Early puberty: rapid progression and reduced final height in girls with low birth weight

Diagnosis of Central Precocious Puberty

A thorough history and physical examination including Tanner staging and growth assessments can guide differential diagnosis and aid in the evaluation of precocious puberty. Basal luteinizing hormone levels measured using a highly sensitive assay can be helpful in diagnosing central precocious puberty (CPP). Brain MRI is indicated with males diagnosed with CPP and females under the age of 6 with CPP. As more information becomes available regarding the genetic etiologies of CPP, genetic testing may preclude the need for imaging studies and other hormonal testing, especially in familial cases.

The effects of gonadotropin-releasing hormone agonist on final adult height among girls with early and fast puberty

Introduction

This study aimed to explore the impact of gonadotropin-releasing hormone agonists (GnRHa) on final adult height (FAH) in girls with early and fast puberty.

Methods

A retrospective study was conducted by reviewing data from the medical records of the Pediatric Endocrinology Clinics between January 1, 2010, and December 31, 2020, at MacKay Children's Hospital. The treatment group included 109 patients who received 3.75 mg monthly for at least 1 year, whereas the control group consisted of 95 girls who received no treatment.

Results

The treatment group was significantly older at the time of inclusion(chronological age (CA1), treatment vs. control, 8.7 vs. 8.4 years, p < 0.001), had a more advanced bone age (BA) (BA1, 11.5 vs. 10.8 years, p < 0.001), BA1-CA1 (2.7 vs. 2.2 years, p < 0.001), and shorter predicted adult height (PAH1) (153.3 vs. 157.1 cm, p = 0.005) that was significantly lower than their target height (Tht)(PAH1-Tht, -3.9 vs. -1.3 cm, p = 0.039). The FAHs of the GnRHa and the control group were similar (157.0 vs. 156.7 cm, p = 0.357) and were not significantly different from their Tht (FAH vs. Tht in the GnRHa group, 157.0 vs. 157.0 cm; control group, 156.7 vs. 157.0 cm). In the subgroup analysis, FAH was significantly higher after GnRHa treatment in those with PAH1 less than 153 cm and Tht (154.0 vs. 152.0 cm, p = 0.041), and those whose CA1 was between 8 and 9 years (158.0 vs. 155.4 cm, p = 0.004). We defined satisfactory FAH outcome as FAH-PAH1≥5 cm and significant factors were GnRHa therapy, PAH1 shorter than their Tht, age younger than 9 years, and faster growth velocity during the first year.

Discussion

GnRHa is effective in restoring the Tht in some early and fast pubertal girls, especially in those with poorly PAH (PAH lower than 153 cm and shorter than their target height). A younger age at initiation of treatment and a faster growth velocity during treatment are associated with a better height gain.

Growth in Infancy and Childhood and Age at Menarche in Five Low- or Middle-Income Countries: Consortium of Health Orientated Research in Transitional Societies (COHORTS)

BACKGROUND

Earlier age at menarche is associated with behavioral and noncommunicable disease risks. The influence of birth weight (BW) (intrauterine) and postnatal growth on age at menarche is not well studied in low- and middle-income countries (LMICs).

OBJECTIVE

Therefore, we investigated these associations in 5 LMIC birth cohorts.

METHODS

We analyzed data from Brazil, Guatemala, India, the Philippines, and South Africa (n = 3983). We derived stunting (< -2 SD scores) at 24 mo using the WHO child growth standards. We generated interaction terms with categorized BW and conditional weight (lighter < 0 or heavier ≥ 0), and height (shorter < 0 or taller ≥ 0) z-scores. We categorized early-, modal-, and late-onset menarche and used multilevel ordinal regression. We used multilevel linear regression on continuous age at menarche.

RESULTS

Mean age at menarche was 12.8 y (95% CI: 12.7 12.9). BW was not associated with age at menarche. Conditional height at 24 mo and mid-childhood (OR: 1.35; 95% CI: 1.27, 1.44 and 1.32; 1.25, 1.41, respectively) and conditional weight at 24 mo and mid-childhood (OR: 1.15; 1.08, 1.22 and 1.18; 1.11, 1.25, respectively) were associated with increased likelihood of early-onset menarche. Being heavier at birth and taller at 24 mo was associated with a 4-mo (95% CI: 0.8, 7.6) earlier age at menarche than being lighter at birth and shorter at 24 mo. Being heavier at birth but lighter in mid-childhood was associated with a 3-mo (95% CI: 0.8, 4.8) later age at menarche than being lighter at birth and mid-childhood. Age at menarche was 7 mo later in stunted than nonstunted girls.

CONCLUSION

Age at menarche is inversely related to relative weight gain but also to rapid linear growth among those born shorter but remained stunted, and those born taller and grew excessively. These findings do not deter the global health goal to reduce growth faltering but emphasize the potential adverse effects of an obesogenic environment on adolescent development.

A systematic review on maternal and perinatal factors influencing breast development

BACKGROUND

A secular trend towards earlier age at menarche has been reported, but the trend in breast development is less clear. We reviewed the evidence on the relationship between in utero and early life events and breast onset/development.

METHODS

Eligible studies were identified in PubMed and Embase databases. We selected studies in which female human exposure during fetal or the first years of life was measured or estimated, and associations with breast onset or development were evaluated.

RESULTS

Of the 49 cohort studies and 5 cross-sectional studies identified, 43 provided sufficient data to assess associations. High maternal weight, primiparity, and early weight gain, were related to an increased risk of early breast onset/development in most of the studies that analysed these associations, whereas late breast onset/development was associated with preterm birth. Results were inconsistent for smoking in pregnancy, maternal hypertensive disorders, breastfeeding, diabetes, and small for gestational age. No association emerged for maternal age at delivery, alcohol drinking, and selected drug use during pregnancy, and low birth weight.

CONCLUSIONS

The results of this review show that high maternal weight, primiparity and early weight gain were associated with an increased risk of early breast onset/development. Late breast onset/development was associated with preterm birth. Breast development is a key physical marker of puberty onset, and early puberty development is linked to consequences that can reverberate throughout life. Answering the questions about the interconnections between pre/postnatal environmental exposures and their impact on puberty, represents an important area of multidisciplinary research.

Birth weight and maternal energy status during pregnancy as predictors of epigenetic age acceleration in young adults from metropolitan Cebu, Philippines

Epigenetic clocks quantify regular changes in DNA methylation that occur with age, or in relation to biomarkers of ageing, and are strong predictors of morbidity and mortality. Here, we assess whether measures of fetal nutrition and growth that predict adult chronic disease also predict accelerated biological ageing in young adulthood using a suite of commonly used epigenetic clocks. Data come from the Cebu Longitudinal Health and Nutrition Survey (CLHNS), a long-running cohort followed since birth in metropolitan Cebu, Philippines. Past work has shown that birth weight (BW) and the mother's arm fat during pregnancy (a measure of pregnancy energy status) relate inversely to health outcomes in the CLHNS but primarily in males. Genome-wide DNA methylation was assessed in whole blood using the Infinium EPIC array. Participants included males (n=895) and females (n=803) measured in 2005 (20.8-22.5 years). Clocks included the Hannum and Horvath clocks trained on chronological age, the DNAmPhenoAge and DNAmGrimAge clocks trained on clinical biomarkers, the Dunedin pace of ageing (DunedinPACE) clock trained on longitudinal changes in ageing biomarkers, and the DNAmTL clock trained on leukocyte telomere length. In males, lower BW predicted advanced biological ageing using the Hannum, DNAmPhenoAge, DunedinPoAm, and DNAmTL clocks. In contrast, BW did not predict any clock in female participants. Participants' mothers' pregnancy arm fat only predicted DNAmTL in males. These findings suggest that epigenetic clocks are a useful tool for gauging long-term outcomes predicted by fetal growth, and add to existing evidence in the CLHNS for sex differences in these relationships.

Timing of Puberty, Pubertal Growth, and Adult Height in Short Children Born Small for Gestational Age Treated With Growth Hormone

CONTEXT

Growth hormone (GH) is used to treat short children born small for gestational age (SGA); however, the effects of treatment on pubertal timing and adult height are rarely studied.

OBJECTIVE

To evaluate adult height and peak height velocity in short GH-treated SGA children.

METHODS

Prospective longitudinal multicenter study. Participants were short children born SGA treated with GH therapy (n = 102). Adult height was reported in 47 children. A reference cohort of Danish children was used. Main outcome measures were adult height, peak height velocity, age at peak height, and pubertal onset. Pubertal onset was converted to SD score (SDS) using Danish reference data.

RESULTS

Gain in height SDS from start of treatment until adult height was significant in both girls (0.94 [0.75; 1.53] SDS, P = .02) and boys (1.57 [1.13; 2.15] SDS, P < .001). No difference in adult height between GH dosage groups was observed. Peak height velocity was lower than a reference cohort for girls (6.5 [5.9; 7.6] cm/year vs 7.9 [7.4; 8.5] cm/year, P < .001) and boys (9.5 [8.4; 10.7] cm/year vs 10.1 [9.7; 10.7] cm/year, P = .002), but no difference in age at peak height velocity was seen. Puberty onset was earlier in SGA boys than a reference cohort (1.06 [-0.03; 1.96] SDS vs 0 SDS, P = .002) but not in girls (0.38 [-0.19; 1.05] SDS vs 0 SDS, P = .18).

CONCLUSION

GH treatment improved adult height. Peak height velocity was reduced, but age at peak height velocity did not differ compared with the reference cohort. SGA boys had an earlier pubertal onset compared with the reference cohort.

Early programming of reproductive health and fertility: novel neuroendocrine mechanisms and implications in reproductive medicine

BACKGROUND

According to the Developmental Origins of Health and Disease (DOHaD) hypothesis, environmental changes taking place during early maturational periods may alter normal development and predispose to the occurrence of diverse pathologies later in life. Indeed, adverse conditions during these critical developmental windows of high plasticity have been reported to alter the offspring developmental trajectory, causing permanent functional and structural perturbations that in the long term may enhance disease susceptibility. However, while solid evidence has documented that fluctuations in environmental factors, ranging from nutrient availability to chemicals, in early developmental stages (including the peri-conceptional period) have discernible programming effects that increase vulnerability to develop metabolic perturbations, the impact and eventual mechanisms involved, of such developmental alterations on the reproductive phenotype of offspring have received less attention.

OBJECTIVE AND RATIONALE

This review will summarize recent advances in basic and clinical research that support the concept of DOHaD in the context of the impact of nutritional and hormonal perturbations, occurring during the periconceptional, fetal and early postnatal stages, on different aspects of reproductive function in both sexes. Special emphasis will be given to the effects of early nutritional stress on the timing of puberty and adult gonadotropic function, and to address the underlying neuroendocrine pathways, with particular attention to involvement of the Kiss1 system in these reproductive perturbations. The implications of such phenomena in terms of reproductive medicine will also be considered.

SEARCH METHODS

A comprehensive MEDLINE search, using PubMed as main interface, of research articles and reviews, published mainly between 2006 and 2021, has been carried out. Search was implemented using multiple terms, focusing on clinical and preclinical data from DOHaD studies, addressing periconceptional, gestational and perinatal programming of reproduction. Selected studies addressing early programming of metabolic function have also been considered, when relevant.

OUTCOMES

A solid body of evidence, from clinical and preclinical studies, has documented the impact of nutritional and hormonal fluctuations during the periconceptional, prenatal and early postnatal periods on pubertal maturation, as well as adult gonadotropic function and fertility. Furthermore, exposure to environmental chemicals, such as bisphenol A, and maternal stress has been shown to negatively influence pubertal development and gonadotropic function in adulthood. The underlying neuroendocrine pathways and mechanisms involved have been also addressed, mainly by preclinical studies, which have identified an, as yet incomplete, array of molecular and neurohormonal effectors. These include, prominently, epigenetic regulatory mechanisms and the hypothalamic Kiss1 system, which likely contribute to the generation of reproductive alterations in conditions of early nutritional and/or metabolic stress. In addition to the Kiss1 system, other major hypothalamic regulators of GnRH neurosecretion, such as γ-aminobutyric acid and glutamate, may be targets of developmental programming.

WIDER IMPLICATIONS

This review addresses an underdeveloped area of reproductive biology and medicine that may help to improve our understanding of human reproductive disorders and stresses the importance, and eventual pathogenic impact, of early determinants of puberty, adult reproductive function and fertility.

Early and precocious puberty during the COVID-19 pandemic

During the year 2020, the COVID-19 pandemic rapidly became a severe health emergency worldwide. In order to contrast the spread of the novel SARS-CoV-2, many countries implemented extraordinary restrictive measures, such as a strict lockdown and school closures. The pandemic had a great impact on children and adolescents' daily life, leading to a much more sedentary lifestyle, to larger use of electronic devices and to an increase in stress-related symptoms. These conspicuous changes acted as disruptors of children's normal development. Since the beginning of the pandemic, many studies reported an increase in the number of precocious puberty cases as well as a faster progression rate of puberty itself, if compared to the pre-pandemic years. In this review, our aim was to evaluate the incidence of new cases of early and precocious puberty during the COVID-19 pandemic, analyzing variations in the timing of puberty and in pubertal progression rate, and to investigate the role of environmental and lifestyle factors during the pandemic in modulating the physiopathology of pubertal development. While a direct effect of SARS-CoV-2 infection remains, at the moment, a remote hypothesis, both physical and psychological factors related to the pandemic seem to have a role in triggering GnRH pulsatile secretion leading to earlier pubertal onset. It is indeed important to stress the need to clarify the exact role of COVID-19 in early pubertal onset comparing data from all over the world; long-term comprehensive studies are also pivotal to explain whether this phenomenon will continue while we resume pre-pandemic habits.

Could maternal thyroid function during pregnancy affect daughters' age at menarche through child growth? A mediation analysis

Early menarche is associated with adverse health outcomes during adolescence as well as breast and other reproductive cancers later in adulthood. However, the causes of early menarche and the pathways through which they operate are not fully understood. Though maternal thyroid function during pregnancy affects child growth, and rapid childhood growth is associated with a decreased age at menarche, the relationship between prenatal maternal thyroid function and daughters' age at menarche has not been examined. We conducted a mediation analysis in a historical cohort of 260 mother-child pairs to estimate the total and indirect effects of maternal prenatal thyroid function on daughters' age at menarche. No association was observed between thyroid stimulating hormone (TSH) or anti-thyroid peroxidase antibodies (ATPO) and daughters' age at menarche. Using a sample-specific, a-priori cutoff at the 10th percentile, low levels of maternal free thyroxine (FT4) were associated with earlier daughter age at menarche, with a hazard ratio (95 % CI) of 1.70 (1.02, 2.84) comparing the bottom 10th percentile with the top 90th percentile of exposure levels. Higher maternal FT4 was associated with rapid child weight gain from ages 5-9, and rapid child weight gain from ages 5-9 was associated with earlier age at menarche; the estimated indirect effect of this pathway was null. While maternal FT4 is associated with earlier age at menarche in daughters, this is not mediated by rapid weight gain in our study population, suggesting that maternal FT4 is operating through a different pathway.

Genetic variation associated with childhood and adult stature and risk of MYCN-amplified neuroblastoma

Background

Neuroblastoma is the most common pediatric solid tumor. MYCN‐amplification is an important negative prognostic indicator and inherited genetic contributions to risk are incompletely understood. Genetic determinants of stature increase risk of several adult and childhood cancers, but have not been studied in neuroblastoma despite elevated neuroblastoma incidence in children with congenital overgrowth syndromes.

Methods

We investigated the association between genetic determinants of height and neuroblastoma risk in 1538 neuroblastoma cases, stratified by MYCN‐amplification status, and compared to 3390 European‐ancestry controls using polygenic scores for birth length (five variants), childhood height (six variants), and adult height (413 variants). We further examined the UK Biobank to evaluate the association of known neuroblastoma risk loci and stature.

Results

An increase in the polygenic score for childhood stature, corresponding to a ~0.5 cm increase in pre‐pubertal height, was associated with greater risk of MYCN‐amplified neuroblastoma (OR = 1.14, P = .047). An increase in the polygenic score for adult stature, corresponding to a ~1.7 cm increase in adult height attainment, was associated with decreased risk of MYCN‐amplified neuroblastoma (OR = 0.87, P = .047). These associations persisted in case‐case analyses comparing MYCN‐amplified to MYCN‐unamplified neuroblastoma. No polygenic height scores were associated with MYCN‐unamplified neuroblastoma risk. Previously identified genome‐wide association study hits for neuroblastoma (N = 10) were significantly enriched for association with both childhood (P = 4.0 × 10⁻³) and adult height (P = 8.9 × 10⁻³) in >250 000 UK Biobank study participants.

Conclusions

Genetic propensity to taller childhood height and shorter adult height were associated with MYCN‐amplified neuroblastoma risk, suggesting that biological pathways affecting growth trajectories and pubertal timing may contribute to MYCN‐amplified neuroblastoma etiology.

Growth to early adulthood following extremely preterm birth: the EPICure study

OBJECTIVE

To investigate growth trajectories from age 2.5 to 19 years in individuals born before 26 weeks of gestation (extremely preterm; EP) compared with term-born controls.

METHODS

Multilevel modelling of growth data from the EPICure study, a prospective 1995 birth cohort of 315 EP participants born in the UK and Ireland and 160 term-born controls recruited at school age. Height, weight, head circumference and body mass index (BMI) z-scores were derived from UK standards at ages 2.5, 6, 11 and 19 years.

RESULTS

129 (42%) EP children were assessed at 19 years. EP individuals were on average 4.0 cm shorter and 6.8 kg lighter with a 1.5 cm smaller head circumference relative to controls at 19 years. Relative to controls, EP participants grew faster in weight by 0.06 SD per year (95% CI 0.05 to 0.07), in head circumference by 0.04 SD (95% CI 0.03 to 0.05), but with no catch-up in height. For the EP group, because of weight catch-up between 6 and 19 years, BMI was significantly elevated at 19 years to +0.32 SD; 23.4% had BMI >25 kg/m² and 6.3% >30 kg/m² but these proportions were similar to those in control subjects. EP and control participants showed similar pubertal development in early adolescence, which was not associated with height at 19 years in either study group. Growth through childhood was related to birth characteristics and to neonatal feeding practices.

CONCLUSIONS

EP participants remained shorter and lighter and had smaller head circumferences than reference data or controls in adulthood but had elevated BMI.

Adult height after gonadotropin-releasing hormone agonist treatment in girls with early puberty: A meta-analysis

OBJECTIVE

This analysis of previously published reports was performed to examine the effects of gonadotropin-releasing hormone (GnRH) agonist treatment on adult height and the factors associated with adult height outcomes.

CONTEXT

GnRH agonists are first-line agents in the treatment of precocious puberty. However, studies regarding the treatment effect on subjects with early puberty have reported inconsistent results.

DESIGN

A total of 14 studies identified from a search of electronic databases (AMED, EMBASE, MEDLINE and RISS) were included. Controlled studies with girls who developed puberty before 10 years of age and measurements of the adult heights of the subjects were selected. Studies using only long-acting GnRH agonists to suppress puberty were included. Adult height, duration of the treatment, age at the start of treatment and bone age advancement were analysed.

RESULTS

The mean age of the subjects ranged from 6.3 to 9.0 years. The meta-analysis showed a pooled mean difference in adult height of 3.2 cm and a 95% confidence interval of 1.3-5.1 cm. The height difference between the treated subjects and controls was significantly associated with the duration of treatment (P = .005) rather than the age at the start of treatment (P = .084) or the difference between bone age and chronological age (P = .427).

CONCLUSIONS

Administration of GnRH agonists in girls who develop early puberty and demonstrate advanced bone age may be effective for increasing adult height, especially if a sufficiently long treatment duration can be achieved.

Body mass index growth trajectories, early pubertal maturation, and short stature

BACKGROUND

Childhood body mass index (BMI) trajectory classes are rarely linked to early puberty risk, particularly among Chinese children. We estimated early puberty risk across BMI trajectory classes, investigated factors contributing to pubertal development, and examined differences in final adult height between children exhibiting early and nonearly pubertal maturation across the classes.

METHODS

The Taiwan Children Health Study recruited 10-year-old children in 2010 from 14 Taiwanese communities and resurveyed them at age 11, 12, and 18 years. The study comprised 3109 children (50.4% boys) with available data for BMI (age 6-11 years) and pubertal stages (age 11, 12, and 18 years).

RESULTS

Classes 1-4 were persistently healthy weight, rapid BMI growth, chronically overweight/obese, and early transient overweight/obese. Children in class 3 exhibited the highest risk of early pubertal maturation. Puberty genetic score, low sleep quality, and high fat-free mass collectively explained 15% of the variance in Tanner stages among class 3 children. Early pubertal maturation was considered to cause short and tall stature in boys and girls, respectively.

CONCLUSIONS

Modifying sleep quality and fat-free mass may reduce early puberty risk in children with chronic overweight/obesity. Vigorous physical activity may reduce adiposity and increase the final adult height in the children.

Early age at menarche and risk of postpartum hemorrhage: a retrospective study in Chinese women

Objective: The objective of this study is to investigate whether early age at menarche is associated with increased risk of postpartum hemorrhage among Chinese women.Materials and methods: Clinical data from 6,383 Chinese women who gave birth to live singleton infants at The First Affiliated Hospital of Chengdu Medical College between October 2016 and October 2019 were extracted from the electronic medical records system. Patients were categorized into four groups according to their age at menarche (≤12, 13, 14 and ≥15 years). Logistic regression analysis was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for postpartum hemorrhage for the different menarche age groups.Results: After controlling for potential confounders, women with menarche at an early age (≤12 years) had a significantly higher risk of developing postpartum hemorrhage than women with an age at menarche of 13 years, and the ORs (95% CIs) for postpartum hemorrhage across the menarche age categories (≤12, 13, 14 and ≥15 years) were 1.27 (1.02-1.81), 1.00 (reference), 0.95 (0.61-1.57), and 0.91 (0.51-1.58), respectively. Moreover, age at menarche was inversely associated with the risk of postpartum hemorrhage after adjustment for all relevant confounding factors, and the OR (95% CI) for postpartum hemorrhage per year of increasing in the age at menarche was 0.93 (0.74-0.99).Conclusion: Early age at menarche was associated with a significantly increased risk of postpartum hemorrhage after adjustment for known confounding factors. This finding could help obstetricians and midwives to identify pregnant women at higher risk of developing postpartum hemorrhage, and allow early preventative strategies to be implemented.

The association between sleep duration, bedtimes, and early pubertal timing among Chinese adolescents: a cross-sectional study

BACKGROUND AND OBJECTIVE

Early pubertal timing is associated with sleep among Western adolescents, but little is known about this association in Chinese adolescents, especially with regard to the association between bedtimes and early pubertal timing. This paper aimed to identify the association between sleep duration, bedtimes, and early pubertal timing in Chinese adolescents.

METHODS

An anonymous cross-sectional survey was conducted among primary and junior middle students (grades 3 to 9) from QiJiang District, ChongQing, China. Participants were recruited by applying stratified cluster sampling. Pubertal timing, sleep duration, and bedtimes were assessed using the Pubertal Development Scale and a self-designed sleep questionnaire. We utilized multivariable logistic linear regression (MLLR) to test the association between sleep duration, bedtimes, and pubertal timing.

RESULTS

A total of 5461 adolescents were evaluated, with mean age and BMI values of 11.41 ± 2.05 and 18.03 ± 3.03, respectively, of whom 1257 (23.02%) were in early pubertal timing. In MLLR controlling for age, BMI, family economic status, and other covariates, sufficient sleep (b = - 0.214, P = 0.032, OR = 0.808, 95% CI 0.664-0.982) was negatively related to early pubertal timing, and later bedtime (b = 0.195, P < 0.001, OR = 1.215, 95% CI 1.104-1.338) was positively associated with early pubertal timing.

CONCLUSION

Students with early pubertal timing had less sleep duration and later bedtimes, which may be the result of increased stress caused by physical and psychological changes. Therefore, more attention should be paid to pubertal health education for adolescents during puberty. Further longitudinal studies are needed to confirm the causality between sleep and early pubertal timing in Chinese adolescents.

A Systematic Literature Review of Factors Affecting the Timing of Menarche: The Potential for Climate Change to Impact Women's Health

Menarche is the first occurrence of a woman’s menstruation, an event that symbolizes reproductive capacity and the transition from childhood into womanhood. The global average age for menarche is 12 years and this has been declining in recent years. Many factors that affect the timing menarche in girls could be affected by climate change. A systematic literature review was performed regarding the timing of menarche and four publication databases were interrogated: EMBASE, SCOPUS, PubMed, and Cochrane Reviews. Themes were identified from 112 articles and related to environmental causes of perturbations in menarche (either early or late), disease causes and consequences of perturbations, and social causes and consequences. Research from climatology was incorporated to describe how climate change events, including increased hurricanes, avalanches/mudslides/landslides, and extreme weather events could alter the age of menarche by disrupting food availability or via increased toxin/pollutant release. Overall, our review revealed that these perturbations in the timing of menarche are likely to increase the disease burden for women in four key areas: mental health, fertility-related conditions, cardiovascular disease, and bone health. In summary, the climate does have the potential to impact women’s health through perturbation in the timing of menarche and this, in turn, will affect women’s risk of disease in future.

Relationship between final adult height and birth weight after gonadotropin-releasing hormone agonist treatment in girls with central precocious puberty

PURPOSE

The clinical significance of birth weight relative to gestational age in girls with central precocious puberty is unclear. This study sought to compare clinical parameters such as final adult height (FAH) and menarche onset after treatment with gonadotropin-releasing hormone agonist (GnRHa) on birth weight in girls with central precocious puberty treated.

METHODS

This retrospective study reviewed data of 69 girls with precocious puberty who had reached their FAH in a long-term trial of GnRHa treatment between January 2007 and December 2017. The subjects were divided into small for gestational age (SGA) (n=19) and appropriate for gestational age (AGA) (n=50) groups.

RESULTS

When starting GnRHa treatment, bone age was 10.9±0.9 and 10.3±0.8 years in the SGA and AGA groups, respectively (P&lt;0.05). The predicted adult height (PAH) (established according to the Bayley-Pinneau average table) and advanced PAH (established according to the Bayley-Pinneau advanced table) were 151.5±4.8 cm and 155.8±4.9 cm in the SGA group, respectively, and 153.4±5.3 cm and 159.0±6.0 cm in the AGA group. After treatment, no significant difference in bone age was found between the groups. The time to menarche after treatment was 12.5±7.6 and 21.1±12.3 months in the SGA and AGA groups, respectively (P&lt;0.05). FAH in the SGA and AGA groups was 161.0±4.7 cm and 161.6±5.0 cm, respectively, without a significant difference.

CONCLUSION

SGA girls with precocious puberty have increased bone age and earlier menarche relative to AGA girls. However, no difference in FAH after treatment was found between these groups.

Birth weight, birth order, and age at first solid food introduction influence child growth and body composition in 6- to 8-year-old Maya children: The importance of the first 1000 days of life

OBJECTIVES

To analyze the relationship of birth weight, birth order, breastfeeding duration, and age of introduction of solid foods with height, fat mass, and fat-free mass in a sample of Maya children when aged 6 to 8 years old.

METHODS

We collected data on anthropometry, body composition, children's birth weight, birth order, early feeding practices, and household socioeconomic characteristics in a sample of 260 Maya children aged 6 to 8 years living in Merida and Motul, two cities in Yucatan, Mexico. Multiple regression models were performed to identify variables associated with height-for-age (HAZ), fat mass index (FMI), and fat-free mass index (FFMI). The predictors included in the models were birth weight (kg), birth order, duration of breastfeeding (months), age at introduction of solid foods (months), maternal age (years), and height (cm). Models were adjusted for the influence of children's age and sex, maternal educational level, and household overcrowding.

RESULTS

HAZ was positively associated with child birthweight and maternal height and age, but inversely associated with birth order and age of introduction of solid foods. FMI was positively associated with birth weight, maternal age, and height, and negatively associated with birth order. FFMI was positively associated with maternal age and birth weight.

CONCLUSIONS

These results are evidence of the importance of the first 1000 days of life for the growth and body composition of Maya children and contributed to understand the development of nutritional dual burden in this population.

The impacts of peer education based on adolescent health education on the quality of life in adolescents: a randomized controlled trial

PURPOSE

During adolescence, adolescents are more susceptible to internalizing and externalizing problems influencing quality of life (QoL). The purpose of the study is to verify the effectiveness of a peer education on improving QoL of adolescents.

METHODS

A cluster randomized controlled trial (RCT) was conducted involving 1564 subjects who were divided into an intervention group (n = 714) and a control group (n = 850). The intervention group received 1-year peer education. Their QoL and basic information were assessed using a Adolescent Quality of Life Scale and a self-designed basic situation questionnaire.

RESULTS

After the intervention, significant increases were found in the psychological, and social, pubertal dimensions, and in total QoL (P < 0.05) in the intervention group relative to the control group. Significant decrease was found in physical dimension (P < 0.05), but the change in the intervention group (0.74 decrease) was much less than that in the control group (1.94 decrease). The improvements of physical (B = 1.215, SE = 0.305, P < 0.001), psychological (B = 1.496, SE = 0.598, P = 0.013), pubertal (B = 0.828, SE = 0.244, P = 0.001), and total (B = 3.455, SE = 1.429, P = 0.016) QoL in the intervention group were higher than in the control group in mixed model.

CONCLUSIONS

The peer education based on adolescent health education is effective in improving the physical, psychological, pubertal, and total QoL of adolescents, but no social QoL.

Heightened HPA-axis stress reactivity and accelerated pubertal progression predicts depressive symptoms over 4-year follow up

Pubertal timing has been suggested as biological factors implicated in the onset of depression in girls. This study aims to examine the prospective association between accelerated pubertal progression with depressive symptoms, and to further explore the possible role of individual reactivity to social stress in this association. A total of 56 girls with early puberty timing (assessed through breast Tanner stage) and 56 age-matched normal breast development girls were recruited at Wave 1 (grade 3) and followed for 4 years biennially. Hypothalamic-pituitary-adrenal axis stress reactivity was indexed by four cortisol samples collected before, during and after the Groningen Social Stress Test (GSST) at Wave 1. Depressive symptoms were interviewed through Mood & Feeling Questionnaire (MFQ) at each wave. About 42.9% (24/56) from early pubertal timing group and 19.6% (11/56) from normal control group were found accelerated breast development during 4-year follow-up. Mixed effects linear models illustrated that among accelerated breast development girls, those with heightened stress reactivity is likely to have a 6.62 (95% CI, 1.14-12.11)-point higher MFQ scores, and 41.9% (95%CI: 25.2 to 58.6%) higher probability for depressive symptoms, compared with girls with persistent normal breast development and moderate stress reactivity. However, no similar effects were found in girls with accelerated breast development but attenuated stress reactivity. The finding suggests that heightened cortisol reactivity to social stress may represent a useful biomarker in identifying girls at greatest risk of development of depressive symptoms following accelerated pubertal progression.

Relative effects of postnatal rapid growth and maternal factors on early childhood growth trajectories

BACKGROUND

A range of postnatal and maternal factors influences childhood obesity, but their relative importance remains unclear. This study aimed to assess the relative impact of postnatal rapid growth and maternal factors on early childhood growth trajectories.

SUBJECTS

Secondary longitudinal analysis of pooled data from the Melbourne Infant Feeding Activity and Nutrition Trial (InFANT) Program and the InFANT Extend Program (n = 977) was performed. Children's height and weight were collected at birth, 3, 9, 18, and 36/42 months. Body mass index-for-age and height-for-age z-scores (BAZ, HAZ) were computed using WHO growth standards. Mixed-effect polynomial regression models were fitted to examine BAZ and HAZ trajectories and their determinants.

RESULTS

Rapid growth from birth to 3 months, maternal country of birth, and pre-pregnancy BMI were each independently associated with BAZ from 3 to 42 months. Children with rapid growth, those whose mothers were Australian-born, and those whose mothers were overweight/obese pre-pregnancy had higher BAZ from 3 to 42 months. Children with rapid growth had an increase in HAZ growth, but their average HAZ from 3 to 42 months was smaller than children without rapid growth. Children of tall mothers (above average height) had higher HAZ than those of short mothers (below average height). Average HAZ from 3 to 42 months did not differ by maternal country of birth.

CONCLUSION

Children who experienced rapid growth from birth to 3 months, whose mothers were Australian-born or whose mothers were overweight/obese pre-pregnancy demonstrated less favourable growth trajectories across early childhood, potentially predispose them for development of future obesity.

Pre- and perinatal factors and incidence of breast cancer in the Black Women's Health Study

PURPOSE

The purpose of the study was to investigate the association between pre- or perinatal factors and breast cancer risk among African American women.

METHODS

Participants in the Black Women's Health Study, a prospective cohort of 59,000 African American women, reported birth weight, preterm birth, twin or triplet status, maternal age at birth, birth order, and having been breastfed during infancy at various times during follow-up from 1997 to 2015. Numbers of incident cases ranged from 312 for breastfed analyses to 1,583 for twin or triplet analyses. Using multivariable Cox proportional hazards regression, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between each factor and breast cancer risk overall and by estrogen receptor (ER) status.

RESULTS

Compared to birth weights of 5 lbs. 8 oz.-8 lbs. 13 oz., low (< 5 lbs. 8 oz.) and high (> 8 lbs. 13 oz.) birth weights were associated with increased breast cancer risk; HRs (95% CI) were 1.19 (0.98-1.44) and 1.26 (0.97-1.63), respectively. Associations were similar by ER status. Having been born to a mother aged ≥ 35 years versus < 20 years was associated with risk of ER+ (HR 1.59, 95% CI 1.10-2.29), but not ER- breast cancer. Other perinatal factors were not associated with breast cancer.

CONCLUSION

African American women with a low or high birth weight or born to older mothers may have increased breast cancer risk. Trends towards delayed child birth and higher birth weights, coupled with disproportionately high rates of low birth weight among African Americans, may contribute to increases in breast cancer incidence.

Metformin for Rapidly Maturing Girls with Central Adiposity: Less Liver Fat and Slower Bone Maturation

BACKGROUND/AIMS

Girls with low-birth weight (LBW) and postnatal weight catch-up tend to develop visceral and hepatic fat excess, which may be accompanied by an upregulated adrenarche with precocious pubarche (PP) and by a rapidly progressive puberty with early menarche and shorter stature. A pilot study suggested that metformin treatment for 4 years reduces central adiposity in LBW-PP girls and normalizes puberty and adult height. In this cohort, we studied the relationship between metformin treatment, bone maturation, and body composition.

METHODS

Longitudinal hand X-rays (0-4 years, analyzed by BoneXpert) were available from 34 LBW-PP girls (89% of the original cohort; n = 17 untreated, n = 17 metformin-treated; age at the start of treatment 8 years) along with body composition (0-4 years, by DXA), hepatic fat, and abdominally subcutaneous and visceral fat (posttreatment, by MRI).

RESULTS

The tempo of bone aging was accelerated in untreated girls (≈16% faster vs. chronological aging) and normal in metformin-treated girls (≈20% slower vs. untreated girls). Metformin-treated girls gained more height per bone-age year and had less visceral and hepatic fat. The tempo of bone maturation was associated (R = 0.55; p < 0.001) with hepatic fat.

CONCLUSION

Metformin treatment in rapidly maturing girls with central adiposity normalized bone maturation. This normalization was accompanied by less central fat and was related closely to hepatic fat.

Life history trade-offs and the partitioning of maternal investment: Implications for health of mothers and offspring

Lay Summary: This review sets out the hypothesis that life history trade-offs in the maternal generation favour the emergence of similar trade-offs in the offspring generation, mediated by the partitioning of maternal investment between pregnancy and lactation, and that these trade-offs help explain widely reported associations between growth trajectories and NCD risk. Growth patterns in early life predict the risk of non-communicable diseases (NCDs), but adaptive explanations remain controversial. It is widely assumed that NCDs occur either because of physiological adjustments to early constraints, or because early ecological cues fail to predict adult environmental conditions (mismatch). I present an inter-generational perspective on developmental plasticity, based on the over-arching hypothesis that a key axis of variability in maternal metabolism derives from life history trade-offs, which influence how individual mothers partition nutritional investment in their offspring between pregnancy and lactation. I review evidence for three resulting predictions: (i) Allocating relatively more energy to growth during development promotes the capacity to invest in offspring during pregnancy. Relevant mechanisms include greater fat-free mass and metabolic turnover, and a larger physical space for fetal growth. (ii) Allocating less energy to growth during development constrains fetal growth of the offspring, but mothers may compensate by a tendency to attain higher adiposity around puberty, ecological conditions permitting, which promotes nutritional investment during lactation. (iii) Since the partitioning of maternal investment between pregnancy and lactation impacts the allocation of energy to 'maintenance' as well as growth, it is expected to shape offspring NCD risk as well as adult size and body composition. Overall, this framework predicts that life history trade-offs in the maternal generation favour the emergence of similar trade-offs in the offspring generation, mediated by the partitioning of maternal investment between pregnancy and lactation, and that these trade-offs help explain widely reported associations between growth trajectories and NCD risk.

Body Burden of Dichlorodiphenyl Dichloroethene (DDE) and Childhood Pulmonary Function

Longitudinal studies have shown that early life exposure to dichlorodiphenyl dichloroethene (DDE) can lead to growth reduction during childhood and adolescence. In addition, DDE exposure has been linked to respiratory tract infections and an increased risk of asthma in children. Our aim was to understand the relationships between DDE exposure and pulmonary function in children, and, particularly, whether associations are mediated by the height of the children. We used data from an environmental epidemiologic study conducted in central Germany in children aged 8-10 years. The pulmonary function (forced vital capacity, FVC, and forced expiratory volume in one second, FEV1) were measured in three consecutive years. Blood DDE levels were measured at 8 and 10 years. We used linear mixed models for repeated measurements and path analyses to assess the association between blood levels of DDE and pulmonary function measurements. All models were adjusted for confounders. Linear mixed approaches and modelling concurrent effects showed no significant associations. The path analytical models demonstrated that DDE measured at eight years had significant, inverse, indirect, and total effects on FVC at ten years (n = 328; −0.18 L per μg/L of DDE) and FEV1 (n = 328; −0.17 L per μg/L of DDE), mediated through effects of DDE on height and weight. The DDE burden reduces pulmonary function through its diminishing effects on height and weight in children. Further studies are required to test these associations in other samples, preferably from a region with ongoing, high DDT application.

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.

Histological characteristics of the gonads of pig fetuses and their relationship with fetal anatomical measurements

The objective was to evaluate the histomorphometric characteristics of the testis and ovaries of pig fetuses at different gestational ages, as well as their correlation with some fetus measurements. Forty-four fetuses were separated for gender (male and female) and gestational age (50, 80 and 106days of gestation). After slaughter, fetuses had their body length, head and thoracic perimeters measured and their gonads submitted to histomorphometric analyses. The gonadal characteristics at different gestational ages were statistically compared, correlations with the fetal measurements were performed and equations to predict the gonadal characteristics from the fetal measurements were obtained. The testis weight logarithmically increased along pregnancy, whereas ovary weight increased in a linear manner. The cordonal length and number of Sertoli cells were positively correlated with the fetal measurements, being higher at 106days gestation, while the nuclear volume of these cells were negatively correlated. The total number of follicles was higher at day 80 and 106 of pregnancy. The number of oogonia decreased along the pregnancy, however, their nucleus size was increased. The number of follicles and volume of oogonia were positively correlated with the fetal measurements, while the number of oogonia was negatively correlated. Equations were obtained for the prediction of gonadal characteristics of fetuses. We concluded that in pigs testis cell proliferation, ovary development and histological organization was more pronounced during the final third of pregnancy. Fetal weight and size were strongly related to gonadal development, and can be used to estimate the histological characteristics of gonads.

Birth weight and prepubertal body size predict menarcheal age in India, Peru, and Vietnam

Evidence on the associations of birth weight and prepubertal nutritional status with menarcheal age for low- and middle-income countries is limited. We investigated these relationships using the Young Lives younger cohort for 2001 Indian, Peruvian, and Vietnamese girls born in 2001-2002. Girls were followed at approximately ages 1, 5, 8, and 12 years. Weibull survival models estimated hazards of earlier menarche on the basis of birth weight Z-scores (BWZ), and age-8 BMI-for-age Z-scores (BMIZ) and height-for-age Z-scores (HAZ). Estimates controlled for potential individual-, mother-, and household-level confounders and for changes in anthropometry between 1 and 8 years. In adjusted models, BWZ predicted later age at menarche (hazard ratio (HR) = 0.90, 95% CI: 0.83-0.97). Conversely, HAZ (HR = 1.66, 95% CI 1.5-1.83) and BMIZ at 8 years (HR = 1.28, 95% CI: 1.18-1.38) predicted earlier menarche. Changes in HAZ and BMIZ between 1 and 8 years were not associated with earlier menarche. Associations were consistent across countries, though with variation in estimated magnitudes. Maternal height and age were associated with later menarche. This evidence points to consistently robust and opposite associations of birth weight versus prepubertal attained height and body mass index with menarcheal age in three diverse settings with regard to nutrition, ethnicity, and socioeconomic status.

Adult height after spontaneous pubertal growth or GnRH analog treatment in girls with early puberty: a meta-analysis

Early puberty (EP) has been defined as the onset of puberty in the low-normal range; it may be a cause for concern regarding a possible impairment of adult height (AH). This paper meta-analysed data on AH after spontaneous growth or after gonadotropin-releasing hormone (GnRH) analog treatment in girls with EP. A computerized literature search was conducted from 1980 to June 30, 2016. Only published studies in English were considered. Eight papers were selected (483 cases). In untreated girls (n = 300), predicted adult height (PAH) at start of follow-up (-0.559 SDS (95%CI -1.110 to 0.001); P = 0.050) was close to mid-parental height (MPH) (-0.557 SDS (95%CI -0.736 to -0.419); P < 0.0001) and AH (-0.663 SDS (95%CI -0.803 to -0.524); P < 0.0001). In GnRH analog treated girls (n = 183), PAH before the start of treatment was slightly reduced (-0.939 SDS (95%CI -1.401 to -0.477; P < 0.0001) vs MPH (-0.678 SDS (95%CI -0.942 to -0.414); P < 0.0000), but AH (-0.604 SDS (95%CI -0.877 to -0.338); P < 0.0000) was close to MPH.

CONCLUSION

Present meta-analysis indicates that girls with EP spontaneously reach their MPH and that GnRH analog treatment does not widely change growth outcome. Differences among the selected studies for definition of EP, inclusion criteria, treatment duration, age at discontinuation of therapy, definition of AH may affect results. What is Known: • Early puberty represents a main cause of consultation in paediatric endocrinology offices due to concerns of both practitioners and parents. • Treatment with GnRH analogs is sometimes attempted with the aim to improve adult height. What is New: • Untreated and GnRH analog treated girls with early puberty reached similar adult height. • Adult height was consistent with mid-parental height in both untreated and GnRH analog treated girls with early puberty.

Evaluation of growth hormone treatment efficacy in short Japanese children born small for gestational age: Five-year treatment outcome and impact on puberty

Some children born small for gestational age (SGA) have short stature and are at an increased risk of developing psychosocial or behavioral problems. Here we evaluated the efficacy of GH and its effects on the timing of pubertal onset in a 3-yr extension of our previous 2-yr (total 5 yr) multicenter, randomized, double-blind, parallel-group clinical trial of 65 short Japanese children born SGA. Patients received low or high doses of GH (0.033 or 0.067 mg/kg/day, respectively). Age at onset of puberty was not statistically different for male and female patients receiving high- or low-dose GH. After the onset of puberty, no difference in height gain was observed between the two GH dose groups. At the onset of puberty, height standard deviation scores for chronological age of boys and girls improved significantly in both dose groups with evidence of a dose-response effect. Mean bone age/chronological age ratios in the low- and high-dose groups were significantly increased compared with baseline, being significantly greater in the high-dose group at 5 yr after treatment initiation. Delayed bone age at baseline was close to chronological age following GH treatment. GH treatment, especially high-dose GH, induced advanced bone age in short children born SGA.

Contextual adversity, telomere erosion, pubertal development, and health: Two models of accelerated aging, or one?

Two independent lines of inquiry suggest that growing up under conditions of contextual adversity (e.g., poverty and household chaos) accelerates aging and undermines long-term health. Whereas work addressing the developmental origins of health and disease highlights accelerated-aging effects of contextual adversity on telomere erosion, that informed by an evolutionary analysis of reproductive strategies highlights such effects with regard to pubertal development (in females). That both shorter telomeres early in life and earlier age of menarche are associated with poor health later in life raises the prospect, consistent with evolutionary life-history theory, that these two bodies of theory and research are tapping into the same evolutionary–developmental process whereby longer term health costs are traded off for increased probability of reproducing before dying via a process of accelerated aging. Here we make the case for such a claim, while highlighting biological processes responsible for these effects, as well as unknowns in the epigenetic equation that might instantiate these contextually regulated developmental processes.

Infection and pubertal timing: a systematic review

The decline in age of pubertal timing has serious public health implications ranging from psychosocial adjustment problems to a possible increase in reproductive cancers. One biologically plausible explanation for the decline is a decrease in exposures to infections. To systematically review studies that assess the role of infection in pubertal timing, Medline, Web of Science and EMBASE were systematically searched and retrieved studies were reviewed for eligibility. Eligible studies examined the association between infections, including microbial exposures, and physical pubertal characteristics (breast, genitalia and pubic hair development) or age at menarche. We excluded studies that were published in a language other than English, focused on precocious puberty, were case studies, and/or included youth with autoimmune diseases. We report on study design, population characteristics, measurement of infection and puberty and the main effects of infection on pubertal development. Based on our search terms we identified 1372 unique articles, of which only 15 human and five animal studies met our eligibility criteria. Not all studies examined all outcomes. Infection was associated with later breast development (4/4 human studies), with less consistent evidence for genitalia and pubic hair development. Seven studies assessed age at menarche with inconsistent findings (three supporting later, four no association). We conclude that a small but consistent literature supports that infection is associated with later breast development; the evidence for other pubertal events and age at menarche is less clear. Where fewer childhood infections coincide with the rise in incidence of hormone-related cancers.

UGT2B4 previously implicated in the risk of breast cancer is associated with menarche timing in Ukrainian females

Age at menarche (AAM) is a multifactorial trait that is regulated by dozens environmental and genetic factors. Recent meta-analysis of GWAS showed significant association of 106 loci with AAM. These polymorphisms need replicating in different ethnic populations in order to confirm their association with menarche timing. This study was aimed to replicate 53 polymorphisms that were previously associated with AAM. DNA samples were collected from 416 Ukrainian young females for further genotyping. After data quality control 47 polymorphisms remained for the association analysis using the linear regression model. SNP rs13111134 located in UGT2B4 showed the most significant association with AAM (0.431years per allele A, padj=0.044 after the Bonferroni correction). Polymorphisms rs7589318 in POMC, rs11724758 in FABP2, rs7753051 in IGF2R, rs2288696 in FGFR1 and rs12444979 in GPRC5B may also contribute to menarche timing. However, none of these associations remained significant after the Bonferroni correction for multiple testing. The obtained results provide evidence that UGT2B4, which was previously associated with predisposition to breast cancer, may play a role in the onset of menarche.

Birthweight Differences in Monozygotic Twins Influence Pubertal Maturation and Near Final Height

OBJECTIVE

To evaluate the influence of unfavorable intrauterine conditions and catch-up growth, we analyzed growth and pubertal maturation in monozygotic twins with significant intra-twin birthweight differences.

STUDY DESIGN

Prospective longitudinal clinical study of 30 twin pairs at birth, prepubertally at ages 2.1, 4.0, 10.0 years, and mid-/postpubertally at age 14.6 years; 14 pairs were concordant (birthweight difference <1 SDS), 16 discordant (birthweight difference >1 SDS).

RESULTS

In 19/30 (63%) pairs, the initially smaller twin started pubertal maturation before the co-twin. In 7/8 (88%) female discordant twin pairs, the initially smaller twin experienced menarche first. Among discordant pairs, highly significant intra-twin differences for height SDS were observed up to 10 years of age, with a further decline between ages 10.0 and 14.6 years. At 10.0 years of age, significant intra-twin differences in mean dehydroepiandrostenedione sulfate were observed in all twin pairs (870.3 vs 1054 ng/mL in the smaller twin, P = .045). This was pronounced in the discordant group: 856.7 vs 1138.2 ng/mL, P = .009. In all twin pairs, highly significant intra-twin correlations were found for gonadotropins during puberty (luteinizing hormone: r = 0.67, P < .001. follicle stimulating hormone: r = 0.70, P < .001) with no significant intra-twin differences for gonadotropins, estradiol, and testosterone before or during puberty.

CONCLUSIONS

Birthweight has an impact on growth and pubertal maturation. The already decreased height in some low birthweight infants may be further impacted by an early start and fast progression of puberty. The high intra-twin correlation coefficients in our study suggest that puberty and sexual steroids are genetically determined. However, the observed adrenal androgen hypersecretion of the smaller twin during late childhood could have effected pubertal maturation and further decreased near final height.

Prenatal smoking and age at menarche: influence of the prenatal environment on the timing of puberty

STUDY QUESTION

Do prenatal exposure to cigarette smoking and birthweight influence age at menarche (AAM) in a cohort of Australian girls?

SUMMARY ANSWER

We find that prenatal smoke exposure and lower birthweight increase the chance of earlier menarche in accordance with theoretical predictions as do confounding factors of maternal AAM and higher BMI of the girls.

WHAT IS KNOWN ALREADY

Much prior research focuses on the role of the early childhood environment in determining AAM but fewer studies consider the role of the prenatal environment. Those studies that examine the prenatal period find an acceleration of maturation associated with maternal smoking and low birthweight. Life history theory predicts that early life exposure to stressful environments should promote more rapid maturation and that this timing can be established before birth, making the prenatal environment particularly important.

STUDY DESIGN, SIZE, DURATION

Statistical analysis of longitudinal survey data collected from a large cohort (n = 2446) of Australian children using data from birth to 12-13 years of age.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Owing to missing data, 1493 girls were included in the final analysis. Using cox regression, we examine how (i) maternal cigarette smoking during gestation and (ii) birthweight influence girls' AAM. Cox regression was used because not all girls had reached menarche.

MAIN RESULTS AND THE ROLE OF CHANCE

We find that older maternal AAM (hazards ratio (HR): 0.75, confidence interval (CI) (95%): 0.71-0.79) and higher birthweight (HR: 0.86, CI (95%): 0.75-0.97) lower the chance of earlier menarche; while higher girls' BMI at 8-9 years (HR: 1.12, CI (95%): 1.10-1.15), and maternal cigarette smoking on 'most days' during gestation (HR: 1.40, CI (95%): 1.10-1.79 with 'no smoking' as the reference level) increased the chance of earlier menarche. All factors were statistically significant at P = 0.05.

LIMITATIONS, REASONS FOR CAUTION

Not all girls had reached menarche, necessitating the use of cox regression. As with other longitudinal studies, there was study sample attrition and some missing data, particularly in reports of maternal smoking. In addition, as the degree of bias in the missing data is unknown, possible inaccurate reporting of maternal smoking may influence the results of birthweight on AAM.

WIDER IMPLICATIONS OF THE FINDINGS

Because of the association between younger AAM and higher risk of uterine, endometrial and breast cancer development, our finding adds to the need to consider the stress caused by prenatal smoke exposure as an important health risk. In addition, this study needs to be extended, when the same girls are 14-15 years of age, and on a larger dataset from a younger cohort within the same Australian Government project.

STUDY FUNDING/COMPETING INTERESTS

No funding was received for this study and there are no competing interests to declare.

Genetic and Environmental Contributions to Covariation Between DHEA and Testosterone in Adolescent Twins

Although several studies have shown that pubertal tempo and timing are shaped by genetic and environmental factors, few studies consider to what extent endocrine triggers of puberty are shaped by genetic and environmental factors. Doing so moves the field from examining correlated developmentally-sensitive biomarkers toward understanding what drives those associations. Two puberty related hormones, dehydroepiandrosterone and testosterone, were assayed from salivary samples in 118 MZ (62 % female), 111 same sex DZ (46 % female) and 103 opposite-sex DZ twin pairs, aged 12-16 years (M = 13.1, SD = 1.3). Pubertal status was assessed with a composite of mother- and self-reports. We used biometric models to estimate the genetic and environmental influences on the variance and covariance in testosterone and DHEA, with and without controlling for their association with puberty, and to test for sex differences. In males, the variance in testosterone and pubertal status was due to shared and non-shared environmental factors; variation in DHEA was due to genetic and non-shared environmental factors. In females, variance in testosterone was due to genetic and non-shared environmental factors; genetic, shared, and non-shared environmental factors contributed equally to variation in DHEA. In males, the testosterone-DHEA covariance was primarily due to shared environmental factors that overlapped with puberty as well as shared and non-shared environmental covariation specific to testosterone and DHEA. In females, the testosterone-DHEA covariance was due to genetic factors overlapping with pubertal status, and shared and non-shared environmental covariation specific to testosterone and DHEA.

FERTILITY INTENTIONS AND EARLY LIFE HEALTH STRESS AMONG WOMEN IN EIGHT INDIAN CITIES: TESTING THE REPRODUCTIVE ACCELERATION HYPOTHESIS

In life history theory, early life adversity is associated with an accelerated reproductive tempo. In harsh and unpredictable conditions in developing societies fertility is generally higher and the reproductive tempo faster than in more secure environments. This paper examines whether differences in female anthropometry, particularly adult height, are associated with fertility intentions of women in urban environments in India. The study population consists of women aged 15–29 (N=4485) in slums and non-slums of eight Indian cities in the National Family Health Survey (NFHS) of 2005–2006. Adult height is taken as a proxy for early childhood health and nutritional condition. Fertility intentions are examined by using two variables: the desire to have a child or another child, and to have it relatively soon, as indicative of accelerated reproductive scheduling. Evidence supporting the acceleration hypothesis is found in two urban frames out of 26 examined in a two-staged multinomial logistic model. In three cases, the relationship between fertility intentions and height is the opposite than expected by the acceleration hypothesis: taller women have a higher predictive probability of desiring a(nother) child and/or narrower birth spacing. Potential explanations for the partly contradictory relationship between the childhood health indicator and fertility intentions are discussed.

Weight at birth and subsequent fecundability: a prospective cohort study

Objective

To examine the association between a woman's birth weight and her subsequent fecundability.

Method

In this prospective cohort study, we included 2,773 Danish pregnancy planners enrolled in the internet-based cohort study “Snart-Gravid”, conducted during 2007–2012. Participants were 18–40 years old at study entry, attempting to conceive, and were not receiving fertility treatment. Data on weight at birth were obtained from the Danish Medical Birth Registry and categorized as <2,500 grams, 2,500–2,999 grams, 3,000–3,999 grams, and ≥4,000 grams. In additional analyses, birth weight was categorized according to z-scores for each gestational week at birth. Time-to-pregnancy measured in cycles was used to compute fecundability ratios (FR) and 95% confidence intervals (CI), using a proportional probabilities regression model.

Results

Relative to women with a birth weight of 3,000–3,999 grams, FRs adjusted for gestational age, year of birth, and maternal socio-demographic and medical factors were 0.99 (95% CI: 0.73;1.34), 0.99 (95% CI: 0.87;1.12), and 1.08 (95% CI: 0.94;1.24) for birth weight <2,500 grams, 2,500–2,999 grams, and ≥4,000 grams, respectively. Estimates remained unchanged after further adjustment for markers of the participant's mother's fecundability. We obtained similar results when we restricted to women who were born at term, and to women who had attempted to conceive for a maximum of 6 cycles before study entry. Results remained similar when we estimated FRs according to z-scores of birth weight.

Conclusion

Our results indicate that birth weight appears not to be an important determinant of fecundability.

[Does childhood obesity affect sexual development?]

The process of pubertal development is only partly understood and is influenced by many different factors. During the twentieth century there was a general trend toward earlier pubertal development. Fat mass is thought to be a major inducer of puberty. Owing to the rising epidemic of childhood obesity, the relationship between body composition in children and the rate and timing of puberty needs to be investigated. Some studies suggest that central obesity is associated with an earlier onset of pubertal development. Rapid weight gain in early life is linked to advanced puberty in both sexes. A clear correlation exists between increasing body mass index (BMI) and earlier pubertal development in girls. In boys the data are controversial: The majority of studies propose that there is an earlier puberty and voice break in obese boys, but some studies show the opposite. There are several factors and mechanisms that seem to link obesity and puberty, for example, leptin, adipocytokines, and gut peptides. Important players include genetic variation and environmental factors (e.g., endocrine-disrupting chemicals). This article presents the latest studies and evidence on this topic, underlining the inconsistencies in the data and, therefore, the need for further research in this area.

The role of early life nutrition in programming of reproductive function

Accumulating evidence suggest that the concept of programming can also be applied to reproductive development and function, representing an ever expanding research area. Recently issues such as peri- or even preconceptional nutrition, transgenerational effects and underlying mechanisms have received considerable attention. The present chapter presents the existed evidence and reviews the available data from numerous animal and human studies on the effects of early life nutritional environment on adult reproductive function. Specific outcomes depend on the severity, duration and stage of development when nutritional perturbations are imposed, while sex-specific effects are also manifested. Apart from undernutrition, effects of relative overnutrition as well as the complex interactions between pre- and postnatal nutrition is of high importance, especially in the context of our days obesity epidemic. Mechanisms underlying reproductive programming are yet unclear, but may include a role for epigenetic modifications. Epigenetic modulation of critical genes involved in the control of reproductive function and potential intergenerational effects represent an exciting area of interdisciplinary research toward the development of new nutritional approaches during pre- and postnatal periods to ensure reproductive health in later life.

Influences on the onset and tempo of puberty in human beings and implications for adolescent psychological development

This article is part of a Special Issue "Puberty and Adolescence". Historical records reveal a secular trend toward earlier onset of puberty in both males and females, often attributed to improvements in nutrition and health status. The trend stabilized during the mid 20th century in many countries, but recent studies describe a recurrence of a decrease in age of pubertal onset. There appears to be an associated change in pubertal tempo in girls, such that girls who enter puberty earlier have a longer duration of puberty. Puberty is influenced by genetic factors but since these effects cannot change dramatically over the past century, environmental effects, including endocrine disrupting chemicals (EDCs), and perinatal conditions offer alternative etiologies. Observations that the secular trends in puberty in girls parallel the obesity epidemic provide another plausible explanation. Early puberty has implications for poor behavioral and psychosocial outcomes as well as health later in life. Irrespective of the underlying cause of the ongoing trend toward early puberty, experts in the field have debated whether these trends should lead clinicians to reconsider a lower age of normal puberty, or whether such a new definition will mask a pathologic etiology.

Ontogeny of polycystic ovary syndrome and insulin resistance in utero and early childhood

Polycystic ovary syndrome (PCOS) is a prevalent hyperandrogenic infertility and cardiometabolic disorder that increases a woman's lifetime risk of type 2 diabetes mellitus. It is heritable and intensely familial. Progress toward a cure has been delayed by absence of an etiology. Evidence is mounting, however, for in utero T excess, together with gestational hyperglycemia, contributing to either early differentiation of PCOS or phenotypic amplification of its genotypes. Abnormal endocrine, ovarian, and hyperinsulinemic traits are detectable as early as 2 months of age in daughters of women with PCOS, with adiposity enhancement of hyperinsulinemia during childhood potentially contributing to hyperandrogenism and LH excess by adolescence. These findings encourage increasing clinical focus on early childhood markers for adiposity and hyperinsulinemia accompanying ovarian and adrenal endocrine abnormalities that precede a diagnosable PCOS phenotype. They raise the possibility for lifestyle or therapeutic intervention before and during pregnancy or during childhood and adolescence alleviating the manifestations of a familial genetic predisposition to PCOS.

Age at menarche and adult height in girls born small for gestational age

PURPOSE

The aim of this study was to evaluate the association between birth characteristics based on birth weight for gestational age, timing of menarche and adult height in girls born small for gestational age (SGA).

METHODS

Thirty subjects born from 1988 through 1999 whose birth weight below 10th percentile for their gestational ages were recruited based on hospital chart reviews. The age of each subject at menarche was recorded, and the subject's heights and bone age were assessed.

RESULTS

The adult height of the girls born SGA was significantly lower than the normal adult height and slightly shorter than their target height. The adult height was associated with the birth weight for gestational age. The age at menarche was not different with the menarche timing of the general population.

CONCLUSION

More attention may need to be paid to the growth outcomes of SGA patients whose birth weight is lower for their gestational age than other SGA subjects.

The longer-term health outcomes for children born as a result of IVF treatment: Part I--General health outcomes

BACKGROUND Several million children have been born from in vitro fertilization (IVF) treatment, but limited data exist regarding their health and development beyond the first year of life. It has been alleged that IVF may lead to long-term adverse consequences, in addition to the documented worse perinatal outcome and increased risk of congenital abnormalities in children born resulting from IVF treatment. METHODS A search strategy restricted to studies relating to the medical condition of children of at least 1 year of age born as a result of IVF treatment was performed to include case series, data linkage and prospective studies published 1 January 2000-1 April 2012. RESULTS Limited long-term follow-up data suggest that there is potentially an increase in the incidence of raised blood pressure, elevated fasting glucose, increase in total body fat composition, advancement of bone age and potentially subclinical thyroid disorder in the IVF offspring. Whether these potential associations are related to the IVF treatment per se, the adverse obstetric outcomes associated with IVF treatment or are related to the genetic origin of the children is yet to be determined. CONCLUSIONS This review provides evidence to suggest that the short-term health outcome for children born from IVF treatment is positive. However, it is expected that the cardiovascular and metabolic risk factors found in childhood and tracking into adulthood could be worse in later life, and may be responsible for chronic cardiometabolic disease. These observations need to be addressed by further studies.

Control of puberty: genetics, endocrinology, and environment

PURPOSE OF REVIEW

The aim of this review is to summarize recent advances regarding the genetic components of the complex and coordinated process of puberty, an update of the genes implicated in disorders of puberty, the endocrinologic changes of puberty, and influences of environment in the light of our current understanding of the mechanism of the onset of puberty.

RECENT FINDINGS

The timing of puberty varies greatly in the general population among ethnic groups throughout the world, suggesting the genetic control of puberty. Several studies on the pathological conditions of pubertal onset provide unique information about the interactions of either the genetic susceptibility of or environmental influences on hypothalamic control of pubertal onset. However, these findings suggested that no isolated pathway or external factor is solely responsible for the neuroendocrine control of puberty.

SUMMARY

Puberty is initiated by gonadotropin-releasing hormone from the hypothalamus followed by a complex sequence of endocrine changes and is regulated by both genetic and environmental factors. New attempts to use genetics and genomics might enhance our understanding of the spectrum of pubertal development.

Pharmacokinetics of metformin in girls aged 9 years

BACKGROUND AND OBJECTIVE

Metformin is a biguanide used in the treatment of type 2 diabetes mellitus. In girls with a low birth weight, and early-normal and rapidly progressive puberty, metformin therapy is capable of modifying this outcome, prolonging pubertal growth, increasing height gain, delaying the age at menarche towards normal and improving the endocrine-metabolic status of these girls. The pharmacokinetics of metformin have been studied in healthy adults and in patients with type 2 diabetes. The objective of this study was to study the pharmacokinetics of metformin in young, non-obese girls.

METHODS

The study population consisted of six girls with a combined history of low birth weight and early-normal onset of puberty. At the time of the study, these girls were aged 9 years and had been receiving metformin (850 mg/day at dinner time) for a mean duration of 8 months. Blood samples were obtained from the girls before metformin intake and for 12 hours thereafter. Serum metformin concentrations were assessed by liquid chromatography with tandem mass spectrometry. The area under the serum concentration-time curve (AUC), maximum serum concentration (C(max)), time to reach the C(max) (t(max)), half-life (t(&frac12;)), volume of distribution (V(d)) and total clearance (CL) were calculated.

RESULTS

Metformin concentration-time curves were similar in girls receiving similar metformin doses (range 21-29 mg/kg): in those girls, the mean AUC was 21 mg · h/L, with a C(max) of 3 mg/L, t(max) of 2.5 hours, t(&frac12;) of 4 hours, V(d) of 111 L and CL of 20 L/h. These values are comparable to those observed in adults.

CONCLUSION

In girls aged 9 years, the pharmacokinetics of metformin were comparable to those in adults. Trial registration number (International Standard Randomized Controlled Trial Number Register): ISRCTN49334271.