The Impact of Adolescent Obesity on Adult Height

Can diffusion tensor imaging unlock the secrets of the growth plate?

"How tall will I be?" Every paediatrician has been asked this during their career. The growth plate is the main site of longitudinal growth of the long bones. The chondrocytes in the growth plate have a columnar pattern detectable by diffusion tensor imaging (DTI). DTI shows the diffusion of water in a tissue and whether it is iso- or anisotropic. By detecting direction and magnitude of diffusion, DTI gives information about the microstructure of the tissue. DTI metrics include tract volume, length, and number, fractional anisotropy (FA), and mean diffusivity. DTI metrics, particularly tract volume, provide quantitative data regarding skeletal growth and, in conjunction with the fractional anisotropy, be used to determine whether a growth plate is normal. Tractography is a visual display of the diffusion, depicting its direction and amplitude. Tractography gives a more qualitative visualization of cellular orientation in a tissue and reflects the activity in the growth plate. These two components of DTI can be used to assess the growth plate without ionizing radiation or pain. Further refinements in DTI will improve prediction of post-imaging growth and growth plate closure, and assessment of the positive and negative effect of treatments like cis-retinoic acid and growth hormone administration.

Height and Growth Velocity in Children and Adolescents Undergoing Obesity Treatment: A Prospective Cohort Study

CONTEXT

Pediatric obesity affects endocrine conditions, which may alter growth.

OBJECTIVE

This work aimed to investigate the effect of obesity severity and obesity treatment outcome on growth.

METHODS

This prospective cohort study included children (aged 3-18 years) enrolled in the Swedish Childhood Obesity Treatment Register (BORIS) (1998-2020). Obesity was categorized as class I and class II obesity. Obesity treatment outcome was measured as body mass index (BMI) z score changes and categorized into good (BMI z score reduction of ≥0.25), intermediate, and poor (increasing BMI z score). Height for age z score, final height, and growth velocity were compared between class I and class II obesity. Further, the effect of obesity treatment outcome on growth velocity during 2-year follow-up was assessed.

RESULTS

A total of 27 997 individuals (mean age 10.2 ± 3.6 years) were included. Individuals with class II obesity were on average taller than those with class I obesity during childhood. Among males, reduced growth spurt was observed in class I obesity, and even absent in class II obesity. Females exhibited a similar but less pronounced pattern. Good obesity treatment outcome yielded lower growth velocity at ages 3 to 9 years but higher growth velocity at ages 10 to 13 years compared to poor treatment outcome.

CONCLUSION

Obesity severity is positively associated with height and growth velocity in childhood. A hampered growth spurt during puberty should be anticipated, particularly in adolescents with severe obesity. Therefore no difference in final height between class I and class II obesity is expected. Successful obesity treatment does not harm, but rather normalizes, the growth velocity pattern.

Just as Tall on Testosterone; a Neutral to Positive Effect on Adult Height of GnRHa and Testosterone in Trans Boys

CONTEXT

Growth is an important topic for many transgender boys. However, few studies have investigated the impact of puberty suppression (PS) and gender-affirming hormone treatment (GAHT) on growth and adult height.

OBJECTIVE

To evaluate the effect of PS and GAHT on growth and adult height.

DESIGN

Retrospective cohort study.

SETTING

Specialized gender identity clinic.

PARTICIPANTS

A total of 146 transgender boys treated with GnRH analogues and testosterone who reached adult height.

MAIN OUTCOME MEASURES

Growth, bone age (BA), adult height, and difference between adult height and predicted adult height (PAH) and midparental height.

RESULTS

In those with BA ≤14 years at start (n = 61), a decrease in growth velocity and bone maturation during PS was followed by an increase during GAHT. Adult height was 172.0 ± 6.9 cm; height SD score was similar to baseline (0.1; 95% CI, -0.2 to 0.4). Adult height was 3.9 ± 6.0 cm above midparental height and 3.0 ± 3.6 cm above PAH at start of PS. A younger BA at start PS was associated with an adult height significantly further above PAH.

CONCLUSION

During PS, growth decelerated followed by an acceleration during GAHT. Although adult height SD score was similar to baseline, adult height was taller than predicted based on BA at baseline, especially in those who started treatment at a younger BA. It is reassuring that PS and GAHT do not have a negative impact on adult height in transgender boys and might even lead to a slightly taller adult height, especially in those who start at a younger age.

Associations of Obesity with Linear Growth and Puberty

BACKGROUND

The prevalence of obesity in childhood has increased dramatically in recent decades with increased risk of developing cardiometabolic and other comorbidities. Childhood adiposity may also influence processes of growth and puberty.

SUMMARY

Growth patterns of obesity during childhood have been shown to be associated with increased linear growth in early childhood, leading to accelerated epiphyseal growth plate (EGP) maturation. Several hormones secreted by the adipose tissue may affect linear growth in the context of obesity, both via the growth hormone IGF-1 axis and via a direct effect on the EGP. The observation that children with obesity tend to mature earlier than lean children has led to the assumption that the degree of body fatness may trigger the neuroendocrine events that lead to pubertal onset. The most probable link between obesity and puberty is leptin and its interaction with the kisspeptin system, which is an important regulator of puberty. However, peripheral action of adipose tissue could also be involved in changes in the onset of puberty. In addition, nutritional factors, epigenetics, and endocrine-disrupting chemicals are potential mediators linking pubertal onset to obesity. In this review, we focused on interactions of obesity with linear growth and pubertal processes, based on basic research and clinical data in humans.

KEY MESSAGE

Children with obesity are subject to accelerated linear growth with risk of impaired adult height and early puberty, with its psychological consequences. The data highlight another important objective in combatting childhood obesity, for the prevention of abnormal growth and pubertal patterns.

[Sex, gender and stature: From biology to culture - and back]

The origin of sexual dimorphism of stature (SSD) in the human species is a subject of debate, likely to have a sociocultural impact. Stature is optimally expressed in good environmental conditions, notably good food, with a strong hereditary determinism. The common academic interpretation, already proposed by Darwin, is that SSD results from sexual selection of stronger males, in most species of mammals, including humans. An alternative hypothesis proposes that it might result from alimentary gender coercion in humans. There is practically no SSD until female growth stops, by ossification of cartilage in the growth plates of long bones, largely under the action of estrogens. The mechanism is the same in males, with a delay due to a lesser and/or later concentration of estrogens. This explanation for SSD has the advantage of being valid for most mammalian species, including those like Pan paniscus where females are dominant. The fitness resulting from high estrogen levels would explain the relatively small stature of women, in spite of obstetric difficulties inversely correlated with height. If patriarchy is involved, it would be by the injunction of fertility rather than by alimentary coercion.

Linear growth and puberty in childhood obesity: what is new?

Pediatric obesity is a growing and alarming global health problem and represents an important determinant of morbidity. Since nutrition plays an important role in regulating growth and development, the excess weight gain related to overnutrition can affect growth patterns, bone maturation and pubertal development. The purpose of this review is to summarize the current knowledge about the effect of primary obesity on linear growth and pubertal development in children and adolescents. Evidences about regulatory hormones and adipokines that may be involved in the physiology of childhood growth in the context of obesity were also discussed. The most recent literature confirms previous studies indicating that linear growth is accelerated (mainly due to longer trunks rather than longer legs) and bone age is advanced in prepubertal children with obesity, while there is a reduction of pubertal height gain and attainment of normal adult height. Conflicting results are reported on the timing of puberty, specifically in boys. Indeed, previous studies suggested earlier onset of puberty in obese girls and overweight boys, and a delayed puberty in obese boys. Conversely, the most recent studies show more consistently an earlier onset and completion of pubertal development also in boys with obesity. Considering the false belief of health associated with transient taller stature in children and the adverse outcomes related to early puberty, interventions on diet and physical activity are urgently needed to tackle the epidemics of childhood obesity in public health and clinical setting.

Dynamic alterations in linear growth and endocrine parameters in children with obesity and height reference values

BACKGROUND

Obesity can affect linear growth of children but there is uncertainty regarding the dynamics and potential causes.

METHODS

In the population-based LIFE Child and the obesity-enriched Leipzig Obesity Childhood cohorts (8,629 children, 37,493 measurements), recruited from 1999 to 2018 in Germany, we compared height, growth, and endocrine parameters between normal-weight and children with obesity (0-20 years). Derived from the independent German CrescNet registry (12,703 children) we generated height reference values specific for children with obesity (data collected from 1999 to 2020).

FINDINGS

Children with obesity were significantly taller than normal-weight peers, differing at maximum by 7·6 cm (1·4 height, standard deviation scores or SDS) at age 6-8 years. Already at birth, children with obesity were slightly taller and thereafter had increased growth velocities by up to 1·2 cm/year. This growth acceleration was unrelated to parental height, but was accompanied by increased levels of insulin-like growth factor-1 (IGF-1), insulin and leptin. During puberty, children with obesity showed a catch-down in height SDS. The reduction in pubertal growth velocity by up to 25% coincided with a decrease in levels of IGF-1 (by 17%) and testosterone (by 62%) in boys and estradiol (by 37%) in girls. We confirmed these alterations in growth in the independent CrescNet cohort and furthermore provide height reference values for children with obesity for open access.

INTERPRETATION

Dynamics of linear growth are altered distinctively in different developmental phases in children with obesity. Early emergence before other profound comorbidities implies predisposition, environmental, and/or endocrine factors affecting growth in early life. Height reference values for children with obesity may enhance the precision of clinical health surveillance.

FUNDING

German Research Foundation, German Diabetes Association, EU, ESF, ERDF, State of Saxony, ESPE, Hexal, Novo Nordisk, Pfizer Pharma.

A cross-sectional magnetic resonance imaging study of factors influencing growth plate closure in adolescents and young adults

Aim

To assess growth plate fusion by magnetic resonance imaging (MRI) and evaluate the correlation with sex, age, pubertal development, physical activity and BMI.

Methods

Wrist, knee and ankle of 958 healthy subjects aged 14.0‐21.5 years old were examined using MRI and graded by two radiologists. Correlations of growth plate fusion score with age, pubertal development, physical activity and BMI were assessed.

Results

Complete growth plate fusion occurred in 75%, 85%, 97%, 98%, 98% and 90%, 97%, 95%, 97%, 98% (radius, femur, proximal‐ and distal tibia and calcaneus) in 17‐year‐old females and 19‐year‐old males, respectively. Complete fusion occurs approximately 2 years earlier in girls than in boys. Pubertal development correlated with growth plate fusion score (ρ = 0.514‐0.598 for the different growth plate sites) but regular physical activity did not. BMI also correlated with growth plate fusion (ρ = 0.186‐0.384). Stratified logistic regression showed increased odds ratio (OR F: 2.65‐8.71; M: 1.71‐4.03) for growth plate fusion of obese or overweight subects versus normal‐weight subjects. Inter‐observer agreement was high (Κ = 0.87‐0.94).

Conclusion

Growth plate fusion can be assessed by MRI; occurs in an ascending order, from the foot to the wrist; and is significantly influenced by sex, pubertal development and BMI, but not by physical activity.

The relationship between adolescent obesity and pelvis dimensions in adulthood: a retrospective longitudinal study

Background

The effect of fat tissue on a developing individual is fundamentally different from the effect on an adult. Several changes caused by obesity during sexual maturation have an irreversible and severe negative effect (lower fertility, reduced final height, type 2 diabetes mellitus) even for those who have subsequently lost weight. Our study was focused on monitoring the skeletal structure substantially influenced by sex hormones—the pelvis. The adult pelvis is strongly sexually dimorphic, which is not the case for the juvenile pelvis; skeletal differences between sexes are not so prominent and start to manifest with the onset of puberty. Evidence from animal models and case studies of treatment of gender dysphoria suggests that estrogens have a stimulatory effect on the growth plates present on the pelvis, leading to morphological change. Male obesity, especially in puberty, is connected with hypogonadism, manifesting in low levels of testosterone, and high levels of estrogens. The goal of our study was to evaluate the influence of obesity during adolescence on the morphology of the adult pelvis in the context of androgen and estrogen status.

Sample and Methods

Our sample consists of 238 individuals (144 females, 94 males) observed after an 8 year follow-up (mean age during enrollment 15.2 years, follow-up 23.3 years). Anthropometry and body composition using bioimpedance analysis (BIA) were obtained. During the follow-up, saliva samples from male participants were also collected to estimate testosterone and estradiol levels using the salivary ELISA kit (Salimetrics LLC, State College, PA, USA).

Results

The body fat (percentage of body fat estimated using BIA) was strongly positively associated with relative pelvic breadths in adulthood (males r = 0.64; females r = 0.56, both with p < 0.001). Adulthood pelvic breadth was a highly sensitive (0.81) and specific (0.74) retrospective marker of obesity during adolescence. The complex regression model (with reduction of dimensionality) including testosterone, estradiol to testosterone ratio and body fat (adolescent and adulthood) was able to describe 54.8% variability of pelvic breadth among males.

Discussion

We observed that adults with a history of obesity from adolescence tend to have a wider dimension of the bony pelvis in adulthood. Based on the parameters of the adult pelvis, the history of obesity can be determined with satisfactory sensitivity and specificity (<70%). One of the explanations for this observation can be the influence of relatively elevated estrogens levels connected with excessive adiposity leading to a wider pelvis. However, the biomechanical stress connected with elevated body mass also has to be considered, as does the influence of physical activity and gait pattern on the skeletal build.

Obesity and Hypogonadism-A Narrative Review Highlighting the Need for High-Quality Data in Adolescents

The prevalence of obesity continues to rise in adult and pediatric populations throughout the world. Obesity has a direct impact on all organ systems, including the reproductive system. This review summarizes current knowledge about the effects of obesity on the male reproductive system across age, highlighting the need for more data in children and adolescents. Male hypogonadism is commonly seen in patients with obesity and affects the onset, duration, and progression of puberty. Different pathophysiologic mechanisms include increased peripheral conversion of testosterone to estrone and increased inflammation due to increased fat, both of which lead to suppression of the hypothalamic-pituitary-gonadotropin (HPG) axis and delayed development of secondary sexual characteristics in adolescent males. Evaluation of the HPG axis in obesity includes a thorough history to exclude other causes of hypogonadism and syndromic associations. Evaluation should also include investigating the complications of low testosterone, including increased visceral fat, decreased bone density, cardiovascular disease risk, and impaired mood and cognition, among others. The mainstay of treatment is weight reduction, but medications such as testosterone and clomiphene citrate used in adults, remain scarcely used in adolescents. Male hypogonadism associated with obesity is common and providers who care for adolescents and young adults with obesity should be aware of its impact and management.

The influence of treatment, age at onset, and metabolic control on height in children and adolescents with type 1 diabetes-A SWEET collaborative study

OBJECTIVE

To describe the association between height, demographics, and treatment in youths with type 1 diabetes participating in an international network for pediatric diabetes centers (SWEET).

METHODS

Data were collected from 55 centers with documented patients' height. All subjects below 20 years of age, diabetes duration >1 year, and without celiac disease were included. World Health Organization growth charts were used to calculate height and body mass index z-scores. Multiple hierarchic regression models adjusting for known confounders were applied.

RESULTS

Data on 22 941 subjects (51.8% male) were analyzed with a median and interquartile range for age 14.8 years (11.2, 17.6), diabetes duration 5.6 years (3.1, 8.9), and height z-score 0.34 (-0.37, 1.03). Children were taller in the youngest age groups: adjusted height z-scores of 0.31 (±0.06) and 0.39 (±0.06), respectively; with shorter diabetes duration (<2 years: 0.36 [±0.06]; 2-<5 years: 0.34 [±0.06]; ≥5 years: 0.21 [±0.06]) and if they were pump users: 0.35 ± 0.05 vs 0.25 ± 0.05 (>three injections/day and 0.19 ± 0.06 [0-3 injections daily]), respectively. High hemoglobin A1c (HbA1c) and low to normal weight were associated with a lower height z-score. Trends were identical in all models except for gender. No gender differences were found except in the final height model where females exhibited higher z-score than males.

CONCLUSION

For youths treated at centers offering modern diabetes management, major growth disturbances are virtually eliminated. For children with a young age at onset, high HbA1c, injections, and/or non-intensive diabetes, treatment still requires attention in order to attain normal growth.