Maternal Age at Menarche and Pubertal Timing in Boys and Girls: A Cohort Study From Chongqing, China

Early or late menarche is associated with reduced fecundability in the Norwegian Mother, Father and Child Cohort Study

STUDY QUESTION

Is age at menarche associated with fecundability?

SUMMARY ANSWER

Both early (<11 years) and late (>15 years) menarche is associated with decreased fecundability.

WHAT IS KNOWN ALREADY

Previous studies on age at menarche and fecundability have been inconclusive. Women with early or late menarche are at increased risks of gynaecological and autoimmune diseases that may affect their ability to conceive.

STUDY DESIGN, SIZE, DURATION

We conducted a retrospective cohort study including 67 613 pregnant women, participating in the Norwegian Mother, Father and Child Cohort Study between 1999 and 2008, with self-reported information on age at menarche and time to pregnancy. We included planned pregnancies that were conceived either naturally or with the help of assisted reproductive technologies.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We calculated fecundability ratios (FRs) with 95% CIs representing the cycle-specific probability of conception by categories of age at menarche. FRs were adjusted for participants' pre-pregnancy body mass index, highest completed or ongoing education level, and age at initiation of trying to conceive.

MAIN RESULTS AND THE ROLE OF CHANCE

We observed a 7% lower probability of conceiving during any given menstrual cycle up to 12 cycles in women with early or late menarche. Among women with menarche >15 years, the adjusted FR was 0.93 (95% CI: 0.90-0.97), and among women with menarche <11 years, the adjusted FR was 0.93 (95% CI: 0.89-0.99), when compared to women with menarche between 12 and 14 years.

LIMITATIONS, REASONS FOR CAUTION

The study-population consisted of women pregnant in their second trimester, excluding those with persistent infertility. Recall of age at menarche and time to pregnancy may be inaccurate.

WIDER IMPLICATIONS OF THE FINDINGS

Both early (<11 years) and late (>15 years) menarche was associated with decreased fecundability. Women experiencing early menarche or late menarche may be counselled accordingly.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the Norwegian Institute of Public Health, Oslo, Norway, and by Telemark Hospital Trust, Porsgrunn, Norway and was partly supported by the Research Council of Norway through its centres of excellence funding scheme (project number 262700) and the Research Council of Norway (project no. 320656). The project was co-funded by the European Union (ERC, BIOSFER, 101071773). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. M.C.M. has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement no. 947684). The authors report no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Evaluation of the differences in the localization of the lingula mandibulae according to pubertal development in children: A new anthropological and forensic approach

OBJECTIVE

This study aims to investigate changes in lingula mandibulae localization before and after puberty and sex differences.

DESIGN

288 panoramic radiographs evaluated retrospectively were divided into four groups according to pubertal development: under and over 10 years old for females and under and over 11 years old for males. Four anatomic sites were used as reference points: (a) the anterior border of the ramus; (b) the posterior border of the ramus; (c) the deepest point of mandibular notch; and (d) the angulus mandibulae. The ratio of the distances from the lingula mandibulae to points (a) and (b) and the ratio of the distances from the lingula mandibulae to points (c) and (d) were determined. Two-way ANOVA was performed to assess differences between subgroups based on sex and puberty, and a Bonferroni post-hoc test was performed for multiple comparisons.

RESULTS

Puberty and sex has a significant interaction effect on the vertical location of the lingula mandibulae. Postpubertal lingula mandibulae is positioned proportionally more anteriorly by prepubertal localization. In addition, the lingula mandibulae is situated more posteriorly in females compared to males. A significant interaction effect of puberty and sex was observed in relation to the vertical positioning of the lingula mandibulae.

CONCLUSIONS

The spatial localization of the lingula mandibulae and its spatial displacement with age can be used both in estimating sex and the onset of puberty. Changes in the localization of lingula mandibulae according to pubertal development and sex can be used in forensic and anthropological contexts.

Pubertal development at age 14 is associated with male adolescents' combustible cigarette smoking and dual use, but not with e-cigarette use - Findings from the UK Millennium Cohort Study

BACKGROUND

Adolescent nicotine exposure via electronic cigarettes (e-cigarettes) is a global health concern. Pubertal development earlier than peers increases the risk of tobacco smoking compared to peers experiencing on-time or late maturation, yet relationships of pubertal timing with e-cigarettes are unknown. We examine whether early pubertal timing is associated with risk for e-cigarette use, tobacco cigarettes, or both by age 14.

METHODS

The Millennium Cohort Study follows a representative cohort of 18,552 9-month-old children born 2000-2002 in the United Kingdom. Our sample includes 11,445 adolescents (5697 boys, 5748 girls) classified at age 14 as early, on-time, or late in pubertal development timing (PDT) relative to same-age, same-sex peers using the Pubertal Development Scale. Outcomes were use of e-cigarettes, tobacco cigarettes, or both by age 14. We included childhood liability confounders and demographics measured from age 7-11.

RESULTS

For girls, no PDT differences in age 14 e-cigarette or tobacco cigarette use were observed. All relative to on-time PDT boys, early maturing boys' odds of tobacco cigarette use were 59% higher (OR=1.59, 95% confidence interval (CI)=1.08,2.35), and odds of dual-use were 49% higher (OR=1.49, CI=1.11,1.99), both compared to odds of never use. Among late PDT boys, dual-use odds were lower than never use by 35% (OR=0.65, CI=0.47,0.91) and lower than e-cigarette use only by 36% (OR=0.64, CI=0.42,0.97).

CONCLUSIONS

At age 14, PDT was not associated with e-cigarette use for either sex, yet it was linked with tobacco use and dual use among boys.

Age at menarche and polycystic ovary syndrome: A Mendelian randomization study

OBJECTIVE

The authors aimed to use a large two-sample Mendelian randomization (MR) study to reveal the causality between age at menarche (AAM) and polycystic ovary syndrome (PCOS) incidence.

METHODS

The authors collected summary statistics from the hitherto largest genome-wide association studies conducted in AAM and PCOS in the same ancestry. MR with inverse variance weighting was conducted as the main analysis method, while weighted median and MR-Egger regression were used for comprehensive analysis. As for pleiotropy detection, inverse variance weighting, MR-Egger regression, Mendelian Randomization Pleiotropy Residual Sum and Outlier, as well as leave-one-out analysis were used to detect pleiotropy. Risk factor analysis was conducted to investigate the underlying mechanisms linking AAM to PCOS.

RESULTS

Each standard deviation increment in AAM was associated with a significantly lower incidence of PCOS (odds ratio, 0.86 [95% confidence interval, 0.75-0.98]). After adjustment in horizontal pleiotropy by eliminating four outliers, this pathogenic association was still statistically detected. All pleiotropy indexes were without statistical differences, which suggested the conclusions were robust. It showed the causal association between later AAM and lower body mass index, lower fasting insulin level and insulin resistance.

CONCLUSION

Our MR analysis verified that a slightly later onset age (15 to 18 years) at menarche could reduce the risk of PCOS. A more comprehensive investigation in a prospective setting is strongly advised.

The effect of environmental factors on precocious puberty in children: a case-control study

BACKGROUND

Recently the prevalence of precocious puberty development is increasing among Chinese children. Proper understanding of the risk factors for precocious puberty in children is pivotal as could help to improve children's health. This study aims to evaluate the effect of environmental factors on precocious puberty in children.

METHODS

We matched the cases and controls by age at the ratio of 1:1 (201 cases and 201 controls) for girls and 1:4 (24 cases and 96 controls) for boys. We used conditional logistic regression to explore the effect of environmental factors on precocious puberty, and a random forest model to identify the most important risk factor.

RESULTS

In the multivariate regression, cesarean section (OR = 1.99, 95% CI: 1.05, 3.76), child body mass index [BMI] (OR = 1.25, 95% CI: 1.10, 1.43), maternal BMI (OR = 1.13, 95%CI: 1.01, 1.26), and exposure to secondhand smoke several times a month but less than once a week (OR = 4.09, 95%CI: 1.79,9.35), and almost every day (OR = 6.48, 95% CI: 2.14, 19.56) were risk factors for precocious puberty in girls. While maternal height (OR = 0.82, 95% CI: 0.75, 0.88), paternal height (OR = 0.91, 95% CI: 0.85, 0.98), bedtime at night (OR = 0.30, 95% CI: 0.17, 0.51), and night sleep (OR = 0.43, 95% CI: 0.21, 0.86) were protective factors. In boys, only exposure to secondhand smoke several times a month but less than once a week (OR = 7.94, 95% CI: 1.25, 50.33) was a risk factor for precocious puberty. In the random forest model, Child BMI was the most important risk factor for precocious puberty in girls.

CONCLUSIONS

Our findings suggest that environmental factors were associated with precocious puberty in children, particularly in girls.

Cohort-based analysis of maternal age at menarche in relation to young adult offspring anthropometric and metabolic parameters

OBJECTIVES

Age of menarche is a determinant factor of cardiometabolic risk, adiposity and stature at adulthood. However, little is known about the transgenerational effects of age of menarche, especially beyond childhood of any offspring, and the studies remain limited to anthropometric outcomes in children at birth or before adolescence. In the present study, we aim to investigate the relationship of maternal age at menarche (MAM) with anthropometric and metabolic parameters in the young adult offspring (aged 15-35 years) in a Persian population.

DESIGN, PATIENTS AND MEASUREMENTS

In this cohort-based cross-sectional study, we recruited 1139 mother-young adult dyads enroled in Rafsanjan Cohort Study (RCS) at adult RCS (aged 35-70 years) and youth RCS (aged 15-35 years) as part of the comprehensive PERSIAN (Prospective Epidemiological Research Studies in IrAN). In this study, MAM was categorized to early (MAM < 12 years), normal (12 ≤ MAM ≤ 14) and late menarche (MAM > 14 years). For these analyses, bivariate and multiple logistic regression models were used to investigate the relationships between late or early MAM and offspring anthropometric and metabolic parameters.

RESULTS

Early MAM displayed a significant association with an increased odds ratio (OR) of tall stature adjusting for sex, age, socioeconomic status index, maternal age at birth and maternal height (as genetically determined factor). Sensitivity analysis by sex indicated this relationship to be specific to male offspring only (adjusted OR: 1.84 95% CI: 1.13-3.00, p value: .014). In addition, late MAM displayed a significant association with reduced OR of overweight/obesity and abdominal obesity in daughters only (obesity adjusted OR: 0.49, 95% CI: 0.27-0.88, p value: .018, abdominal obesity adjusted OR: 0.44, 95% CI: 0.23-0.82, p value: .010). dose-response analysis by categorization of MAM, further supported our results. On the contrary, our analyses do not support a significant relationship between MAM and youth metabolic indices, that is, metabolic syndrome, fasting blood sugar (FBS), high-density lipoprotein (HDL) and triglyceride (TG).

CONCLUSIONS

The results of the present study indicate an association of maternal age of menarche with anthropometric measures of offspring in young adulthood in a sex differential manner. The data does not support a significant relationship between the metabolic indices FBS, TG and HDL in offspring with MAM. Overall, this study provides evidence for the intergenerational effects of age at menarche in the development of anthropometric measures in offspring in young adulthood (15-35), which is the first study of this kind in this age range.

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

BACKGROUND

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

AIM

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

SUBJECTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Exploring Overweight Risk Trajectories During Childhood and Their Associations With Elevated Blood Pressure at Late Adolescence: a Retrospective Cohort Study

BACKGROUND

Overweight during childhood is significantly associated with higher risk of high blood pressure (HBP) in later life. However, recognition of critical intervention period is limited. We aimed to analyze the changes in overweight risk during school-age and its relationship with HBP.

METHODS

Seventeen thousand eight hundred sixteen school-aged children (53.9% boys) with a mean follow-up time of 8.2 years were involved. Children's overweight was defined as body mass index Z score ≥1 and was fitted with a group-based trajectory model. The 4 trajectories were labeled as constant low, high decreasing, low rising, and constant high according to the change of overweight risk during follow-up. Population-averaged logit model and log-binomial regression models were used to analyze HBP risk. Cox proportional hazard model was used to analyze the HBP incidence among distinct groups.

RESULTS

Children with higher overweight risk generally had higher HBP risk during follow-up. However, the HBP risk in low rising group was low at baseline and increased to 3.14 (95% CI, 2.54-3.88; P<0.001) for boys and 3.23 (95% CI, 2.08-5.01; P=0.004) for girls at end point, which were comparable to the relative risk in the constant high group (4.60 [95% CI, 4.02-5.27] for boys and 5.28 [95% CI, 3.94-7.07] for girls).

CONCLUSIONS

Findings of this study provide insights on patterns of overweight risks during childhood. Children with transition from normal to overweight during teen years would be high-risk in HBP incidence.

Identification and Optimization of Contributing Factors for Precocious Puberty by Machine/Deep Learning Methods in Chinese Girls

BACKGROUND AND OBJECTIVES

As the worldwide secular trends are toward earlier puberty, identification of contributing factors for precocious puberty is critical. We aimed to identify and optimize contributing factors responsible for onset of precocious puberty via machine learning/deep learning algorithms in girls.

METHODS

A cross-sectional study was performed among girls aged 6-16 years from 26 schools in Beijing based on a cluster sampling method. Information was gleaned online via questionnaires. Machine/deep learning algorithms were performed using Python language (v3.7.6) on PyCharm platform.

RESULTS

Of 11308 students enrolled, there are 5527 girls, and 408 of them had experienced precocious puberty. Training 13 machine learning algorithms revealed that gradient boosting machine (GBM) performed best in predicting precocious puberty. By comparison, six top factors including maternal age at menarche, paternal body mass index (BMI), waist-to-height ratio, maternal BMI, screen time, and physical activity were sufficient in prediction performance, with accuracy of 0.9530, precision of 0.9818, and area under the receiver operating characteristic curve (AUROC) of 0.7861. The performance of the top six factors was further validated by deep learning sequential model, with accuracy reaching 92.9%.

CONCLUSIONS

We identified six important factors from both parents and girls that can help predict the onset of precocious puberty among Chinese girls.

The association between pubertal timing and quality of life among children and adolescents: a cross-sectional study in Chongqing, China

BACKGROUND

To determine the relationship between pubertal timing and quality of life (QOL) in children and adolescents and to provide a basis for QOL intervention in pubertal children in the future to promote good adaptation and healthy physical and mental development of children.

METHODS

The survey was conducted in one county using a stratified cluster sampling method. The five physiological change items of the Puberty Development Scale (PDS) were used to assess the timing of puberty in students. Compared to students of the same age and the same sex, students who scored higher than the mean + standard deviation (SD) of individual developmental scores were defined as an early pubertal timing group. A 39-item QOL Scale for Children in Puberty was used to assess the QOL of the respondents. Multiple linear regression models were fitted separately for boys and girls.

RESULTS

Of the 7223 students, 3754 (51.97%) were boys and 3469 (48.03%) were girls. The prevalence of early pubertal periods was 16.07%. The total QOL score in the early pubertal timing group (137.16 ± 18.67) was significantly lower than in the normal (on time) group (142.02 ± 17.98) and the late group (142.76 ± 18.35) (F = 37.311, P < 0.001). A multiple linear regression model showed that early pubertal timing was a risk factor for QOL (P < 0.0014), compared with normal and late pubertal timing.

CONCLUSIONS

The early pubertal timing was associated with poorer QOL in children and adolescents. More attention should be paid to children with early pubertal timing in intervening children's QOL during pubertal development. Future longitudinal studies are needed to confirm the association between pubertal timing and QOL.

The Chinese Adolescent Cohort Study: Design, Implementation, and Major Findings

The importance of diet quality on children's growth is being increasingly recognized. The Chinese Adolescent Cohort (CAC) is a longitudinal cohort study to comprehensively investigate the health impacts of nutritional factors on child growth. From 2013 to 2018, 6,967 children aged 6-8 years have been recruited from 23 primary schools in Sichuan, Guizhou, and Chongqing, which have been planned to be followed up annually until their age of 15 years. Regular assessments included the measurement of height, weight, waist circumference, and skinfold thicknesses; pubertal development was examined by trained investigators according to Tanner stages; dietary intake was obtained by three 24-h recalls and food frequency questionnaire; validated questionnaires were used to estimate socio-demographic characteristics, physical activity, and sedentary behaviors. Findings from the CAC baseline and the first follow-up data suggested that higher protein intake among girls and unhealthy eating habits among children might increase the risk for childhood obesity. Also, higher intakes of grain and meat and lower overall diet quality and intakes of dietary fiber and tuber might be associated with advanced pubertal development. Those results indicated that the CAC study could contribute to the development of strategies for optimizing Chinese children's health.