New liquid chromatography tandem mass spectrometry reference data for estradiol show mini-puberty in both sexes and typical pre-pubertal and pubertal patterns.

Context: Reliable estradiol (E2) reference intervals (RIs) are crucial in pediatric endocrinology.

Objectives: This study aims to develop a sensitive ultra-performance liquid chromatographic tandem mass spectrometry (UPLC-MS/MS) method for E2 in serum, to establish graphically represented RI percentiles and annual RIs for both sexes, and to perform a systematic literature comparison.

Methods: First, a UPLC-MS/MS method for E2 was developed.

Cardiorespiratory fitness in adolescents and young adults with Klinefelter syndrome - a pilot study.

Background: Klinefelter syndrome (KS) may be associated with a wide spectrum of phenotypic changes including endocrine, metabolic, cognitive, psychiatric and cardiorespiratory pathologies in adults. However, in adolescence the clinical phenotype of KS is not well described, especially regarding physical fitness. The present study reports on cardiorespiratory function in adolescents and young adults with KS.

Childhood obesity is associated with changes in the serum metabolite profile.

Objective: The human serum metabolite profile is reflective of metabolic processes, including pathophysiological changes characteristic of diseases. Therefore, investigation of serum metabolite concentrations in obese children might give new insights into biological mechanisms associated with childhood obesity.

Methods: Serum samples of 80 obese and 40 normal-weight children between 6 and 15 years of age were analyzed using a mass spectrometry-based metabolomics approach targeting 163 metabolites.

SDCCAG8 obesity alleles and reduced weight loss after a lifestyle intervention in overweight children and adolescents.

Genome-wide association analyses (GWAS) contributed to the detection of a number of single-nucleotide polymorphisms (SNPs) associated with obesity. However, little is known about the impact of the obesity-risk alleles on weight loss-related phenotypes after lifestyle interventions. A recent meta-analysis of GWAS reported five genomic loci near or in the genes FTO, MC4R, TMEM18, SDCCAG8, TNKS/MSRA that were associated with obesity in children and adolescents.

Effect of lifestyle intervention on features of polycystic ovarian syndrome, metabolic syndrome, and intima-media thickness in obese adolescent girls.

Context: Polycystic ovarian syndrome (PCOS) is associated with cardiovascular risk factors (CRF). Lifestyle intervention is regarded as therapy of choice even if studies in adolescent girls with PCOS are scarce.

Objective: Our objective was to analyze the impact of lifestyle intervention on menses irregularities, hyperandrogenemia, CRF, and intima-media thickness (IMT) in adolescent girls with PCOS.

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.

Risk factors for impaired glucose tolerance in obese children and adolescents.

Aim: To investigate which obese children have an increased risk for impaired glucose tolerance (IGT), a risk factor for later diabetes.

Methods: We studied 169 European untreated obese children and adolescents with normal glucose tolerance at baseline. Waist circumference, fasting glucose, lipids, blood pressure, pubertal stage, 2 h glucose in oral glucose tolerance test (oGTT), and HbA1c were determined at baseline and 1 year later.

Relationship between MTNR1B (melatonin receptor 1B gene) polymorphism rs10830963 and glucose levels in overweight children and adolescents.

Aims: The G-allele of the single nucleotide polymorphism (SNP) rs10830963 in MTNR1B (melatonin receptor 1B gene) is associated with type 2 diabetes mellitus and glucose levels in adults. The aim of this study was to analyze whether there is an allele-dosage effect on glucose metabolism in overweight children and to explore if changes in glucose metabolism in a lifestyle intervention do also depend on genotype.

Methods: We genotyped rs10830963 in 1118 overweight children and adolescents [mean age 10.

Longitudinal association between IGFBP-1 levels and parameters of the metabolic syndrome in obese children before and after weight loss.

Background: Insulin-like growth factor binding protein 1 (IGFBP-1) is a marker of insulin resistance. We hypothesized that IGFBP-1 is associated with the metabolic syndrome (MetS), which is related to insulin resistance.

Methods: We examined 51 obese Caucasian children (mean age 12.

Body mass index patterns over 5 y in obese children motivated to participate in a 1-y lifestyle intervention: age as a predictor of long-term success.

Background: Long-term outcome after lifestyle interventions in obese children is largely unknown but important to improving intervention.

Objective: The aim was to identify predictors of long-term changes in body mass index (BMI) after lifestyle intervention.

Design: Annual changes in the BMI SD score (BMI-SDS) over 5 y in 663 obese children (aged 4-16 y) motivated to participate in an outpatient lifestyle intervention were analyzed.

Former small for gestational age (SGA) status is associated to changes of insulin resistance in obese children during weight loss.

Objective: Former small for gestational age (SGA) children are at risk of both obesity and insulin resistance. Longitudinal studies are required to assess a possible relationship between former SGA status and insulin resistance independent of weight status. We hypothesized that obese children with former appropriate for gestational age (AGA) status improve their insulin resistance during weight loss more effectively compared to obese children with former SGA status.

Leptin concentrations are a predictor of overweight reduction in a lifestyle intervention.

Objective: Leptin resistance is discussed to be involved in the genesis of obesity. Therefore, we hypothesized that leptin levels were negatively associated with degree of weight loss in obese children participating in a lifestyle intervention.

Methods: We studied 248 obese children aged 8-14 years attending the "Obeldicks" lifestyle intervention (mean age 10.

Association between androgens, intima-media thickness and the metabolic syndrome in obese adolescent girls.

Background: While an association between androgens and the metabolic syndrome (MS) is well established in obese women, studies concerning this relationship are scarce in obese adolescent girls. Therefore, we analysed the relationships between androgens, MS and intima-media thickness (IMT) in this age-group.

Methods: In 160 obese girls (aged 12-18 years, mean BMI: 32.

Lifestyle intervention in obese children is associated with a decrease of the metabolic syndrome prevalence.

Background: Weight loss is the appropriate approach to reduce the obesity-related health risk. However, the effect of lifestyle interventions on the metabolic syndrome prevalence has been rarely studied in obese children.

Methods: We analyzed changes of weight status, 2h glucose levels from oral glucose tolerance tests (oGTT), fasting glucose, lipids, blood pressure, and the prevalence of metabolic syndrome in relation to a 1-year outpatient lifestyle intervention in 288 obese children (45% male; mean age 12.

Small for gestational age status is associated with metabolic syndrome in overweight children.

Objective: Small for gestational age (SGA) children are at risk of both later obesity and metabolic syndrome (MetS). However, it is unknown whether obesity or SGA status leads to MetS in these subjects. We hypothesized that overweight children with former SGA status had more present components of the MetS than overweight children with former appropriate for gestational age (AGA) status.

Parental diabetes, pubertal stage, and extreme obesity are the main risk factors for prediabetes in children and adolescents: a simple risk score to identify children at risk for prediabetes.

Objectives: The current worldwide increase of prediabetes defined as impaired fasting glucose or impaired glucose tolerance and type 2 diabetes mellitus (T2DM) coincides the increase of obesity. However, it is unclear that which children have an increased risk and should be screened for prediabetes.

Methods: We studied 437 overweight children and adolescents to identify risk factors for prediabetes.