Lessons from large population studies on timing and tempo of puberty (secular trends and relation to body size): the European trend

Size at birth, infant growth, and age at pubertal development in boys and girls

Purpose

This study investigated whether size at birth and infant growth were associated with age of indicators of pubertal development in boys and girls. We hypothesized that restricted fetal growth and accelerated infant growth lead to earlier pubertal age.

Patients and methods

In total, 15,822 boys and girls answered questionnaires half-yearly with information on pubertal development: age at menarche, first ejaculation, voice break, Tanner stages, axillary hair, and acne. Birth weight and gestational age were used to calculate birth weight Z-scores. Changes in infant weight Z-score from 0 to 5, 5 to 12, and 0 to 12 months were estimated. We estimated the mean monthly difference in timing of puberty between children born small-for-gestational age (SGA) and large-for-gestational age (LGA) with children born appropriate-for-gestational age (AGA) as reference. We further investigated whether increasing infant weight Z-scores were associated with age at attaining indicators of pubertal development.

Results

Girls born SGA reached all pubertal markers at an earlier mean age than girls born AGA, as indicated by mean age differences below zero (eg, age at menarche: -2.3 months, 95% CI: -3.4, -1.2), except for breast development. Girls born LGA reached pubertal markers later than girls born AGA (eg, age at menarche: 1.7 months, 95% CI 0.5, 2.9). Boys born SGA and LGA achieved puberty earlier than boys born AGA, though with CIs crossing zero (eg, age at voice break for SGA: -0.7 months, 95% CI -2.1, 0.7 and for LGA: -0.7 months, 95% CI -2.1, 0.8). A 1-unit increase in weight Z-score from 0 to 12 months was associated with a mean age difference of -1.7 to -0.3 months for pubertal development in both sexes.

Conclusion

Small size at birth and rapid infant growth were associated with early pubertal age, most consistent and pronounced in girls.

Maternal pre-pregnancy body mass index, smoking in pregnancy, and alcohol intake in pregnancy in relation to pubertal timing in the children

Background

Earlier pubertal timing has been observed in many countries. We aimed to explore if prenatal exposure to maternal obesity, smoking, and alcohol intake was associated with timing of puberty by use of a novel marker of pubertal timing: ‘the height difference in standard deviations’ (HD:SDS).

Methods

HD:SDS is the difference between pubertal height in standard deviations and adult height in standard deviations, and it correlates well with age at peak height velocity. Pubertal height was measured by health care professionals at approximately 13 years in boys and 11 years in girls, and the children’s adult height was predicted from parental height reported by the mothers during pregnancy. Information on HD:SDS was available for 42,849 of 56,641 eligible boys and girls from the Danish National Birth Cohort born 2000–2003. In a subsample, HD:SDS was validated against age at the following self-reported pubertal milestones: Tanner stages, menarche, first ejaculation, voice break, acne, and axillary hair. Prenatal exposures were reported by mothers during pregnancy.

Results

HD:SDS correlated moderately with the pubertal milestones considered (correlation coefficients: − 0.20 to − 0.53). With normal weight (body mass index (BMI): 18.5–24.9 kg/m²) as the reference, maternal pre-pregnancy obesity (BMI: 30.0+ kg/m²) was associated with earlier pubertal timing: 0.23 (95% confidence interval (CI): 0.18, 0.28) higher HD:SDS in boys and 0.19 (95% CI, 0.14, 0.24) higher HD:SDS in girls. Maternal smoking was not associated with pubertal timing. Compared to alcohol abstainers, maternal intake of > 3 units of alcohol weekly was associated with later puberty in boys only: 0.14 (95% CI, 0.05, 0.24) lower HD:SDS.

Conclusion

As correlations between HD:SDS and the considered pubertal milestones were comparable to those reported in the literature between age a peak height velocity and the considered pubertal milestones, the validity of HD:SDS seems acceptable. Maternal pre-pregnancy obesity was associated with earlier pubertal timing in both sexes, and maternal alcohol intake during pregnancy was associated with later pubertal timing in boys. Maternal smoking has been linked to earlier timing of puberty, but this was not replicated in our setting using HD:SDS as a marker of pubertal timing.

Growth and Puberty in Juvenile Dermatomyositis: A Longitudinal Cohort Study

OBJECTIVE

To study growth and puberty in a multinational longitudinal prospective cohort of children with juvenile dermatomyositis (DM).

METHODS

Children from 31 countries who were ages <18 years and had juvenile DM in active phase were studied, and analyses of height, weight, and pubertal development were conducted in those who had follow-up visits during a 2-year period and for whom anthropometric data was available.

RESULTS

A total of 196 of 275 children (71%) were included. We found a significant reduction in parent-adjusted height Z score over time in female patients (P < 0.0001) and male patients (P = 0.001), but with catch-up growth at the final study visit. Median body mass index Z score peaked at 6 months (P < 0.0001) and was still significantly above baseline at the final study visit, which was at a median of 26 months after baseline (P = 0.007), with no difference between sexes. Female patients with a disease duration ≥12 months after onset had significantly lower parent-adjusted height Z score (P = 0.002) and no 2-year catch-up growth. At the final study visit, growth failure was seen in 20 of 97 female patients (21%) and in 11 of 73 male patients (15%). Height deflection (∆height Z score less than -0.25/year) was observed in 29 of 116 female patients (25%) and 25 of 80 male patients (31.3%). Delayed puberty was seen in 20 of 55 female patients (36.4%) and in 11 of 31 male patients (35.5%). Children in early pubertal stage at baseline had the highest risk of growth failure.

CONCLUSION

Juvenile DM in the active phase and/or its treatment has a significant impact on growth and puberty in affected children. Children with recent onset of puberty or previous growth failure have the highest risk of delayed pubertal development and further growth retardation.

Parents of early-maturing girls die younger

According to the life-history theory, rates of sexual maturation have coevolved with mortality rates so that individuals who mature faster tend to die younger. We used two data sets, providing different markers for the speed of pubertal development to test whether rates of sexual maturation of women predict the age at death of their parents. In the data set of Estonian schoolgirls born between 1936 and 1961, the rate of breast development predicted lifespan of both mothers and fathers (irrespectively of their socio-economic position), so that parents of rapidly maturing girls died at younger age. This finding supports the view that fast maturation rates in humans have coevolved with short lifespans and that such trade-offs can be detected as intergenerational phenotypic correlations in modern populations. Menarcheal age of participants of Estonian Biobank (born between 1925 and 1996) did not predict the age of death of their mothers; however, it did predict survival of their fathers, but only in environment where the genetic variation is exposed (families where at least one parent had tertiary education). In such families (where girls also matured 0.2-0.4 years earlier than in poorly educated families), 1-year delay in daughter's menarche corresponded to 9% lower hazard of father's death. Heritability of menarcheal age was also highest in well-educated families. The latter findings are consistent with the idea that genetic differences in the rate of pubertal maturation may be expressed most clearly in well-off families because in such families, the contribution of environmental variance to total phenotypic variance in menarcheal age is smallest. Our findings suggest that with global improvement and equalization of growth conditions, reductions of environmental variation in the rate of maturation increasingly expose the genetic differences in menarcheal age to selection. Under such conditions, selection on menarcheal age has a potential to affect the evolution of lifespan.

Age at Menarche and Blood Pressure in Pregnancy

Objectives

To investigate whether age at menarche is related to maternal blood pressure in pregnancy and, if so, whether obesity and insulin resistance can modify the associations.

Study Design

Analysis of data collected from 438 pregnant women from the longitudinal and prospective Cambridge Baby Growth Study.

Main Outcome

Testing associations between questionnaire-derived age at menarche and blood pressure measurements in pregnancy collected from hospital notes, and investigating whether any associations were altered by maternal pre-pregnancy body mass index (BMI) and insulin resistance.

Measures

Mean arterial blood pressure at four time points across pregnancy, age at menarche, (Homeostasis Model Assessment) insulin resistance around week 28 of pregnancy.

Results

For each increased year in age at menarche there was a drop in mean arterial blood pressure (mmHg) of 0.6 at 11.9 weeks, 0.9 at 31.4 and 37.0 weeks, and 0.4 at 38.8 weeks (a maximal difference of over 7 mmHg across extremes of AAM). Each association was attenuated by both maternal pre-pregnancy BMI and insulin resistance.

Conclusions

Age at menarche is negatively associated with future blood pressure in pregnancy, so those with the earliest age at menarche have the highest blood pressures. Either these associations may be mediated by links between age at menarche and obesity/insulin resistance, or there may be a confounder (e.g. systemic inflammation) that links age at menarche to each of them.

Puberty timing associated with obesity and central obesity in Chinese Han girls

Background

There is growing scientific evidence supports a link between increased childhood adiposity and early onset of puberty in girls worldwide in recent decades. However, the data from Chinese girls remain ambiguous. The aims of this study were to estimate the puberty milestones and examine attainment of puberty associated with obesity and central obesity in Chinese Han schoolgirls.

Methods

The cross-sectional school-based study examined 2996 Han schoolgirls aged 9 to 19 years from 6 provinces in China. Trained clinicians assessed  the girls for height, weight, waist circumference, Tanner stages of breast and pubic hair development, and menarcheal status. We classified girls as normal weight, overweight, or obese based on BMI, and as normal weight or central obese based on the waist-height ratio, then estimated and compared median age at a given Tanner stage or greater by weight class using Probit models.

Results

The median age at menarche was 12.36 years. The median ages at breast stages(B) 2 through 5 were 10.03, 11.38, 13.39, and 15.79 years, respectively, and at pubic hair stages(PH) 2 through 5 were 11.62, 12.70, 14.38, and 16.92 years, respectively. Girls from urban areas experienced menarche, B3 and B4 stages, and PH3 through PH5 stages earlier. Girls with central obesity and overweight/obesity reached puberty earlier at almost every Tanner stage of breast and pubic hair than normal girls. Girls with obesity developed PH2 and PH3 earlier than their overweight peers. However, we did not find any significant differences between girls with overweight and obesity at all stages of breast development.

Conclusions

Childhood obesity, including both overweight/obesity and central obesity, is associated with earlier attainment of puberty in Chinese Han schoolgirls.

ERICA: age at menarche and its association with nutritional status

OBJECTIVE

To estimate the mean age at menarche and its association with nutritional status in Brazilian adolescents.

METHODS

The study sample included female adolescents aged 12-17 who participated in a multicenter, school-based, country-wide, cross-sectional study entitled The Study of Cardiovascular Risk in Adolescents (Estudo de Riscos Cardiovasculares em Adolescentes [ERICA]). Mean and median ages at menarche in Brazil were estimated. The association of age at menarche with sociodemographic data and nutritional status were described as means and their respective 95% confidence intervals. Survival analysis was used to assess the age at menarche according to nutritional status categories and the log-rank test was used to compare the medians. Bivariate and multivariate analyses were performed using Cox regression to verify the association between menarche and other variables.

RESULTS

A total of 73,624 students were evaluated, comprising 40,803 girls, of whom 37,390 reported menarche at a mean age of 11.71 years and a median of 12.41 years. Median age at menarche was lower in overweight and obese girls (p<0.001). The multivariate analysis showed that excess weight (HR=1.28; 95% CI 1.21-1.36; p<0.001) and studying in a private school (HR=1.06; 95% CI 1.02-1.10; p=0.003) were associated with menarche.

CONCLUSIONS

This is a pioneering study in Brazil with national and regional representativeness to estimate the mean and the median age of occurrence of menarche. Adolescents with excess weight had an earlier menarche than their peers, even after adjustment for confounding factors.

Maternal Smoking During Pregnancy and Timing of Puberty in Sons and Daughters: A Population-Based Cohort Study

Because early puberty has been linked to diseases later in life, identification of modifiable causes of early puberty is of interest. We explored the possible associations between maternal smoking during pregnancy and pubertal development in sons and daughters. Between 2012 and 2017, 15,819 children from the Danish National Birth Cohort, born during 2000-2003, provided half-yearly information on puberty from the age of 11 years. We estimated adjusted age differences (in months) at attaining various pubertal milestones, including Tanner stages, per 10 daily cigarettes smoked in the first trimester of gestation. In sons, exposure to smoking in utero was associated with earlier genital development (Tanner 2, -1.3 months, 95% confidence interval (CI): -2.5, 0.0; Tanner 5, -3.7 months, 95% CI: -5.3, -2.0), pubic hair development (Tanner 2, -1.8 months, 95% CI: -2.9, -0.6; Tanner 5, -2.9 months, 95% CI: -4.2, -1.7), and voice break (-2.4 months, 95% CI: -3.6, -1.3). In daughters, maternal smoking was associated with earlier breast development (Tanner 2, -3.4 months, 95% CI: -5.3, -1.5; Tanner 5, -4.7 months, 95% CI: -6.5, -2.9), pubic hair development stages 3-5 (Tanner 5, -2.5 months, 95% CI: -4.1, -1.0), and menarche (-3.1 months, 95% CI: -4.0, -2.3). Fetal exposure to tobacco smoke might advance timing of puberty in boys and girls.

Timing of puberty in boys and girls: A population-based study

BACKGROUND

A secular trend towards earlier puberty has been observed in girls, while a similar trend has been more uncertain in boys. We estimated current ages at pubertal development in both boys and girls.

METHODS

In this population-based cohort study, 14 759 of 22 439 invited boys and girls born from 2000 to 2003 in the Danish National Birth Cohort gave half-yearly self-reported information on puberty from the age of 11.5 years and throughout puberty. This late start of follow-up limits the estimation of age at onset of puberty but not later pubertal milestones. We estimated mean age at attaining the following pubertal milestones in years with 95% confidence intervals (CI): age at menarche, voice break, first ejaculation of semen and Tanner stages for pubic hair development and breast development or genital development. Further, the difference in mean age at menarche between mothers and daughters was estimated.

RESULTS

In boys, voice break occurred at 13.1 (95% CI 13.0, 13.1) years, first ejaculation of semen occurred at 13.4 (95% CI 13.3, 13.4) years, and Tanner Genital Stage 5 occurred at 15.6 (95% CI 15.5, 15.6) years. In girls, age at menarche occurred at 13.0 (95% CI 13.0, 13.1) years and Tanner Breast Stage 5 occurred at 15.8 (95% CI 15.7, 15.9) years. Daughters had menarche 3.6 (95% CI 3.1, 4.2) months earlier than their mothers had.

CONCLUSION

These data indicate that age at menarche has declined and to some extent support a decline in age at attaining other markers of pubertal development among boys.

Genes underlying delayed puberty

The genetic control of pubertal timing has been a field of active investigation for the last decade, but remains a fascinating and mysterious conundrum. Self-limited delayed puberty (DP), also known as constitutional delay of growth and puberty, represents the extreme end of normal pubertal timing, and is the commonest cause of DP in both boys and girls. Familial self-limited DP has a clear genetic basis. It is a highly heritable condition, which often segregates in an autosomal dominant pattern (with or without complete penetrance) in the majority of families. However, the underlying neuroendocrine pathophysiology and genetic regulation has been largely unknown. Very recently novel gene discoveries from next generation sequencing studies have provided insights into the genetic mutations that lead to familial DP. Further understanding has come from sequencing genes known to cause GnRH deficiency, next generation sequencing studies in patients with early puberty, and from large-scale genome wide association studies in the general population. Results of these studies suggest that the genetic basis of DP is likely to be highly heterogeneous. Abnormalities of GnRH neuronal development, function, and its downstream pathways, metabolic and energy homeostatic derangements, and transcriptional regulation of the hypothalamic-pituitary-gonadal axis may all lead to DP. This variety of different pathogenic mechanisms affecting the release of the puberty 'brake' may take place in several age windows between fetal life and puberty.

Is there a causal relationship between obesity and puberty?

The onset of puberty in adolescents and whether it is related to obesity is an ongoing topic for debate. Epidemiological cross-sectional and longitudinal studies show a shift towards earlier onset of puberty in girls who are obese; however, the situation is less clear in boys. Boys who are overweight seem to mature earlier, and boys who are obese mature later, than boys at a healthy weight. The underlying mechanisms are not yet fully understood, and whether earlier onset of puberty in obese girls is based on the activation of the hypothalamic-pituitary-gonadal axis is unclear. The most promising link between obesity and puberty is the adipokine leptin and its interaction with the kisspeptin system, which is an important regulator of puberty. However, peripheral action of adipose tissue (eg, via other adipokines, aromatase activity) could also be involved in changes to the onset of puberty. In addition, nutritional factors, epigenetics, or endocrine disrupting chemicals are potential mediators linking the onset of puberty to obesity. This Review summarises our knowledge concerning the relationship between obesity and onset and tempo of puberty, and the consequences of early puberty on obesity.

Association of prepubertal obesity with pubertal development in Chinese girls and boys: A longitudinal study

OBJECTIVES

The purpose of this study was to examine the association of prepubertal body mass index (BMI) and weight status with pubertal development in boys and girls in Chongqing, China.

METHODS

In a longitudinal study, 1237 students (695 boys and 542 girls) were recruited from Chongqing, China, and examined at baseline, then followed every 6 months for three and a half years. Height, weight, testicular volume, and breast development were measured at every examination. Age of first spermatorrhea and menarche were obtained from self-report. Subjects were divided into normal weight, overweight, and obese groups according to baseline BMI. Multivariable Cox regression analysis was used to examine the association of BMI and weight status with pubertal development.

RESULTS

In girls, higher prepubertal BMI increased the chance of earlier menarche (hazards ratio (HR): 1.205, 95% confidence interval (95% CI): 1.151-2.261) and breast development (HR: 1.092, 95% CI: 1.045-1.142). Girls in the overweight (HR: 2.605, 95% CI: 1.716-3.956) and obese (HR: 2.565, 95% CI: 1.603-4.103) groups had an increased risk of early menarche compared with those in the normal weight group, while only overweight was associated with an increased risk for earlier breast development (HR: 1.469, 95% CI: 1.024-2.108). In boys, higher prepubertal BMI was significantly associated with the timing of first spermatorrhea (HR: 1.054, 95% CI: 1.004-1.106) and testicular development (HR: 1.098, 95% CI: 1.063-1.135). Overweight (HR: 1.672, 95% CI: 1.204-2.322) and obesity (HR: 1.598, 95% CI: 1.135-2.249) increased the hazard of earlier testicular development compared with the normal weight group, while no significant differences were detected among the three weight groups in terms of time to first spermatorrhea.

CONCLUSIONS

Higher prepubertal BMI was associated with earlier puberty in both Chinese boys and girls.

Overweight and lower age at menarche: evidence from the Italian HBSC cross-sectional survey

Background

A unique standardized national dataset on adolescent girls (21 regions) participating in the Italian Health Behaviour in School-aged Children Study (HBSC) was used to investigate the correlation between body mass index (BMI) and age at menarche.

Methods

Two independent nationally representative survey datasets: one on 15-year-olds (n = 6907, in 21 regions, year 2013/2014) and one on 11-year-olds (n = 10,128, in 20 regions, year 2009/2010) were analysed. The survey instrument was a self-report questionnaire. Median age at menarche and 95% confidence intervals (CIs) were estimated by means of Kaplan–Meier analysis. Hierarchical models were used to assess the relationship between BMI and age at menarche (months). “Region-level obesity” was measured as the prevalence of overweight/obesity (%) in each region.

Results

Region-level median age at menarche ranged between 12 years/3 months and 13 years/4 months. Region-level prevalence of overweight among 15-year-old girls ranged between 4 and 19%. Age at menarche was inversely associated with individual BMI (unstandardized regression coefficient beta = − 0.70; 95% CI, − 0.84 to − 0.56). Individual- and class-level measures of BMI accounted for 50% of the region-level variance in age at menarche.

Conclusions

The results show that overweight in childhood is in relation with the early puberty in girls. Future surveys may take into account this report to clarify if overweight is the cause or consequence of early menarche.

New perspectives on the definition and management of polycystic ovary syndrome

BACKGROUND

There is a growing debate on the opportunity of improving the understanding in the diagnosis and management of polycystic ovary syndrome (PCOS).

OBJECTIVE

This review article summarizes recent research related to the definition of polycystic ovary syndrome (PCOS).

METHODS

Review of the recent literature on the topic.

RESULTS

New ideas on the definition of hyperandrogenism, based on new scientific data and clinical perspectives are presented. (i) In fact, recent studies have pointed out the need to improve the concept of androgen excess by using a larger androgen profile, rather than simply measuring the testosterone blood levels. (ii) Due to the poor correlation between androgen blood levels and the degree of hirsutism, it is proposed that the definition of hyperandrogenism should be based on the presence of blood androgen excess and hirsutism, considered separately, because their pathophysiological mechanisms may differ according to the different phenotypes of PCOS. (iii) The potential role of obesity in favoring the development of PCOS during adolescence is also discussed and the concept of "PCOS secondary to obesity" is developed. (iv) Finally, the need for greater appropriateness in the evaluation of possible coexistence is highlighted, in patients with PCOS who have fasting or glucose-stimulated very high insulin levels, or severe insulin-resistant states.

CONCLUSIONS

Based on what was discussed in this review, we believe that there are margins for modifying some of the current criteria that define the various PCOS phenotypes.

Low digit ratio (2D:4D) and late pubertal onset indicate prenatal hyperandrogenziation in alcohol binge drinking

BACKGROUND

Alcohol binge drinking behavior is an important public health issue. Causal rodent and human associational studies show that reinforcement of prenatal androgen signaling increases alcohol consumption in adulthood. However, the effects of prenatal androgen exposure on adult binge drinking patterns have not been investigated yet.

METHOD

We analyzed data from 2225 participants of an online survey (conducted 06-07/2016) to evaluate biomarkers for prenatal androgen exposure (second-to-fourth finger length ratio [2D:4D], age at spermarche or menarche as hallmark for pubertal onset) in binge drinking (≥1 episode of 15+, 10+, and/or 5+ standard drinks of ~13 g of alcohol within 2 h during the 24 month- and 2 week-recall periods).

RESULTS

Men reported binge drinking more often than women (ORs > 1.4, P < .001). For the 24 month-recall period, binge drinkers showed lower 2D:4D (P = .006) and reported later pubertal onset (P = .022) than non-binge drinkers. These findings consistently suggest excess prenatal androgen exposure in adult binge drinkers. Moreover, 2D:4D was negatively associated with severity (15+/10+/5+/non-binge drinking, P = .005) and frequency of binge drinking episodes (P = .044). All of these effects were stronger in men than in women. For the 2 week-recall period, the biomarkers were not significantly related to binge drinking behavior.

CONCLUSION

Our results indicate that increased prenatal androgen exposure is involved in the development of alcohol binge drinking behavior in adults.

Self-assessment of pubertal development in a puberty cohort

Background We evaluated the inter-rater agreement between self-assessed Tanner staging and clinical examination and the intra-individual agreement of self-assessed information on various puberty markers in late adolescents from the longitudinal nationwide Puberty Cohort, a sub-cohort of the Danish National Birth Cohort (DNBC). Methods We invited 715 children from the ongoing Puberty Cohort between June 2016 and January 2017. In total, 366 children (51%) returned an add-on questionnaire identical to the questionnaire used to collect information on puberty markers, including Tanner staging, in the Puberty Cohort. Of these, 197 (54%) also participated in a clinical examination with Tanner staging. We used percentage agreement and weighted kappa statistics to evaluate the inter-rater and intra-individual agreement. Results Due to late entry, more than 75% of children were Tanner stage 4 or above at clinical examination. In girls, the inter-rater agreement for pubic hair and breast staging was 54% and 52%, respectively, yielding weighted kappas of fair strength. In boys, pubic hair and genital staging agreed in 55% and 33%, respectively, corresponding to weighted kappas of fair to moderate strength. Boys tended to underestimate genitalia staging consistently. The intra-individual agreement on Tanner staging was 75-77% in girls and 69% in boys, whereas the intra-individual agreement on axillary hair and acne was above 92%. Conclusions Self-assessment of late stages of pubertal development may be misclassified, leading to random errors in studies of puberty timing. However, self-assessment continues to serve as an important time- and cost-saving tool in large prospective puberty cohorts.

Body height and age at menarche of girls from eastern Poland in the period of political transformation

Biological state of a group of people or particular individuals in various phases of ontogenesis should be treated as a positive health measure. The aim of the study was to assess the directions of changes in body height and age at menarche of girls from eastern Poland in the years 1986-2016. The data regarding 30784 students aged 10-16 living in towns and villages of the eastern parts of such regions as Podkarpackie, Lubelskie, Podlaskie, Warminsko-mazurskie and, to a slight extent, Mazowieckie were used in the study. Body height was measured and information concerning the place of living and age at menarche (yes-no) was gathered during interviews. Acceleration of body height and age at menarche was observed in girls from the east of Poland in the period of political transformation and after European Union (EU) accession, while the level of secular trends was connected with the pace of changes in the environment. Biological effects of the EU preservation of Polish agriculture and particular care of the eastern provinces of Poland reduced developmental differences between these provinces and other regions of Poland. Moreover, in the analysed period of three decades (1986-2016), the disappearance of differences in body height and age at menarche between the inhabitants of rural and urban areas was noted, which indicates larger positive socio-economic changes in the countryside. In turn, greater body height was noted in non-menstruating girls compared to their menstruating counterparts. However, in subsequent observations, smaller differences between these groups were observed.

Maternal diabetes mellitus and timing of pubertal development in daughters and sons: a nationwide cohort study

OBJECTIVE

To study the association between maternal diabetes and timing of pubertal development in daughters and sons.

DESIGN

Prospective cohort study.

SETTING

Not applicable.

PATIENT(S)

A total of 15,822 mother-child pairs included in the Danish National Birth Cohort and the Puberty Cohort with prospectively collected, register-based and self-reported information on maternal diabetes and self-reported information on pubertal development.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Adjusted mean monthly difference in age at attaining pubertal milestones in children born of mothers with diabetes compared with children born of mothers without diabetes.

RESULT(S)

A total of 502 children were born of mothers with diabetes during pregnancy. In daughters exposed to gestational diabetes mellitus, we observed advanced onset in all pubertal milestones. The associations were statistically significant with regard to pubic hair Tanner stage 2 (-4.8 months) (95% confidence interval [CI] -7.7, -2.0), pubic hair Tanner stage 3 (-2.2 months) (95 % CI -4.4, 0.0), pubic hair Tanner stage 5 (-6.0 months) (95% CI -10.8, -1.2), and menarche (-2.5 months) (95 % CI -4.9, 0.0). We observed no tendencies between maternal type 1 or type 2 diabetes mellitus and pubertal development in daughters. We observed no associations between maternal diabetes and pubertal development in sons.

CONCLUSION(S)

Our findings suggest that gestational diabetes mellitus may accelerate the pubertal development in daughters. Our results did not support an association between type 1 or type 2 diabetes mellitus and daughters' pubertal development, as well as between any type of maternal diabetes and sons' pubertal development.

Evaluation of age-dependent morphometrics of the meniscofemoral ligaments in reference to the posterior cruciate ligament in routine MRI

OBJECTIVES

To quantify the morphological correlation between the posterior cruciate ligament (PCL) and the meniscofemoral ligaments (MFLs), to propose normal ranges for different age populations, and to define guidelines for correct identification and differentiation of MFLs in routine MRI.

METHODS

Three hundred forty-two subjects were included retrospectively and subdivided into five age groups. Morphometrics of the PCL and the MFLs were measured on standard MRI in the sagittal, coronal, and axial planes. Student's t test, Mann-Whitney U test, and ANOVA and Kruskal-Wallis tests with Bonferroni correction were used for comparison.

RESULTS

The MFLs did not vary significantly between sexes (p > 0.05) or in those older than 10 years (p > 0.05). Longitudinal MFL growth is completed before age 11 years, with cross-sectional area (CSA) increasing until age 20. The CSA of the PCL was significantly (p = 0.028) larger in knees without a pMFL (Mdn = 39.7 mm2) than with a pMFL (Mdn = 35.4 mm2). MFLs were more often detected on sagittal than coronal images.

CONCLUSIONS

This study describes the morphometric relation between the PCL and the MFLs on routine MRI. When reporting imaging findings in preparation for arthroscopic knee surgery, evaluation of MFLs, first in the sagittal and then the coronal plane, will achieve the best results.

KEY POINTS

• The MFLs and the PCL have distinct morphological patterns throughout life. • These patterns show intimate anatomical relationships and a potential biomechanical impact. • Those patterns and relationships can be quantified with MRI. • A correlation exists between age and morphometrics of the MFLs. • Recommendations for correct identification of the MFLs are provided.

The relative resistance of children to sepsis mortality: from pathways to drug candidates

Attempts to develop drugs that address sepsis based on leads developed in animal models have failed. We sought to identify leads based on human data by exploiting a natural experiment: the relative resistance of children to mortality from severe infections and sepsis. Using public datasets, we identified key differences in pathway activity (Pathprint) in blood transcriptome profiles of septic adults and children. To find drugs that could promote beneficial (child) pathways or inhibit harmful (adult) ones, we built an in silico pathway drug network (PDN) using expression correlation between drug, disease, and pathway gene signatures across 58,475 microarrays. Specific pathway clusters from children or adults were assessed for correlation with drug‐based signatures. Validation by literature curation and by direct testing in an endotoxemia model of murine sepsis of the most correlated drug candidates demonstrated that the Pathprint‐PDN methodology is more effective at generating positive drug leads than gene‐level methods (e.g., CMap). Pathway‐centric Pathprint‐PDN is a powerful new way to identify drug candidates for intervention against sepsis and provides direct insight into pathways that may determine survival.

Is age at menarche associated with total mortality? The Tromsø Study

Purpose

Early age at menarche (AAM) has been associated with increased mortality and morbidity, including premature death from all causes, breast cancer and cardiovascular diseases. The aim of this study was to examine the association between AAM and all-cause mortality.

Subjects and methods

A total of 12,409 women aged 25–94 years who took part in the fourth Tromsø Study in Norway during 1994–1995 were included in this prospective population-based study with a mean 18.7 years of follow-up. Multivariate Cox proportional hazard analysis was used to investigate the association between AAM and all-cause mortality with adjustment for known confounders (age, body mass index, physical activity, level of education and smoking history).

Results

During the 18.7 years of follow-up, a total of 2,203 women died. There was no association between AAM and all-cause mortality before or after adjusting for possible confounding factors.

Conclusion

This prospective study of 12,409 women did not find any association between AAM and all-cause mortality

Childhood and adolescent phenol and phthalate exposure and the age of menarche in Latina girls

BACKGROUND

The age of menarche has been associated with metabolic and cardiovascular disease, as well as cancer risk. The decline in menarcheal age over the past century may be partially attributable to increased exposure to endocrine disrupting chemicals (EDCs).

METHODS

We assessed the influence of 26 phenol and phthalate biomarkers on the timing of menarche in a longitudinal cohort of Chilean girls. These EDCs were quantified in urine collected prior to the onset of breast development (Tanner 1; B1), and during adolescence (Tanner 4; B4). Multivariable accelerated failure time (AFT) models were used to analyze associations between biomarker concentrations and the age of menarche adjusting for body mass index (BMI) Z-score and maternal education, accounting for within-subject correlation.

RESULTS

Several biomarkers were significantly associated with the age at menarche; however, these associations were dependent on the timing of biomarker assessment. A log(ng/ml) increase in B1 concentrations of di(2-ethylhexyl) phthalate biomarkers was associated with later menarche (hazard ratio (HR): 0.77; 95% CI: 0.60, 0.98), whereas higher B1 concentrations of 2,5-dichlorophenol and benzophenone-3 were associated with earlier menarche (HR: 1.13; 95% CI: 1.01, 1.27; HR: 1.17; 95% CI: 1.06, 1.29, respectively). Elevated B4 concentrations of monomethyl phthalate were similarly associated with earlier menarche (HR: 1.30; 95% CI: 1.10, 1.53). The impact of monoethyl phthalate and triclosan concentrations on pubertal timing were significantly modified by BMI Z-score. Higher monoethyl phthalate and triclosan concentrations were associated with earlier menarche among overweight or obese girls, but not among those that were normal weight.

CONCLUSIONS

This study identifies modulation of sexual maturation by specific EDC biomarkers in Latina girls.

Faster ticking rate of the epigenetic clock is associated with faster pubertal development in girls

Epigenetic age is an indicator of biological aging, capturing the impact of environmental and behavioral influences across time on cellular function. Deviance between epigenetic age and chronological age (AgeAccel) is a predictor of health. Pubertal timing has similarly been associated with cancer risk and mortality rate among females. We examined the association between AgeAccel and pubertal timing and adolescent breast composition in the longitudinal Growth and Obesity Cohort Study. AgeAccel was estimated in whole blood using the Horvath method at breast Tanner 2 (B2) and 4 (B4). Total breast volume, absolute fibro-glandular volume (FGV), and %FGV were evaluated at B4 using dual X-ray absorptiometry. The impact of AgeAccel (mean: 0; SD: 3.78) across puberty on the time to breast development (thelarche), menarche, and pubertal tempo (thelarche to menarche) was estimated using accelerated failure time models; generalized estimating equations were used to evaluate associations with breast density. A five-year increase in average adolescent AgeAccel was associated with a significant decrease in time to menarche [hazard ratio (HR): 1.37; 95% confidence interval (CI): 1.04, 1.80] adjusting for birth weight, maternal pre-pregnancy body mass index, maternal height, maternal education, B2 height, fat percentage, and cell composition. AgeAccel displayed a stronger inverse association with pubertal tempo (HR: 1.48; 95% CI: 1.10, 1.99). A five-year increase in AgeAccel was associated with 5% greater %FGV, adjusting for B4 percent body fat, and maternal traits (95% CI: 1.01, 1.10). Our study provides unique insight into the influence of AgeAccel on pubertal development in girls, which may have implications for adult health.

Contribution of the Endocrine Perspective in the Evaluation of Endocrine Disrupting Chemical Effects: The Case Study of Pubertal Timing

Debate makes science progress. In the field of endocrine disruption, endocrinology has brought up findings that substantiate a specific perspective on the definition of endocrine disrupting chemicals (EDCs), the role of the endocrine system and the endpoints of hormone and EDC actions among other issues. This paper aims at discussing the relevance of the endocrine perspective with regard to EDC effects on pubertal timing. Puberty involves particular sensitivity to environmental conditions. Reports about the advancing onset of puberty in several countries have led to the hypothesis that the increasing burden of EDCs could be an explanation. In fact, pubertal timing currently shows complex changes since advancement of some manifestations of puberty (e.g. breast development) and no change or delay of others (e.g. menarche, pubic hair development) can be observed. In a human setting with exposure to low doses of tenths or hundreds of chemicals since prenatal life, causation is most difficult to demonstrate and justifies a translational approach using animal models. Studies in rodents indicate an exquisite sensitivity of neuroendocrine endpoints to EDCs. Altogether, the data from both human and animal studies support the importance of concepts derived from endocrinology in the evaluation of EDC effects on puberty.

Modified Maturity Offset Prediction Equations: Validation in Independent Longitudinal Samples of Boys and Girls

BACKGROUND

Predicted maturity offset and age at peak height velocity are increasingly used with youth athletes, although validation studies of the equations indicated major limitations. The equations have since been modified and simplified.

OBJECTIVE

The objective of this study was to validate the new maturity offset prediction equations in independent longitudinal samples of boys and girls.

METHODS

Two new equations for boys with chronological age and sitting height and chronological age and stature as predictors, and one equation for girls with chronological age and stature as predictors were evaluated in serial data from the Wrocław Growth Study, 193 boys (aged 8-18 years) and 198 girls (aged 8-16 years). Observed age at peak height velocity for each youth was estimated with the Preece-Baines Model 1. The original prediction equations were included for comparison. Predicted age at peak height velocity was the difference between chronological age at prediction and maturity offset.

RESULTS

Predicted ages at peak height velocity with the new equations approximated observed ages at peak height velocity in average maturing boys near the time of peak height velocity; a corresponding window for average maturing girls was not apparent. Compared with observed age at peak height velocity, predicted ages at peak height velocity with the new and original equations were consistently later in early maturing youth and earlier in late maturing youth of both sexes. Predicted ages at peak height velocity with the new equations had reduced variation compared with the original equations and especially observed ages at peak height velocity. Intra-individual variation in predicted ages at peak height velocity with all equations was considerable.

CONCLUSION

The new equations are useful for average maturing boys close to the time of peak height velocity; there does not appear to be a clear window for average maturing girls. The new and original equations have major limitations with early and late maturing boys and girls.

Secular Trends on Birth Parameters, Growth, and Pubertal Timing in Girls with Turner Syndrome

BACKGROUND

Whether children with chromosomal disorders of growth and puberty are affected by secular trends (STs) as observed in the general population remains unanswered, but this question has relevance for expectations of spontaneous development and treatment responses.

OBJECTIVES

The aim of the study was to evaluate STs in birth parameters, growth, and pubertal development in girls with Turner syndrome (TS).

STUDY DESIGN

Retrospective analysis of KIGS data (Pfizer International Growth Database). We included all TS patients who entered KIGS between 1987 and 2012 and were born from 1975 to 2004, who were prepubertal and growth treatment naïve at first entry (total number: 7,219). Pretreatment height and ages at the start of treatment were compared across 5-year birth year groups, with subgroup analyses stratified by induced or spontaneous puberty start.

RESULTS

We observed significant STs across the birth year groups for birth weight [+0.18 SD score (SDS), p < 0.001], pretreatment height at mean age 8 years (+0.73 SDS, p < 0.001), height at the start of growth hormone (GH) therapy (+0.38 SDS, p < 0.001) and start of puberty (+0.42 SDS, p < 0.001). Spontaneous puberty onset increased from 15 to 30% (p < 0.001). Mean age at the start of GH treatment decreased from 10.8 to 7.4 years (-3.4 years; p < 0.001), and substantial declines were seen in ages at onset of spontaneous and induced puberty (-2.0 years; p < 0.001) and menarche (-2.1 years; p < 0.001).

CONCLUSION

Environmental changes leading to increased height and earlier and also more common, spontaneous puberty are applicable in TS as in normal girls. In addition, greater awareness for TS may underlie trends to earlier start of GH therapy and induction of puberty at a more physiological age.

Association between Small Fetuses and Puberty Timing: A Systematic Review and Meta-Analysis

Background: Epidemiological studies reporting the effect of small fetuses (SF) on puberty development have shown inconsistent results. Objective: To examine current study evidence and determine the strength and direction of the association between SF and puberty timing. Methods: PubMed, OVID, Web of Science, EBSCO, and four Chinese databases were searched from their date of inception to February 2016. All cohort studies that examined the association between SF and puberty timing in children were identified. Two reviewers independently screened the studies, assessed the quality of included studies, and extracted the data. The quality of the included cohort studies was assessed by the Newcastle-Ottawa Scale. Risk ratio (RR), Weighted Mean Difference (WMD), and 95% confidence intervals (CIs) were calculated and pooled by RevMan5.3 (Cochrane Collaboration, London, UK). Results: A total of 10 cohort studies involving 2366 subjects was included in the final analysis. The pooled estimates showed that SF did not significantly increase the number of pubertal children in boys (RR: 0.97; 95% CI: 0.82 to 1.15), or in girls (RR: 0.91; 95% CI: 0.79 to 1.04). Compared with the control group, the SF group had an earlier onset of puberty in girls (WMD: -0.64; 95% CI: -1.21 to -0.06), and in precocious pubarche (PP) girls (WMD: -0.10; 95% CI: -0.13 to -0.07). There was no difference in the onset of puberty in boys (WMD: -0.48; 95% CI: -1.45 to 0.50) between SF and control groups. The pooled result indicated an earlier age at menarche in girls born small for gestational age (WMD: -0.30; 95% CI: -0.58 to -0.03), but no difference in the age at menarche in the SF group of PP girls. Conclusions: SF may be associated with an earlier age of onset of puberty, especially among girls, as well as earlier age at menarche for girls. Well-designed studies with larger sample sizes and long-term follow-up among different countries and ethnicities are needed.

Early menarche and risk-taking behavior in Korean adolescent students

INTRODUCTION

The aim of this study is to assess the correlation between early menarche and risk-taking behavior in a representative sample of Korean adolescent students.

METHODS

Data were drawn from a cross-sectional, nationally representative sample of 33 829 female adolescents (grades 7-12) from the 2014 Korean Youth Risk Behavior Web-based Survey. Logistic regression analysis was conducted to test the association between early menarche and risk-taking behavior.

RESULTS

Female adolescents who experienced menarche at an earlier age tended to have an earlier initiation of sexual intercourse (odds ratio [OR] 4.61, 95% CI, 3.05-6.98, P = .001), smoking (OR 4.29, 95% CI, 3.75-4.9, P < .001), alcohol drinking (OR 1.13, 95% CI, 1.02-1.24, P < .001), and substance use (OR 25.16, 95% CI, 18.78-33.72, P < .001). These adolescents were also at greater risk of pregnancy (OR 4.05, 95% CI, 2.56-6.41, P = .01) and sexually transmitted diseases (OR 2.35, 95% CI, 1.66-3.33, P < .001).

DISCUSSION

Early menarche is significantly associated with risk-taking behavior in Korean adolescent students. This finding suggests that early educational intervention and social programs are needed for female adolescents with early menarche.

Timing of menarche in Norwegian girls: associations with body mass index, waist circumference and skinfold thickness

Background

Research studies show conflicting results regarding the association between menarche and body weight. The purpose of the present study was to investigate if anthropometric indicators of body composition, body mass index (BMI), waist circumference (WC), triceps (TSF) and subscapular skinfold (SSF) thicknesses, were differentially associated with age at menarche in Norwegian girls.

Methods

The association between menarche and BMI, WC, TSF and SSF was investigated in 1481 girls aged 8–15.5 years, and in a subgroup of 181 girls with menarche during the 12 months prior to examination. Anthropometric measures were categorized as low (< −1SDS), average (−1 ≤ SDS ≤ +1) or high (> 1SDS), and menarche according to this classification was analysed with Kaplan-Meier curves and unadjusted and adjusted Cox regression.

Results

The median age at menarche in the total sample was 13.1 years. In the unadjusted models, low categories of all traits were associated with later menarche, and high categories with earlier menarche. When adjusted for other covariates, earlier menarche was only related with a high BMI (Hazard Ratio 1.41, 95% confidence interval (CI) 1.07, 1.85), and later menarche with a low BMI (HR 0.53, 95%CI 0.38, 0.75) and low SSF (HR 0.54, 95%CI 0.39, 0.75). In girls with recent menarche, early menarche was significantly associated with a high BMI in the final model (HR 1.79, 95%CI 1.23, 2.62).

Conclusions

The timing of menarche was associated with the BMI, WC, TSF and SSF, but more strongly so with the BMI. These associations may be related to a common tempo of growth, as the mean age at menarche has remained stable during the last decades during a time period while the prevalence of overweight and obesity has increased significantly.

Age at menarche and its socioeconomic determinants among female students in an urban area in Bangladesh

This cross-sectional study aimed to determine the age at menarche and its socioeconomic determinants among urban female students (n=680) in Bangladesh. The mean age of the respondents was 14±1.43years. Majority of the respondents were unmarried (98.4%). The mean age at menarche was 11.6±3.6years, median 12years. Almost one-third (35.7%) of the participants had menarche at the age of 12years. There was no statistically significant difference between age at menarche before and after 12years with the socio-economic characteristics, except education (p=<0.001). In the multivariate model, only higher education was statistically significant predictor of age at menarche.

Older age at the completion of linear growth is associated with an increased risk of adult glioma

PURPOSE

To examine the association of age when adult height was attained with glioma risk.

METHODS

We analyzed data from a US-based case-control study of glioma risk factors. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) associated between age at attainment of adult height and glioma risk. Multivariate models were adjusted for age, race, sex, education, and state of residence. We examined associations overall, and according to glioma grade, sex, and final adult height.

RESULTS

The study set included n = 951 controls and n = 776 cases, with a median age of 56 (18-92); the majority was male (53.8%) and identified as Caucasian. Older age at height completion was associated with an increased risk of glioma. A significant positive trend was observed both for glioblastoma (OR 1.10; 95% CI 1.04-1.17 per 1-year increase in age) and lower grade non-glioblastoma subtypes combined (OR 1.18; 95% CI 1.10-1.28 per year increase in age). The association was observed in men and women, and in all categories of final adult height.

CONCLUSIONS

We observed for the first time a positive association between glioma risk and a prolonged adolescent growth phase. Our results suggest a role for factors governing the timing and intensity of growth in adolescence as risk-determining exposures in adult glioma.

Invited Commentary: An Ingenious Approach to Examining the Relationship Between Maternal Stress and Offspring Health?

The potentially deleterious effects on offspring health of excess maternal stress in pregnancy are important to understand-both whether observed associations are causal and through what mechanisms their effects may exert an influence. In this issue of the Journal, Räikkönen et al. (Am J Epidemiol. 2012;000(0):000-000) provide an ingenious test of a potential pathway through which maternal stress may influence offspring development. Licorice consumption is known to disrupt the ability of the placental enzyme 11β-hydroxysteroid dehydrogenase type 2 to inactivate cortisol before it reaches the fetus, leading to higher levels of cortisol exposure. Higher levels of cortisol exposure are also hypothesized to underlie the mechanism through which maternal stress may disrupt fetal development. Thus licorice consumption may serve, in some ways, to mimic maternal stress. The authors report associations between heavy licorice consumption during pregnancy and a wide range of offspring outcomes, including changes in pubertal timing, intelligence quotient, and mental health. In our view, these results should be considered preliminary; more work needs to be completed to determine the relationship of prenatal licorice consumption to these outcomes. Nonetheless, these intriguing and suggestive results demonstrate that this line of work should be given high priority, and they set the stage for additional research moving forward.

Exercise and Sports Medicine Issues in Underserved Populations

Primary care providers can make a strong argument for exercise promotion in underserved communities. The benefits are vitally important in adolescent physical, cognitive, and psychological development as well as in adult disease prevention and treatment. In counseling such patients, we should take into account a patient's readiness for change and the barriers to exercise.

Earlier age at menarche in girls with rapid early life growth: cohort and within sibling analyses

PURPOSE

The purpose of the article was to examine the association of early life growth with age at menarche.

METHODS

Using data from a prospective birth cohort (n = 1134 women, 290 sibling sets), we assessed the association between postnatal growth at 4 months, 1 year, and 4 years and age at menarche, using generalized estimating equations and generalized linear random effects models.

RESULTS

Overall, 18% of the cohort experienced early menarche (<12 years). After accounting for postnatal growth in length, faster postnatal change in weight (per 10-percentile increase) in all three periods was associated with an increase (range 9%-20%) in the likelihood of having an early menarche. In adjusted linear models, faster weight gains in infancy and childhood were associated with an average age at menarche that was 1.1-1.3 months earlier compared with stable growth. The overall results were consistent for percentile and conditional growth models. Girls who experienced rapid growth (defined as increasing across two major Centers for Disease Control and Prevention growth percentiles) in early infancy had an average age at menarche that was 4.6 months earlier than girls whose growth was stable.

CONCLUSIONS

Faster postnatal weight gains in infancy and early childhood before the age of 4 years are associated with earlier age at menarche.

Age at menarche predicts age at onset of major affective and anxiety disorders

BACKGROUND

Menarche age has been associated inconsistently with the occurrence, timing or severity of major depressive disorder (MDD), but rarely studied in women with bipolar (BDs) or anxiety disorders.

METHODS

We investigated women patients at a Sardinian mood disorder center for associations of age at menarche with age at illness onset for major affective or anxiety disorders, year of birth, and other selected factors, using bivariate comparisons and multivariate regression modeling.

RESULTS

Among women (n=1139) with DSM-IV MDD (n=557), BD-I (n=223), BD-II (n=178), or anxiety disorders (n=181), born in 1904-1998, of mean age 42.9 years, menarche age averaged 12.8 [CI: 12.7-12.9] years. Illness onset age averaged 30.9 [30.1-31.8] years, ranking: BD-I, 25.8; anxiety disorders, 28.0; BD-II, 30.3; MDD, 34.1 years. Menarche age declined secularly over birth years, and was associated with younger illness-onset, having no or fewer siblings, more psychiatrically ill first-degree relatives, living in rural environments, being suicidal, substance abuse, and being unemployed. Earlier menarche and earlier illness-onset were significantly associated for onset age groups of ≤ 20, 20-39, and > 40 years. Menarche age versus diagnosis ranked: BD-II<BD-I<anxiety disorders<MDD.

CONCLUSIONS

Age at menarche in Sardinia, as elsewhere, has declined over the past decades. It was strongly associated with age at onset of bipolar and anxiety, as well as major depressive disorders across the age range, suggesting sustained effects of biological maturational factors.

Biological maturation of youth athletes: assessment and implications

The search for talent is pervasive in youth sports. Selection/exclusion in many sports follows a maturity-related gradient largely during the interval of puberty and growth spurt. As such, there is emphasis on methods for assessing maturation. Commonly used methods for assessing status (skeletal age, secondary sex characteristics) and estimating timing (ages at peak height velocity (PHV) and menarche) in youth athletes and two relatively recent anthropometric (non-invasive) methods (status-percentage of predicted near adult height attained at observation, timing-predicted maturity offset/age at PHV) are described and evaluated. The latter methods need further validation with athletes. Currently available data on the maturity status and timing of youth athletes are subsequently summarised. Selection for sport and potential maturity-related correlates are then discussed in the context of talent development and associated models. Talent development from novice to elite is superimposed on a constantly changing base-the processes of physical growth, biological maturation and behavioural development, which occur simultaneously and interact with each other. The processes which are highly individualised also interact with the demands of a sport per se and with involved adults (coaches, trainers, administrators, parents/guardians).

Decline in menarcheal age among Saudi girls

Objectives:

To estimate age at menarche and to assess trends in menarcheal age among Saudi women.

Methods:

A prospective longitudinal study was conducted among healthy prepubertal female school children and adolescents from September 2006 to July 2012 in Riyadh, Kingdom of Saudi Arabia. Study participants were invited from diverse socioeconomic backgrounds. Tanner stage, height, weight, body mass index, and socioeconomic parameters including parent’s level of education were collected. Age at menarche was compared with maternal age at menarche.

Results:

The study included 265 girls and mothers. Mean±standard deviation (SD) age at menarche for girls was 13.08 ± 1.1 years, and their distribution category across the ≤10 years was 4 (1.5%), 11-14 years was 239 (90.2%), and ≥15 years was 22 (8.3%) girls. Anthropometric measurements, mother’s level of education, and family income were not statistically significant determining factors associated with age at menarche. Mean ± SD age at menarche for mothers was 13.67 ± 1.4 years, and their distribution category across the ≤10 years was 7 (2.6%), 11-14 years was 172 (64.9%), and ≥15 years was 86 (32.5%). Girls attained menarche at younger age compared with their mothers (p<0.0001). A downward secular trend in age of menarche was observed (Cuzick test for trend = 0.049).

Conclusion:

Saudi girls attain menarcheal age earlier than their mothers, reflecting a downward secular trend in menarcheal age.

Toward a multi-country monitoring system of reproductive health in the context of endocrine disrupting chemical exposure

BACKGROUND

Worrying trends regarding human reproductive endpoints (e.g. semen quality, reproductive cancers) have been reported and there is growing circumstantial evidence for a possible causal link between these trends and exposure to endocrine disrupting chemicals (EDCs). However, there is a striking lack of human data to fill the current knowledge gaps. To answer the crucial questions raised on human reproductive health, there is an urgent need for a reproductive surveillance system to be shared across countries.

METHODS

A multidisciplinary network named HUman Reproductive health and Global ENvironment Network (HURGENT) was created aiming at designing a European monitoring system for reproductive health indicators. Collaborative work allowed setting up the available knowledge to design such a system. Furthermore we conducted an overview of 23 potential indicators, based upon a weight of evidence (WoE) approach according to their potential relation with EDC exposure.

RESULTS

The framework and purposes of the surveillance system are settled as well as the approach to select suitable reproductive indicators. The indicators found with the highest scores according to the WoE approach are prostate and breast cancer incidence, sex ratio, endometriosis and uterine fibroid incidence, indicators related to the testicular dysgenesis syndrome, precocious puberty incidence and reproductive hormone levels.

CONCLUSION

Not only sentinel health endpoints, but also diseases with high burdens in public health are highlighted as prior indicators in the context of EDC exposure. Our work can serve as a basis to construct, as soon as possible, the first multi-country reproductive monitoring system.

Childhood Passive Smoking Exposure and Age at Menarche in Chinese Women Who Had Never Smoked: The Guangzhou Biobank Cohort Study

OBJECTIVE

We examined the associations between childhood passive smoking exposure and age at menarche in women who had never smoked in southern China.

METHODS

Among 30,518 participants in Guangzhou Biobank Cohort Study (GBCS) from 2003-2008, 20,061 women who had never smoked and had complete outcome data were included. Childhood passive smoking exposure was defined as living with 1 or more smokers in the same household during childhood. Data on the number of smokers in the household and frequency of exposure (density and frequency) were also obtained. Age at menarche was measured as a continuous variable.

RESULTS

11,379 (56.7%) participants were exposed to passive smoking during childhood. Compared to those with no passive smoking exposure during childhood, those with exposure ≥ 5 days/week had menarche 0.19 year (95% confidence interval (CI): 0.13-0.25) earlier on average. Those exposed to more than two smokers had menarche 0.38 year earlier (95% CI: 0.29-0.47). Childhood exposure was associated with early age at menarche (≤ 13 vs. >13 years), with an adjusted odds ratio of 1.34 (95% CI: 1.21-1.48) for high density, and 1.17 (95% CI: 1.09-1.26) for high frequency of exposure.

CONCLUSION

Childhood passive smoking exposure was associated with earlier age at menarche, with a dose-response relationship in Chinese women who had never smoked. If causal, the results support the promotion of smoking cessation in families with children, particularly young girls.

Developmental variations in environmental influences including endocrine disruptors on pubertal timing and neuroendocrine control: Revision of human observations and mechanistic insight from rodents

Puberty presents remarkable individual differences in timing reaching over 5 years in humans. We put emphasis on the two edges of the age distribution of pubertal signs in humans and point to an extended distribution towards earliness for initial pubertal stages and towards lateness for final pubertal stages. Such distortion of distribution is a recent phenomenon. This suggests changing environmental influences including the possible role of nutrition, stress and endocrine disruptors. Our ability to assess neuroendocrine effects and mechanisms is very limited in humans. Using the rodent as a model, we examine the impact of environmental factors on the individual variations in pubertal timing and the possible underlying mechanisms. The capacity of environmental factors to shape functioning of the neuroendocrine system is thought to be maximal during fetal and early postnatal life and possibly less important when approaching the time of onset of puberty.

Puberty in a sample of Brazilian schoolgirls: timing and anthropometric characteristics

OBJECTIVE

The objective of this study was to determine the age at which puberty begins, age of menarche and anthropometric data of the participants at different stages of puberty.

SUBJECTS AND METHODS

This is a cross-sectional study in which we evaluated 665 girls, a sample representing the female schoolchildren population in Uberaba.

RESULTS

We found that thelarche, pubarche, underarm hair and menarche were attained at the age of 9.8 ± 1.4, 10.2 ± 1.4, 10.5 ± 1.5 and 11.7 ± 1.3 years, respectively. The mean interval between thelarche and menarche (ITM) was 1.7 ± 1.3 years. The prevalence of overweight and obesity was 31.3% and 95% of the participants began at thelarche between the age of 7 and 12 years.

CONCLUSION

These values indicate a secular tendency to the decrease of the age of menarche and an earlier start of puberty. It is very important to understand these parameters to establish public policies aimed at plans to prevent these early events, especially regarding control of the prevalence of obesity.