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

Small for gestational age and age at menarche in a contemporary population-based U.S. sample

Children born small for gestational age (SGA) may be at risk for earlier puberty and adverse long-term health sequelae. This study investigates associations between SGA and age at menarche using secondary data on 1,027 female children in a population-based U.S. birth cohort that over-sampled non-marital births, which in the U.S. is a policy-relevant population. SGA was defined as <10th percentile of weight for gestational age compared to the national U.S. distribution. We estimated unadjusted and adjusted Ordinary Least Squares (OLS) models of associations between SGA and age at menarche in years, as well as unadjusted and adjusted logistic regression models of associations between SGA and early menarche (before age 11). SGA was not significantly associated with earlier age at menarche, even when adjusting for maternal sociodemographic characteristics, prenatal smoking, and maternal pre-pregnancy overweight and obesity. Similarly, SGA was not significantly associated with the odds of menarche occurring before age 11. However, maternal non-Hispanic Black race-ethnicity, Hispanic ethnicity, and pre-pregnancy obesity all had independent associations with average earlier age at menarche and menarche before age 11. Thus, maternal risk factors appear to play more influential roles in determining pubertal development.

Lead contamination in human milk affects infants' language trajectory: results from a prospective cohort study

Infants growing up in low- and middle-income countries are at increased risk of suffering adverse childhood experiences, including exposure to environmental pollution and lack of cognitive stimulation. In this study, we aimed to examine the levels of metals in the human milk of women living in São Paulo City, Brazil, and determine the effects on infants' neurodevelopment. For such, a total of 185 human milk samples were analyzed for arsenic (As), lead (Pb), mercury (Hg), and cadmium (Cd) using inductively coupled plasma mass spectrometry (ICP-MS). We applied the Bayley scales of infant and toddler development Third Edition (Bayley-III) to assess developmental milestones. In our analysis, we found a mean (standard deviation) concentration of As in human milk equal to 2.76 (4.09) μg L-1, followed by Pb 2.09 (5.36) and Hg 1.96 (6.68). Cd was not detected. We observed that infants exposed to Pb presented language trajectories lower than non-exposed infants (β = -0.413; 95% CI -0.653, -0.173) after adjustment for infant age, maternal education, socioeconomic status, infant sex, and sample weights. Our results report As, Pb, and Hg contamination in human milk, and that infant exposure to Pb decreased infants' language development. These results evidence maternal-child environmental exposure and its detrimental impact on infants' health.

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

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

Reproductive risk factors across the female lifecourse and later metabolic health

Metabolic health is characterized by optimal blood glucose, lipids, cholesterol, blood pressure, and adiposity. Alterations in these characteristics may lead to the development of type 2 diabetes mellitus or dyslipidemia. Recent evidence suggests that female reproductive characteristics may be overlooked as risk factors that contribute to later metabolic dysfunction. These reproductive traits include the age at menarche, menstrual irregularity, the development of polycystic ovary syndrome, gestational weight change, gestational dysglycemia and dyslipidemia, and the severity and timing of menopausal symptoms. These risk factors may themselves be markers of future dysfunction or may be explained by shared underlying etiologies that promote long-term disease development. Disentangling underlying relationships and identifying potentially modifiable characteristics have an important bearing on therapeutic lifestyle modifications that could ease long-term metabolic burden. Further research that better characterizes associations between reproductive characteristics and metabolic health, clarifies underlying etiologies, and identifies indicators for clinical application is warranted in the prevention and management of metabolic dysfunction.

The relation between preterm birth and self-reported spinal pain in pre-adolescence-a study of 47,063 subjects from the Danish National Birth Cohort

Repeated exposure to pain and stress in early life may cause alterations in pain sensitivity later in life. Children born preterm are often exposed to painful invasive procedures. This study aimed to explore the relationship between being born preterm and self-report of spinal pain in pre-adolescence. This prospective study was based on the Danish National Birth Cohort and consisted of 47,063 11-14-year-olds. Data from the Danish National Birth Cohort were linked with national registers through Statistics Denmark. Analyses were performed as multiple logistic regression models estimating odds ratios and 95% confidence intervals. Spinal pain (neck, mid back, and/or low back pain) was assessed using a subdivision of the Young Spine Questionnaire. Severe spinal pain was defined as having pain often or once in a while with an intensity of four to six on the Revised Faces Pain Scale. Inverse probability weighting was used to account for potential selection bias. Girls born very preterm (< 34 full weeks of gestation) were less likely to report spinal pain (OR: 0.60; 95% CI: 0.40-0.93) compared with those term-born. The associations were weaker when examining moderate to severe spinal pain and when examining the three spinal regions separately. None of these was statistically significant.

CONCLUSION

We found no associations for boys. In conclusion, this study indicates that girls born very preterm are seemingly less likely to have severe spinal pain in pre-adolescence than girls born at term.

WHAT IS KNOWN

• Spinal pain is one of the largest disease burdens globally, and the evidence regarding the etiology of spinal pain in children and adolescents is limited. • Repeated exposure to pain and stress in early life (i.e., being preterm) may cause alterations in pain sensitivity later in life.

WHAT IS NEW

• Girls born very preterm (< 34 full weeks of gestation) seem less likely to report severe spinal pain in pre-adolescence compared with girls born at full term. • There is no association between gestational age and later experience of spinal pain in pre-adolescent boys.

Endocrine and metabolic disorders in adolescent and adult patients born small for gestational age

Children born small for gestational age (SGA), defined by a birth weight and/or length standard deviation score (SDS) of < -2 based on an appropriate reference population, represent a diverse group due to multiple underlying causes of reduced growth. This classification results in a heterogeneous patient cohort. SGA children are prone to endocrinological and metabolic issues not only in childhood but also extending into adolescence and adulthood. This population faces elevated health risks, including persistent short stature, premature adrenarche, pubertal development alterations, neurocognitive problems, and metabolic syndrome. Insulin resistance emerges as a pivotal factor c nht6j7ikontributing to these metabolic complications, prominently featuring obesity, insulin resistance, hypertension, and an increased risk of type 2 diabetes mellitus in adulthood. These medium- to long-term complications significantly impact their quality of life. Growth hormone (GH) therapy for short children born SGA facilitates height normalization throughout childhood, adolescence, and into adulthood. Catch-up growth, however, correlates with heightened risks of obesity, insulin resistance, and metabolic syndrome. Conversely, those without catch-up growth tend to exhibit pronounced short stature and cognitive dysfunction. Given these determinants, comprehensive management and clinical monitoring of SGA children should commence in the neonatal period and extend into adulthood. Recognizing and addressing these challenges early in life can mitigate the long-term impact on health and well-being, emphasizing the importance of a lifelong approach to their care.

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.

Endocrine Health and Health Care Disparities in the Pediatric and Sexual and Gender Minority Populations: An Endocrine Society Scientific Statement

Endocrine care of pediatric and adult patients continues to be plagued by health and health care disparities that are perpetuated by the basic structures of our health systems and research modalities, as well as policies that impact access to care and social determinants of health. This scientific statement expands the Society's 2012 statement by focusing on endocrine disease disparities in the pediatric population and sexual and gender minority populations. These include pediatric and adult lesbian, gay, bisexual, transgender, queer, intersex, and asexual (LGBTQIA) persons. The writing group focused on highly prevalent conditions-growth disorders, puberty, metabolic bone disease, type 1 (T1D) and type 2 (T2D) diabetes mellitus, prediabetes, and obesity. Several important findings emerged. Compared with females and non-White children, non-Hispanic White males are more likely to come to medical attention for short stature. Racially and ethnically diverse populations and males are underrepresented in studies of pubertal development and attainment of peak bone mass, with current norms based on European populations. Like adults, racial and ethnic minority youth suffer a higher burden of disease from obesity, T1D and T2D, and have less access to diabetes treatment technologies and bariatric surgery. LGBTQIA youth and adults also face discrimination and multiple barriers to endocrine care due to pathologizing sexual orientation and gender identity, lack of culturally competent care providers, and policies. Multilevel interventions to address these disparities are required. Inclusion of racial, ethnic, and LGBTQIA populations in longitudinal life course studies is needed to assess growth, puberty, and attainment of peak bone mass. Growth and development charts may need to be adapted to non-European populations. In addition, extension of these studies will be required to understand the clinical and physiologic consequences of interventions to address abnormal development in these populations. Health policies should be recrafted to remove barriers in care for children with obesity and/or diabetes and for LGBTQIA children and adults to facilitate comprehensive access to care, therapeutics, and technological advances. Public health interventions encompassing collection of accurate demographic and social needs data, including the intersection of social determinants of health with health outcomes, and enactment of population health level interventions will be essential tools.

Association of size for gestational age and dehydroepiandrosterone sulfate with cardiometabolic risk in central precocious puberty girls

Objective

The aim of this study was to assess whether size for gestational age and dehydroepiandrosterone sulfate (DHEAS) are associated with cardiometabolic risk in central precocious puberty (CPP) girls.

Methods

The retrospective study included 443 patients with newly diagnosed CPP. Subjects were categorized by birth weight for gestational age (appropriate [AGA], small [SGA], and large [LGA] for gestational age) and serum DHEAS concentration (high [≥75th percentile] and normal [<75th percentile] DHEAS). Cardiometabolic parameters were examined. Composite cardiometabolic risk (CMR) score was calculated based on BMI, blood pressure, glucose, insulin, triglyceride, and HDL cholesterol. Non-obesity CMR score was computed, omitting the value from BMI. Logistic regression models, general linear models, and partial correlation analyses were used to evaluate associations. Propensity score matching was performed for sensitivity analyses.

Results

Overall, 309 patients (69.8%) were born AGA, 80 (18.1%) were born SGA, and 54 (12.2%) were born LGA. Compared with AGA counterparts, CPP girls born SGA were more prone to have elevated HbA1c (adjusted OR = 4.54; 95% CI, 1.43-14.42) and low HDL cholesterol (adjusted OR = 2.33; 95% CI, 1.18-4.61). In contrast, being born LGA was not associated with increased risk for any glucose or lipid derangements. Despite the fact that elevated CMR score was more common among individuals born LGA than AGA (adjusted OR = 1.84; 95% CI, 1.07-4.35), no significant difference was found on non-obesity CMR score (adjusted OR = 0.75; 95% CI, 0.30-1.88). When controlling for age, birth weight SDS, and current BMI-SDS, individuals with high DHEAS exhibited higher HDL cholesterol and apolipoprotein A-1 concentrations and lower triglyceride level and non-obesity CMR score. Furthermore, DHEAS correlated positively with HDL cholesterol and apolipoprotein A-1 and negatively with triglyceride, prominently in girls born SGA, after adjustments for the three abovementioned confounders. Sensitivity analyses corroborated the findings.

Conclusion

Among CPP girls, those born SGA were more likely to possess cardiometabolic risk factors compared to their AGA peers. The difference we observed in cardiometabolic risk between individuals born LGA and AGA was driven by BMI. High DHEAS was associated with favorable lipid profile in CPP girls, even in subjects born SGA.

Causal relationships between birth weight, childhood obesity and age at menarche: A two-sample Mendelian randomization analysis

OBJECTIVES

Observational studies suggest birth weight and childhood obesity are closely associated with age at menarche. However, the relationships between them are currently inconsistent and it remains elusive whether such associations are causal. Therefore, the aim of the study was to investigate whether there existed causal relationships between birth weight, childhood obesity and age at menarche.

DESIGN, PATIENTS AND MEASUREMENTS

A two-sample Mendelian randomization (MR) study. The standard inverse variance weighted MR analyses were adopted to evaluate the causal effects of birth weight (n = 143,677), childhood body mass index (BMI) (n = 39,620) on age at menarche (n = 182,416) with summary statistics from large-scale genome-wide association studies (GWASs). Meanwhile, we validated our MR results with some sensitivity analyses including maximum likelihood, weighted-median and MR pleiotropy residual sum and outlier methods.

RESULTS

The present study showed that each one standard deviation (1-SD) lower birth weight was predicted to result in a 0.1479 years earlier of age at menarche (β = .1479, 95% confidence interval [CI] = 0.0422-0.2535; p = 0.0061). We also found that genetically predicted 1-SD increase in childhood BMI was causally associated with early age at menarche (β = -.3966, 95% CI = -0.5294 to -0.2639; p = 4.73E-09).

CONCLUSIONS

Our MR study suggests the causal effect of lower birth weight and higher childhood BMI on the increased risk of earlier menarche. It may be the opportune time to carry out weight control intervention in prenatal and early childhood development periods to prevent early menarche onset, thus decreasing the future adverse consequences.

Catch-Up Growth as a Risk Factor for Rapid Weight Gain, Earlier Menarche and Earlier Pubertal Growth Spurt in Girls Born Small for Gestational Age (SGA)-A Longitudinal Study

Most children born small for gestational age (SGA) have rapid postnatal growth. Despite its positive aspects, catch-up growth may affect the level of adipose tissue in the pre-pubertal and pubertal periods and therefore affect the age of puberty. The aim of this study was to determine the associations between size at birth, catch-up growth in infancy, BMI in peripubertal period, age at menarche, and the parameters of adolescent growth spurt of body height in girls born SGA. For 297 girls (22.6% SGA; 77.4% appropriate for gestational age (AGA)) complete body weight and height measurements and age at menarche were obtained. Adolescent growth spurt parameters were estimated using the JPA2 model (AUXAL SSI 3.1). Calculations were made in the Statistica 13 program using the Kruskal-Wallis and Kaplan-Meier tests. Girls born SGA with catch-up had the highest BMIs at the age of 8 years (H = 94.22, p < 0.001) and at menarche (H = 58.21, p < 0.001), experienced menarche earliest (H = 21.77, p < 0.001), same as the onset (H = 6.54, p = 0.012) and peak height velocity (H = 11.71, p = 0.003) of their adolescent growth spurt compared to SGA girls without catch-up and AGA girls. In SGA girls, catch-up growth has far-reaching consequences such as increased risk of fat accumulation and a rapid transition to puberty.

Associations of maternal urinary bisphenol and phthalate concentrations with offspring reproductive development

Fetal exposure to bisphenols and phthalates may influence development of the reproductive system. In a population-based, prospective cohort study of 1059 mother-child pairs, we examined the associations of maternal gestational urinary bisphenols and phthalates concentrations with offspring reproductive development from infancy until 13 years. We measured urinary bisphenol and phthalate concentrations in each trimester. We obtained information on cryptorchidism or hypospadias after birth from medical records. At 9.7 years, we measured testicular and ovarian volume by MRI. At 13.5 years, we measured child Tanner stages and menstruation through questionnaire. We performed linear or logistic regression models for boys and girls to assess the associations of maternal urinary average and trimester-specific bisphenols and phthalates with child reproductive outcomes. Next, to further explore potential synergistic or additive effects of exposures together, we performed mixed exposure models using a quantile g computation approach. Models were adjusted for maternal age, ethnicity, body-mass index, education, parity, energy intake, smoking and alcohol use, and child's gestational age at birth, birthweight and body-mass index. In boys, no associations of maternal gestational phthalate or bisphenol with offspring cryptorchidism and hypospadias were found. Higher maternal high-molecular-weight phthalate and total bisphenol, but not phthalic acid or low-molecular-weight phthalate, were associated with larger child testicular volume at 10 years. Higher maternal phthalic acid and total bisphenol were associated with earlier genital and pubic hair development at 13 years, respectively (p-values<0.05). In girls, we found no associations of maternal urinary bisphenol and phthalate with ovarian volume or menstrual age. Only higher maternal urinary high-molecular-weight phthalate was associated with earlier pubic hair development at 13 years (p-values <0.05). Higher mixture exposure was associated with earlier pubic hair development in both sexes. In conclusion, higher maternal gestational urinary bisphenol and phthalate concentrations were associated with alterations in offspring reproductive development, mainly in boys.

Puberty disorders among ART-conceived singletons: a Nordic register study from the CoNARTaS group

STUDY QUESTION

Do ART-conceived children have an increased risk for puberty disorders?

SUMMARY ANSWER

Both ART-conceived boys and girls had a higher risk of puberty disorders; early puberty was more common among girls and late puberty among boys.

WHAT IS KNOWN ALREADY

Some physiological differences in growth and metabolism have been reported for ART-conceived children compared to non-ART-conceived children. Knowledge on pubertal development and disorders in ART-conceived children is limited.

STUDY DESIGN, SIZE, DURATION

A register-based cohort study was carried out including data from 1985 to 2015. The Committee of Nordic Assisted Reproductive Technology and Safety (CoNARTaS) study population consists of all live and stillborn children, as well as their mothers, registered in the Medical Birth Registers during the study period in Denmark, Sweden, Finland and Norway.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 122 321 ART-conceived singletons and 6 576 410 non-ART singletons born in Denmark (1994–2014), Finland (1990–2014), Norway (2002–2015) and Sweden (1985–2015) were included. Puberty disorders were defined using International Classification of Diseases and Related Health Problems (ICD)-9/ICD-10 codes and classified in the following groups: late puberty (6268/E30.0), early puberty (2591 and 2958/E30.1 and E30.8) and unspecified disorders (V212 and V579/E30.9 and Z00.3 as well as Z51.80 for Finland). The results in Cox regression were adjusted for maternal age, parity, smoking, gestational diabetes, chronic hypertension, hypertensive disorders during pregnancy and country, and further for either gestational age, birthweight, small for gestational age or large for gestational age.

MAIN RESULTS AND THE ROLE OF CHANCE

There were 37 869 children with diagnoses related to puberty disorders, and 603 of them were born after ART. ART-conceived children had higher risks for early (adjusted hazard ratio (aHR) 1.45, 95% CI: 1.29–1.64) and late puberty (aHR 1.47, 95% CI: 1.21–1.77). Girls had more diagnoses related to early puberty (aHR 1.46, 95% CI: 1.29–1.66) and boys with late puberty (aHR 1.55, 95% CI: 1.24–1.95).

LIMITATIONS, REASONS FOR CAUTION

Using reported puberty disorders with ICD codes in health care registers might vary, which may affect the numbers of cases found in the registers. Register data may give an underestimation both among ART and non-ART-conceived children, especially among non-ART children, who may not be as carefully followed as ART-conceived children. Adjustment for causes and duration of infertility, mothers’ own puberty characteristics and BMI, as well as children’s BMI, was not possible because data were not available or data were missing for the early years. It was also not possible to compare ART to non-ART siblings or to study the pubertal disorders by cause of subfertility owing to a small number of discordant sibling pairs and a large proportion of missing data on cause of subfertility.

WIDER IMPLICATIONS OF THE FINDINGS

This large, register-based study suggests that ART-conceived children have a higher risk for puberty disorders. However, the mechanisms of infertility and pubertal onset are complex, and ART is a rapidly advancing field with various treatment options. Studying the pubertal disorders of ART-conceived offspring is a continuing challenge.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Nordic Trial Alliance: a pilot project jointly funded by the Nordic Council of Ministers and NordForsk (71450), the Central Norway Regional Health Authorities (46045000), the Nordic Federation of Obstetrics and Gynaecology (NF13041, NF15058, NF16026 and NF17043), the Interreg Öresund-Kattegat-Skagerrak European Regional Development Fund (ReproUnion project), the Research Council of Norway’s Centre of Excellence funding scheme (262700), the Swedish state under the agreement between the Swedish government and the county councils, the ALF-agreement (ALFGBG-70940) and FLUX Consortium ‘Family Formation in Flux—Causes, Consequences and Possible Futures’, funded by the Strategic Research Council, Academy of Finland (DEMOGRAPHY 345130). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. The authors have no conflicts of interest to disclose.

TRIAL REGISTRATION NUMBER

N/A.

Maternal and prenatal factors and age at thelarche in the LEGACY Girls Study cohort: implications for breast cancer risk

BACKGROUND

Earlier onset of breast development (thelarche) is associated with increased breast cancer risk. Identifying modifiable factors associated with earlier thelarche may provide an opportunity for breast cancer risk reduction starting early in life, which could especially benefit girls with a greater absolute risk of breast cancer due to family history.

METHODS

We assessed associations of maternal pre-pregnancy body mass index (BMI), physical activity during pregnancy, gestational weight gain and daughters' weight and length at birth with age at thelarche using longitudinal Weibull models in 1031 girls in the Lessons in Epidemiology and Genetics of Adult Cancer from Youth (LEGACY) Girls Study-a prospective cohort of girls, half of whom have a breast cancer family history (BCFH).

RESULTS

Girls whose mothers had a pre-pregnancy BMI of ≥25 and gained ≥30 lbs were 57% more likely to experience earlier thelarche than girls whose mothers had a pre-pregnancy BMI of <25 and gained <30 lbs [hazard ratio (HR) = 1.57, 95% CI: 1.16, 2.12]. This association was not mediated by childhood BMI and was similar in girls with and without a BCFH (BCFH: HR = 1.41, 95% CI: 0.87, 2.27; No BCFH: HR = 1.62, 95% CI: 1.10, 2.40). Daughters of women who reported no recreational physical activity during pregnancy were more likely to experience earlier thelarche compared with daughters of physically active women. Birthweight and birth length were not associated with thelarche.

CONCLUSION

Earlier thelarche, a breast cancer risk factor, was associated with three potentially modifiable maternal risk factors-pre-pregnancy BMI, gestational weight gain and physical inactivity-in a cohort of girls enriched for BCFH.

Associations between infant growth and pubertal onset timing in a multiethnic prospective cohort of girls

BACKGROUND

Early puberty increases risk of adverse health conditions throughout the life course. US girls are experiencing earlier puberty without clear reasons. Studies suggest early life factors, such as infant growth, may influence pubertal timing. We assessed the associations between infant growth and onset of breast development (thelarche), pubic hair development (pubarche), and menarche in girls.

METHODS

A prospective cohort of girls born at a Kaiser Permanente Northern California medical facility in 2005-11 was used. Weight-for-age z-scores were calculated at birth and 24 months. Difference in z-scores greater than 0.67 represent rapid "catch-up" growth, less than -0.67 represent delayed "catch-down" growth, and between -0.67 and 0.67 represent "normal" growth. Pubertal onset was measured using clinician-assessed sexual maturity ratings (SMRs) and defined as the age at transition from SMR 1 to SMR 2 + for both thelarche and pubarche. SMR data was collected through June 2020. Menarche was analyzed as a secondary outcome. Weibull and modified Poisson regression models were used. Models were adjusted for potential confounders.

RESULTS

There were 15,196 girls included in the study. Approximately 30.2% experienced catch-up growth, 25.8% experienced catch-down growth, and 44% had normal growth. Girls with catch-up growth had increased risk of earlier thelarche (hazard ratio = 1.26, 95% confidence interval (CI): 1.18, 1.35), pubarche (1.38, 95% CI: 1.28, 1.48), and menarche (< 12y, relative risk = 1.52, 95% CI: 1.36, 1.69) compared to those with normal growth, after adjusting for covariates. These associations were partially mediated by childhood body mass index. Catch-down growth was associated with later pubertal onset.

CONCLUSIONS

Girls who experience infant catch-up growth have higher risk of earlier pubertal development compared to girls with normal growth and the associations are partially explained by childhood obesity. This information may help clinicians to monitor girls who are at high risk of developing earlier.

Timing of Pubertal Development in Boys and Girls With Congenital Heart Defects: A Nationwide Cohort Study

Background

Children with congenital heart defects (CHD) have an increased risk of developmental delay. It remains sparsely investigated if these patients also have a delayed pubertal development. In this nationwide cohort study, we evaluated if CHD was associated with timing of puberty using longitudinally collected data on pubertal milestones.

Methods and Results

We used data from the Danish nationwide Puberty Cohort. Information on CHD was obtained from the Danish National Patient Register. Information on pubertal development was obtained from 15 780 children through questionnaires answered half‐yearly from 11 years until 18 years or full maturity. Using a multivariable regression model for censored time‐to‐event data, mean difference in age at attaining each pubertal milestone was estimated, including a combined pubertal marker. Compared with children without CHD, analyses were performed for both CHD overall and subdivided into simple and complex CHD. In a subanalysis, analyses were repeated in children born at term. In total, 137 children (62 boys and 75 girls) had a CHD diagnosis. Overall, no difference in age at pubertal timing was observed for children with CHD compared with unaffected children. The average differences were small for both boys (1.6 [95% CI, −2.6 to 5.7] months) and girls (1.0 [95% CI, −2.5 to 4.4] months). The same differences were observed when subdividing into simple or complex CHD and when restricting to children born at term.

Conclusions

We found no association between CHD and pubertal timing. For the group of children with complex CHD, we were unable to exclude a later pubertal timing.

Association of mode of delivery with offspring pubertal development in Project Viva: a prospective pre-birth cohort study in the USA

STUDY QUESTION

Is cesarean delivery associated with earlier offspring pubertal development?

SUMMARY ANSWER

We identified that boys born by cesarean delivery developed puberty earlier, evidenced by an earlier age at peak height velocity and earlier attainment of puberty score > 1, than boys born by vaginal delivery.

WHAT IS KNOWN ALREADY

Cesarean delivery is posited to have long-term effects on health outcomes. However, few studies have examined whether mode of delivery is related to pubertal development.

STUDY DESIGN, SIZE, DURATION

Prospective pre-birth cohort study consisting of 1485 mother-child pairs enrolled during pregnancy from obstetric practices and followed up until early adolescence (median age 12.9 years). Participant inclusion required data on mode of delivery and at least one measure of pubertal development.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants are children from the Project Viva study. We abstracted information on delivery mode from electronic medical records from children followed since birth (1999-2002) and examined the following markers of pubertal development: age at peak height velocity (APHV); age at menarche (girls only); parent-reported pubertal development score; and child-reported pictograph Tanner pubic hair staging. We used multivariable regression models to examine associations of delivery mode with these four pubertal indices, adjusting for the following confounders: demographic and socioeconomic factors; maternal height, pre-pregnancy BMI, total gestational weight gain, pregnancy conditions, parity, and maternal age at menarche; paternal height and BMI; gestational age at delivery and birthweight-for-gestational-age z-score.

MAIN RESULTS AND THE ROLE OF CHANCE

In this study, 23.2% of children were born by cesarean delivery. Girls had an earlier APHV, had a higher pubertal score throughout childhood and in early adolescence, and were more likely to attain puberty score >1 and Tanner pubic hair Stage >1 earlier compared to boys. Mean (SD) age at menarche in girls was 12.4 (1.0) years. Boys born by cesarean delivery had significantly earlier APHV (β -0.23 years; 95% CI -0.40, -0.05) and higher risk of earlier attainment of puberty score > 1 (hazard ratio 1.09; 95% CI 1.01, 1.19) than boys born by vaginal delivery, after adjusting for confounders. These associations were not mediated by pre-pubertal BMI and were similar for planned (no labor) and unplanned (labor) cesarean delivery. No associations were observed between delivery mode and time to attain Tanner pubic hair Stage > 1 in boys. In girls, mode of delivery was not associated with any of the measured pubertal development markers.

LIMITATIONS, REASONS FOR CAUTION

This study used, as secondary outcomes, parent- and child-reported measures of pubertal development, which may be more prone to error and misclassification than information collected by trained observers or physicians during clinical examinations. The findings may also not be generalizable to populations from different settings, because all participants lived in one geographic area, were well educated, and had health care.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings provide support for cesarean delivery as a potential indicator of identifying children who are likely to experience earlier pubertal development; however, more studies are needed to confirm or refute these observations.

STUDY FUNDING/COMPETING INTEREST(S)

The project was funded by grants from the National Institutes of Health. The authors have no financial relationships or competing interests to disclose.

TRIAL REGISTRATION NUMBER

N/A.

Early-life exposures and age at thelarche in the Sister Study cohort

BACKGROUND

Early age at breast development (thelarche) has been associated with increased breast cancer risk. Average age at thelarche has declined over time, but there are few established risk factors for early thelarche. We examined associations between pre- and postnatal exposures and age at thelarche in a US cohort of women born between 1928 and 1974.

METHODS

Breast cancer-free women ages 35-74 years who had a sister diagnosed with breast cancer were enrolled in the Sister Study from 2003 to 2009 (N = 50,884). At enrollment, participants reported information on early-life exposures and age at thelarche, which we categorized as early (≤ 10 years), average (11-13 years), and late (≥ 14 years). For each exposure, we estimated odds ratios (ORs) and 95% confidence intervals (CIs) for early and late thelarche using polytomous logistic regression, adjusted for birth cohort, race/ethnicity and family income level in childhood.

RESULTS

Early thelarche was associated with multiple prenatal exposures: gestational hypertensive disorder (OR = 1.25, 95% CI 1.09-1.43), diethylstilbestrol use (OR = 1.23, 95% CI 1.04-1.45), smoking during pregnancy (OR = 1.20, 95% CI 1.13-1.27), young maternal age (OR 1.30, 95% CI 1.16-1.47 for < 20 vs. 25-29 years), and being firstborn (OR = 1.25, 95% CI 1.17-1.33). Birthweight < 2500 g and soy formula use in infancy were positively associated with both early and late thelarche.

CONCLUSIONS

Associations between pre- and postnatal exposures and age at thelarche suggest that the early-life environment influences breast development and therefore may also affect breast cancer risk by altering the timing of pubertal breast development.

Patterns of Early Life Weight Gain and Female Onset of Puberty

Context

Prepubertal obesity is a well-established predictor of earlier pubertal onset, which is itself a risk factor for poor health and well-being. Identifying specific patterns of weight gain in early life may help explain differential risk for earlier pubertal onset.

Objective

The objective of the study was to examine patterns of weight gain across infancy and early childhood in relation to pubertal onset outcomes.

Design, Setting, and Participants

Participants were 426 girls in the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development, a longitudinal birth cohort of children and their families followed between birth and adolescence.

Main Outcome Measures

Three pubertal onset outcomes were examined, including age at menarche and ages at Tanner stage II for dimensions of breast and pubic hair development.

Results

In infancy (birth to 15 months), greater percent weight gain and higher birthweight predicted earlier pubertal onset for all outcomes (Ps < 0.05). In early childhood (24 months to grade 1), body mass index (BMI) trajectories reflecting BMI values that were persistently high or changed from low to high over time (vs BMI values that were stable at median or low levels), predicted younger ages at menarche and the onset of breast (Ps < 0.05), but not pubic hair (Ps > 0.05), development. All associations were independent of breastfeeding, maternal menarcheal age, and race/ethnicity.

Conclusions

Distinct patterns of early life weight gain predict differential risk for earlier onset puberty. Focusing on these patterns for earlier and more targeted intervention may help lessen life course linkages between prepubertal obesity, accelerated pubertal development, and negative postpubertal outcomes.

Long-term residential exposure to air pollution is associated with hair cortisol concentration and differential leucocyte count in Flemish adolescent boys

BACKGROUND

Exposure to air pollution and traffic noise are associated with adverse health outcomes in adolescents. Chronic endocrine stress and systemic inflammation have been hypothesized to underlie the adverse health effects. Simultaneous assessment of inflammation and chronic endocrine stress in epidemiological studies is lacking. The aim of the study was to investigate biomarkers of chronic endocrine stress and inflammation in relation to long-term residential exposure to air pollution and traffic noise in adolescents.

METHODS

In Flemish adolescents (14-15 years), we determined hair cortisol concentration (HCC) as a chronic stress biomarker in 3-cm scalp-near hair sections (n = 395), and leucocyte and leucocyte subtype counts (neutrophils, monocytes, lymphocytes) as inflammatory biomarkers in peripheral blood (n = 385). Daily particulate matter (PM_2.5, PM₁₀), nitrogen dioxide (NO₂) and black carbon (BC) concentrations were modelled at the residential address and averaged over 3-month and 1-year periods prior to sampling. Residential traffic noise level was estimated and classified in 5 dB intervals. Sex-specific associations between residential exposures and effect biomarkers were studied using linear regression models, adjusted for a priori selected covariates.

RESULTS

In boys, HCC increased with a factor 1.30 (95% CI: 1.10, 1.54) for an increase in 1-year mean NO₂ from the 25th to 75th percentile (p75/p25), after adjustment for age, BMI, personal and neighborhood socioeconomic status. The corresponding estimate for PM₁₀ was 1.24 (95% CI: 1.02, 1.51). Total leucocyte count in boys, adjusted for the aforementioned covariates and recent health complaints, was positively associated with PM_2.5, PM₁₀, NO₂ and BC. In particular, the neutrophil count increased with a factor 1.11 (95% CI: 1.03, 1.19) for a (p75/p25)-factor increase in 1-year mean BC, corresponding estimates for PM_2.5, PM₁₀ and NO₂ were 1.10 (95% CI: 1.01, 1.19), 1.10 (95% CI: 1.01, 1.20) and 1.08 (95% CI: 1.00, 1.16). Lymphocyte count increased with a factor 1.05 (95% CI: 1.01, 1.10) for a (p75/p25)-factor increase in 1-year mean NO₂. Similar results were observed for 3-month mean exposures. Results were robust to adjustment for recent air pollution exposure. In girls, air pollutants were not associated with HCC or differential leucocyte count. Residential traffic noise level was not associated with HCC or leucocyte counts in boys nor girls.

CONCLUSIONS

Long-term residential exposure to air pollutants was positively associated with chronic endocrine stress and inflammation in adolescent boys, not in girls. This study may contribute to a better understanding of the early pathophysiological changes that may underlie adverse health effects of air pollution exposure in adolescents.

Breast feeding and timing of puberty in boys and girls: A nationwide cohort study

BACKGROUND

Breast feeding has been associated with improved infant health, but its impact on pubertal timing remains uncertain, particularly in boys.

OBJECTIVE

The objective of this study was to investigate the association between duration of breast feeding and pubertal timing in boys and girls.

METHODS

This population-based cohort study included 13 511 boys and girls from the Puberty Cohort nested within the Danish National Birth Cohort. The children gave half-yearly, self-reported information on pubertal development through questionnaires (Tanner stages, age at menarche, first ejaculation, voice break, axillary hair growth, and acne). Information on breast feeding was provided by the mothers when the children were 6 months of age. We estimated mean differences (in months) in age at attaining each pubertal marker and for overall timing of puberty (combined estimate) for every additional month of exclusive breast feeding. Furthermore, we estimated differences in pubertal age when comparing children never exclusively breastfed and exclusively breastfed <4 months using children exclusively breastfed ≥4 months as reference. In sub-analyses, we further adjusted for infant weight gain and childhood BMI at 7 years to investigate whether these variables mediated the association.

RESULTS

Boys tended to reach pubertal markers later for every additional month of exclusive breast feeding (combined estimate: 0.2 (95% confidence interval [CI] 0.0, 0.4 months). Never exclusively breastfed boys reached pubertal markers earlier than the boys exclusively breastfed ≥4 months (combined estimate: -4.1 (95% CI -6.7, -1.6) months). Boys exclusively breastfed <4 months also reached pubertal markers earlier than those never exclusively breastfed but with smaller differences. In girls, duration of breast feeding was not associated with pubertal development. When including infant weight gain or childhood BMI, the results remained essentially unchanged.

CONCLUSIONS

Shorter duration of exclusive breast feeding was associated with earlier pubertal development in boys but not in girls.

Pubarche and Gonadarche Onset and Progression Are Differently Associated With Birth Weight and Infancy Growth Patterns

Context

Controversy exists regarding associations between early-life growth patterns and timing of puberty.

Objective

This work aims to investigate associations between birth anthropometry, early growth patterns, and onset/progression of pubertal milestones in boys and girls.

Methods

Among children examined at birth (1997-2003) and at age 36 months in a mother-child cohort, pubertal Tanner stages (B1-5, PH1-5, G1-5) and testicular volume were examined by trained physicians at 1 to 5 follow-up examinations during childhood and adolescence (672 girls and 846 boys, 2006-2013).With parametric survival models we analyzed associations between birth weight, changes in SD scores (SDS) from birth to 36 months (ΔSDS 0-36 > 0.67 SD defining catch-up growth), and age at pubertal onset/attainment of late pubertal stages/menarche.

Results

A 1-kg higher birth weight was associated with earlier onset of B2+ (thelarche): -3.9 months (CI, -6.7 to -1.1 months), G2+ (gonadarche): -2.7 months (-5.3 to -0.1 months), Tvol3+ (testis size > 3 mL): -2.8 months (CI, -4.9 to -0.7 months), but with later G4+ and PH4+ in boys, and a slower progression from B2 to menarche (5.3 months [CI, 1.2 to 9.4 months]) in girls. Catch-up growth was associated with earlier PH2+ (pubarche) in girls (-4.1 months [CI, -7.6 to -0.6 months]), earlier PH2+ in boys (-3.4 months [CI, -6.6 to -0.2 months]), faster progression from B2 to menarche in girls (-9.1 months [CI, 14.6 to 3.5 months]), and earlier G4+ and PH4+ in boys.

Conclusion

Associations between birthweight and infancy catch-up growth differed for gonadarche and pubarche, and for early and late pubertal markers, with similar patterns in both sexes.

New Horizons in Short Children Born Small for Gestational Age

Children born small for gestational age (SGA) comprise a heterogeneous group due to the varied nature of the cause. Approximately 85-90% have catch-up growth within the first 4 postnatal years, while the remainder remain short. In later life, children born SGA have an increased risk to develop metabolic abnormalities, including visceral adiposity, insulin resistance, and cardiovascular problems, and may have impaired pubertal onset and growth. The third "360° European Meeting on Growth and Endocrine Disorders" in Rome, Italy, in February 2018, funded by Merck KGaA, Germany, included a session that examined aspects of short children born SGA, with three presentations followed by a discussion period, on which this report is based. Children born SGA who remain short are eligible for GH treatment, which is an approved indication. GH treatment increases linear growth and can also improve some metabolic abnormalities. After stopping GH at near-adult height, metabolic parameters normalize, but pharmacological effects on lean body mass and fat mass are lost; continued monitoring of body composition and metabolic changes may be necessary. Guidelines have been published on diagnosis and management of children with Silver-Russell syndrome, who comprise a specific group of those born SGA; these children rarely have catch-up growth and GH treatment initiation as early as possible is recommended. Early and moderate pubertal growth spurt can occur in children born SGA, including those with Silver-Russell syndrome, and reduce adult height. Treatments that delay puberty, specifically metformin and gonadotropin releasing hormone analogs in combination with GH, have been proposed, but are used off-label, currently lack replication of data, and require further studies of efficacy and safety.

Association of Infant Physical Development and Rapid Growth With Pubertal Onset Among Girls in Rural China

IMPORTANCE

Whether physical development and rapid growth during the first 2 years of life are associated with puberty onset in girls remains unclear.

OBJECTIVE

To examine the associations of infant physical development and rapid growth with the timing of puberty onset in girls.

DESIGN, SETTING, AND PARTICIPANTS

This prospective birth cohort study included girls whose mothers had participated in a randomized, double-blind cluster trial of micronutrient supplementation with a daily capsule of folic acid, iron and folic acid, or multiple micronutrients during pregnancy. A total of 547 singleton girls in rural western China who were born after 2004 were followed up at 3, 6, 12, and 24 months of age and were eligible for long-term follow-up. Of these, 294 adolescent girls (aged 10-12 years), representing 53.7% of the total sample, were included in the follow-up interview that was conducted from June 1 through December 31, 2016. Data analyses were conducted from November 1, 2019, to May 30, 2020.

EXPOSURES

Infant weight and length were assessed at birth and 3, 6, 12, and 24 months of age. Rapid growth, defined as a weight-for-age or length-for-age z score increase of greater than 0.67, was calculated during 5 periods: birth to 3 months, birth to 6 months, 6 to 12 months, 12 to 24 months, and birth to 24 months of age.

MAIN OUTCOMES AND MEASURES

Puberty stage was assessed using the standardized Tanner staging system. Onset of puberty was defined as attaining Tanner stage 2 of breast development or pubic hair growth, and the corresponding age at follow-up was recorded.

RESULTS

Of 294 girls included in the analysis (mean [SD] age, 11.25 [0.57] years), the median age of puberty onset was 11 (interquartile range, 10-11) years. A significant association with puberty onset was found for infancy weight-for-age z score at 12 months of age (adjusted hazard ratio [HR], 1.20; 95% CI, 1.01-1.44) and rapid weight gain from birth to 24 months of age (adjusted HR, 1.40; 95% CI, 1.01-1.93) and birth to 3 months of age (adjusted HR, 1.39; 95% CI, 1.02-1.91). However, length-related indicators during early life were not associated with adolescent puberty onset.

CONCLUSIONS AND RELEVANCE

This study found that a higher weight-for-age z score and rapid weight gain during infancy, particularly from birth to 3 months of age, were associated with an increased likelihood of puberty onset in girls. These findings suggest that weight-related indicators may serve as proxies of puberty onset among adolescent girls.

Placental weight Z-score and pubertal timing: A population-based cohort study

BACKGROUND

The placenta provides nutrients, oxygen, and hormonal support for adequate fetal growth and development of the hormonal axes, which are important for pubertal timing later in life.

OBJECTIVES

We investigated if an indicator of poor placental function, low gestational age-specific Z-score for placental weight at birth, was associated with earlier pubertal timing.

METHODS

The study is based on a population-based cohort of 15 195 singleton boys and girls (68% of 22 439 invited) born 20 to 43 weeks of gestation (2000-2003) nested within the Danish National Birth Cohort. Placental Z-score was estimated from data collected at birth. Between 2012 and 2018, the children returned half-yearly web-based questionnaires from age of 11 years on status of the pubertal milestones: Tanner stages, voice break, first ejaculation, menarche, acne, and axillary hair. We estimated adjusted monthly differences in mean age at attaining the pubertal milestones and pubertal timing overall with placental Z-score continuously and as restricted cubic splines. Further, we explored whether growth by birthweight Z-score and body mass index Z-score around 7 years mediated the associations.

RESULTS

Placental Z-score was positively associated with age at attaining most of the pubertal milestones in girls, particularly for age at menarche, but not in boys. Effect sizes were modest, and when combining all pubertal milestones, one standard deviation increase in placental Z-score was associated with 0.5 months (95% confidence interval [CI] 0.2, 0.9) later pubertal timing overall in girls. The associations in girls were largely mediated through fetal growth.

CONCLUSIONS

Assuming that placental Z-score correlates with placental function, these findings suggest that placental dysfunction (low placental Z-score) advances pubertal timing in girls slightly by reducing fetal growth. Future studies need to evaluate whether placental weight sufficiently captures intrauterine growth of importance for pubertal development and search for other potential candidates reflecting placental function.

The Role of Fetal, Infant, and Childhood Nutrition in the Timing of Sexual Maturation

Puberty is a crucial developmental stage in the life span, necessary to achieve reproductive and somatic maturity. Timing of puberty is modulated by and responds to central neurotransmitters, hormones, and environmental factors leading to hypothalamic-pituitary-gonadal axis maturation. The connection between hormones and nutrition during critical periods of growth, like fetal life or infancy, is fundamental for metabolic adaptation response and pubertal development control and prediction. Since birth weight is an important indicator of growth estimation during fetal life, restricted prenatal growth, such as intrauterine growth restriction (IUGR) and small for gestational age (SGA), may impact endocrine system, affecting pubertal development. Successively, lactation along with early life optimal nutrition during infancy and childhood may be important in order to set up timing of sexual maturation and provide successful reproduction at a later time. Sexual maturation and healthy growth are also influenced by nutrition requirements and diet composition. Early nutritional surveillance and monitoring of pubertal development is recommended in all children, particularly in those at risk, such as the ones born SGA and/or IUGR, as well as in the case of sudden weight gain during infancy. Adequate macro and micronutrient intake is essential for healthy growth and sexual maturity.

Growth status of children and adolescents born small for gestational age at full term in Korea: data from the KNHANES-V

Objectives Small for gestational age (SGA) status is known to show stunted growth and results in short stature in adults. The aim of this study was to describe the current short stature in subjects born SGA in Korea and to assess catch-up growth (CUG) or non-CUG. Methods We analyzed data from 3,524 subjects (1,831 male) aged 1-18 years who were born as full-term singletons and who participated in the Fifth Korean National Health and Nutrition Examination Survey (2010-2011). Results The prevalence of SGA was 13.4% (n=471). Subjects born SGA had fathers with shorter height, shorter mother's height, and mid-parental height than non-SGA subjects (p<0.05 for all). The odds ratios (ORs) for SGA birth of a short statured father and a short statured mother were 2.00 (95% CI; 1.15-3.47) and 2.11 (95% CI; 1.30-3.40), respectively. Among 471 SGA subjects, 28 subjects (5.9%) were non-CUG, which made up 36.4% of all subjects with short stature. The CUG subjects had a higher father's height, mother's height, mid-parental height, and current BMI (p<0.05 for all). The non-CUG subjects had a higher percentage of fathers being near-short stature (height<10th percentile; 33.3 vs. 12.7%; p=0.008) and mothers being near-short stature (39.3 vs. 13.9%; p<0.001). Conclusion Korean subjects born SGA had a higher risk of current short stature. This population-based nationwide survey also showed that both father's and mother's short stature are risk factors of not only SGA birth but also non-CUG in their children.