Salivary microbiome differences in prepubertal children with and without adrenal androgen excess.

BACKGROUND: Premature adrenarche is a condition of childhood adrenal androgen excess (AAE) in the absence of gonadotropin-dependent puberty, and has been linked to insulin resistance and progression to metabolic syndrome. Microbial dysbiosis is associated with progression of inflammatory states and chronic diseases. Here, we aimed to examine the salivary microbiomes of children with AAE and assess the relationship with adrenal androgens and metabolic parameters. METHODS: In a prospective cross-sectional study of children with AAE and healthy controls, adrenal and metabolic parameters were characterized and salivary microbiome was profiled using V3-V4 16S rDNA gene amplicon sequencing. RESULTS: There was increased α-diversity in AAE (5 M, 15 F) compared to controls (3 M, 8 F), with positive correlation of 11OHA4, 11KA4, testosterone, androstenedione, DHEA, and DHEAS. Subanalyses showed increased α-diversity in both overweight/obese AAE and normal weight AAE compared to normal weight controls. Genus Peptostreptococcus, Veillonella, and Streptococcus salivarius were increased in normal weight AAE. Genus Prevotella, Abiotrophia, and Neisseria were increased in overweight/obese AAE. CONCLUSION: These pilot data demonstrate differences in salivary microbiome profiles of children with and without AAE. Further studies are needed to assess the causal relationships between adrenal androgens, metabolic dysfunction, and salivary microbiome composition. IMPACT: This study is the first to report the salivary microbiome of prepubertal children with adrenal androgen excess (AAE). α-Diversity is increased in the salivary microbiome of children with AAE independent of weight status, and in this study cohort several serum androgens are positively associated with α-diversity. Several taxa that have been associated with periodontal disease and inflammation are found to be significantly increased in AAE.

Prenatal exposure to polybrominated diphenyl ethers and BMI Z-scores from 5 to 14 years.

BACKGROUND: Polybrominated diphenyl ethers (PBDEs) are flame-retardant compounds widely used in household products until phase out in 2004. PBDEs are endocrine disruptors and are suggested to influence signaling related to weight control. Prenatal exposures to PBDEs may alter childhood adiposity, yet few studies have examined these associations in human populations. METHODS: Data were collected from a birth cohort of Dominican and African American mother-child pairs from New York City recruited from 1998 to 2006. PBDE congeners BDE-47, - 99, - 100, and - 153 were measured in cord plasma (ng/µL) and dichotomized into low (< 80th percentile) and high (>80th percentile) exposure categories. Height and weight were collected at ages 5, 7, 9, 11, and an ancillary visit from 8 to 14 years (n = 289). Mixed-effects models with random intercepts for participant were used to assess associations between concentrations of individual PBDE congeners or the PBDE sum and child BMI z-scores (BMIz). To assess associations between PBDEs and the change in BMIz over time, models including interactions between PBDE categories and child age and (child age)2 were fit. Quantile g-computation was used to investigate associations between BMIz and the total PBDE mixture. Models were adjusted for baseline maternal covariates: ethnicity, age, education, parity, partnership status, and receipt of public assistance, and child covariates: child sex and cord cholesterol and triglycerides. RESULTS: The prevalence of children with obesity at age 5 was 24.2% and increased to 30% at age 11. Neither cord levels of individual PBDEs nor the total PBDE mixture were associated with overall BMIz in childhood. The changes in BMIz across childhood were not different between children with low or high PBDEs. Results were similar when adjusting for postnatal PBDE exposures. CONCLUSIONS: Prenatal PBDE exposures were not associated with child growth trajectories in a cohort of Dominican and African American children.

Adolescent polycystic ovary syndrome according to the international evidence-based guideline.

BACKGROUND: Diagnosing polycystic ovary syndrome (PCOS) during adolescence is challenging because features of normal pubertal development overlap with adult diagnostic criteria. The international evidence-based PCOS Guideline aimed to promote accurate and timely diagnosis, to optimise consistent care, and to improve health outcomes for adolescents and women with PCOS. METHODS: International healthcare professionals, evidence synthesis teams and consumers informed the priorities, reviewed published data and synthesised the recommendations for the Guideline. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework was applied to appraise the evidence quality and the feasibility, acceptability, cost, implementation and strength of the recommendations. RESULTS: This paper focuses on the specific adolescent PCOS Guideline recommendations. Specific criteria to improve diagnostic accuracy and avoid over diagnosis include: (1) irregular menstrual cycles defined according to years post-menarche; > 90 days for any one cycle (> 1 year post-menarche), cycles< 21 or > 45 days (> 1 to < 3 years post-menarche); cycles < 21 or > 35 days (> 3 years post-menarche) and primary amenorrhea by age 15 or > 3 years post-thelarche. Irregular menstrual cycles (< 1 year post-menarche) represent normal pubertal transition. (2) Hyperandrogenism defined as hirsutism, severe acne and/or biochemical hyperandrogenaemia confirmed using validated high-quality assays. (3) Pelvic ultrasound not recommended for diagnosis of PCOS within 8 years post menarche. (4) Anti-Müllerian hormone levels not recommended for PCOS diagnosis; and (5) exclusion of other disorders that mimic PCOS. For adolescents who have features of PCOS but do not meet diagnostic criteria an 'at risk' label can be considered with appropriate symptomatic treatment and regular re-evaluations. Menstrual cycle re-evaluation can occur over 3 years post menarche and where only menstrual irregularity or hyperandrogenism are present initially, evaluation with ultrasound can occur after 8 years post menarche. Screening for anxiety and depression is required and assessment of eating disorders warrants consideration. Available data endorse the benefits of healthy lifestyle interventions to prevent excess weight gain and should be recommended. For symptom management, the combined oral contraceptive pill and/or metformin may be beneficial. CONCLUSIONS: Extensive international engagement accompanied by rigorous processes honed both diagnostic criteria and treatment recommendations for PCOS during adolescence.

Update on adrenarche.

PURPOSE OF REVIEW: Adrenarche is the pubertal maturation of the innermost zone of the adrenal cortex, the zona reticularis. The onset of adrenarche occurs between 6 and 8 years of age when dehydroepiandrosterone sulfate (DHEAS) concentrations increase. This review provides an update on adrenal steroidogenesis and the differential diagnosis of premature development of pubic hair. RECENT FINDINGS: The complexity of adrenal steroidogenesis has increased with recognition of the alternative 'backdoor pathway' and the 11-oxo-androgens pathways. Traditionally, sulfated steroids such as DHEAS have been considered to be inactive metabolites. Recent data suggest that intracellular sulfated steroids may function as tissue-specific intracrine hormones particularly in the tissues expressing steroid sulfatases such as ovaries, testes, and placenta. SUMMARY: The physiologic mechanisms governing the onset of adrenarche remain unclear. To date, no validated regulatory feedback mechanism has been identified for adrenal C19 steroid secretion. Available data indicate that for most children, premature adrenarche is a benign variation of development and a diagnosis of exclusion. Patients with premature adrenarche tend to have higher BMI values. Yet, despite greater knowledge about C19 steroids and zona reticularis function, much remains to be learned about adrenarche.

The diagnosis and treatment of PCOS in adolescents: an update.

PURPOSE OF REVIEW: Polycystic ovary syndrome (PCOS) is often difficult to diagnose in adolescents. Recent recommendations and concepts regarding the diagnosis and treatment of PCOS in the adolescent girl are considered. RECENT FINDINGS: The diagnosis of PCOS in adolescents should be primarily based on clinical and biochemical signs of hyperandrogenism and presentation with irregular menses. Because of the similarity of normal pubertal development and features of PCOS, the diagnosis should be deferred until at least 2 years following menarche. For girls who do not fulfill the diagnostic criteria, the focus should be on treatment of symptoms. SUMMARY: PCOS is a complex, multifaceted disorder, and should be diagnosed and treated in adolescents after taking into consideration the patient's full diagnostic picture, metabolic risks, and individual concerns, to both avoid overdiagnosis but yet be able to provide early and meaningful interventions.

Prenatal exposure to airborne polycyclic aromatic hydrocarbons and childhood growth trajectories from age 5-14 years.

There is evidence that exposures to polycyclic aromatic hydrocarbons (PAH) and fine particles in air pollution are associated with higher childhood body mass index (BMI). Birth cohort analyses of prenatal exposures to PAH and child BMI Z-scores from age 5-14 years were conducted. African-American and Hispanic children born in the Bronx or Northern Manhattan, New York (1998-2006), whose mothers underwent personal air monitoring for airborne PAH exposure during pregnancy, were followed up with measurements of height and weight at approximate ages 5, 7, 9, 10, 11, 12.5 and 13.5 years. Multivariable generalized estimating equation analyses were used to relate prenatal airborne PAH exposures to child BMI Z-scores through time. The analyses adjusted for many known risk factors for childhood obesity and included interactions terms between age and exposure tertiles and age squared and exposure tertiles. In total, 535 children had at least one height and weight measure during follow-up. The prevalence of obesity was 20.6% at age 5 and increased across follow-ups until age 11 when it was 33.0%. At age 5, BMI Z-scores were significantly greater for children in the third tertile of exposure relative to the first tertile (0.35 Z-score units, 95% CI 0.09, 0.61, p = 0.007) and were non-significantly higher for the second tertile of exposure compared to the first tertile (0.25 Z-score units, 95% CI -0.02, 0.52, P = 0.075). The trajectories of BMI Z-scores by tertiles of exposure converged as the children aged, such that by age 11 years the estimated mean BMI Z-scores associated with each tertile of exposure were not different. Prenatal exposures to airborne PAH were associated with higher childhood BMI Z-scores at a young age, but growth trajectories converged by age 11 years. Accordingly, highly exposed children spend a greater proportion of their childhood with higher BMI Z-scores.

Present Knowledge on the Etiology and Treatment of Adrenarche.

Premature adrenarche (PA) has been assumed to be a benign variant of normal pubertal development. Yet, current collective information suggests associations between PA and potential risks for development of polycystic ovary syndrome and adult diseases such as the metabolic syndrome. Adrenarche refers to the increased secretion of the adrenal androgen precursors DHEA, DHEAS, and androstenedione, which normally occurs in children at age 6-8 years. PA may be identified clinically by early pubarche, which is defined as the development of pubic or axillary hair before 8 years in girls or 9 years in boys. This paper will consider adrenal steroidogenesis, genetic markers, neurobiological changes, skeletal maturation, and associations with adult disorders. The differential diagnosis will be reviewed because PA remains a diagnosis of exclusion. Finally, synthesis of current knowledge regarding PA, suggestions for evaluation, management, and treatment are offered.

A trans-ethnic genome-wide association study identifies gender-specific loci influencing pediatric aBMD and BMC at the distal radius.

Childhood fractures are common, with the forearm being the most common site. Genome-wide association studies (GWAS) have identified more than 60 loci associated with bone mineral density (BMD) in adults but less is known about genetic influences specific to bone in childhood. To identify novel genetic factors that influence pediatric bone strength at a common site for childhood fractures, we performed a sex-stratified trans-ethnic genome-wide association study of areal BMD (aBMD) and bone mineral content (BMC) Z-scores measured by dual energy X-ray absorptiometry at the one-third distal radius, in a cohort of 1399 children without clinical abnormalities in bone health. We tested signals with P < 5 × 10(-6) for replication in an independent, same-age cohort of 486 Caucasian children. Two loci yielded a genome-wide significant combined P-value: rs7797976 within CPED1 in females [P = 2.4 × 10(-11), ß =- 0.30 standard deviations (SD) per T allele; aBMD-Z] and rs7035284 at 9p21.3 in males (P = 1.2 × 10(-8), ß = 0.28 SD per G allele; BMC-Z). Signals at the CPED1-WNT16-FAM3C locus have been previously associated with BMD at other skeletal sites in adults and children. Our result at the distal radius underscores the importance of this locus at multiple skeletal sites. The 9p21.3 locus is within a gene desert, with the nearest gene flanking each side being MIR31HG and MTAP, neither of which has been implicated in BMD or BMC previously. These findings suggest that genetic determinants of childhood bone accretion at the radius, a skeletal site that is primarily cortical bone, exist and also differ by sex.

BMD Loci Contribute to Ethnic and Developmental Differences in Skeletal Fragility across Populations: Assessment of Evolutionary Selection Pressures.

Bone mineral density (BMD) is a highly heritable trait used both for the diagnosis of osteoporosis in adults and to assess bone health in children. Ethnic differences in BMD have been documented, with markedly higher levels in individuals of African descent, which partially explain disparity in osteoporosis risk across populations. To date, 63 independent genetic variants have been associated with BMD in adults of Northern-European ancestry. Here, we demonstrate that at least 61 of these variants are predictive of BMD early in life by studying their compound effect within two multiethnic pediatric cohorts. Furthermore, we show that within these cohorts and across populations worldwide the frequency of those alleles associated with increased BMD is systematically elevated in individuals of Sub-Saharan African ancestry. The amount of differentiation in the BMD genetic scores among Sub-Saharan and non-Sub-Saharan populations together with neutrality tests, suggest that these allelic differences are compatible with the hypothesis of selective pressures acting on the genetic determinants of BMD. These findings constitute an explorative contribution to the role of selection on ethnic BMD differences and likely a new example of polygenic adaptation acting on a human trait.

Menstrual Bleeding as a Manifestation of Mini-Puberty of Infancy in Severe Prematurity.

We report 2 infants with severe prematurity who presented with uterine bleeding at age 6 months (approximately 2.5 months corrected for gestational age). Mini-puberty of infancy should be considered in the differential diagnosis of girls who present with uterine bleeding during the first 6 months of life.

Childhood acromegaly due to X-linked acrogigantism: long term follow-up.

PURPOSE: Acromegaly in infancy is extremely rare. We describe a 32 year old woman who presented at 6 months of age with isolated macrocephaly, followed by accelerated linear growth. At 21 months of age, her head circumference was 55 cm (+5.5 SD), height was 97.6 cm (+4.4 SD) and weight was 20.6 kg (+6.2 SD). She had markedly elevated levels of growth hormone (GH) (135 ng/ml), IGF-1 (1540 ng/ml) and prolactin (370 ng/ml). A pituitary macroadenoma was surgically resected. Immunohistochemical staining was positive for GH. Post-operatively, she developed ACTH and TSH deficiency and diabetes insipidus. METHODS: Long term clinical follow-up and genetic testing with chromosomal microarray analysis. RESULTS: Despite GH deficiency, she grew well until 7 ½ years old, with subsequent decline in growth velocity, and received GH therapy for 5 years. Puberty was initiated with estrogen therapy. As an adult, she has no stigmata of acromegaly, with a height of 164.5 cm and non-acromegalic features. IGF-1 has remained in the low normal range. Prolactin has been mildly elevated. Serial MRIs have shown no evidence of tumor recurrence. She receives replacement therapy with hydrocortisone, levothyroxine and DDAVP. Chromosomal microarray analysis revealed that she has X-linked acrogigantism (X-LAG) due to a de novo duplication of Xq26.3 (516 kb). She recently became pregnant following ovarian stimulation and chorionic villus sampling revealed that she is carrying a male with the same duplication. CONCLUSION: This report provides detailed long term clinical follow-up of a patient with X-LAG syndrome.

Gestational weight gain and obesity, adiposity and body size in African-American and Dominican children in the Bronx and Northern Manhattan.

Gestational weight gain (GWG) is potentially modifiable and is associated with infant size and body composition; however, long-term effects on childhood obesity have not been reported among multi-ethnic urban populations. We examined the association between GWG and child anthropometric measures and body composition at 7 years [waist circumference (WC), body mass index z-score (BMIZ), obesity (BMIZ ≥95%ile) and bioelectrical impedance analysis estimates of percentage body fat (%fat)] in African-American and Dominican dyads (n = 323) in the Columbia Center for Children's Environmental Health prospective birth cohort study from 1998 to 2013. Linear and logistic regression evaluated associations between excessive GWG [>Institute of Medicine (IOM) 2009 guidelines] and outcomes, adjusting for pre-pregnancy BMI and covariates. Pre-pregnancy BMI (mean ± standard deviation, all such values) and total GWG were 25.8 ± 6.2 kg m(-2) (45% overweight/obese) and 16.4 ± 7.9 kg (64% > IOM guidelines), respectively. Excessive GWG was associated with higher BMIZ {0.44 [95% confidence interval (CI): 0.2, 0.7], P < 0.001}, WC [ß: 2.9 cm (95% CI: 1.1, 4.6), P = 0.002], %fat at 7 years [ß: 2.2% (95% CI: 1.0, 3.5), P = 0.001)] and obesity [odds ratio: 2.93 (95% CI: 1.5, 5.8), P = 0.002]. Pre-pregnancy BMI was positively associated with child size, adiposity and obesity (all P < 0.05). Excessive GWG was highly prevalent and was associated with child obesity, greater percentage body fat and abdominal adiposity. Strategies to support healthy GWG are warranted to promote healthy growth and prevent childhood obesity.

Longitudinal tracking of dual-energy X-ray absorptiometry bone measures over 6 years in children and adolescents: persistence of low bone mass to maturity.

OBJECTIVES: Early assessment of bone mass may be useful for predicting future osteoporosis risk if bone measures "track" during growth. This prospective longitudinal multicenter study examined tracking of bone measures in children and adolescents over 6 years to sexual and skeletal maturity. STUDY DESIGN: A total of 240 healthy male and 293 healthy female patients, ages 6-17 years, underwent yearly evaluations of height, weight, body mass index, skeletal age, Tanner stage, and dual-energy x-ray absorptiometry (DXA) bone measurements of the whole body, spine, hip, and forearm for 6 years. All subjects were sexually and skeletally mature at final follow-up. Correlation was performed between baseline and 6-year follow-up measures, and change in DXA Z-scores was examined for subjects who had baseline Z < -1.5. RESULTS: DXA Z-scores (r = 0.66-0.87) had similar tracking to anthropometric measures (r = 0.64-0.74). Tracking was stronger for bone mineral density compared with bone mineral content and for girls compared with boys. Tracking was weakest during mid- to late puberty but improved when Z-scores were adjusted for height. Almost all subjects with baseline Z < -1.5 had final Z-scores below average, with the majority remaining less than -1.0. CONCLUSIONS: Bone status during childhood is a strong predictor of bone status in young adulthood, when peak bone mass is achieved. This suggests that bone mass measurements in children and adolescents may be useful for early identification of individuals at risk for osteoporosis later in life.

Postpartum Obesity Is Associated With Increases in Child Adiposity in Midchildhood in a Cohort of Black and Dominican Youth.

Background: Obesity disproportionately affects marginalized and low-income populations. Birth parent obesity from the prenatal period and childhood has been associated with child obesity. It is unknown whether prenatal or postnatal birth parent obesity has differential effects on subsequent changes in adiposity and metabolic health in children. Objectives: We evaluated how birth parent obesity 7 y after delivery was associated with child body composition changes and cardiometabolic health in midchildhood and further assessed the influence of the perinatal and postpartum period on associations. Methods: Black and Dominican pregnant individuals were enrolled, and dyads (n = 319) were followed up at child age 7 and 9 y. Measures included, height, weight, waist circumference (WC), and percent body fat (BF%). Multiple linear regression was used to relate postpartum weight status with child outcomes accounting for attrition, and a series of secondary analyses were conducted with additional adjustment for perinatal weight status, gestational weight gain (GWG), and/or long-term weight retention to evaluate how these factors influenced associations. Results: Almost one-quarter (23%) of birth parents and 24.1% children were classified with obesity at child age 7 y, while at 9 y, 30% of children had obesity. Birth parent obesity at child age 7 y was associated with greater changes, from ages 7 to 9 y, in child BMI z-score (ß: 0.13; 95% CI: 0.02, 0.24) and BF% (ß: 1.15; 95% CI: 0.22, 2.09) but not obesity at age 9 y. All observed associations crossed the null after additional adjustment for prenatal factors. Conclusions: Birth parent obesity at 7-y postpartum is associated with greater gains in child BMI z-score and BF% in midchildhood. These associations diminish after accounting for prenatal size, suggesting a lasting impact of the perinatal environment and that interventions supporting families from the prenatal period through childhood are needed.

Inverse associations of cord blood mitochondrial DNA copy number with childhood adiposity.

OBJECTIVE: The objective of this study was to examine associations between umbilical cord mitochondrial DNA copy number (mtDNAcn) and adiposity across childhood. METHODS: In a prospective birth cohort of Dominican and African American children from New York City, New York (1998-2006), mtDNAcn was measured in cord blood. Children (N = 336) were evaluated for their height, weight, and bioimpedance at age 5, 7, 9, and 11 years. We used linear mixed-effects models to assess associations of mtDNAcn tertiles in cord blood with child BMI, BMI z scores, fat mass index, and body fat percentage. Latent class growth models and interactions between mtDNAcn and child age or child age2 were used to assess associations between age and adiposity trajectories. RESULTS: BMI was, on average, 1.5 kg/m2 higher (95% CI: 0.58, 2.5) in individuals with mtDNAcn in the low- compared with the middle-mtDNAcn tertile. Results were similar for BMI z score, fat mass index, and body fat percentage. Moreover, children in the low-mtDNAcn group had increased odds of being in an "increasing" or "high-stable" adiposity class. CONCLUSIONS: Lower mtDNAcn at birth may predict greater childhood adiposity, highlighting the potential key role of perinatal mitochondrial function in adiposity during development.

The Relationship Between Metabolic Comorbidities and Post-surgical Weight Loss Outcomes in Adolescents Undergoing Laparoscopic Sleeve Gastrectomy.

BACKGROUND: Little is known about the relationship between metabolic factors and weight loss success in adolescents undergoing bariatric surgery. METHODS: The objective of this study was to assess if baseline metabolic characteristics associate with weight loss in adolescents undergoing laparoscopic sleeve gastrectomy. A retrospective study was conducted in a comprehensive adolescent bariatric surgery center of 151 subjects (34 male, 117 female). Anthropometric measurements and metabolic factors including blood pressure, fasting glucose, HbA1c, Metabolic Syndrome (MeS), liver function, triglycerides, and waist circumference were collected at one pre-surgical visit, and at 6 and/or 12 months post-laparoscopic sleeve gastrectomy. Weight loss was compared between subjects with normal or abnormal baseline metabolic factors. Absolute BMI change was used to measure successful weight loss. RESULTS: Higher baseline systolic blood pressure (SBP) was associated with greater weight loss as measured by body mass index (BMI) change and BMI standard deviation score (BMI-SDS) change at 6 and 12 months. Those patients in the 6-month follow up group with an abnormal hemoglobin A1C (HbA1c) at baseline had significantly more weight loss as measured by BMI-SDS. None of the other parameters, including fasting glucose, Metabolic Syndrome (MeS), liver function, triglycerides and waist circumference showed a predictive relationship. DISCUSSION/CONCLUSION: Elevated SBP and HbA1c in adolescents with morbid obesity may reflect a population more likely to achieve successful weight loss, and thus, may be a good target for bariatric surgery, specifically laparoscopic sleeve gastrectomy, as an intervention for severe obesity. An assessment of behavioral differences in patients with and without elevated BP and HbA1c might explain the mechanism for the improved weight loss.

Reference ranges for body composition indices by dual energy X-ray absorptiometry from the Bone Mineral Density in Childhood Study Cohort.

BACKGROUND: Body composition assessment aids evaluation of energy stores and the impact of diseases and interventions on child growth. Current United States pediatric reference ranges from the National Health and Nutrition Examination Survey (NHANES) include 20% of children with obesity, body mass index of ≥95th percentile. OBJECTIVES: This study aimed to develop dual energy X-ray absorptiometry (DXA) based reference ranges in a diverse cohort with low-obesity prevalence from the Bone Mineral Density in Childhood Study (BMDCS). METHODS: This is a secondary analysis of a longitudinal, prospective, observational cohort. Healthy children (height and BMI within 3rd to 97th percentiles, ages 5-19 y at enrollment), from 5 United States centers were measured annually for ≤7 visits. Whole body scans were acquired using Hologic scanners. A subsample underwent repeat measurements to determine precision. We generated reference ranges for appendicular and total lean soft tissue mass index (LSTM Index), fat mass index (FMI), and other body composition measures. Resulting curves were compared to NHANES and across subgroups. Sex and age-specific equations were developed to adjust body composition Z-scores for height Z score. RESULTS: We obtained 9846 scans of 2011 participants (51% female, 22% Black, 17% Hispanic, 48% White, 7% Asian/Pacific Islander, and 6% with obesity). Precision (percent coefficient of variation) ranged from 0.7% to 1.96%. Median and-2 standard deviation curves for BMDCS and NHANES were similar, but NHANES +2 standard deviation LSTM Index and FMI curves were distinctly greater than the respective BMDCS curves. Subgroup differences were more extreme for appendicular LSTM Index-Z (mean ± SD: Asian -0.52 ± 0.93 compared with Black 0.77 ± 0.87) than for FMI-Z (Hispanic 0.29 ± 0.98 compared with Black -0.14 ± 1.1) and were smaller for Z-scores adjusted for height Z-score. CONCLUSIONS: These reference ranges add to sparse normative data regarding body composition in children and adolescents and are based on a cohort with an obesity prevalence similar to current BMI charts. Awareness of subgroup differences aids in interpreting results.

Association of childhood obesity with maternal exposure to ambient air polycyclic aromatic hydrocarbons during pregnancy.

There are concerns that prenatal exposure to endocrine-disrupting chemicals increases children's risk of obesity. African-American and Hispanic children born in the Bronx or Northern Manhattan, New York (1998-2006), whose mothers underwent personal air monitoring for polycyclic aromatic hydrocarbon (PAH) exposure during pregnancy, were followed up to ages 5 (n = 422) and 7 (n = 341) years. At age 5 years, 21% of the children were obese, as were 25% of those followed to age 7 years. After adjustment for child's sex, age at measurement, ethnicity, and birth weight and maternal receipt of public assistance and prepregnancy obesity, higher prenatal PAH exposures were significantly associated with higher childhood body size. In adjusted analyses, compared with children of mothers in the lowest tertile of PAH exposure, children of mothers in the highest exposure tertile had a 0.39-unit higher body mass index z score (95% confidence interval (CI): 0.08, 0.70) and a relative risk of 1.79 (95% CI: 1.09, 2.96) for obesity at age 5 years, and they had a 0.30-unit higher body mass index z score (95% CI: 0.01, 0.59), a 1.93-unit higher percentage of body fat (95% CI: 0.33, 3.54), and a relative risk of 2.26 (95% CI: 1.28, 4.00) for obesity at age 7 years. The data indicate that prenatal exposure to PAHs is associated with obesity in childhood.

Racial disparity in fracture risk between white and nonwhite children in the United States.

OBJECTIVES: To examine risk factors for fracture in a racially diverse cohort of healthy children in the US. STUDY DESIGN: A total of 1470 healthy children, aged 6-17 years, underwent yearly evaluations of height, weight, body mass index, skeletal age, sexual maturation, calcium intake, physical activity levels, and dual-energy x-ray absorptiometry (DXA) bone and fat measurements for up to 6 years. Fracture information was obtained at each annual visit, and risk factors for fracture were examined using the time-dependent Cox proportional hazards model. RESULTS: The overall fracture incidence was 0.034 fracture per person-year with 212 children reporting a total of 257 fractures. Being white (hazard ratio [HR] = 2.1), being male (HR = 1.8), and having skeletal age of 10-14 years (HR = 2.2) were the strongest risk factors for fracture (all P ≤ .001). Increased sports participation (HR = 1.4), lower body fat percentage (HR = 0.97), and previous fracture in white girls (HR = 2.1) were also significant risk factors (all P ≤ .04). Overall, fracture risk decreased with higher DXA z scores, except in white boys, who had increased fracture risk with higher DXA z scores (HR = 1.7, P < .001). CONCLUSIONS: Boys and girls of European descent had double the fracture risk of children from other backgrounds, suggesting that the genetic predisposition to fractures seen in elderly adults also manifests in children.

Disorders of Puberty in Girls.

Puberty is the process through which reproductive competence is achieved and comprises gonadarche and adrenarche. Breast development is the initial physical finding of pubertal onset in girls and typically occurs between 8 and 13 years. Menarche normally occurs 2 to 3 years after the onset of breast development. Pubertal onset is controlled by the gonadotropin-releasing hormone pulse generator in the hypothalamus; however, environmental factors such as alterations in energy balance and exposure to endocrine-disrupting chemicals can alter the timing of pubertal onset. Improvement in nutritional and socioeconomic conditions over the past two centuries has been associated with a secular trend in earlier pubertal onset. Precocious puberty is defined as onset of breast development prior to 8 years and can be central or peripheral. Delayed puberty can be hypogonadotropic or hypergonadotropic and is defined as lack of breast development by 13 years or lack of menarche by 16 years. Both precocious and delayed puberty may have negative effects on self-esteem, potentially leading to psychosocial stress. Patients who present with pubertal differences require a comprehensive assessment to determine the underlying etiology and to devise an effective treatment plan.