The Association Between Puberty Timing and Body Mass Index in a Longitudinal Setting: The Contribution of Genetic Factors

Joint models reveal genetic architecture of pubertal stage transitions and their association with BMI in admixed Chilean population

Early or late pubertal onset can lead to disease in adulthood, including cancer, obesity, type 2 diabetes, metabolic disorders, bone fractures, and psychopathologies. Thus, knowing the age at which puberty is attained is crucial as it can serve as a risk factor for future diseases. Pubertal development is divided into five stages of sexual maturation in boys and girls according to the standardized Tanner scale. We performed genome-wide association studies (GWAS) on the "Growth and Obesity Chilean Cohort Study" cohort composed of admixed children with mainly European and Native American ancestry. Using joint models that integrate time-to-event data with longitudinal trajectories of body mass index (BMI), we identified genetic variants associated with phenotypic transitions between pairs of Tanner stages. We identified $42$ novel significant associations, most of them in boys. The GWAS on Tanner $3\rightarrow 4$ transition in boys captured an association peak around the growth-related genes LARS2 and LIMD1 genes, the former of which causes ovarian dysfunction when mutated. The associated variants are expression and splicing Quantitative Trait Loci regulating gene expression and alternative splicing in multiple tissues. Further, higher individual Native American genetic ancestry proportions predicted a significantly earlier puberty onset in boys but not in girls. Finally, the joint models identified a longitudinal BMI parameter significantly associated with several Tanner stages' transitions, confirming the association of BMI with pubertal timing.

Acceleration of skeletal maturation in Central Europe over the last two decades: insights from two cohorts of healthy children

BACKGROUND

Deviations between the determination of bone age (BA) according to Greulich and Pyle (G&P) and chronological age (CA) are common in Caucasians. Assessing these discrepancies in a population over time requires analysis of large samples and low intra-observer variability in BA estimation, both can be achieved with artificial intelligence-based software. The latest software-based reference curve contrasting the BA determined by G&P to the CA of Central European children dates back over two decades.

OBJECTIVE

To examine whether the reference curve from a historical cohort from the Netherlands (Rotterdam cohort) between BA determined by G&P and CA still applies to a current Central European cohort and derive a current reference curve.

MATERIALS AND METHODS

This retrospective single-center study included 1,653 children and adolescents (aged 3-17 years) who had received a radiograph of the hand following trauma. The G&P BA estimated using artificial intelligence-based software was contrasted with the CA, and the deviations were compared with the Rotterdam cohort.

RESULTS

Among the participants, the mean absolute error between BA and CA was 0.92 years for girls and 0.97 years for boys. For the ages of 8 years (boys) and 11 years (girls) and upward, the mean deviation was significantly greater in the current cohort than in the Rotterdam cohort. The reference curves of both cohorts also differed significantly from each other (P < 0.001 for both boys and girls).

CONCLUSION

The BA of the current Central European population and that of the curve from the Rotterdam cohort from over two decades ago differ. Whether this effect can be attributed to accelerated bone maturation needs further evaluation.

Evaluation and comparison of nine growth and development-based measures of pubertal timing

BACKGROUND

Pubertal timing is heritable, varies between individuals, and has implications for life-course health. There are many different indicators of pubertal timing, and how they relate to each other is unclear. Our aim was to quantitatively compare nine indicators of pubertal timing.

METHODS

We used data from questionnaires and height, weight, and bone measurements from ages 7-17 y in a population-based cohort of 4267 females and 4251 males to compare nine growth and development-based indicators of pubertal timing. We summarise age of each indicator, their phenotypic and genetic correlations, and how they relate to established genetic risk score (GRS) for puberty timing, and phenotypic childhood body composition measures.

RESULTS

We show that pubic hair in males (mean: 12.6 y) and breasts in females (11.5 y) are early indicators of puberty, and voice breaking (14.2 y) and menarche (12.7 y) are late indicators however, there is substantial variation between individuals in pubertal age. All indicators show evidence of positive phenotypic intercorrelations (e.g., r = 0.49: male genitalia and pubic hair ages), and positive genetic intercorrelations. An age at menarche GRS positively associates with all other pubertal age indicators (e.g., difference in female age at peak height velocity per SD higher GRS: 0.24 y, 95%CI: 0.21 to 0.26), as does an age at voice breaking GRS (e.g., difference in age at male axillary hair: 0.11 y, 0.07 to 0.15). Higher childhood fat mass and lean mass associated with earlier puberty timing.

CONCLUSIONS

Our findings provide insights into the measurements of the timing of pubertal growth and development and illustrate value of various pubertal timing indicators in life-course research.

Prenatal, newborn and childhood factors and the timing of puberty in boys and girls

BACKGROUND

Our aim was to determine if prenatal factors, gestational age, birth weight and length, and childhood body mass index (BMI) are associated with the timing of puberty.

METHODS

Our population-based study comprised 4826 girls and 5112 boys born between 1997 and 2002. Multiple linear regression modeled the relationships between the maternal and child predictors and the age at peak height velocity (PHV).

RESULTS

Maternal smoking throughout pregnancy was associated with earlier age at PHV (-1.8 months in girls, 95%CI = -3.2 to -0.3, p = 0.015 and -1.7 months in boys, 95%CI = -3.1 to -0.3, p = 0.016). Older gestational age predicted later age at PHV in boys. One SDS increase in birth weight led to 1.7 months later age at PHV in girls (95%CI = 1.2 to 2.2, p < 0.001) and 0.8 months in boys (95%CI = 0.2 to 1.3, p = 0.005). At the age of 9 years, each increment of BMI by 1 kg/m2 was associated with 1.7 months (95%CI = -1.9 to -1.6, p < 0.001) and 1.3 months (95%CI = -1.4 to -1.1, p < 0.001) earlier age at PHV in girls and boys, respectively.

CONCLUSIONS

Fetal exposure to smoking can potentially exert enduring effects on pubertal timing. Birth weight and childhood nutritional status are significant determinants of pubertal timing in both sexes.

IMPACT

Maternal smoking was associated with earlier timing of puberty and greater birth weight with later timing of puberty in both girls and boys. Most previous studies have focused on girls and used surveys to assess pubertal development, but we studied both sexes and used the same objective measure (age at peak height velocity) for the timing of puberty. Our study increases knowledge especially regarding factors associated with the timing of puberty among boys.

Long-term health consequences of central precocious/early puberty (CPP) and treatment with Gn-RH analogue: a short update

BACKGROUND

The relationship between precocious or early puberty and its treatment has received significant research attention, yielding diverse outcomes. This short review aims to comprehensively analyze and summarize research articles to elucidate the potential link between precocious or early pubertal onset (CPP) and crucial health factors.

METHODS

We conducted a systematic review of studies published from -January 2000 to March 2023, sourced from databases of Medline, PubMed, Google Scholar and Web of Science. We assessed the relationship between CPP and final adult height (FHt), bone health, reproductive function, body mass index, metabolic and cardiovascular abnormalities, and increased cancer risk.

RESULTS

Upon reviewing and analyzing selected studies, the following key findings emerged: (a) treating CPP in girls before age 6-7 and in boys before age 9 improves FHt; (b) bone mineral density (BMD) decreases during GnRHa treatment but normalizes afterward, with no lasting effects on peak bone mass during puberty; (c) GnRH treatment does not negatively affect menstrual cycles; however, untreated CPP increases the risk of premature or early-onset menopause; (d) the incidence of PCOS/hyperandrogenemia may be slightly elevated in women with a history of CPP, but overall reproductive function remains largely unaffected; (e) earlier thelarche and menarche may enhance susceptibility to breast carcinogenesis; (f) CPP contributes to an increased risk of obesity and type 2 diabetes in both genders; (g) early menarche may slightly increase the risk of coronary heart disease and ischemic strokes and (h) early pubertal timing increases the risk of depression and anxiety disorders.

CONCLUSION

Monitoring and early diagnosis of these conditions are of paramount importance for successful management.

DNA methylation sites in early adulthood characterised by pubertal timing and development: a twin study

BACKGROUND

Puberty is a highly heritable and variable trait, with environmental factors having a role in its eventual timing and development. Early and late pubertal onset are both associated with various diseases developing later in life, and epigenetic characterisation of pubertal timing and development could lead to important insights. Blood DNA methylation, reacting to both genotype and environment, has been associated with puberty; however, such studies are relatively scarce. We investigated peripheral blood DNA methylation profiles (using Illumina 450 K and EPIC platforms) of 1539 young adult Finnish twins associated with pubertal development scale (PDS) at ages 12 and 14 as well as pubertal age (PA).

RESULTS

Fixed effect meta-analysis of the two platforms on 347,521 CpGs in common identified 58 CpG sites associated (p < 1 × 10-5) with either PDS or PA. All four CpGs associated with PA and 45 CpGs associated with PDS were sex-specific. Thirteen CpGs had a high heritability (h2: 0.51-0.98), while one CpG site (mapped to GET4) had a high shared environmental component accounting for 68% of the overall variance in methylation at the site. Utilising twin discordance analysis, we found 6 CpG sites (5 associated with PDS and 1 with PA) that had an environmentally driven association with puberty. Furthermore, genes with PDS- or PA-associated CpGs were consistently linked to various developmental processes and diseases such as breast, prostate and ovarian cancer, while methylation quantitative trait loci of associated CpG sites were enriched in immune pathways developing during puberty.

CONCLUSIONS

By identifying puberty-associated DNA methylation sites and examining the effects of sex, environment and genetics, we shed light on the intricate interplay between environment and genetics in the context of puberty. Through our comprehensive analysis, we not only deepen the understanding of the significance of both genetic and environmental factors in the complex processes of puberty and its timing, but also gain insights into potential links with disease risks.

Clinical Management and Therapy of Precocious Puberty in the Sapienza University Pediatrics Hospital of Rome, Italy

Puberty identifies the transition from childhood to adulthood. Precocious puberty is the onset of signs of pubertal development before age eight in girls and before age nine in boys, it has an incidence of 1/5000-1/10,000 with an F:M ratio ranging from 3:1 to 20:1. Precocious puberty can be divided into central, also known as gonadotropin-dependent precocious puberty or true precocious puberty, and peripheral, also recognized as gonadotropin-independent precocious puberty or precocious pseudopuberty. Thus, the main aim of this narrative report is to describe the standard clinical management and therapy of precocious puberty according to the experience and expertise of pediatricians and pediatric endocrinologists at Policlinico Umberto I, Sapienza University of Rome, Italy. In the suspicion of early sexual maturation, it is important to collect information regarding the age of onset, the speed of maturation of secondary sexual features, exposure to exogenous sex steroids and the presence of neurological symptoms. The objective examination, in addition to the evaluation of secondary sexual characteristics, must also include the evaluation of auxological parameters. Initial laboratory investigations should include serum gonadotropin levels (LH and FSH) and serum levels of the sex steroids. Brain MRI should be performed as indicated by the 2009 Consensus Statement in all boys regardless of chronological age and in all girls with onset of pubertal signs before 6 years of age. The gold standard in the treatment of central precocious puberty is represented by GnRH analogs, whereas, as far as peripheral forms are concerned, the triggering cause must be identified and treated. At the moment there are no reliable data establishing the criteria for discontinuation of GnRH analog therapy. However, numerous pieces of evidence suggest that the therapy should be suspended at the physiological age at which puberty occurs.

Testing Environmental Effects on Age at Menarche and Sexual Debut within a Genetically Informative Twin Design

Life-history-derived models of female sexual development propose menarche timing as a key regulatory mechanism driving subsequent sexual behavior. The current research utilized a twin subsample of the National Longitudinal Study of Adolescent to Adult Health (Add Health; n = 514) to evaluate environmental effects on timings of menarche and sexual debut, as well as address potential confounding of these effects within a genetically informative design. Results show mixed support for each life history model and provide little evidence rearing environment is important in the etiology of individual differences in age at menarche. This research calls into question the underlying assumptions of life-history-derived models of sexual development and highlights the need for more behavior genetic research in this area.

A Women's health perspective on managing obesity

While the prevalence of obesity in US men and women is nearly equivalent, obesity management in women requires a different approach that considers age and life stage in development including sexual maturation/reproduction, menopause and post-menopause. In this review, the diagnosis and treatment of obesity using lifestyle modification, pharmacotherapy and metabolic and bariatric surgery are discussed from a women's health perspective, with emphasis on management during pregnancy and post-partum.

The critical BMI hypothesis for puberty initiation and the gender prevalence difference: Evidence from an epidemiological survey in Beijing, China

BACKGROUND

Although previous studies suggested that there is a certain level of body fat mass before puberty can be initiated, most studies have focused on girls.

OBJECTIVE

To investigate the relationship between precocious puberty and physical growth in school-aged children in Beijing, China.

METHODS

7590 Chinese children (3591 girls and 3999 boys) aged 6-11 years were recruited in Beijing, China. Body mass index (BMI) categories were defined by WHO Child Growth Standards and central obesity were defined by sex-specific waist-to-height ratio cut-offs (≥0.46 for girls, ≥0.48 for boys). Sexual development was assessed using Tanner criteria.

RESULTS

The prevalence of general obesity and central obesity among boys was higher than that in girls. Girls had a significantly higher precocious puberty rate than boys (5.93% vs. 0.87%), particularly in those aged 7 years old (9.20%). Children in the general obesity and central obesity groups have a higher prevalence of precocious puberty and earlier median ages for the attainment of Tanner B₂/T₂. For girls with Tanner stages≥II at 6-year-old and 7-year-old, the mean BMI was equivalent to the 50th centile of a normal 9.9-year-old and 11.9-year-old girl, respectively. The mean BMI of boys with Tanner stages≥II at 7-year-old and 8-year-old was correspondent to the 50th centile of a normal 14-year-old and 15.3-year-old boy, respectively. For girls, general obesity appears to contribute to the risk of the development of precocious puberty to a greater extent than central obesity does. For boys, central obesity, but not general obesity, was an independent risk factor for precocious puberty.

CONCLUSIONS

The prevalence of childhood obesity and precocious puberty was high in China. Precocious puberty was correlated with a large BMI. Boys had a higher threshold of BMI for puberty development than girls. Children with precocious puberty, particularly those with central obesity, should be aware of adverse cardiovascular events.