Effect of obesity on linear growth

Influence of BMI percentile on craniofacial morphology and development in adolescents,Part II: elevated BMI is associated with larger final facial dimensions

BACKGROUND

Prevalence of adolescent obesity has markedly increased from 5.2% in 1974 to 19.7% in 2021. Understanding the impacts of obesity is important to orthodontists, as growth acceleration and greater pre-pubertal facial dimensions are seen in children with elevated body mass index (BMI).

METHODS

To identify whether adolescent obesity shifts the timing and rate of craniofacial growth resulting in larger post-treatment dimensions, we evaluated cephalometric outcomes in overweight/obese (BMI > 85%, n = 168) and normal weight (n = 158) adolescents (N = 326 total). Cephalometric measurements were obtained from pre- and post-treatment records to measure growth rates and final dimensions and were statistically evaluated with repeated measures analysis of variance and linear regression models.

RESULTS

Overweight and obese adolescents began and finished treatment with significantly larger, bimaxillary prognathic craniofacial dimensions, with elevated mandibular length [articulare-gnathion (Ar-Gn)], maxillary length [condylion-anterior nasal spine (Co-ANS), posterior nasal spine-ANS (PNS-ANS)], and anterior lower face height (ANS-Me), suggesting overweight children grow more overall. However, there was no difference between weight cohorts in the amount of cephalometric change during treatment, and regression analyses demonstrated no correlation between change in growth during treatment and BMI. BMI percentile was a significant linear predictor (P < 0.05) for cephalometric post-treatment outcomes, including Ar-Gn, Co-ANS, ANS-Me, upper face height percentage (UFH:total FH, inverse relationship), lower face height percentage (LFH:total FH), sella-nasion-A-point (SNA), and SN-B-point (SNB).

LIMITATIONS

The study is retrospective.

CONCLUSIONS

Growth begins earlier in overweight and obese adolescents and continues at a rate similar to normal-weight children during orthodontic treatment, resulting in larger final skeletal dimensions. Orthodontics could begin earlier in overweight patients to time care with growth, and clinicians can anticipate that overweight/obese patients will finish treatment with proportionally larger, bimaxillary-prognathic craniofacial dimensions.

The Effects of Nutrition on Linear Growth

Linear growth is a complex process and is considered one of the best indicators of children’s well-being and health. Genetics, epigenetics and environment (mainly stress and availability of nutrients) are the main regulators of growth. Nutrition exerts its effects on growth throughout the course of life with different, not completely understood mechanisms. Cells have a sophisticated sensing system, which allows growth processes to occur in the presence of an adequate nutrient availability. Most of the nutritional influence on growth is mediated by hormonal signals, in turn sensitive to nutritional cues. Both macro- and micro-nutrients are required for normal growth, as demonstrated by the impairment of growth occurring when their intake is insufficient. Clinical conditions characterized by abnormal nutritional status, including obesity and eating disorders, are associated with alterations of growth pattern, confirming the tight link between growth and nutrition. The precise molecular mechanisms connecting nutrition to linear growth are far from being fully understood and further studies are required. A better understanding of the interplay between nutrients and the endocrine system will allow one to develop more appropriate and effective nutritional interventions for optimizing child growth.

Altered IGF-I activity and accelerated bone elongation in growth plates precede excess weight gain in a mouse model of juvenile obesity

Nearly one-third of children in the United States are overweight or obese by their preteens. Tall stature and accelerated bone elongation are characteristic features of childhood obesity, which cooccur with conditions such as limb bowing, slipped epiphyses, and fractures. Children with obesity paradoxically have normal circulating IGF-I, the major growth-stimulating hormone. Here, we describe and validate a mouse model of excess dietary fat to examine mechanisms of growth acceleration in obesity. We used in vivo multiphoton imaging and immunostaining to test the hypothesis that high-fat diet increases IGF-I activity and alters growth plate structure before the onset of obesity. We tracked bone and body growth in male and female C57BL/6 mice (n = 114) on high-fat (60% kcal fat) or control (10% kcal fat) diets from weaning (3 wk) to skeletal maturity (12 wk). Tibial and tail elongation rates increased after brief (1-2 wk) high-fat diet exposure without altering serum IGF-I. Femoral bone density and growth plate size were increased, but growth plates were disorganized in not-yet-obese high-fat diet mice. Multiphoton imaging revealed more IGF-I in the vasculature surrounding growth plates of high-fat diet mice and increased uptake when vascular levels peaked. High-fat diet growth plates had more activated IGF-I receptors and fewer inhibitory binding proteins, suggesting increased IGF-I bioavailability in growth plates. These results, which parallel pediatric growth patterns, highlight the fundamental role of diet in the earliest stages of developing obesity-related skeletal complications and validate the utility of the model for future studies aimed at determining mechanisms of diet-enhanced bone lengthening.NEW & NOTEWORTHY This paper validates a mouse model of linear growth acceleration in juvenile obesity. We demonstrate that high-fat diet induces rapid increases in bone elongation rate that precede excess weight gain and parallel pediatric growth. By imaging IGF-I delivery to growth plates in vivo, we reveal novel diet-induced changes in IGF-I uptake and activity. These results are important for understanding the sequelae of musculoskeletal complications that accompany advanced bone age and obesity in children.

Metabolic syndrome and cardiorespiratory fitness in children and adolescents: the role of obesity as a mediator

OBJECTIVES

To analyse the prevalence and association between metabolic syndrome (MetS), clustered cardiometabolic risk (CCMR), obesity (body mass index [BMI], fat mass [FM] and waist circumference [WC]), and cardiorespiratory fitness (CRF); and to assess whether obesity (BMI, FM, and WC) acts as a mediator between CRF and MetS or CCMR.

METHODS

This cross-sectional study included a subsample of the AFINA-te Study (n = 209; 11.51 ± 0.72 years old). BMI, FM, and WC were assessed. The Course-Navette test was used to assess CRF. MetS was calculated following the International Diabetes Federation (IDF) definitions, and assessed using WC, triglycerides (TGs), high density lipoprotein (HD), fasting glucose (FG), and systolic and diastolic blood pressures (SBP/DBP). CCMR was calculated based on the sex and age-specific z score.

RESULTS

The prevalence of overweightness, obesity, MetS, and CCMR were 17.22, 1.44, 5.74, and 18.36%, respectively. After including BMI, FM, or WC into the model, the association between CRF and MetS was no longer significant, and the association between CRF and CCMR was only significant when it was mediated by BMI (β = -0.006; p = 0.026). The rest of the analysis of the mediation did not show a direct effect, although a significant indirect effect with a significant value for the Sobel test was observed (all p < 0.001).

CONCLUSIONS

BMI, FM, and WC act as full mediators in the association between CRF and MetS; FM and WC act as full mediators in the association between CRF and CCMR; and BMI acts as a partial mediator. The use of FM or WC as obesity variables is recommended.

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.

Obesity in childhood: how to improve male adolescence incoming

INTRODUCTION

Earlier or delayed puberty can be determined by numerous causes, but the exact mechanisms are not fully known. Anyway, those may be independent from the hypothalamicpituitary-gonadal axis involvement. Certainly, obesity is one of the main factors. In fact, obesity and infertility are strongly linked. For this reason, we want to analyse the relationship between puberty and obesity and give an updated state-of-the-art starting by discussing a 14-year-old obese boy's clinical case.

EVIDENCE ACQUISITION

Literature data are conflicting. Main criticisms are related to study design and evaluation criteria. Indeed, examined populations are not homogeneous by age, Tanner stage and BMI classification. The obesity epidemic is involved in earlier puberty, and puberty seems to be anticipated in all BMI groups. Very few studies evaluate the level of adiposity in the diagnosis of obesity. However, the role of the adipose tissue is crucial for hormone synthesis and regulation. Therefore, fat mass age-related and not simply BMI has to be considered by clinicians for appropriate diagnosis.

EVIDENCE SYNTHESIS

Regarding the clinical case, in three months our patient recovered delayed pubertal development following an anti-inflammatory and antioxidant Mediterranean Diet. Loss of weight, as in decrease of fat mass but saving of lean mass, increased testicular volume and testosterone levels occurred.

CONCLUSIONS

Puberty depends on several factors, including obesity. Further studies are needed to evaluate age groups, Tanner stage, diet and lifestyle, ethnicity and above all the fat/lean mass ratio. Lack of adequate tools could hinder a clinician's ability to recognize when or if therapeutic intervention is needed.

Adiposity in Survivors of Cancer in Childhood: How is it Measured and Why Does it Matter?

Survival of cancer in childhood is increasingly common with modern therapeutic protocols but leads frequently to adverse long-term impacts on health, including metabolic and cardiovascular disease. Changes in body composition, especially an increase in fat mass and a decrease in muscle mass, are found early in patients with pediatric cancer, persist long after treatment has been completed and seem to contribute to the development of chronic disease. This review details the effects of such changes in body composition and reviews the underlying pathophysiology of the development of sarcopenic obesity and its adverse metabolic impact. The authors discuss the particular challenges in identifying obesity accurately in survivors of pediatric cancer using available measurement techniques, given that common measures, such as body mass index, do not distinguish between muscle and adipose tissue or assess their distribution. The authors highlight the importance of a harmonized approach to the assessment of body composition in pediatric cancer survivors and early identification of risk using "gold-standard" measurements. This will improve our understanding of the significance of adiposity and sarcopenia in this population, help identify thresholds predictive of metabolic risk, and ultimately prevent or ameliorate the long-term metabolic and cardiovascular impacts on health experienced by survivors of cancer in childhood.

Sex, puberty, and ethnicity have a strong influence on growth and metabolic comorbidities in children and adolescents with obesity: Report on 1300 patients (the Madrid Cohort)

BACKGROUND

The capacity to correctly assess insulin resistance and its role in further obesity-associated metabolic derangement in children is under debate, and its determinants remain largely unknown.

OBJECTIVE

We investigated the association of the insulin secretion profile with other metabolic derangements and anthropometric features in children and adolescents with obesity, exploring the role of ethnicity.

PATIENTS AND METHODS

Growth and metabolic features, including fasting insulin levels and insulin secretory profile in an oral glucose tolerance test (OGTT), were analyzed according to ethnicity in 1300 patients with obesity (75.8% Caucasians/19.0% Latinos).

RESULTS

Height and bone age were influenced by sex, ethnicity, and insulinemia. Latino patients had higher insulin (P < .001), but similar glycemia both prepubertally and postpubertally, compared with Caucasians. Type 2 diabetes was uncommon (0.1%). Impaired glucose tolerance was associated to higher age, BMI, uric acid, and triglyceride levels (all P < .05), as was fasting hyperinsulinism. Impaired fasting glucose or HbA1c 5.7% to 6.4% showed no association with further metabolic derangement. A delayed insulin peak in the OGTT was associated to more severe metabolic disturbances.

CONCLUSIONS

Obesity-associated hyperglycemia is unusual in our environment whereas fasting and late postprandial hyperinsulinemia are highly prevalent, with this being influenced by race and closely related with lipid metabolism impairment.

The association between obesity and secular trend of stature: a nationwide study of 2.8 million adolescents over five decades

BACKGROUND/OBJECTIVES

It is unclear whether adolescent obesity is associated with limited linear growth. We assessed this association in a nationwide sample of adolescents.

METHODS

We conducted a population-based, study of 2,785,227 Israeli adolescents (60% males) who were examined before military service since 1967 through 2015. Height and weight were measured along with assessment of medical status at age 17.4 ± 0.4 years. The secular trend of height was plotted using United States Center for Disease Control (US CDC) age- and sex-adjusted BMI percentile groups. We accounted for health status at enrollment and computed the expected height based on parental data that was available for 512,978 examinees.

RESULTS

Over five decades, the mean height increased by 3.1 cm among males, but remained unchanged among females. Among males, gain in height was attained predominantly during the first 25 years and has stabilized since. Males with obesity were taller than their normal-weight and underweight counterparts. Underweight girls had a prominent increase in mean height during the first two decades, exceeding the mean height of their counterparts with obesity by over 2 cm. There was a gradual decrease in the difference between measured and expected height in males and females regardless of BMI status, with the exception of the underweight females who achieved consistently higher stature than expected (≥3 cm).

CONCLUSIONS

During five decades, excessive BMI was not a limiting factor in growth potential compared with normal BMI in both sexes. The only group that exceeded its growth potential, when accounting for expected mid-parental height, were underweight females with unimpaired health.

[Effect of changing reference growth charts on the prevalence of short stature]

INTRODUCTION

Short stature is a family concern, and is a common reason for consultations in paediatrics. Growth charts are an essential diagnostic tool. The objective of this study is to evaluate the impact of changing reference charts in the diagnosis of short stature in a health area.

SUBJECTS AND METHODS

A population-based-cross-sectional-descriptive-study was performed in which the height of children of 4, 6, 10 and 13 years-old were compared with the growth charts of the Fundación Orbegozo 2004 Longitudinal and 2011. The prevalence of short stature and the 3rd percentile of the study sample were calculated.

RESULTS

There were 12,256 valid records (89% of the population). The prevalence of short stature increased at all ages with the change in the growth charts, with differences of prevalence of 3.6% (95% CI: 2.8 to 4.5) at 4 years; 1.8% (95% CI: 1.3 to 2.3) at 6 years; 2.8% (95% CI: 2.2 to 3.4) at 10 years, and 1.4% (95% CI: 0.8 to 1.9) at 13 years. In absolute numbers, it went from 58 diagnoses of short stature with the 2004 Longitudinal charts (34 boys and 24 girls) to 352 with the 2011 (155 boys and 197 girls).

CONCLUSIONS

The change in reference growth charts has increased by 6-fold the number of diagnoses of short stature. The pathological condition found in the cases diagnosed with the 2011 growth charts that had not been diagnosed with the previous charts will allow us to evaluate the suitability of the change.

Pseudoacromegaly

Individuals with acromegaloid physical appearance or tall stature may be referred to endocrinologists to exclude growth hormone (GH) excess. While some of these subjects could be healthy individuals with normal variants of growth or physical traits, others will have acromegaly or pituitary gigantism, which are, in general, straightforward diagnoses upon assessment of the GH/IGF-1 axis. However, some patients with physical features resembling acromegaly - usually affecting the face and extremities -, or gigantism - accelerated growth/tall stature - will have no abnormalities in the GH axis. This scenario is termed pseudoacromegaly, and its correct diagnosis can be challenging due to the rarity and variability of these conditions, as well as due to significant overlap in their characteristics. In this review we aim to provide a comprehensive overview of pseudoacromegaly conditions, highlighting their similarities and differences with acromegaly and pituitary gigantism, to aid physicians with the diagnosis of patients with pseudoacromegaly.

Predictors of bone maturation, growth rate and adult height in children with central precocious puberty treated with depot leuprolide acetate

BACKGROUND

Children with central precocious puberty (CPP) are treated with gonadotropin-releasing hormone agonists (GnRHa) to suppress puberty. Optimizing treatment outcomes continues to be studied. The relationships between growth, rate of bone maturation (bone age/chronological age [ΔBA/ΔCA]), luteinizing hormone (LH), predicted adult stature (PAS), as well as variables influencing these outcomes, were studied in children treated with depot leuprolide (LA Depot) Methods: Subjects (64 girls, seven boys) with CPP received LA Depot every 3 months for up to 42 months. Multivariate regression analyses were conducted to examine the predictors affecting ΔBA/ΔCA, PAS and growth rate.

RESULTS

Ninety percent of subjects (18 of 20) were suppressed (LH levels <4 IU/L) at 42 months. Over 42 months, the mean growth rate declined 2 cm/year, the mean BA/CA ratio decreased 0.21 and PAS increased 8.90 cm for girls (n=64). PAS improved to mid-parental height (MPH) in 46.2% of children by 30 months of treatment. Regression analysis showed that only the Body Mass Index Standardized Score (BMI SDS) was significantly associated (β+0.378 and +0.367, p≤0.05) with growth rate. For PAS, significant correlations were with MPH (β+0.808 and +0.791, p<0.001) and ΔBA/ΔCA (β+0.808 and +0.791, p<0.001). For ΔBA/ΔCA, a significant association was found only with BA at onset of treatment (β-0.098 and -0.103, p≤0.05). Peak-stimulated or basal LH showed no significant influence on growth rate, ΔBA/ΔCA or PAS.

CONCLUSIONS

Growth rate and bone maturation rate normalized on treatment with LA Depot. LH levels were not significantly correlated with growth rate, ΔBA/ΔCA or PAS, suggesting that suppression was adequate and variations in gonadotropin levels were below the threshold affecting outcomes.

[Investigation of tall stature in children: Diagnostic work-up, review of the main causes]

Tall stature is not a common motive for medical consultation, even though by definition 2.5 % of children in the general population are concerned. It is usually defined as height greater than+2 standard deviations (SD) using the appropriate growth chart for age and gender, or a difference greater than +2 SD between actual height and target height. With a patient presenting tall stature, the physician has to determine whether it is a benign feature or a disease. Indeed, making the diagnosis is essential for hormonal disease or genetic overgrowth syndromes. The past medical history including parents' height, prenatal and birth data, physical examination along with anthropometry (height, weight, head circumference, body mass index), and growth chart evaluation with the detailed growth pattern are generally sufficient to make the diagnosis such as familial tall stature, obesity, or early puberty. Bone age estimation may be helpful for some specific etiologies and is also necessary to help predict final adult height. After exclusion of common causes, further investigation is required. Sudden growth acceleration often reveals endocrine pathology such as early puberty, hyperthyroidism, or acrogigantism. Tall stature accompanied by dysmorphic features, congenital malformations, developmental delay, or a family medical history may be related to genetic disorders such as Marfan, Sotos, or Wiedemann-Beckwith syndromes. We relate here the most frequent etiologies of overgrowth syndromes.

Tri-Ponderal Mass Index vs Body Mass Index in Estimating Body Fat During Adolescence

IMPORTANCE

Body mass index (BMI) is used to diagnose obesity in adolescents worldwide, despite evidence that weight does not scale with height squared in adolescents. To account for this, health care providers diagnose obesity using BMI percentiles for each age (BMI z scores), but this does not ensure that BMI is accurate in adolescents.

OBJECTIVE

To compare the accuracy of BMI vs other body fat indices of the form body mass divided by heightn in estimating body fat levels in adolescents.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional data from the 1999 to 2006 US National Health and Nutrition Examination Survey were analyzed between September 2015 and December 2016.

MAIN OUTCOMES AND MEASURES

Dual-energy x-ray absorptiometry and anthropometric data were used to determine changes in body fat levels, body proportions, and the scaling relationships among body mass, height, and percent body fat. To assess the merits of each adiposity index, 3 criteria were used: stability with age, accuracy in estimating percent body fat, and accuracy in classifying adolescents as overweight vs normal weight.

RESULTS

Participants included 2285 non-Hispanic white participants aged 8 to 29 years. Percent body fat varied with both age and height during adolescence, invalidating the standard weight-to-height regression as the way of finding the optimal body fat index. Because the correct regression model (percent body fat is proportional to mass divided by heightn) suggested that percent body fat scales to height with an exponent closer to 3, we therefore focused on the tri-ponderal mass index (TMI; mass divided by height cubed) as an alternative to BMI z scores. For ages 8 to 17 years, TMI yielded greater stability with age and estimated percent body fat better than BMI (R2 = 0.64 vs 0.38 in boys and R2 = 0.72 vs 0.66 in girls). Moreover, TMI misclassified adolescents as overweight vs normal weight less often than BMI z scores (TMI, 8.4%; 95% CI, 7.3%-9.5% vs BMI, 19.4%; 95% CI, 17.8%-20.0%; P < .001) and performed equally as well as updated BMI percentiles derived from the same data set (TMI, 8.4%; 95% CI, 7.3%-9.5% vs BMI, 8.0%; 95% CI, 6.9%-9.1%; P = .62).

CONCLUSIONS AND RELEVANCE

The tri-ponderal mass index estimates body fat levels more accurately than BMI in non-Hispanic white adolescents aged 8 to 17 years. Moreover, TMI diagnoses adolescents as overweight more accurately than BMI z scores and equally as well as updated BMI percentiles but is much simpler to use than either because it does not involve complicated percentiles. Taken together, it is worth considering replacing BMI z scores with TMI to estimate body fat levels in adolescents.

MANAGEMENT OF ENDOCRINE DISEASE: Diagnostic and therapeutic approach of tall stature

Tall stature is defined as a height of more than 2 standard deviations (s.d.) above average for same sex and age. Tall individuals are usually referred to endocrinologists so that hormonal disorders leading to abnormal growth are excluded. However, the majority of these patients have familial tall stature or constitutional advance of growth (generally associated with obesity), both of which are diagnoses of exclusion. It is necessary to have familiarity with a large number of rarer overgrowth syndromes, especially because some of them may have severe complications such as aortic aneurysm, thromboembolism and tumor predisposition and demand-specific follow-up approaches. Additionally, endocrine disorders associated with tall stature have specific treatments and for this reason their recognition is mandatory. With this review, we intend to provide an up-to-date summary of the genetic conditions associated with overgrowth to emphasize a practical diagnostic approach of patients with tall stature and to discuss the limitations of current growth interruption treatment options.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Should children with overweight or obesity be excluded from height references?

BACKGROUND AND OBJECTIVES

Growth reference charts are usually based on measurements of children free from a medical condition that affects growth. However, samples collected during the past decades often contain a large proportion of overweight or obese children. Because obesity increases linear growth, the question arises to what extent the percentiles curves for length/height are affected by the presence of children with overweight or obesity.

METHODS

Data from two cross-sectional samples of 2-year-old to 18-year-old children were analysed: 12,252 Belgian children, measured in 2002-2004, and 6159 Norwegian children, measured in 2003-2006. The LMS method was used to estimate height-for-age curves with and without children considered overweight or obese according to the International Obesity Task Force thresholds.

RESULTS

The prevalence of overweight (including obesity) and obesity was 13.0% and 2.8% in the Belgian and 13.8% and 2.3% in the Norwegian sample. Children were taller when overweight (+0.49 and 0.43 SD, in the Belgian and Norwegian sample, respectively) or obese (+0.73 and 0.72 SD in the Belgian and Norwegian sample, respectively). Effect sizes were smaller in younger and older children, which points to an advanced age of maturation as a possible cause. Excluding overweight and obese children had only a minor impact on the growth curves with largest difference in mean height SD scores -0.09 in the Belgian and -0.12 in the Norwegian sample with a corresponding increase of up to 0.5% and 1.2% in number of children >+2 SD.

CONCLUSIONS

Current Belgian and Norwegian growth references for length/height were found to be largely unaffected by the current proportion of overweight and obese children. There is, therefore, no need for revised height charts that exclude overweight or obese children.

Worldwide variation in human growth and the World Health Organization growth standards: a systematic review

OBJECTIVE

The World Health Organization (WHO) has established a set of growth curves for use as international standards in children up to age 5. The WHO's position is that all economically advantaged children who were breastfed as infants grow similarly. As a result, a single set of growth charts can be used to judge growth in any child, regardless of race or ethnicity. The goal of this study was to compare mean heights, weights and head circumferences from a variety of studies with the WHO's data.

DESIGN

We compared data from the WHO's Multicentre Growth Reference Study (MGRS) with data from studies performed in 55 countries or ethnic groups.

DATA SOURCES

PubMed, WHO Global Database on Child Growth and Malnutrition, SciELO, Google Scholar, Textbooks and Ministries of Statistics and Public Health.

ELIGIBILITY CRITERIA

Large recent studies (1988-2013) of economically advantaged groups, including comparisons with cohorts of breastfed children wherever possible.

RESULTS

Height varied somewhat among different national and ethnic groups. Means were generally within 0.5 of an SD of the MGRS means. Weight varied more than height, but the low MGRS means were seen as endorsing slenderness in the midst of an obesity epidemic. The mean head circumference varied widely. In many groups, means were consistently 0.5-1 SD above the MGRS mean. Head size in breastfed children at any age examined was far closer to local norms than to the MGRS means.

CONCLUSIONS

Height and weight curves may not be optimal fits in all cases. The differences between national or ethnic group head circumference means were large enough that using the WHO charts would put many children at risk for misdiagnosis of macrocephaly or microcephaly. Our findings indicate that the use of a single international standard for head circumference is not justified.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO (# CRD42013003675).

The Relationship between Subnormal Peak-Stimulated Growth Hormone Levels and Auxological Characteristics in Obese Children

CONTEXT

The hypothesis that obese children are overdiagnosed with growth hormone deficiency (GHD) has not been adequately investigated in the context of adiposity-related differences in auxology.

AIM

To investigate the differences in auxological parameters between short, prepubertal, obese children, and normal-weight peers who underwent growth hormone stimulation testing (GHST).

HYPOTHESIS

Over-weight/obese children with GHD [peak growth hormone (GH) < 10 μg/L] will have higher values for growth velocity (GV) standard deviation score (SDS), bone age minus chronological age (BA - CA), and child height SDS minus mid-parental height (MPTH) SDS when compared to normal-weight GHD peers.

SUBJECTS AND METHODS

A retrospective review of anthropometric and provocative GHST data of 67 prepubertal, GH-naïve children of age 10.21 ± 2.56 years (male n = 45, age 10.8 ± 2.60 years; female n = 22, age 8.94 ± 2.10).

INCLUSION CRITERIA

GHST using arginine and clonidine.

EXCLUSION CRITERIA

hypopituitarism, abnormal pituitary magnetic resonance imaging scan, syndromic obesity, or syndromic short stature. Data were expressed as mean ± SD.

RESULTS

The over-weight/obese children with peak GH of <10 μg/L had significantly lower value for natural log (ln) peak GH (1.45 ± 0.09 vs. 1.83 ± 0.35, p = 0.022), but similar values for GV SDS, insulin-like growth factor-I, insulin-like growth factor binding protein-3, bone age, BA - CA, MPTH, and child height SDS minus MPTH SDS compared to normal-weight peers with GHD. After adjusting for covariates, the over-weight/obese children (BMI ≥ 85th percentile) were >7 times more likely than normal-weight subjects (BMI < 85th percentile) to have a peak GH of <10 μg/L, and 23 times more likely to have a peak GH of <7 μg/L (OR = 23.3, p = 0.021). There was a significant inverse relationships between BMI SDS and the ln of peak GH (β = -0.40, r (2) = 0.26, p = 0.001), but not for BMI SDS vs. GV SDS, ln peak GH vs. BA, or ln peak GH vs. GV SDS.

CONCLUSION

Subnormal peak GH levels in obese prepubertal children are not associated with unique pre-GHST auxological characteristics.