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Specific social media behaviors have been found to be differentially associated with adjustment outcomes; however, the extant research has yet to consider the motivations behind why adolescents engage in these specific behaviors. This study examined the role of two developmentally relevant motivational correlates (social goals and pubertal status) on four social media behaviors (self-disclosure, self-presentation, social monitoring, and lurking) and two time-based measures of social media use (daily number of hours on social media and frequency of social media use). Self-report data were collected from 426 middle-school students (54.2% female, 73.6% White, 11.5% Black, 4.8% Hispanic, 10.1% other ethnicity, and mean age = 12.91). Social goals and pubertal status were distinctly associated with different social media behaviors, with some relevant sex differences. Popularity goal was positively associated with all six measures of social media engagement, although the associations for self-presentation and social monitoring were stronger for girls. Sex differences in lurking followed the same pattern but did not reach significance. Acceptance goal was associated with fewer hours spent on social media for girls only. Early developers reported more self-disclosure and lurking behaviors, and marginally more social monitoring (girls only). These findings indicate the importance of identifying motivational factors, especially social goals, when considering early adolescents' social media behaviors.

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The purpose of this ERP P3 study was to test a peer observation manipulation (being observed by a peer versus being alone) on neural markers of attention to reward (win-feedback) and punishment (loss-feedback) during the Balloon Analogue Risk Task. Participants (126 children, 53 % male, 8-10 years; 196 early adolescents, 50 % male, 11-13 years; and 121 mid-adolescents, 52 % male, 14-16 years) were assessed by age group and pubertal status. Individual differences in how participants felt about being observed by a peer, and self-report personality factors, also were examined. Findings indicated that early and mid-adolescents (and individuals in mid-puberty and late-puberty) were sensitive to peer observation as both groups showed larger neural responses to loss-feedback in the peer condition than in the alone condition. Conversely, children (and individuals in pre- and early-puberty) were unaffected by peer observation. In addition, there clearly were individual differences in how rewarding versus anxiety-provoking participants found the peer experience. Early adolescents and mid-adolescents (and individuals in mid- and late-puberty) who reported feeling more anxious about the peer observation elicited larger neural responses to loss-feedback, and individuals in mid- and late-puberty in particular reported higher worry and lower sensation-seeking scores than those who reported a positive experience.

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Longitudinal changes of physical activity (PA) from childhood into adolescence have not been accurately described yet for the Spanish population. The aim of this study is to evaluate the changes of PA, assessed by accelerometry and anthropometric measures in a cohort of 213 children from the prepubertal to pubertal period, focusing on those with valid data from both time points (n = 75). Sedentary time (ST) increased about 50%, while all PA intensities declined from the pre-pubertal to pubertal period. Light PA (LPA) was the major contributor, decreasing by about 30%. Boys were more active than girls in both periods, but they showed a higher decline in PA, especially moderate-to-vigorous PA (MVPA). The proportion who reached the recommendation of 60 min of MVPA decreased by 33.3% in boys and 4.6% in girls. Children with obesity or overweight had lower MVPA than those with normal-weight in the pre-pubertal period, but no differences were found in the pubertal period. This study shows a decrease of PA and an increase of sedentarism in the transition from childhood to adolescence, particularly in boys. Regardless of body weight, adolescents tend to be less active. Therefore, prevention programs should be implemented to achieve optimal PA and reduce sedentarism during infancy considering the differences found by sex.

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PURPOSE: The discriminatory performance of insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) was investigated by correlating their values with chronological age (CA), bone age (BA), and pubertal status (PS) for diagnosis of isolated growth hormone deficiency (IGHD). METHODS: We evaluated IGF-1 and IGFBP-3 levels in 310 short-stature subjects subdivided into 2 groups: IGHD (n=31) and non-IGHD (n=279). IGF-1 and IGFBP-3 were assayed using immune-radiometric assay and transformed into standard deviation score (SDS) according to CA, BA, and PS. RESULTS: The highest sensitivity was found in IGF-1-SDS for CA and IGFBP-3-SDS for CA (22.6% and 30.0%, respectively). The highest specificity was found in IGF-1-SDS for PS and IGFBP-3-SDS for PS (98.2% and 94.4%, respectively). Groups with the highest positive predictive values were IGF-1-SDS for BA and IGFBP-3-SDS for BA (10.9% and 5.1%, respectively). Highest negative predictive values were seen in IGF-1-SDS for CA and IGFBP-3-SDS for CA (98.4% and 98.4%, respectively). CONCLUSION: IGF-1-SDS for CA, instead of IGF-1-SDS for BA or PS, could be used as a standard variable for IGHD screening. The sufficiently high specificity of IGF-1-SDS for PS suggests that this value is a useful tool for identification of IGHD.

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In lifecourse studies that encompass the adolescent period, the assessment of pubertal status is important, but can be challenging. We aimed to identify current methods for pubertal assessment and assess their appropriateness for population-based research by combining a review of the literature with the views of experts in the field. We searched bibliographic databases, extracted data and assessed study quality to inform a workshop with 21 experts. Acceptability of different approaches was explored with a panel of ten adolescents. We screened 11,935 abstracts, assessed 157 articles and summarised results from 38 articles. Combining these with the opinions of experts, self-assessment was found to be a practical method for use in studies where agreement with the gold standard of clinical assessment by physical examination to within one Tanner stage was acceptable. Serial measures of height and foot size accurately indicated timing of the pubertal growth spurt and age at peak height velocity, and were seen as feasible within longitudinal studies. Hormonal and radiological methods did not offer a practical means of assessing pubertal status. Assessment of voice maturation was promising, but needed validation. Young people thought that self-assessment, foot size and voice assessments were acceptable, and preferred an assessor of the same sex for clinical assessment. This review thus informs researchers working in lifecourse and adolescent health, and identifies future directions in order to improve validity of the methods.

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INTRODUCTION: Patients with suspected adrenal insufficiency undergo screening with a serum morning cortisol level and confirmatory testing with an adrenocorticotropic hormone (ACTH) stimulation test. However, much of the data collected to determine appropriate values for morning cortisol levels are derived from adult populations and may not accurately represent pediatric physiology. The purpose of this study was to evaluate the mean morning cortisol level in the pediatric population based on pubertal status and sex in order to better understand such influences on laboratory evaluation of adrenal insufficiency. METHODS: A retrospective chart review was conducted using electronic medical records of patients seen at Children's Mercy Kansas City from 11/01/2007 to 11/01/2017. Patients between 2 and 18 years of age who had pubertal staging assessed by a pediatric endocrinologist and confirmed adrenal sufficiency by high-dose ACTH stimulation testing were included. Two-sample Wilcoxon rank sum (Mann-Whitney) tests or t tests were used to compare morning cortisol levels between females and males - both independent of Tanner stage and by Tanner stage. Multivariable regression models were used to evaluate associations among covariates on two outcomes: morning cortisol levels and peak cortisol values with ACTH stimulation. RESULTS: Morning cortisol levels were greater in females than males independent of Tanner staging (p = 0.0054) and also in Tanner stage 1 (p = 0.0042). No differences in mean morning cortisol levels between Tanner stage 2-5 females and males were found (p = 0.4652). Morning cortisol levels were not significantly different between Tanner 1 patients and Tanner 2-5 patients independent of sex (p = 0.0575). Sex was predictive of serum morning cortisol levels (p = 0.015), and morning cortisol levels were predictive of peak cortisol levels during ACTH stimulation testing (p < 0.001). CONCLUSIONS: These data suggest that different normative cortisol values may need to be established for pediatric females and males, and by pubertal status. Larger prospective studies are needed to evaluate the role of sex and pubertal status in identifying adrenal insufficiency in the -pediatric population.

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BACKGROUND: We compared differences in physical activity (PA) between pre/mid-pubertal and post-pubertal participants according to gender. METHODS: The study included a total of 1842 healthy participants aged 12.5-17.4 years, who participated in the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study. Participants wore a uniaxial accelerometer (ActiGraph© GT1M, Pensacola, FL, USA) attached to their lower back for seven consecutive days to measure PA. Pubertal status was assessed by physical examination and the population was classified as pre/mid-pubertal (Tanner stages 1-3) or post-pubertal (Tanner stages 4-5). PA was compared between these groups according to gender during the whole week, on school-free days and on school days, before and after school, and during lessons and recesses. RESULTS: When comparing the pre/mid-pubertal group with the post-pubertal group, girls' total PA did not differ between groups. However, a slight difference was observed in boys, among whom PA on school-free days showed a difference of 17.6% between the pre/mid-pubertal group and the post-pubertal group (679 kcounts vs 564 kcounts, respectively; P = 0.0007) and 20% (162 kcount vs 135 kcounts; P = 0.006) for school recess. There was no difference among girls. CONCLUSIONS: A reduced level of PA in the post-pubertal groups was only observed in boys during non-organized times such as on school-free days and during school recesses, with a moderate impact on total PA.

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This study examined the effect of pubertal development on Amplitude Dependent Speed of Sound (AD-SoS), accounting for the growth in stature among adolescents. A mixed-longitudinal design with 3 assessments across a 15-mo period in 439 adolescents (girls: 215; boys: 224) aged 9-16 y was used. Bayesian multilevel models were used to describe gender-specific AD-SoS variations among participants during pubertal years. Substantial increments in AD-SoS during pubertal years were observed in both genders. AD-SoS changes were positively related to stature, and the rate of stature growth per year. Quantitative ultrasonography was sensible to describe age-related changes of bone mass during pubertal development. It seemed clinically reliable to use AD-SoS in the study of bone growth and development.

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STUDY OBJECTIVES: This study aimed to explore the moderation of pubertal status on the onset of sex differences in the prevalence of insomnia symptoms and their health correlates. METHODS: A total of 7,507 children and adolescents (weighted percentage of female: 48.5%) aged between 6-17 y were recruited from thirty-one primary and secondary schools. Participants with difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS), and/or early morning awakening (EMA) ≥ 3 times/week in the past month were considered as having insomnia symptoms. The severity of insomnia was measured by the Insomnia Severity Index (ISI). RESULTS: The prevalence of insomnia symptoms increased from 3.4% to 12.2% in girls (3.6-fold) and from 4.3% to 9.1% in boys (2.1-fold) from Tanner stage 1 to 5. There was a significant interaction between sex and Tanner stage in the prevalence of insomnia (P < 0.001) with an emergence of female preponderance at Tanner stage 4 even after controlling for age, family income, and school start time. Similar sex-Tanner stage interactions were found in DIS, DMS, and ISI total score but not EMA. Insomnia symptoms were strongly associated with behavioral problems, poor mental health, and poor general health in both sexes. Boys with insomnia would report more maladaptive lifestyles (smoking, alcohol, and energy drinks) whereas girls with insomnia were more susceptible to emotional and relationship difficulties. CONCLUSIONS: Pubertal maturation was associated with a progressive increase in the prevalence of insomnia symptoms with the emergence of female preponderance in both the prevalence and severity of insomnia symptoms at late puberty. CLINICAL TRIALS REGISTRATION: Chinese Clinical Trial Register, http://www.chictr.org.cn, ID: ChiCTR-TRC-12002798.

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How and why are teenagers different from children and adults? A key question concerns the ways in which pubertal development shapes psychological changes in adolescence directly through changes to the brain and indirectly through the social environment. Empirical work linking pubertal development to adolescent psychological function draws from several different perspectives, often with varying approaches and a focus on different outcomes and mechanisms. The main themes concern effects of atypical pubertal timing on behavior problems during adolescence, effects of pubertal status (and associated hormones) on normative changes in behaviors that can facilitate or hinder development (especially risk-taking, social reorientation, and stress responsivity), and the role of puberty in triggering psychopathology in vulnerable individuals. There is also interest in understanding the ways in which changes in the brain reflect pubertal processes and underlie psychological development in adolescence. In this chapter, we consider the ways that puberty might affect adolescent psychological development, and why this is of importance to developmentalists. We describe the processes of pubertal development; summarize what is known about pubertal influences on adolescent development; consider the assumptions that underlie most work and the methodological issues that affect the interpretation of results; and propose research directions to help understand paths from puberty to behavior. Throughout, we emphasize the importance of pubertal change in all aspects of psychological development, and the ways in which puberty represents an opportunity to study the interplay of biological and social influences.

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The present meta-analysis studies the relations of pubertal timing and status with sexual behavior and sexual risk behavior among youth aged 10.5-22.4 years. We included biological sex, age, and ethnicity as potential moderators. Four databases were searched for studies (published between 1980 and 2012) on the relation between pubertal timing or status and sexual behavior. The outcomes were (1) sexual intercourse; (2) combined sexual behavior; and (3) risky sexual behavior. Earlier pubertal timing or more advanced pubertal status was related to earlier and more sexual behavior, and earlier pubertal timing was related to more risky sexual behavior. Further, the links between (1) pubertal status and combined sexual behavior and (2) pubertal timing and sexual intercourse status, combined sexual behavior, and risky sexual behavior were stronger for girls than boys. Most links between pubertal status, timing, and sexual behavior and sexual risk behavior were stronger for younger adolescents. Moderation by ethnicity did not yield consistent results. There was significant variation in results among studies that was not fully explained by differences in biological sex, age, and ethnicity. Future research is needed to identify moderators that explain the variation in effects and to design sexual health interventions for young adolescents.

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The objective of this study was to examine the association between hangrip strength and physical fitness in children and adolescents at different stages of sexual maturation. We measured body composition and handgrip strength in 233 children and adolescents (10 - 17 years-old), who varied in terms of pubertal status. The subjects also performed the vertical jump test, standing long jump and sit-ups, as well as tests of flexibility, agility and speed. The level of energy expenditure was assessed with the international physical activity questionnaire. Handgrip strength differed by pubertal status, regardless of gender, whereas other parameters of physical fitness differed by gender and in the sample as a whole. Handgrip strength was consistently and independently associated with all other physical fitness variables, regardless of gender; some of those were mediated by energy expenditure (i.e., speed in seconds and in meters per second for the sample as a whole). The strength of the association between handgrip strength and physical fitness ranged from 20% (vertical jump test: R 2=.20; P=.001) to 47% (speed in meters per second: R 2=.47; P=.001). Our results support the idea that handgrip strength is consistently associated with several distinct parameters of physical fitness, regardless of age, gender or sexual maturation, suggesting that handgrip strength could be a highly accurate, independent predictor of physical fitness.

O objetivo deste estudo foi examinar a associação entre a força de preensão manual e a aptidão física de crianças e adolescentes de diferentes estágios de maturação sexual. Foram medidos a composição corporal e a força de preensão em 233 crianças e adolescentes (10 - 17 anos de idade), de diferentes estágios de maturação biológica. Também foram realizados os testes de impulsão vertical sem auxílio dos membros superiores, teste de abdominal, flexibilidade, agilidade e velocidade. O gasto de energético foi avaliado através das respostas ao questionário IPAQ. A força de preensão manual diferiu entre os diferentes estágios de maturação sexual. As outras variáveis de aptidão física diferiram entre os sexos. A força de preensão manual esteve associada com todas as outras variáveis ​​da aptidão física, independentemente do sexo e da maturação sexual. Algumas dessas associações foram mediadas pelo gasto energético. A força da associação entre a força de preensão e de aptidão física variou de 20 % (teste de salto vertical: R2=0,20, P = 0,001) a 47% (velocidade em metros por segundo: R2=0,47, P = 0,001). Nossos resultados suportam a hipótese de que a força de preensão manual está associada com vários parâmetros distintos de aptidão física, independentemente da idade, sexo ou maturação sexual, sugerindo que a força de preensão manual pode ser um preditor da aptidão física geral de crianças e adolescentes. .

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The purpose of the current study was to examine the relationship between prenatal cocaine exposure (PCE) and pubertal development. Children (n=192; 41% with PCE) completed the Pubertal Development Scale (Petersen et al. 1988) and provided salivary dehydroepiandrosterone (DHEA) samples at 6month intervals from 11 to 13years. PCE was examined as a predictor of pubertal status, pubertal tempo, and DHEA levels in mixed models analyses controlling for age, sex, environmental risk, neonatal medical problems, other prenatal exposures, and BMI. PCE interacted with age such that PCE predicted slower pubertal tempo during early adolescence. PCE also interacted with age to predict slower increases in DHEA levels during early adolescence. These findings suggest that PCE may affect pubertal development and, if slower pubertal tempo continues, could lead to delayed pubertal status in mid-adolescence.

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Growth and nutritional status are important issues in paediatric inflammatory bowel disease (IBD). While linear growth is easy to assess, nutritional status is more complicated, with reports often compromised by the use of simple measures, such as weight and the body mass index, to assess nutritional status rather than more appropriate and sophisticated techniques to measure body composition. This review is an update on what is currently known about nutritional status as determined by body composition in paediatric IBD. Further, this review will focus on the impact of biologics on growth in paediatric IBD. Significant lean mass deficits have been reported in children with IBD compared with controls, and there is evidence these deficits persist over time. Furthermore, data imply that gender differences exist in body composition, both at diagnosis and in response to treatment. With respect to growth improvements following treatment with biologics, there are conflicting data. While some studies report enhancement of growth, others do not. The relationship between disease severity, impaired growth and the requirement for biologics needs to be considered when interpreting these data. However, key features associated with improvements in growth appear to be successful clinical response to treatment, patients in early stages of puberty, and the presence of growth failure at the onset of treatment.

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Adolescence is an important period for brain development. White matter growth is influenced by sex hormones such as testosterone, and the corpus callosum-the largest white matter structure in the human brain-may change structurally during the hormone-laden period of adolescence. Little is known about puberty's relationship to structural brain development, even though pubertal stage may better predict cognitive and behavioral maturity than chronological age. We therefore aimed to establish the presence and direction of pubertal effects on callosal anatomy. For this purpose, we applied advanced surface-based mesh-modeling to map correlations between callosal thickness and pubertal stage in a large and well-matched sample of 124 children and adolescents (62 female and 62 male) aged 5-18years from a normative database. When linking callosal anatomy to pubertal status, only positive correlations reached statistical significance, indicating that callosal growth advances with puberty. In tests of differences in callosal anatomy at different stages of puberty, callosal growth was concentrated in different locations depending on the pubertal stage. Changing levels of circulating sex hormones during different phases of puberty likely contributed to the observed effects, and further research is clearly needed. Direct quantification of sex hormone levels and regional fiber connectivity-ideally using fiber tractography-will reveal whether hormones are the main drivers of callosal change during puberty. These callosal findings may lead to hypotheses regarding cortical changes during puberty, which may promote or result from changes in inter-hemispheric connectivity.

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OBJECTIVE: Childhood obesity is associated with an increased risk for insulin resistance. The underlying mechanism for the physiological increase in insulin levels in puberty is not clearly understood. The aim of the present study was to determine the cut-off values for homeostasis model assessment for insulin resistance (HOMA-IR) in obese children and adolescents according to gender and pubertal status. METHODS: Two hundred and eight obese children and adolescents (141 girls, 127 boys) aged between 5 and 18 years were included in the study. The children were divided into prepubertal and pubertal groups. A standard oral glucose tolerance test (OGTT) was carried out in all children. A total insulin level exceeding 300 µU/mL in the blood samples, collected during the test period, was taken as the insulin resistance criterion. Cut-off values for HOMA-IR were calculated by receiver operating characteristic (ROC) analysis. RESULTS: In the prepubertal period, the rate of insulin resistance was found to be 37% in boys and 27.8% in girls,while in the pubertal period, this rate was 61.7% in boys and 66.7% in girls. HOMA-IR cut-off values for insulin resistance in the prepubertal period were calculated to be 2.67 (sensitivity 88.2%, specificity 65.5%) in boys and 2.22 (sensitivity 100%, specificity 42.3%) in girls, and in the pubertal period, they were 5.22 (sensitivity 56%, specificity 93.3%) in boys and 3.82 (sensitivity 77.1%, specificity 71.4%) in girls. CONCLUSIONS: Since gender, obesity and pubertal status are factors affecting insulin resistance, cut-off values which depend on gender and pubertal status, should be used in evaluation of insulin resistance.

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