). We performed a meta-analysis of raw data and the inverse variance method, employing the standardized mean difference, of the age at menarche and BMI of adolescents. RESULTS: Participants totaled 1,718 from nine selected studies. The meta-analysis showed that the PCOS group had a higher BMI than the NPCOS group (SMD 0.334; CI95% 0.073 - 0.595; p = .012). The degree of heterogeneity of the studies was approximately 40%. No significant difference in age at menarche (SMD - 0.027; CI95% -0.227 - 0.172; p = 0.790) and menstrual patterns was found, but amenorrhea was described only in adolescents with PCOS. CONCLUSIONS: The main characteristic in menstrual pattern that differentiated PCOS patients from girls with HPO axis immaturity was amenorrhea. Also, the BMI of PCOS patients was nearly one third higher than that of adolescents with HPO axis immaturity.

Metabolome-wide Mendelian randomization for age at menarche and age at natural menopause.

BACKGROUND: The role of metabolism in the variation of age at menarche (AAM) and age at natural menopause (ANM) in the female population is not entirely known. We aimed to investigate the causal role of circulating metabolites in AAM and ANM using Mendelian randomization (MR). METHODS: We combined MR with genetic colocalization to investigate potential causal associations between 658 metabolites and AAM and between 684 metabolites and ANM. We extracted genetic instruments for our exposures from four genome-wide association studies (GWAS) on circulating metabolites and queried the effects of these variants on the outcomes in two large GWAS from the ReproGen consortium. Additionally, we assessed the mediating role of the body mass index (BMI) in these associations, identified metabolic pathways implicated in AAM and ANM, and sought validation for selected metabolites in the Avon Longitudinal Study of Parents and Children (ALSPAC). RESULTS: Our analysis identified 10 candidate metabolites for AAM, but none of them colocalized with AAM. For ANM, 76 metabolites were prioritized (FDR-adjusted MR P-value ≤ 0.05), with 17 colocalizing, primarily in the glycerophosphocholines class, including the omega-3 fatty acid and phosphatidylcholine (PC) categories. Pathway analyses and validation in ALSPAC mothers also highlighted the role of omega and polyunsaturated fatty acids levels in delaying age at menopause. CONCLUSIONS: Our study suggests that metabolites from the glycerophosphocholine and fatty acid families play a causal role in the timing of both menarche and menopause. This underscores the significance of specific metabolic pathways in the biology of female reproductive longevity.

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.

Mammographic density mediates the protective effect of early-life body size on breast cancer risk.

The unexplained protective effect of childhood adiposity on breast cancer risk may be mediated via mammographic density (MD). Here, we investigate a complex relationship between adiposity in childhood and adulthood, puberty onset, MD phenotypes (dense area (DA), non-dense area (NDA), percent density (PD)), and their effects on breast cancer. We use Mendelian randomization (MR) and multivariable MR to estimate the total and direct effects of adiposity and age at menarche on MD phenotypes. Childhood adiposity has a decreasing effect on DA, while adulthood adiposity increases NDA. Later menarche increases DA/PD, but when accounting for childhood adiposity, this effect is attenuated. Next, we examine the effect of MD on breast cancer risk. DA/PD have a risk-increasing effect on breast cancer across all subtypes. The MD SNPs estimates are heterogeneous, and additional analyses suggest that different mechanisms may be linking MD and breast cancer. Finally, we evaluate the role of MD in the protective effect of childhood adiposity on breast cancer. Mediation MR analysis shows that 56% (95% CIs [32%-79%]) of this effect is mediated via DA. Our finding suggests that higher childhood adiposity decreases mammographic DA, subsequently reducing breast cancer risk. Understanding this mechanism is important for identifying potential intervention targets.