Growth and development in simple obesity

Association between bone age maturity and childhood adiposity

BACKGROUND

Evidence shows that overweight and obesity are associated with advanced bone age (BA).

OBJECTIVE

To analyse the effect of adiposity on BA among Mexican children.

METHODS

This cross-sectional study included 902 children (5-18 years old). Anthropometric measurements, dual-energy X-ray absorptiometry (DXA) and automated hand X-ray-based BA measurements were obtained. BA curves of children stratified by sex and age were created based on nutritional status. We also calculated odds ratios for advanced BA associated with the body mass index (BMI), waist/height ratio and adiposity estimated using DXA (total and truncal fat mass).

RESULTS

Participants with overweight/obesity by BMI (SDS ≥1) advanced earlier in BA than did normal weight participants (6.0 vs. 12.0 years in boys and 6.0 vs. 10.3 in girls, p < 0.01); similarly, participants with a greater body fat percentage (SDS ≥1) exhibited earlier advanced BA (7.5 vs. 10.0 years in boys and 6.0 vs. 9.6 in girls, p < 0.01). Differences were also observed according to the waist/height ratio and truncal fat. Children with a BMI or DXA SDS ≥1 had greater odds of presenting an advanced BA of more than 1 year (OR 1.79-3.55, p < 0.05).

CONCLUSIONS

Increased adiposity in children, mainly in boys, is associated with advanced BA at earlier ages.

Beyond the Metabolic Syndrome: Non-Obvious Complications of Obesity in Children

Obesity is currently one of the most significant public health challenges worldwide due to the continuous increase in obesity rates among children, especially younger children. Complications related to obesity, including serious ones, are increasingly being diagnosed in younger children. A search was performed from January 2023 to September 2023 using the PubMed, Cochrane Library, Science Direct, MEDLINE, and EBSCO databases. The focus was on English-language meta-analyses, systematic reviews, randomized clinical trials, and observational studies worldwide. Four main topics were defined as follows: disorders of glucose metabolism; liver disease associated with childhood obesity; the relationship between respiratory disorders and obesity in children; and the effects of obesity on the hypothalamic-pituitary-gonadal axis and puberty. Understanding potential complications and their underlying mechanisms can expedite the diagnostic process and enhance the effectiveness of treatment. We aspire that this study will bring insight into the often-overlooked complications associated with obesity.

Idiopathic adolescent scoliosis and obesity: prevalence study

PURPOSE

Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal deformity that affects 5% of the population. This pathology has multiple known etiological factors such as family predisposition, female gender, low body mass index, decrease in lean and fat masses. However, recent studies suggest that ciliary dysfunction could be the origin of certain types of obesity and AIS. This study aims to verify the existence of a link between these two pathologies.

METHODS

A retrospective, cross-sectional, descriptive and monocentric study, based on a cohort of adolescents with obesity treated in a paediatric rehabilitation centre for specific care between 1 January 2010 and 1 January 2019. The prevalence of AIS was calculated by radiographic measurements. The diagnosis of AIS was established if the Cobb angle was ≥ 10°, associated with intervertebral rotation.

RESULTS

196 adolescents with obesity were included in the study (mean age 13.2 years, mean BMI 36 kg/cm2, gender ratio 2.1 of female to male.) The prevalence of AIS in adolescents with obesity was 12.2%, twice the prevalence of AIS in the general population. The characteristics of AIS in adolescents with obesity are predominantly female, 58.3% left thoracolumbar or lumbar principal curvatures, mean Cobb angle 26° and progressive in 29% of cases.

CONCLUSIONS

Our study established a correlation between AIS and obesity with a higher prevalence than in the general population. The morphology of these adolescents makes screening for AIS more difficult.

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.

Longitudinal study of body mass index and percentage of overweight in Japanese children grouped by maturity

Childhood obesity is a known risk factor for adult diseases, making its evaluation highly important. However, the evaluation is complex because there is no gold standard method. Body mass index (BMI) and percentage of overweight (POW) are widely used in Japan. However, they have the following limitations: it is difficult to set cutoffs for BMI because it dynamically varies in childhood, and POW has not been studied extensively, especially regarding its difference during maturity. Therefore, our study analyzed BMI/POW in Japanese children grouped by maturity. We used longitudinal school check-up data collected from elementary and junior high schools in 20 municipalities. We made percentile curves of BMI/POW and calculated the percentage of participants considered overweight/obese by sex, age, and maturity. Maximum increment age (MIA) was calculated using the graphical fitting method. We included 35,461 subjects aged 15 in 2018. Early-maturing children had higher BMI. The difference among maturity groups decreased by shifting the percentile curves by differences in MIA. Therefore, the use of BMI might lead to the overestimation of overweight/obesity in early-maturing children and underestimation in late-maturing children. The POW percentile curves were "N"-shaped around the MIA, indicating the inappropriate evaluation during this period. The percentile curves of children categorized as overweight/obese were also "N"-shaped, confirming that MIA affects the evaluation of childhood obesity. The possibility of overestimation/underestimation needs verification with the data of accurate age, pubertal changes, and adult diseases. In conclusion, it is difficult to evaluate childhood obesity only with height and weight.

Gene polymorphisms in leptin and its receptor and the response to growth hormone treatment in patients with idiopathic growth hormone deficiency

This study aimed to investigate the relationships between genetic polymorphisms of leptin/receptor genes and clinical/biochemical characteristics in children with growth hormone deficiency (GHD). Ninety-three GHD children and 69 age-matched normal controls were enrolled. Anthropometric measurements, bone age, and laboratory test results were obtained. Polymorphisms in the LEP gene promoter locus (LEP-2548, rs7799039) and LEPR genes (K109R, rs1137100 and Q223R, rs1137101) were analyzed using PCR-RFLP. The serum leptin levels were measured using an ELISA kit. The median height and BMI z-scores of all GHD subjects were -2.20 and -0.26, respectively, and those of normal controls were -0.30 and -0.13, respectively. The serum leptin levels were similar between GHD subjects and normal controls (p = 0.537), but those were different between the complete GHD (6.97 ng/mL) and partial GHD (4.22 ng/mL) groups (p = 0.047). There were no differences in the genotypic distributions of LEP-2548, LEPR K109R, and Q223R between GHD subjects and normal controls. However, GHD subjects with the G allele at LEP-2548 showed higher IGF-1 (p = 0.047) and IGFBP-3 SDSs (p = 0.027) than GHD subjects with the A allele. GHD subjects with the G allele at LEPR Q223R showed lower stimulated GH levels (p = 0.023) and greater height gain after 1 year of GH treatment (p = 0.034) than GHD subjects with the A allele. In conclusion, leptin/leptin receptor genes are suggested to have the role of growth-related factors, which can affect various growth responses in children who share the same disease entity.

Influences of Socioeconomic Status on Short Stature in Childhood

Objectives Short stature in childhood is defined to the cases in which the stature is below 3 percentiles of the standard value in accordance with that of those in the same age and gender group. The influence of the socioeconomic status on the short stature in childhood are analyzed. Methods 154 children from the community child center in a region of poor socioeconomic status and 78 children in normal socioeconomic status who visited the Busan Medical Center due to the issue of short stature were selected for examination and analysis. Results The prevalence rate of short stature at the community child center in 2 municipalities in Busan was confirmed to be 7.3%. In the comparison of the average growth parameters of poor socioeconomic status and normal socioeconomic status in the short stature group, there was no observation of significant difference in terms of the chronological age, mid-parental height, bone age, bone age/chronological age, height standard deviation score (SDS), body mass index(BMI) percentile and insulin like growth factor binding protein 3 (IGFBP3) SDS. In the short stature suspicious group, there was observation of significant difference in the averages of bone age, weight, BMI percentile, IGFBP3 and IGFBP3 SDS. Conclusions Although the prevalence rate of short stature in children belonging to the poor socioeconomic class was observed to be higher than the existing results, there was no significant difference in the growth parameters associated with the growth of the height from those of the children in normal socioeconomic status.

Long-term effects of GnRH agonist treatment on body mass index in girls with idiopathic central precocious puberty

Introduction Studies evaluating effects of gonadotropin-releasing hormone agonist (GnRHa) on weight and body-mass-index (BMI) in girls with idiopathic central precocious puberty (iCPP) include short-term effects. The aim of this study is to investigate changes in BMI during and 2 years after completion of GnRHa to determine the factors that may impact BMI in girls with iCPP. Methods Medical files of 138 girls who completed GnRHa were evaluated. All patients had weight and height measurements at the beginning and end of treatment, and 111 patients had anthropometric measurements 2 years after the completion of treatment. Results In the beginning, 82 (59.4%) had normal weight (NW), 42 (30.4%) were overweight (OW), and 14 (10.2%) were obese (OB). Analysis of BMI-standard deviation score (SDS) in the whole group showed an overall increase during GnRHa treatment (0.92 ± 0.74 vs. 1.20 ± 0.51, p < 0.001). Changes in BMI-SDS (ΔBMI-SDS) during GnRHa differed between NW and OW/OB (0.45 ± 0.31 vs. 0.03 ± 0.20, p < 0.001). BMI-SDSs of both groups returned to baseline scores (or initial levels) 2 years after the completion of treatment. Two factors affecting ΔBMI-SDS in multiple linear regression analyses were baseline BMI and Δheight-SDS, both correlated negatively with ΔBMI-SDS. Conclusions The present study is one of the studies evaluating BMI change over a long period of time in girls with CPP. Although BMI-SDS increased during GnRHa in NW girls, it was reversible in follow-up after treatment. However, BMI-SDS did not change during and in follow-up in OW/OB girls. Conserving BMI-SDS in OW/OB girls may be related to the fact that weight management programs were recommended for these patients. Dietary recommendations should be provided for children with NW who undergo GnRHa, as is the case for OW patients.

Adiposity and attained height in adolescents: a longitudinal analysis from the LabMed Physical Activity Study

Background To investigate the associations between adiposity and attained height over a 2-year period in healthy adolescents. Methods One thousand and seventeen adolescents aged 12-18 years participated in this cohort study; 893 (87.8%) were reevaluated 1 year later (T2) and 734 (72.2%) subjects 2 years later (T3). Body fat and anthropometry were measured according to standardized procedures. Socioeconomic status, pubertal stage and lifestyles determinants were gathered and used as confounders. Prospective associations between adiposity and height were examined using generalized linear models. Results Greater adiposity at T1 was significantly associated with a lower attained height over time, when adjusting for confounders, which varied between 0.03 and 1 cm in T2 and 0.1 and 1 cm in T3. Conclusions Excess of adiposity in early adolescence may exert an effect on attained height in late adolescence. This study supports future lifestyles intervention studies aiming at preventing overweight and obesity and improving attained height.

Drug Dose Selection in Pediatric Obesity: Available Information for the Most Commonly Prescribed Drugs to Children

Obesity rates continue to rise in children, and little guidance exists regarding the need for adjustment away from total body weight-based doses for those prescribing drugs to this population of children. A majority of drugs prescribed to children with obesity result in either sub-therapeutic or supra-therapeutic concentrations, placing these children at risk for treatment failure and drug toxicities. In this review, we highlight available obesity-specific pharmacokinetic and dosing information for the most frequently prescribed drugs to children in the inpatient and outpatient clinical settings. We also comment on available dosing recommendations for drugs prescribed to treat common pediatric obesity-related comorbidities. This review highlights that there is no safe or proven 'rule of thumb,' for dosing drugs for children with obesity, and a striking lack of pharmacokinetic data to support the creation of dosing guidelines for children with obesity for the most commonly prescribed drugs. It is important that those prescribing for children with obesity are aware of these gaps in knowledge and of potential drug treatment failure or adverse events related to drug toxicity as a result of these knowledge gaps. Until more data are available, we recommend close monitoring of drug response and adverse events in children with obesity receiving commonly prescribed drugs.

Longitudinal associations between body composition and regional fat distribution and later attained height at school entry among preschool children predisposed to overweight

BACKGROUND/OBJECTIVES

To investigate the associations between indicators of obesity and fat distribution, such as body mass index (BMI), fat mass, and skinfold measures during preschool age, and attained height at school entry.

SUBJECTS/METHODS

The Healthy Start primary intervention study comprised 1100 obesity-prone preschool children from the greater Copenhagen area, with a mean [standard deviation (SD)] age of 4.0 (1.1) years at baseline. Anthropometry was measured by trained health professionals at baseline (preschool age) and follow-up height at school entry was gathered by school nurses. Prospective associations between body fat measures and later attained height were examined using generalized linear models with adjustments for potential confounders.

RESULTS

Greater adiposity at preschool age was directly associated with a higher attained height at follow-up at school-age, when adjusting for confounders. A baseline difference of one BMI unit was associated with a greater attained height of 0.8 cm [(95% confidence interval (CI) 0.5; 1.2]. Furthermore, a difference of 1 mm in the sum of four skinfolds measured at baseline was associated with a greater attained height of 0.1 cm (95% CI 0.03; 0.2) at follow-up. Children with overweight or obesity at baseline attained a significantly higher height of 2.9 (95% CI 1.6; 4.1) cm at follow-up after full adjustment than normal weight children.

CONCLUSIONS

Our results supports that greater adiposity at preschool age is associated with greater tallness. Although a greater height is assumed to be desirable, accelerated growth in childhood may in itself be a risk factor for obesity later in life.

Body proportionality and adiposity are not related in 6- to 8-year-old Yucatec Maya children

OBJECTIVE

The aim of this study was to analyze the association between relative leg length (RLL) (leg length × 100/height) and adiposity in a sample of 6- to 8-year-old children of Maya ancestry from Motul and Merida, Mexico.

METHODS

This cross-sectional study included 260 children (128 girls) measured between 2011 and 2015. The RLL was used as a measure of body proportionality. Linear regression models were performed to examine the association between RLL (predictor) and three adiposity indicators (outcome variables): fat mass index (kg/m² ), waist circumference (z-score), and sum of triceps and subscapular skinfolds (z-score).

RESULTS

The prevalence of stunting was 12%, and a higher prevalence (19%) of short RLL (leg stunting) was found. The prevalence of overweight and obesity were 16% and 20%, respectively, but the highest prevalence was found for abdominal obesity (40%). None of the adiposity indicators were related to RLL (P > .05), even after adjusting for the influence of children's sex and age.

CONCLUSIONS

Our results suggest that the coexistence of short RLL and high body adiposity is not observed in all populations. Our findings do not discount the possibility that a negative association between RLL and adiposity is expressed at older ages.

The effect of a high-calorie diet on bone growth is mediated by the insulin receptor

Obese children grow faster than their normal-weight peers. Insulin resistance and hyperinsulinemia have been associated with obesity-related growth acceleration. To determine whether obesity-associated hyperinsulinemia promotes bone growth by activating the insulin receptor in the growth plate, we generated ^TamCartIR^flox/flox mice. The injection of 4 doses of tamoxifen in these mice (beginning at postnatal day 5th with 2 days interval between injections) resulted in the Insulin Receptor (IR) gene excision exclusively in the cartilage. ^TamCartIR^flox/flox tamoxifen-treated mice (KO mice) and their IR^flox/flox control littermates (C mice) at 3 weeks of age were exposed to a standard or hypercaloric (high-fat) diet for 4 weeks. At the end of study, C and KO mice fed with a high-fat diet exhibited greater weight gain than the respective strains fed with a standard diet. Body and tibial growth and growth plate height of C mice fed with high-fat diet were greater than those of standard-diet-fed C mice; however, no difference was observed between KO mice fed with standard or high-fat diet with respect to body and tibial growth and growth plate height. Circulating levels of insulin, IGF-1 and leptin were significantly higher in C and KO mice exposed to high-fat diet compared to those in the same strain exposed to standard diet. Increased phosphorylation of Akt (one of the intracellular mediators of insulin action in bone) in the growth plate of C mice on high-fat diet (compared to those on standard diet) suggests that high-fat-mediated increased circulating insulin levels may directly affect growth plate function and bone growth. High-fat diet was not associated with any change of Akt phosphorylation in KO mice. In addition, in vitro studies in cultured primary chondrocytes revealed that Akt mediates the stimulatory effects of insulin on chondrocyte proliferation and differentiation. In conclusion, the activation of the insulin receptor in the growth plate of mice fed with a hypercaloric diet stimulates skeletal growth and growth plate chondrogenesis.

Factors affecting height velocity in normal prepubertal children

PURPOSE

To analyze the effects of clinical and laboratory factors, including insulinlike growth factor (IGF) levels, on the height velocity of normal prepubertal children.

METHODS

Ninety-five healthy prepubertal children (33 boys, 62 girls) were enrolled. The mean chronological age was 6.3±1.4 years, with a height standard deviation score (SDS) of -0.88±0.70. IGF-1, IGF binding protein-3 (IGFBP-3), SDS for anthropometric measurements, and changes in SDS for anthropometric measurements were analyzed for 1 year, and their associations with 1-year height velocity were investigated.

RESULTS

The group of children with a 1-year height velocity of ≥6 cm were chronologically younger than the group with a 1-year height velocity of &lt;6 cm (5.9±1.3 years vs. 6.7±1.3 years, P=0.004), with a lesser increase of SDS for body mass index (BMI) over 1 year (-0.18±0.68 vs. 0.13±0.53, P=0.014). There were no differences between the 2 groups in IGF-1 SDS and IGFBP-3 SDS. Multiple linear regression showed that baseline chronological age (r=0.243, P=0.026) and height SDS (r=0.236, P=0.030) were positively associated with IGF-1 SDS. Binomial logistic regression showed that an older chronologic age at referral (odds ratio [OR], 0.68; 95% confidence interval [CI], 0.47-0.99) and an increase of BMI SDS over 1 year (OR, 0.41; 95% CI, 0.18-0.89) were associated with a decreased growth possibility of an above-average height velocity (≥6 cm/yr).

CONCLUSION

Height velocity of normal prepubertal children is affected by an increase of BMI SDS and chronological age. Prepubertal IGF-1 SDS reflects height SDS at the time of measurement but is not associated with subsequent height velocity.

Effect of Nutrition on Statural Growth

In children, proper growth and development are often regarded as a surrogate marker for good health. A complex system controls the initiation, rate, and cessation of growth, and thus gives a wonderful example of the interactions between genetics, epigenetics, and environmental factors (especially stress and nutrition). Malnutrition is considered a leading cause of growth attenuation in children. This review summarizes our current knowledge regarding the mechanisms linking nutrition and skeletal growth, including systemic factors, such as insulin, growth hormone, insulin-like growth factor-1, fibroblast growth factor-21, etc., and local mechanisms, including mTOR, miRNAs, and epigenetics. Studying the molecular mechanisms regulating skeletal growth may lead to the establishment of better nutritional and therapeutic regimens for more effective linear growth in children with malnutrition and growth abnormalities. 
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Body Mass Index Categories and Attained Height in Portuguese Adults

OBJECTIVE

To analyze the associations between height and BMI categories in a Portuguese representative sample.

METHODS

This is a cross-sectional study with a representative sample of 32,644 Portuguese adults (52.4% females). Sociodemographic and lifestyle characteristics were obtained along with self-reported height and weight. We performed generalized linear models to assess the differences in attained height across BMI categories; analyses were adjusted for age, gender, education, family income per month, proxy reporting information, dietary patterns, and smoking.

RESULTS

BMI categories included underweight and normal weight (46.4%), overweight (37.6%), obese class I and II (15.2%), and obese class III (0.8%). Adults with normal weight had a significantly higher height (females +7 cm and males +5 cm) when compared to obese class III. As BMI categories increased, height decreased. In females and males, after adjusting for confounders, estimates of attained height decreased when compared to the unadjusted model (β = -0.049, 95% CI = -0.050; -0.049 and β = -0.030, 95% CI = -0.031; -0.029, respectively), although they remained still significant.

CONCLUSION

Our results suggest a significant difference in attained height between BMI categories. Future intervention programs aiming at preventing overweight and obesity should monitor sociodemographic, health and environmental conditions that affect attained height potential.

Pubertal Development and Prepubertal Height and Weight Jointly Predict Young Adult Height and Body Mass Index in a Prospective Study in South Africa

BACKGROUND

Height and adiposity track over childhood, but few studies, to our knowledge, have longitudinally examined the mediating relation of the timing and progression of puberty.

OBJECTIVE

We assessed interrelations between prepubertal height and body mass index, the progression through puberty, and young adult height and adiposity.

METHODS

We analyzed data from the Birth to Twenty Plus study (females, n = 823; males, n = 765). Serial measures of anthropometry and pubertal development were obtained between ages 9 and 16 y. We used latent class growth analysis to categorize pubertal development with respect to pubic hair (females and males), breasts (females), and genitalia (males) development. Adult height and weight were obtained at ages 18 to 20 y.

RESULTS

Among females, higher latent class (earlier initiation and faster progression through puberty) was associated with an increased risk of obesity [pubic hair class 3 compared with class 1: RR, 3.41 (95% CI: 1.57, 7.44)] and inconsistent associations with height. Among males, higher latent class was associated with increased adult height [pubic hair development class 3 compared with class 1: 2.43 cm (95% CI: 0.88, 4.00)] and increased risk of overweight/obesity [pubic hair development class 3 compared with class 1: OR, 3.44 (95% CI: 1.44, 8.20)]. In females, the association with adult height became inverse after adjusting for prepubertal height [pubic hair development class 3 compared with class 1: females, -1.31 cm (95% CI: -2.32, -0.31)]; in males, the association with height was attenuated with this adjustment [-0.56 cm (95% CI: -1.63, 0.52)]. Associations with adiposity were attenuated after adjusting for prepubertal adiposity.

CONCLUSIONS

Progression through puberty modifies the relation between prepubertal and adult anthropometry. Screening for early or rapid progression of puberty might identify children at an increased risk of becoming overweight or obese adults.

Changing Etiological Trends in Male Precocious Puberty: Evaluation of 100 Cases with Central Precocious Puberty over the Last Decade

BACKGROUND/AIMS

There are few studies in the literature that have evaluated the etiological factors in boys with central precocious puberty (CPP), and these studies are limited in terms of the sample size. In the present study, we aimed to evaluate the etiological factors in male CPP cases.

METHODS

One hundred male CPP subjects, aged between 9 months and 10.5 years, were included. The medical records were screened, and age at diagnosis, bone age, body weight, height, pubertal stage, imaging findings of the pituitary gland, testosterone, and basal and stimulated gonadotropin levels were recorded.

RESULTS

There was no underlying cause in 74% of the cases, and an organic cause was determined in only 26%. Most of the organic cases had been diagnosed before the age of 7 years, whereas most of the idiopathic cases had been diagnosed after the age of 7 years.

CONCLUSION

An organic cause was determined in 26% of the male patients with CPP. This rate is one of the lowest rates in the literature and indicates that the number of idiopathic male CPP cases is increasing over time. When a boy is diagnosed with CPP above the age of 7 years, the odds of detecting an underlying pathology are very low, and these cases are mostly idiopathic.

Early Life Growth Predicts Pubertal Development in South African Adolescents

BACKGROUND

Given global trends toward earlier onset of puberty and the adverse psychosocial consequences of early puberty, it is important to understand the childhood predictors of pubertal timing and tempo.

OBJECTIVE

We examined the association between early growth and the timing and tempo of puberty in adolescents in South Africa.

METHODS

We analyzed prospectively collected data from 1060 boys and 1135 girls participating in the Birth-to-Twenty cohort in Soweto, South Africa. Height-for-age z scores (HAZs) and body mass index-for-age z scores (BMIZs) were calculated based on height (centimeters) and body mass index (kilograms per meter squared) at ages 5 y and 8 y. The development of genitals, breasts, and pubic hair was recorded annually from 9 to 16 y of age with the use of the Tanner sexual maturation scale (SMS). We used latent class growth analysis to identify pubertal trajectory classes and also characterized children as fast or slow developers based on the SMS score at 12 y of age. We used multinomial logistic regression to estimate associations of HAZ and BMIZ at ages 5 and 8 y with pubertal development.

RESULTS

We identified 3 classes for pubic hair development (for both girls and boys) and 4 classes for breast (for girls) and genital (for boys) development. In girls, both HAZ and BMIZ at age 5 y were positively associated with pubic hair development [relative risk ratio (RRR): 1.57, P < 0.001 and RRR: 1.51, P < 0.01, respectively], as was BMI at age 8 y (RRR: 2.06, P = 0.03); similar findings were observed for breast development. In boys, HAZ and BMIZ at age 5 y were positively associated with pubic hair development (RRR: 1.78, P < 0.001 and RRR: 1.43, P < 0.01, respectively); HAZ at age 5 y was associated with development of genitals (RRR: 2.19, P < 0.01).

CONCLUSION

In boys and girls, both height and body mass index in early childhood predicted the trajectory of pubertal development. This may provide a tool to identify children at risk of early pubertal onset.

Fibroblast growth factor 21 (FGF-21) in obese children: no relationship to growth, IGF-1, and IGFBP-3

BACKGROUND

Fibroblast growth factor 21 (FGF-21) is a hepatic protein that plays a critical role in liver, adipose tissue, and bone metabolism. Animal models reported an increase of FGF-21 and associated growth disturbances in undernutrition. Therefore, we studied the impact of weight loss in obese children on growth, FGF-21, and insulin-like factor 1 (IGF-1) concentrations.

METHODS

We analyzed height, serum concentrations of FGF-21, IGF-1, IGFBP-3, leptin, and insulin at baseline and 1 year later in 30 obese children with substantial weight loss (reduction >0.5 BMI-SDS) and in 30 obese children of similar age, gender, and pubertal stage with stable BMI-SDS. All children participated in a 1-year lifestyle intervention. Height and IGF-1 was transformed to standard deviation score (SDS). Multiple linear regression analyses adjusted for age, gender, and pubertal stage were performed.

RESULTS

At baseline, height-SDS was significantly related to IGF-1-SDS (β-coefficient 0.68 95% confidence interval (95% CI)±0.49; p=0.008) and leptin (β-coefficient 0.042 95% CI±0.030; p=0.008), but not to FGF-21 or insulin. FGF-21 was not significantly associated with IGF-1 or IGFBP-3. In longitudinal analysis, changes of FGF-21 were not significantly related to changes of height, IGF-1-SDS or IGFBP-3. However, in the subgroup of 30 children with substantial BMI-SDS reduction, FGF-21, leptin, insulin, and HOMA decreased significantly.

CONCLUSION

As there was no significant association between FGF-21 and growth or IGF-1 both in cross-sectional and longitudinal analyses, these findings do not support the hypothesis that FGF-21 is involved in growth of obese children. Further studies are necessary to understand the multiple alterations in the growth hormone (GH) axis in obese children.

Androgens and obesity in male adolescents

PURPOSE OF REVIEW

Data on sex steroid levels and pubertal development in obese adolescent boys are scarce and contrasting. The present review summarizes the most recent results obtained with improved methodology to measure low sex steroid levels in children.

RECENT FINDINGS

Obese pubertal boys have lower serum sex hormone-binding globulin and consequently lower total testosterone levels compared to normal-weight peers. However, during pubertal development, free testosterone levels in obese adolescents are not different from controls, indicating preserved androgen exposure as is additionally suggested by similar clinical genital staging (Tanner), serum gonadotropins levels, and serum prostate-specific antigen concentrations compared to nonobese adolescents. In pre and early puberty, total testosterone levels is not decreased, notwithstanding low sex hormone-binding globulin, and free testosterone is slightly increased in obese boys. This may result from increased adrenal activity as revealed by elevated serum androstenedione and dehydroepiandrosterone sulfate. In obese adolescent boys, increased aromatization of testosterone to estradiol tends to accelerate skeletal maturation.

SUMMARY

In obese adolescent boys, free testosterone is a better index than total testosterone levels of androgen status, which is not different from nonobese controls. Increased aromatization of testosterone to estradiol underlies the dissociation between normal clinical sexual maturation and advanced skeletal maturation in the obese adolescent.

Sex steroids in relation to sexual and skeletal maturation in obese male adolescents

BACKGROUND

Childhood obesity is associated with an accelerated skeletal maturation. However, data concerning pubertal development and sex steroid levels in obese adolescents are scarce and contrasting.

OBJECTIVES

To study sex steroids in relation to sexual and skeletal maturation and to serum prostate specific antigen (PSA), as a marker of androgen activity, in obese boys from early to late adolescence.

METHODS

Ninety obese boys (aged 10-19 y) at the start of a residential obesity treatment program and 90 age-matched controls were studied cross-sectionally. Pubertal status was assessed according to the Tanner method. Skeletal age was determined by an x-ray of the left hand. Morning concentrations of total testosterone (TT) and estradiol (E2) were measured by liquid chromatography-tandem mass spectrometry, free T (FT) was measured by equilibrium dialysis, and LH, FSH, SHBG, and PSA were measured by immunoassays.

RESULTS

Genital staging was comparable between the obese and nonobese groups, whereas skeletal bone advancement (mean, 1 y) was present in early and midadolescence in the obese males. Although both median SHBG and TT concentrations were significantly (P < .001) lower in obese subjects during mid and late puberty, median FT, LH, FSH, and PSA levels were comparable to those of controls. In contrast, serum E2 concentrations were significantly (P < .001) higher in the obese group at all pubertal stages.

CONCLUSION

Obese boys have lower circulating SHBG and TT, but similar FT concentrations during mid and late puberty in parallel with a normal pubertal progression and serum PSA levels. Our data indicate that in obese boys, serum FT concentration is a better marker of androgen activity than TT. On the other hand, skeletal maturation and E2 were increased from the beginning of puberty, suggesting a significant contribution of hyperestrogenemia in the advancement of skeletal maturation in obese boys.

Stage specific effect of leptin on the expressions of estrogen receptor and extracellular matrix in a model of chondrocyte differentiation

Endochondral ossification is a dynamic process. The interaction between leptin and estrogen in this process is complicated. Whether there is a stage specific crosstalk between leptin and estrogen in the differentiation process of the chondrocytes in the growth plate remains unknown. The aim of our study was to investigate the effect of leptin on the expression of estrogen receptors and extracellular matrix in ATDC5 cells, an in vitro model of endochondral ossification. First, we quantified the physiological expressions of estrogen receptors α, β (ERα, ERβ), leptin receptor (Ob-Rb), type II and type X collagens in definite stages of endochondral ossification in ATDC5 cells using real-time PCR. Dynamic and stage specific expression characteristics of these target genes were observed. Simultaneous expressions of Ob-Rb with ERα or ERβ in ATDC5 cells were also found with dual-label confocal immunofluorescency. Then using Western blotting analysis and/or real-time PCR, we detected that, leptin treatment up-regulated the expressions of ERα, ERβ and type II collagen, but down-regulated type X collagen expression and the ERα/ERβ ratio in the chondrogenic differentiation stage. Meanwhile, leptin down-regulated the expressions of ERα, type II and type X collagens, and the ERα/ERβ ratio, but up-regulated the expression of ERβ in the hypertrophic differentiation stage. Significant positive correlation existed between ERα and type II collagen expression, and between the ratio of ERα/ERβ and type X collagen production. In summary, the crosstalk between leptin and estrogen receptor might be differentiation stage specific in ATDC5 cells.

Update on statural growth and pubertal development in obese children

Childhood obesity is a growing and alarming problem, associated with several short-term and long-term metabolic and cardiovascular complications. In addition, it has also been suggested that excess adiposity during childhood influences growth and pubertal development. Several studies have shown that during pre-pubertal years, obese patients present higher growth velocity and that this pre-pubertal advantage tends to gradually decrease during puberty, leading to similar final heights between obese and non-obese children. Excess body weight might also influence pubertal onset, leading to earlier timing of puberty in girls. In addition, obese girls are at increased risk of hyperandrogenism and polycystic ovary syndrome. In boys, a clear evidence does not exist: some studies suggesting an earlier puberty associated with the obesity status, whereas other have found a delayed pubertal onset. Overall, the existing evidence of an association between obesity and modification of growth and pubertal patterns underlines a further reason for fighting the epidemics of childhood obesity.

Nutritional quality of foods and beverages on child-care centre menus in Mexico

OBJECTIVE

The purpose of the present study was to assess the nutritional quality of foods and beverages listed on menus serving children in government-sponsored child-care centres throughout Mexico.

DESIGN

For this cross-sectional menu assessment, we compared (i) food groups and portion sizes of foods and beverages on the menus with MyPlate recommendations and (ii) macronutrients, sugar and fibre with Daily Reference Intake standards.

SETTING

Menus reflected foods and beverages served to children attending one of 142 government-sponsored child-care centres throughout Mexico.

SUBJECTS

There were fifty-four distinct menus for children aged 4–6 months, 7–9 months, 10–12 months, 13–23 months, 24–47 months and 48–72 months.

RESULTS

Menus included a variety of foods meeting minimum MyPlate recommendations for each food category except whole grains for children aged 48–72 months. Menus listed excessive amounts of high-energy beverages, including full-fat milk, fruit juice and sugar-sweetened beverages for children of all ages. The mean daily energy content of menu items yielded an average of 2?76 MJ for infants, 4.77 MJ for children aged 13–23 months, 5.36 MJ for children aged 24–47 months and 5.87 MJ for children aged 48–72 months. Foods and beverages on menus provided sufficient grams of carbohydrate and fat, but excessive protein.

CONCLUSIONS

Menus provided a variety of foods but excessive energy. Whole grains were limited, and high-energy beverages were prevalent. Both may be appropriate targets for nutrition intervention. Future studies should move beyond menus and assess what children actually consume in child care.

Impact of obesity on orthopaedics

The prevalence of obesity among children and adults is increasing worldwide. There are substantial health risks and financial costs associated with the obesity epidemic that impact the practice of orthopaedic surgery. Patients with increased body mass index are more prone to sustaining distal extremity injuries than are those with a normal body mass index. Obese individuals are more likely than nonobese individuals to seek treatment for osteoarthritis of the knee.

Obesity in children and adolescents: relationship to growth, pubarche, menarche, and voice break

OBJECTIVE

The relationships between obesity, pubertal development, and height are controversial. Therefore, we compared the prevalence of pubarche, menarche, and voice break between a large collective of obese and normal-weight children and adolescents aged 10-16 years.

METHODS

We assessed weight, height, pubarche, menarche, and voice break in 1383 obese German children and in 6615 children of a representative national German cohort aged 10-16 years. In all obese children, gonadotropins were determined and birth weight data were collected.

RESULTS

Independently of gender, the height standard deviation score (SDS) was significantly greater (0.3-1.0) in obese children <14 years compared to the reference cohort. Independently of age, the percentage of obese boys with pubarche was significantly lower compared to age-matched normal-weight boys. In girls <13 years, the prevalence of obese girls with pubarche was significantly lower compared to age-matched normal-weight girls. In boys > or =11 years, the percentage of obese boys with change of voice was significantly lower compared to age-matched normal-weight boys. In girls > or =11 years, the prevalence of obese girls with menarche was significantly lower compared to age-matched normal-weight girls. Birth weight had no impact on pubarche in the obese children. Luteinizing hormone was > 0.3 IU/L in 86% of the children > or =10 years with pubarche.

CONCLUSIONS

Obese children are taller than normal-weight children up to the age of 14 years. Since obese children demonstrated pubarche, menarche, and voice break later than their normal-weight peers, the increase in height in obese children does not seem to be attributable to earlier onset of puberty.

Testosterone, obesity and insulin resistance in young males: evidence for an association between gonadal dysfunction and insulin resistance during puberty

OBJECTIVE

To assess the relationships among obesity, insulin sensitivity, and testosterone in pubertal boys.

PARTICIPANTS

This study included 20 lean, obese, and type 2 diabetic (T2DM) males, the majority of whom underwent a hyperinsulinemic-euglycemic clamp (n=16).

METHODS

Glucose disposal (M value), serum testosterone, and body mass index (BMI) z-score were measured. Differences in testosterone were evaluated by group (lean vs. obese vs. T2DM), while regression was performed to evaluate the relationships among testosterone, obesity and insulin sensitivity.

RESULTS

Controlling for Tanner stage, testosterone concentration was significantly lower in obese (p=0.02) and T2DM males (p=0.001) compared to lean males. Furthermore, M value was significantly associated with serum testosterone, even after controlling for BMI and Tanner stage.

CONCLUSIONS

These data suggest that obese adolescent boys have lower serum testosterone than controls of the same Tanner stage, and echo the data in adult males associating obesity and insulin resistance with hypogonadism.

Hypothalamic and pituitary c-Jun N-terminal kinase 1 signaling coordinately regulates glucose metabolism

c-Jun N-terminal kinase (JNK) 1-dependent signaling plays a crucial role in the development of obesity-associated insulin resistance. Here we demonstrate that JNK activation not only occurs in peripheral tissues, but also in the hypothalamus and pituitary of obese mice. To resolve the importance of JNK1 signaling in the hypothalamic/pituitary circuitry, we have generated mice with a conditional inactivation of JNK1 in nestin-expressing cells (JNK1(DeltaNES) mice). JNK1(DeltaNES) mice exhibit improved insulin sensitivity both in the CNS and in peripheral tissues, improved glucose metabolism, as well as protection from hepatic steatosis and adipose tissue dysfunction upon high-fat feeding. Moreover, JNK1(DeltaNES) mice also show reduced somatic growth in the presence of reduced circulating growth hormone (GH) and insulin-like growth factor 1 (IGF1) concentrations, as well as increased thyroid axis activity. Collectively, these experiments reveal an unexpected, critical role for hypothalamic/pituitary JNK1 signaling in the coordination of metabolic/endocrine homeostasis.

Body mass index and timing of pubertal initiation in boys

OBJECTIVE

To examine the association between body mass index (BMI [calculated as weight in kilograms divided by height in meters squared]) and timing of pubertal onset in a population-based sample of US boys.

DESIGN

Longitudinal prospective study.

SETTING

Ten US sites that participated in the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development.

PARTICIPANTS

Of 705 boys initially enrolled in the study, information about height and weight measures and pubertal stage by age 11.5 years was available for 401 boys.

MAIN EXPOSURE

The BMI trajectory created from measured heights and weights at ages 2, 3, 4.5, 7, 9, 9.5, 10.5, and 11.5 years.

MAIN OUTCOME MEASURE

Onset of puberty at age 11.5 years as measured by Tanner genitalia staging.

RESULTS

Boys in the highest BMI trajectory (mean BMI z score at age 11.5 years, 1.84) had a greater relative risk of being prepubertal compared with boys in the lowest BMI trajectory (mean BMI z score at age 11.5 years, -0.76) (adjusted relative risk = 2.63; 95% confidence interval, 1.05-6.61; P = .04).

CONCLUSIONS

The relationship between body fat and timing of pubertal onset is not the same in boys as it is in girls. Further studies are needed to better understand the physiological link between body fat and timing of pubertal onset in both sexes.

Local leptin production in osteoarthritis subchondral osteoblasts may be responsible for their abnormal phenotypic expression

INTRODUCTION

Leptin is a peptide hormone with a role in bone metabolism and rheumatic diseases. The subchondral bone tissue plays a prominent role in the pathophysiology of osteoarthritis (OA), related to abnormal osteoblast (Ob) differentiation. Although leptin promotes the differentiation of Ob under normal conditions, a role for leptin in OA Ob has not been demonstrated. Here we determined if endogenous leptin produced by OA Ob could be responsible for the expression of the abnormal phenotypic biomarkers observed in OA Ob.

METHODS

We prepared primary normal and OA Ob from subchondral bone of tibial plateaus removed for knee surgery of OA patients or at autopsy. We determined the production of leptin and of the long, biologically active, leptin receptors (OB-Rb) using reverse transcriptase-polymerase chain reaction, ELISA and Western blot analysis. We determined the effect of leptin on cell proliferation by BrdU incorporation and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, and we determined by Western blot analysis phospho 42/44 MAPK (p42/44 Erk1/2) and phospho p38 levels. We then determined the effect of the addition of exogenous leptin, leptin receptor antagonists, inhibitors of leptin signaling or siRNA techniques on the phenotypic features of OA Ob. Phenotypic features of Ob were determined by measuring alkaline phosphatase activity (ALP), osteocalcin release (OC), collagen type 1 production (CICP) and of Transforming Growth Factor-beta1 (TGF-beta1).

RESULTS

Leptin expression was increased approximately five-fold and protein levels approximately two-fold in OA Ob compared to normal. Leptin stimulated its own expression and the expression of OB-Rb in OA Ob. Leptin dose-dependently stimulated cell proliferation of OA Ob and also increased phosphorylated p42/44 Erk1/2 and p38 levels. Inactivating antibodies against leptin reduced ALP, OC, CICP and TGF-beta1 levels in OA Ob. Tyrphostin (AG490) and piceatannol (Pce), inhibitors of leptin signaling, reproduced this effect. Inhibition of endogenous leptin levels using siRNA for leptin or inhibiting leptin signaling using siRNA for OB-Rb expression both reduced ALP and OC about 60%. Exogenous leptin addition stimulated ALP, yet this failed to further increase OC or CICP.

CONCLUSIONS

These results suggest that abnormal production of leptin by OA Ob could be responsible, in part, for the elevated levels of ALP, OC, collagen type 1 and TGF-beta1 observed in these cells compared to normal. Leptin also stimulated cell proliferation, and Erk 1/2 and p38 signaling. Taken together, these data suggest leptin could contribute to abnormal osteoblast function in OA.

Pathogenesis of adolescent idiopathic scoliosis in girls - a double neuro-osseous theory involving disharmony between two nervous systems, somatic and autonomic expressed in the spine and trunk: possible dependency on sympathetic nervous system and hormones with implications for medical therapy

Anthropometric data from three groups of adolescent girls - preoperative adolescent idiopathic scoliosis (AIS), screened for scoliosis and normals were analysed by comparing skeletal data between higher and lower body mass index subsets. Unexpected findings for each of skeletal maturation, asymmetries and overgrowth are not explained by prevailing theories of AIS pathogenesis. A speculative pathogenetic theory for girls is formulated after surveying evidence including: (1) the thoracospinal concept for right thoracic AIS in girls; (2) the new neuroskeletal biology relating the sympathetic nervous system to bone formation/resorption and bone growth; (3) white adipose tissue storing triglycerides and the adiposity hormone leptin which functions as satiety hormone and sentinel of energy balance to the hypothalamus for long-term adiposity; and (4) central leptin resistance in obesity and possibly in healthy females. The new theory states that AIS in girls results from developmental disharmony expressed in spine and trunk between autonomic and somatic nervous systems. The autonomic component of this double neuro-osseous theory for AIS pathogenesis in girls involves selectively increased sensitivity of the hypothalamus to circulating leptin (genetically-determined up-regulation possibly involving inhibitory or sensitizing intracellular molecules, such as SOC3, PTP-1B and SH2B1 respectively), with asymmetry as an adverse response (hormesis); this asymmetry is routed bilaterally via the sympathetic nervous system to the growing axial skeleton where it may initiate the scoliosis deformity (leptin-hypothalamic-sympathetic nervous system concept = LHS concept). In some younger preoperative AIS girls, the hypothalamic up-regulation to circulating leptin also involves the somatotropic (growth hormone/IGF) axis which exaggerates the sympathetically-induced asymmetric skeletal effects and contributes to curve progression, a concept with therapeutic implications. In the somatic nervous system, dysfunction of a postural mechanism involving the CNS body schema fails to control, or may induce, the spinal deformity of AIS in girls (escalator concept). Biomechanical factors affecting ribs and/or vertebrae and spinal cord during growth may localize AIS to the thoracic spine and contribute to sagittal spinal shape alterations. The developmental disharmony in spine and trunk is compounded by any osteopenia, biomechanical spinal growth modulation, disc degeneration and platelet calmodulin dysfunction. Methods for testing the theory are outlined. Implications are discussed for neuroendocrine dysfunctions, osteopontin, sympathoactivation, medical therapy, Rett and Prader-Willi syndromes, infantile idiopathic scoliosis, and human evolution. AIS pathogenesis in girls is predicated on two putative normal mechanisms involved in trunk growth, each acquired in evolution and unique to humans.

Weight loss and the effect on stature in children during a residential intervention program

Weight loss is generally high in residential weight-loss programs but the effect of a large weight loss on linear growth is not known. We report the weight loss and the influence on linear growth in a large group of children during a residential weight-loss program focusing on nutrition and physical activity. In a longitudinal noncontrolled intervention study of 990 overweight children (540 girls) attending the weight reduction program from 1990 to 2001 for about 11 weeks (age: 10-14 years, mean BMI-standard deviation score (SDS) at enrollment: 2.83) weight and height were measured initially and after end of treatment. Weekly measurements of height and weight were performed on 138 children. The children lost on average 9.4 kg, reduced their BMI by 4.5 kg/m(2) and BMI-SDS by 0.98. In a multiple regression analysis (P < or = 0.001) weight loss was higher in boys than girls (1.7 kg), higher if the weight was higher at admission (-0.192 kg/kg at baseline) and was positively associated with duration of stay (-80 g/day). Initially the boys' BMI-SDS was higher than the girls' BMI-SDS (P < or = 0.05) but after 8 weeks of treatment the boys had lower BMI-SDS than the girls. There was no negative effect on linear growth during the treatment; on the contrary, linear growth accelerated during the stay as the average increase in height was 2.38 cm corresponding to 11.4 cm/year. In conclusion the children lost close to 1 kg/week during the stay without any negative effect on linear growth. The cause of the linear growth acceleration needs further investigation.

Leptin gene expression in subcutaneous adipose tissue in girls before and during puberty

OBJECTIVES

Leptin functions as a neuroendocrine hormone and it is related to the onset of puberty in animal models. Its role in normal human sexual maturation is still incompletely defined. The aim of the study was to assess the relationships between leptin mRNA (gene) expression, thickness of subcutaneous fat tissue and the serum concentration of leptin in girls before and during puberty.

STUDY DESIGN

Twenty-nine lean girls were studied (mean age 10.8+/-1.9 years). The subjects were divided into two groups according to pubertal status. The first group consisted of 14 prepubertal girls and second group of 15 girls who were in puberty. Body height, weight, arm circumference, skin fold thickness at abdominal, triceps and subscapular sites were measured. Serum leptin was assessed by RIA method. Leptin mRNA was measured in subcutaneous abdominal adipose tissue by semi-quantitative assays based on reverse transcription (RT) of the mRNA and polymerase chain reaction (PCR) amplification of the cDNA.

RESULTS

Girls in pubertal stages had higher serum leptin concentration than prepubertal girls. The mean values of leptin mRNA level in subcutaneous abdominal adipose tissue were not statistically different between groups. There was also no difference between the thickness of skin folds in investigated girls. A positive correlation between leptin mRNA expression and skin fold thickness, BMI and arm circumference as well as between the leptin concentration and skin fold thickness, BMI and arm circumference were observed.

CONCLUSIONS

The level of leptin gene expression and serum leptin concentrations depend on the amount of fat tissue. We can propose that initiation of pubertal events does not result from increased of leptin mRNA expression in subcutaneous abdominal fat cells or from its increased concentration in blood.

Link between body fat and the timing of puberty

Several recent studies suggest that the timing of the onset of puberty in girls has become earlier over the past 30 years, and there is strong evidence that the increasing rates of obesity in children over the same time period is a major factor. This article reviews studies from the United States that examined the age of menarche and the age of onset of breast development and pubic hair as a function of body mass index, which is a good surrogate measure of body fat. These studies are nearly all cross-sectional, so many questions remain unanswered. However, at least several studies show that girls who have relatively higher body mass index are more likely to have earlier menses, as well as a relationship between body mass index and other measures of pubertal onset. The evidence published to date suggests that obesity may be causally related to earlier puberty in girls rather than that earlier puberty causes an increase in body fat. In contrast, few studies have found a link between body fat and earlier puberty in boys. A growing body of evidence from both rodent and human studies suggests that leptin may be the critical link between body fat and earlier puberty. Leptin-deficient mice and humans fail to enter puberty unless leptin is administered, and rodent studies indicate that very low levels of leptin stimulate gonadotropin secretion both at the hypothalamic and the pituitary level. Current evidence indicates that leptin appears to play a permissive role rather than act as the critical metabolic signal initiating puberty. The linkage between body fat and the reproductive axis in girls may have evolved in mammals as a mechanism for ensuring that pregnancy will not occur unless there are adequate fat stores to sustain both the mother and the growing fetus.

Anthropometric, bone age, and bone mineral density changes after a family-based treatment for obese children

Our objective was to identify anthropometric, bone age, and bone mineral density (BMD) changes after a family-based treatment program for obese children. We conducted a longitudinal prospective study of 50 obese children (body mass index percentage [BMI%] > or =120%) aged 9.12 +/- 1.72 years (range 6-13) at baseline. A family-based treatment program, based on inadequate feeding style with progressive modification, aerobic physical exercise increase, active parental involvement, and the use of behavioural strategies (contracting, self-monitoring, social reinforcement), was developed during a 12-month period. Anthropometric data, lumbar spine (L2-L4) BMD by dual-energy X-ray absorptiometry, bone age (BA), bone age to chronological age ratio (BA/CA), and predicted adult height (PAH) were determined at baseline and 12 months. The statistical method used was analysis of variance and the paired Student t-test. Mean BMI standard deviation score (SDS) loss was -0.61 +/- 0.76 and BMI% loss was -5.17 +/- 9.73%. Height SDS significantly decreased, BA/CA ratio also decreased significantly, and PAH change was not significant. Lumbar spine BMD SDS and BMD% did not significantly change. A family-based treatment program was effective in obese children by reducing by 5% the BMI in 1 year and increasing the activity level. Treatment reduced growth velocity and delayed bone maturation rate without affecting PAH, reflecting a situation of previous early maturation. The treatment did not modify gaining bone mass.

Pubertal development in obese children and adolescents

OBJECTIVE

To investigate clinical and laboratory markers of pubertal development in a large sample of obese children and adolescents.

METHODS

Analysis of parameters of sexual maturation in 1232 obese individuals (582 boys) aged 6-18 years (mean 13.0+/-2.42 years). Clinical evaluation of pubertal stage and determination of bone age in a subset (227 patients).

RESULTS

Mean Height--standard deviation scores (height-SDS) was positive during childhood and reached zero approximately at age 14 years followed by a turn to negative mean height-SDS in both genders. Accordingly, bone age was accelerated until age 14. No significant differences in average time points of occurrence of pubic hair stages PH 2 to PH 4 in boys and PH 2 to PH 5 in girls were observed as compared to references of the First Zurich Longitudinal Study. In girls, breast stage B 3 was reached earlier (11.6 vs 12.2 years, P=0.03). In boys, mean volume of testis revealed no significant deviation from reference. Mean dehydroepiandrosterone sulfate (DHEAS) levels were elevated in boys (within age ranges 8-10 years and 12-16 years, P<0.02) and in girls (within age ranges 6-8 years and 12-18 years, P<0.005) and mean testosterone levels in boys >12 years were lower as compared to reference ranges (all P-values <0.0001).

CONCLUSION

The study data suggest normal development of pubarche and gonadarche in obese German boys and normal timing of pubarche in girls. Breast development in obese girls seems to be slightly advanced. In obese boys, an obvious dissociation of clinical and laboratory parameters of pubertal development was observed. Despite significantly increased height-SDS and increased DHEAS levels, gonadal development was normal and testosterone levels were decreased. Elevated DHEAS levels in both genders may contribute to the acceleration of bone maturation, a lower final body height and could increase cardiovascular risk.

Definable somatic disorders in overweight children and adolescents

OBJECTIVE

To analyze the frequencies and clinical presentation of definable somatic disorders in children who are overweight.

STUDY DESIGN

We assessed prospectively 1405 children aged 4 to 16 years who were overweight and came to our specialized clinic for endocrinology and obesity with a standardized diagnostic procedure. In a subgroup of 223 children, we sought mutations in the melanocortin-4-receptor gene (MC4R).

RESULTS

Endocrine or syndromal disorders were diagnosed in 13 children (<1%; 4 with hypothyroidism, 1 with Cushing's syndrome, 1 with growth hormone deficiency, 2 with pseudohypoparathyroidism, 1 with pseudopseudohypoparathyroidism, 2 with Prader-Willi syndrome, 1 with Bardet-Biedl syndrome, 1 with Klinefelter syndrome). A total of 85% of these children had short stature, in marked contrast to only 0.6% of the other children. Moderately elevated thyrotropin and cortisol concentrations were observed in 4% and 5%, respectively, of all children. Non-synonymous MC4R mutations were found in 6% of the children.

CONCLUSIONS

In contrast to MC4R mutations, endocrine and clinically identifiable syndromal disorders were rare in children who were overweight and always associated with further symptoms. All children who are overweight with short stature or reduced growth velocity should be carefully examined for endocrine or syndromal disorders. A general screening with laboratory measurements cannot be recommended because thyrotropin and cortisol levels are frequently moderately elevated in children who are overweight, thus entailing further superfluous diagnostic procedures.

The role of the central melanocortin system in the regulation of food intake and energy homeostasis: lessons from mouse models

A little more than a decade ago, the molecular basis of the lipostat was largely unknown. At that time, many laboratories were at work attempting to clone the genes encoding the obesity, diabetes, fatty, tubby and agouti loci, with the hope that identification of these obesity genes would help shed light on the process of energy homeostasis, appetite and energy expenditure. Characterization of obesity and diabetes elucidated the nature of the adipostatic hormone leptin and its receptor, respectively, while cloning of the agouti gene eventually led to the identification and characterization of one of the key neural systems upon which leptin acts to regulate intake and expenditure. In this review, we describe the neural circuitry known as the central melanocortin system and discuss the current understanding of its role in feeding and other processes involved in energy homeostasis.

The growth of children in relation to the timing of obesity development

OBJECTIVE

To examine whether there is an association between the timing of the development of obesity and children's growth.

RESEARCH METHODS AND PROCEDURES

This study investigated 141 prepubertal obese children (76 girls) and 72 healthy non-obese children (39 girls). The target height standard deviation score (SDS), the percentage weight for height, and the height SDS (H-SDS) at presentation and at the age of 2 years were calculated. Patients were classified, according to whether obesity developed before or after the age of 3 years, as presenting with early-onset or late-onset obesity, respectively.

RESULTS

Mean age (+/-SD) at presentation was 9.4 (2.1) years. At the age of 2 years, the H-SDS of the children with early-onset obesity was 1.3 (1.0) vs. 0.9 (1.3) for the late-onset obese (p > 0.5) and 0.4 (1.0) for controls (p < 0.001), and the children with late-onset obesity were also significantly taller than controls (p < 0.005). At presentation, children with early-onset obesity were significantly taller than children with late-onset obesity [1.1 (0.8) vs. 0.6 (1.0); p < 0.001] and controls [0.2 (0.8); p < 0.001]. There was no increase in H-SDS after the age of 2 years in the late-onset obese children (p > 0.05). H-SDS values were below average in 21% of the children with late-onset obesity and in only 4% of the children with early-onset obesity.

DISCUSSION

These findings indicate that late development of obesity is not associated with increased stature in prepubertal children; however, it may be preceded by growth acceleration in the early years of life. Growth acceleration in early life may be a predictor for future obesity.

Combined influence of early sexual maturation and central adiposity on subsequent stature. A four-year follow-up of 1,605 Norwegian boys and girls: the Young-HUNT study

INTRODUCTION

Shorter adult stature has been attributed to early sexual maturation, as well as early adiposity, but it is not clear if these factors are interrelated.

RESULTS AND DISCUSSION

A number of 1,605 Norwegian adolescents were followed from early (baseline) to late adolescence (follow-up). Maturational timing was assessed by self-reports of pubertal status (pubertal development scale, PDS) in boys and age at menarche (AAM) in girls. Height, weight and waist circumference were measured at baseline and at follow-up. Differences in height at follow-up and height gain related to the timing of sexual maturation and the level of central adiposity (i.e. high or low waist circumference) at baseline were estimated using general linear modelling. At follow-up, the median height was 180 cm in boys and 167 cm in girls. Early maturing boys and girls with relatively high central adiposity at baseline were, on average, 5.7 cm (P value<0.001) and 3.6 cm (P value<0.001) taller than early maturing boys and girls with low central adiposity. Differences in stature related to central adiposity were less pronounced for intermediate and late maturing boys and girls. The height was lowest in boys (176.6 cm) and girls (163.8 cm) who had matured early and had low central adiposity at baseline. Height gain during follow-up was independent of the level of central adiposity, but was closely related to the timing of sexual maturation. The association between the early timing of sexual maturation and subsequent height was modified by the level of central adiposity in early adolescence.

CONCLUSION

The results suggest that early maturity combined with adiposity yields higher stature than early maturity and leanness.

Relationships of IGF-I and andrrogens to skeletal maturation in obese children and adolescents

IGF-I and androgens are postulated to accelerate skeletal maturation in obese children.

METHODS

We studied weight status (BMI-SDS), height-SDS, IGF-I, cortisol, DHEA-S, and testosterone in 356 obese children (aged 4-15 years; 54% females) and correlated them to differences between bone age and chronological age (deltaBA-CA). Direct multivariate linear regression analyses were conducted for the dependent variable deltaBA-CA, including BMI, age, gender, pubertal stage, IGF-I-SDS, cortisol, DHEA-S, and testosterone as independent variables separately in prepubertal and pubertal girls, and prepubertal and pubertal boys.

RESULTS

Height-SDS (r = 0.52), IGF-I (r = 0.33), and IGF-I-SDS (r = 0.36) were significantly (p < 0.001) correlated to deltaBA-CA. In multiple regression analyses, BMI and IGF-I-SDS were significantly positively (p < 0.001) correlated to deltaBA-CA independently of gender and pubertal stage. Testosterone was significantly positively correlated to detaBA-CA only in prepubertal girls (p = 0.035).

CONCLUSIONS

Since IGF-I concentrations were positively associated to deltaBA-CA independently of pubertal stage and gender, we put forward the hypothesis that this hormone may contribute to acceleration of skeletal maturation in obese children.

Bone age and onset of puberty in normal boys

Many conditions that delay skeletal maturation also delay the onset of puberty, whereas conditions that accelerate skeletal maturation often hasten the onset puberty, raising the possibility that skeletal maturation influences pubertal onset. To determine whether this concordance is also present in normal children, we analyzed data from 30 normal boys participating in a longitudinal study. Height, weight, and serum testosterone concentrations were assessed every 6 months and bone age (Fels method) every year. Pubertal onset was defined by serum testosterone > or =30 ng/dL. The variability in bone age at onset of puberty was not less than the variability in chronological age. In addition, there was no significant correlation between skeletal advancement and pubertal advancement (r=0.01, P=0.9). Similarly, there was not a significant correlation between pubertal advancement and height age advancement, weight age advancement, or BMI age advancement. Our findings do not support the hypothesis that skeletal maturation directly influences the age of pubertal onset in normal boys.

Growth curves of anthropometric indices in a general population of French children and comparison with reference data

BACKGROUND

The description of growth patterns of the different anthropometric measurements mainly used in epidemiological studies is useful to better understand the development of obesity in children and its consequences.

OBJECTIVE

Our aim was to establish growth curves of anthropometric indices in a general population of French children born during the 1980s and to compare them with the French reference curves based on children born in the 1950s.

DESIGN

As part of the Fleurbaix Laventie Ville Santé Studies I and II (FLVS), 441 girls and 467 boys were examined at least twice between 1993 and 2001. Height, weight and four skinfold thicknesses were measured. Body mass index (BMI), sum of peripheral and truncal skinfolds and truncal-to-peripheral ratio were calculated. Mean growth curves from ages 5 to 17 years were assessed for these indices, calculating means and 95% confidence interval per 1 year age group and by gender.

RESULTS

Trajectories with age differed importantly according to the index considered; BMI was the one with the smallest difference between genders and the most linear shape with age. From the age of 5 years and after, the FLVS children were on average taller and had a higher subcutaneous adiposity than children born 30 years earlier. Truncal-to-peripheral ratio was higher in our population; this difference became more marked with puberty in girls.

DISCUSSION

This study suggests the existence of a secular trend towards a precocious accelerated growth, and a more truncal adiposity distribution, especially in girls. It is a disquieting trend considering its expected consequences on adult health.

Endocrine regulation of the growth plate

Longitudinal bone growth occurs at the growth plate by endochondral ossification. Within the growth plate, chondrocyte proliferation, hypertrophy, and cartilage matrix secretion result in chondrogenesis. The newly formed cartilage is invaded by blood vessels and bone cells that remodel the newly formed cartilage into bone tissue. This process of longitudinal bone growth is governed by a complex network of endocrine signals, including growth hormone, insulin-like growth factor I, glucocorticoid, thyroid hormone, estrogen, androgen, vitamin D, and leptin. Many of these signals regulate growth plate function, both by acting locally on growth plate chondrocytes and also indirectly by modulating other endocrine signals in the network. Some of the local effects of hormones are mediated by changes in paracrine factors that control chondrocyte proliferation and differentiation. Many human skeletal growth disorders are caused by abnormalities in the endocrine regulation of the growth plate. This review provides an overview of the endocrine signals that regulate longitudinal bone growth, their interactions, and the mechanisms by which they affect growth plate chondrogenesis.

The role of growth hormone in determining birth size and early postnatal growth, using congenital growth hormone deficiency (GHD) as a model

OBJECTIVE

The role of GH in early human growth is unclear. Congenital GH deficiency (CGHD) provides a useful tool to explore this putative role. We have assessed the effects of CGHD on birth size and early postnatal growth, and the further impact of the presence of additional pituitary hormone deficiencies and midline brain defects on these parameters.

DESIGN, PATIENTS AND MEASUREMENTS

Weight, length and BMI expressed as standard deviation scores (SDS), over the first two years of life, were retrospectively compared in 44 GH-deficient children (M:F 26 : 18). Thirty-eight of 44 patients underwent GH provocation testing and all patients had neuro-imaging of the brain. The patients were divided into three groups of increasing phenotypic complexity {group A [n = 12, isolated GHD, no midline defects], group B [n = 10, combined pituitary hormone deficiency (CPHD); no midline defects], group C (n = 22, CPHD with midline defects)}.

RESULTS

Mean birth weight, length and BMI SDS were -0.4, -0.9 and +0.1 SDS, respectively. The differences were significant for weight (P = 0.03) and BMI (P = 0.003), but not length (P = 0.3) SDS, between groups A and C. Of the three groups, group A had a lower weight and BMI SDS than group C. The prevalence of postnatal complications (n = 25) was significantly different in the three groups [group A (8%), group B (80%), group C (73%); P < 0.001] and particularly between patients with isolated GH deficiency (IGHD) (group A) and CPHD (groups B and C; P < 0.0001). No patients in group A presented with neonatal hypoglycaemia as compared with 70% of those in group B and 59% in group C (P = 0.001). A reduced length SDS was observed in all patients within 6 months of birth and the reduction was greatest in group B (P = 0.03). Group C remained significantly (P < 0.05) heavier at 12, 18 and 24 months compared to group A. BMI SDS was significantly (P < 0.05) greater at all study points in CPHD patients (groups B and C) as compared with IGHD. Serum GH concentrations at testing did not correlate significantly with birth length (r = -0.08, P = 0.7), birth weight (r = -0.08, P = 0.6) or the age at induction of GH treatment (r = 0.12, P = 0.5). There were no significant differences between peak serum GH concentrations in patients in groups A (7.8 +/- 6.3 mU/l), B (3.9 +/- 4.8 mU/l) or C (8.7 +/- 5.4 mU/l).

CONCLUSIONS

Length, weight and BMI data from our study groups suggest that GH per se has a minimal effect on intrauterine growth but a significant effect during the infancy period. Early growth may also be influenced by the complexity of the hypopituitary phenotype reflected by the presence of additional pituitary hormone deficiencies and midline forebrain defects.

Macronutrient intake, physical activity, serum lipids and increased body weight in primary schoolchildren in Istanbul

BACKGROUND

The aim of this cross-sectional study was to record the prevalence of underweight, overweight and obesity in primary school children living in Istanbul and to examine the relationship between increased body weight and certain cardiovascular disease (CVD) risk factors.

METHODS

A total of 510 randomly selected children aged 12 and 13 years of age (257 boys, 253 girls) were examined. Information regarding anthropometrical indices, energy and macronutrient intake, physical activity, physical fitness and lipid profile were collected. Classification of children in overweight and obese subgroups was based on the cut-off points proposed by Cole et al.

RESULTS

The prevalence of underweight, overweight and obesity was found to be 15.3%, 10.6% and 1.6%, respectively. Both overweight boys and girls were found to have lower physical fitness compared to their normal-weight counterparts, but no difference was observed for energy and macronutrient intake. Overweight boys were found to have higher total cholesterol (P < 0.001), low-density lipoprotein cholesterol (P < 0.01), triglycerides (P < 0.01) and total cholesterol/high-density lipoprotein cholesterol (HDL-C) ratio (P < 0.05) compared to their normal-weight counterparts, while overweight girls were found to have lower HDL-C (P < 0.05) compared to their normal-weight peers.

CONCLUSIONS

Underweight and overweight coexisted in the current population. Increased body weight was accompanied by unfavorable lipid profiles and lower fitness levels. Consequently, there is an emergent need for early identification and understanding of behavioral and physiological variables related to obesity and CVD, so that appropriate interventions can be targeted to children who are at risk for adult onset of these diseases.