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Background/Aims: Untreated girls with Turner syndrome (TS) have growth failure, and adult height is, on average, 20 cm less than predicted height. Treatment with growth hormone (GH) is now standard of care. The objective of this study was to investigate the benefit of adding oxandrolone (Ox) to GH in a long-term, randomized, placebo (Pl)-controlled prospective trial to near adult height in TS. Methods: Prospective, randomized, Pl-controlled study: 76 girls with TS (ages 10–14.9 years) were randomized to receive Ox (0.06 mg/kg/day) or Pl in combination with GH (0.35 mg/kg/week, daily) over 2 years. Auxologic data, breast and pubic hair Tanner stages, and hormone and lipid levels were measured. Subjects who chose to continue were followed in a 2-year double-blind extension, also received estrogen therapy (years 3, 4), and had dual-energy X-ray absorptiometry evaluation of bone density (years 3, 4). Results: At year 4, the change in absolute height and height SDS was greater in the GH/Ox versus GH/Pl group [26.2 ± 6.7 vs. 22.2 ± 5.1 cm, analysis of covariance (ANCOVA) p < 0.001; 1.8 ± 0.9 vs. 1.2 ± 0.7 standard deviation scores, ANCOVA p < 0.001]. Bone mineral density (BMD) of the wrist (0.51 ± 0.17 vs. 0.54 ± 0.05 g/cm 2 ) and spine (0.91 ± 0.34 vs. 0.96 ± 0.13 g/cm 2 ) in the GH/Ox versus GH/Pl groups was similar after 4 years. Breast development was slower in the GH/Ox versus GH/Pl group [year 4: Tanner stage 2.9 ±1.3 (Ox) vs. 4.1 ± 1.3 (Pl), p = 0.003], and menarche was approximately 1 year later. Conclusions: The addition of Ox to GH at mean age 12.0 ± 1.7 year augmented height gain after 4 years of treatment, slowed breast development and did not affect BMD in girls with TS. Whether initiation of Ox prior to initiation of pubertal development would optimize height gain without impeding breast development will require further study.

Abstract Context Hormonal interventions in adolescents with gender dysphoria may have adverse effects, such as reduced bone mineral accrual. Objective To describe bone mass development in adolescents with gender dysphoria treated with gonadotropin-releasing hormone analogues (GnRHa), subsequently combined with gender-affirming hormones. Design Observational prospective study. Subjects 51 transgirls and 70 transboys receiving GnRHa and 36 transgirls and 42 transboys receiving GnRHa and gender-affirming hormones, subdivided into early- and late-pubertal groups. Main Outcome Measures Bone mineral apparent density (BMAD), age- and sex-specific BMAD z-scores, and serum bone markers. Results At the start of GnRHa treatment, mean areal bone mineral density (aBMD) and BMAD values were within the normal range in all groups. In transgirls, the mean z-scores were well below the population mean. During 2 years of GnRHa treatment, BMAD stabilized or showed a small decrease, whereas z-scores decreased in all groups. During 3 years of combined administration of GnRHa and gender-affirming hormones, a significant increase of BMAD was found. Z-scores normalized in transboys but remained below zero in transgirls. In transgirls and early pubertal transboys, all bone markers decreased during GnRHa treatment. Conclusions BMAD z-scores decreased during GnRHa treatment and increased during gender-affirming hormone treatment. Transboys had normal z-scores at baseline and at the end of the study. However, transgirls had relatively low z-scores, both at baseline and after 3 years of estrogen treatment. It is currently unclear whether this results in adverse outcomes, such as increased fracture risk, in transgirls as they grow older.

Background After the discovery of fluoride as a caries-preventing agent in the mid-twentieth century, fluoridation of community water has become a widespread intervention, sometimes hailed as a mainstay of modern public health. However, this practice results in elevated fluoride intake and has become controversial for two reasons. First, topical fluoride application in the oral cavity appears to be a more direct and appropriate means of preventing caries. Second, systemic fluoride uptake is suspected of causing adverse effects, in particular neurotoxicity during early development. The latter is supported by experimental neurotoxicity findings and toxicokinetic evidence of fluoride passing into the brain. Method An integrated literature review was conducted on fluoride exposure and intellectual disability, with a main focus on studies on children published subsequent to a meta-analysis from 2012. Results Fourteen recent cross-sectional studies from endemic areas with naturally high fluoride concentrations in groundwater supported the previous findings of cognitive deficits in children with elevated fluoride exposures. Three recent prospective studies from Mexico and Canada with individual exposure data showed that early-life exposures were negatively associated with children’s performance on cognitive tests. Neurotoxicity appeared to be dose-dependent, and tentative benchmark dose calculations suggest that safe exposures are likely to be below currently accepted or recommended fluoride concentrations in drinking water. Conclusion The recent epidemiological results support the notion that elevated fluoride intake during early development can result in IQ deficits that may be considerable. Recognition of neurotoxic risks is necessary when determining the safety of fluoride-contaminated drinking water and fluoride uses for preventive dentistry purposes.

Adolescence is an important neurodevelopmental period marked by rapidly escalating rates of alcohol and drug use. Over the past decade, research has attempted to disentangle pre- and post-substance use effects on brain development by using sophisticated longitudinal designs. This review focuses on recent, prospective studies and addresses the following important questions: (1) what neuropsychological and neural features predate adolescent substance use, making youth more vulnerable to engage in heavy alcohol or drug use, and (2) how does heavy alcohol and drug use affect normal neural development and cognitive functioning? Findings suggest that pre-existing neural features that relate to increased substance use during adolescence include poorer neuropsychological functioning on tests of inhibition and working memory, smaller gray and white matter volume, changes in white matter integrity, and altered brain activation during inhibition, working memory, reward, and resting state. After substance use is initiated, alcohol and marijuana use are associated with poorer cognitive functioning on tests of verbal memory, visuospatial functioning, psychomotor speed, working memory, attention, cognitive control, and overall IQ. Heavy alcohol use during adolescence is related to accelerated decreases in gray matter and attenuated increases in white matter volume, as well as increased brain activation during tasks of inhibition and working memory, relative to controls. Larger longitudinal studies with more diverse samples are needed to better understand the interactive effects of alcohol, marijuana, and other substances, as well as the role of sex, co-occurring psychopathology, genetics, sleep, and age of initiation on substance use.

Chemotherapy for the treatment of maternal cancers during pregnancy has become more acceptable in the past decade; however, the effect of prenatal exposure to chemotherapy on cardiac and neurodevelopmental outcomes of the offspring is still uncertain. We aimed to record the general health, cardiac function, and neurodevelopmental outcomes of children who were prenatally exposed to chemotherapy. We did an interim analysis of a multicentre observational cohort study assessing children who were prenatally exposed to maternal cancer staging and treatment, including chemotherapy. We assessed children at birth, at age 18 months, and at age 5–6, 8–9, 11–12, 14–15, or 18 years. We did clinical neurological examinations, tests of the general level of cognitive functioning (Bayley or intelligence quotient [IQ] test), electrocardiography and echocardiography, and administered a questionnaire on general health and development. From age 5 years, we also did audiometry, the Auditory Verbal Learning Test, and subtasks of the Children's Memory Scale, and the Test of Everyday Attention for Children, and we also completed the Child Behavior Checklist. This study is registered with ClinicalTrials.gov, number NCT00330447. 236 cycles of chemotherapy were administered in 68 pregnancies. We assessed 70 children, born at a median gestational age of 35·7 weeks (range 28·3–41·0; IQR 3·3; 47 women at <37 weeks), with a median follow-up period of 22·3 months (range 16·8–211·6; IQR 54·9). Although neurocognitive outcomes were within normal ranges, cognitive development scores were lower for children who were born preterm than for those born at full term. When controlling for age, sex, and country, the score for IQ increased by an average 11·6 points (95% CI 6·0–17·1) for each additional month of gestation (p<0·0001). Our measurements of the children's behaviour, general health, hearing, and growth corresponded with those of the general population. Cardiac dimensions and functions were within normal ranges. We identified a severe neurodevelopmental delay in both members of one twin pregnancy. Fetal exposure to chemotherapy was not associated with increased CNS, cardiac or auditory morbidity, or with impairments to general health and growth compared with the general population. However, subtle changes in cardiac and neurocognitive measurements emphasise the need for longer follow-up. Prematurity was common and was associated with impaired cognitive development. Therefore, iatrogenic preterm delivery should be avoided when possible. Research Foundation-Flanders; Research Fund-K U Leuven; Agency for Innovation by Science and Technology; Stichting tegen Kanker; Clinical Research Fund-University Hospitals Leuven; and Belgian Cancer Plan, Ministery of Health.

Children born small for gestational age (SGA) with a poor adult height (AH) expectation benefit from treatment with GH and additional gonadotropin-releasing hormone analog (GnRHa). Because both SGA birth and GnRHa treatment might negatively influence cognition, health-related quality of life (HRQoL), and psychosocial functioning, we assessed these outcomes at AH. A randomized, dose-response GH study until AH involving 99 adolescents born SGA, of whom 61 children received 2 additional years of GnRHa treatment. At AH, the Wechsler Adult Intelligence Scale and TNO-AZL Adults Quality of Life questionnaire were administered to the study group. Additionally, the study group and 67 adolescents born SGA (19 GnRHa) from a second study group completed the Self-Perception Profile of Adolescents and Child/Adolescent Behavior Checklist at AH. Scores in GH-treated young adults with GnRHa treatment (GH/GnRHa group) were compared with GH-treated adolescents without GnRHa treatment (GH group) and a reference population. Mean age (SD) at AH was 17.5 (1.2) and 17.4 (1.4) years in the GH/GnRHa and GH group, respectively. Intelligence quotient scores were similar in GH/GnRHa and GH groups (96.33 vs 92.47). HRQoL was similar between both groups and also when compared with the reference population, but the GH/GnRHa group had a significantly lower perception of cognitive functioning. Self-perception and problem behavior were similar in the GH/GnRHa and GH groups. AH did not correlate with HRQoL, self-perception, or problem behavior. Combined GH/GnRHa treatment has no long-term negative effects on cognition, HRQoL, self-perception, and behavior in early adulthood, compared with GH treatment only.

Studies over the last decade demonstrate that adolescence is a brain maturation period from childhood to adulthood. Plastic and dynamic processes drive adolescent brain development, creating flexibility that allows the brain to refine itself, specialize, and sharpen its functions for specific demands. Maturing connections enable increased communication among brain regions, allowing greater integration and complexity. Compelling evidence has shown that the developing brain is vulnerable to the damaging effects of ethanol. It is possible to infer, therefore, that alcohol exposure during the critical adolescent developmental stages could disrupt the brain plasticity and maturation processes, resulting in behavioral and cognitive deficits. Recent neuroimaging studies have provided evidence of the impact of human adolescent drinking in brain structure and functions. Findings in experimental animals have also given new insight into the potential mechanisms of the toxic effects of ethanol on both adolescent brain maturation and the short- and long-term cognitive consequences of adolescent drinking. Adolescence is also characterized by the rapid maturation of brain systems mediating reward and by changes in the secretion of stress-related hormones, events that might participate in the increasing in anxiety and the initiation pattern of alcohol and drug consumption. Studies in human adolescents demonstrate that drinking at early ages can enhance the likelihood of developing alcohol-related problems. Experimental evidence suggests that early exposure to alcohol sensitizes the neurocircuitry of addiction and affects chromatin remodeling, events that could induce abnormal plasticity in reward–related learning processes that contribute to adolescents' vulnerability to drug addiction. In this article, we review the potential mechanisms by which ethanol impacts brain development and lead to brain impairments and cognitive and behavioral dysfunctions as well as the neurobiological and neurochemical processes underlying the adolescent-specific vulnerability to drug addiction.

Dynamic changes in neurochemistry, fiber architecture, and tissue composition occur in the adolescent brain. The course of these maturational processes is being charted with greater specificity, owing to advances in neuroimaging and indicate grey matter volume reductions and protracted development of white matter in regions known to support complex cognition and behavior. Though fronto-subcortical circuitry development is notable during adolescence, asynchronous maturation of prefrontal and limbic systems may render youth more vulnerable to risky behaviors such as substance use. Indeed, binge-pattern alcohol consumption and comorbid marijuana use are common among adolescents, and are associated with neural consequences. This review summarizes the unique characteristics of adolescent brain development, particularly aspects that predispose individuals to reward seeking and risky choices during this phase of life, and discusses the influence of substance use on neuromaturation. Together, findings in this arena underscore the importance of refined research and programming efforts in adolescent health and interventional needs.

Introduction Prenatal exposure to supraphysiological glucocorticoid (GC) levels may lead to long‐lasting developmental changes in numerous biological systems. Our prior study identified an association between prenatal GC prophylaxis and reduced cognitive performance, electrocortical changes, and altered autonomic nervous system (ANS) activity in children aged 8–9 years. This follow‐up study aimed to examine whether these findings persisted into adolescence. Material and Methods Prospective observational follow‐up study involving twenty‐one 14‐ to 15‐year‐old adolescents born to mothers who received betamethasone for induction of fetal lung maturation in threatened preterm birth, but who were born with a normal weight appropriate for their gestational age (median 37+4 gestational weeks). Thirty‐five children not exposed to betamethasone served as the reference group (median 37+6 gestational weeks). The primary endpoint was cognitive performance, measured by intelligence quotient (IQ). Key secondary endpoints included symptoms of attention‐deficit/hyperactivity disorder (ADHD) and metabolic markers. Additionally, we determined electrocortical (electroencephalogram), hypothalamus–pituitary–adrenal axis (HPAA), and ANS activity in response to a standardized stress paradigm. Results No statistically significant group difference was observed in global IQ (adjusted mean: betamethasone 103.9 vs references 105.9, mean difference −2.0, 95% confidence interval [CI]: −7.12 to 3.12, p = 0.44). Similarly, ADHD symptoms, metabolic markers, the overall and stress‐induced activity of the HPAA and the ANS did not differ significantly between groups. However, the betamethasone group exhibited reduced electrocortical activity in the frontal brain region (spectral edge frequency–adjusted means: 16.0 Hz vs 17.8 Hz, mean difference −1.83 Hz, 95% CI: −3.21 to −0.45, p = 0.01). Conclusions In 14‐ to 15‐year‐old adolescents, prenatal GC exposure was not associated with differences in IQ scores or ANS activity compared to unexposed controls. However, decelerated electrocortical activity in the frontal region potentially reflects disturbances in the maturation of cortical and/or subcortical brain structures. The clinical significance of these changes remains unknown. Given the small sample size, selective participation/loss of follow‐up and potential residual confounding, these findings should be interpreted cautiously. Further research is required to replicate these results in larger cohorts before drawing firm clinical conclusions. In our follow‐up study on 14‐ to 15‐years‐olds prenatally exposed to glucocorticoid prophylaxis for respiratory distress syndrome, we found that earlier discrepancies in prepubertal IQ scores and autonomic nervous system activity, in comparison to unexposed subjects, do not continue into adolescence.

Many studies have suggested that adolescence is a period of particular vulnerability to neurocognitive effects associated with substance misuse. However, few large studies have measured differences in cognitive performance between chronic cannabis users who started in early adolescence (before age 15) with those who started later. To examine the executive functioning of individuals who started chronic cannabis use before age 15 compared with those who started chronic cannabis use after 15 and controls. We evaluated the performance of 104 chronic cannabis users (49 early-onset users and 55 late-onset users) and 44 controls who undertook neuropsychological tasks, with a focus on executive functioning. Comparisons involving neuropsychological measures were performed using generalised linear model analysis of variance (ANOVA). The early-onset group showed significantly poorer performance compared with the controls and the late-onset group on tasks assessing sustained attention, impulse control and executive functioning. Early-onset chronic cannabis users exhibited poorer cognitive performance than controls and late-onset users in executive functioning. Chronic cannabis use, when started before age 15, may have more deleterious effects on neurocognitive functioning.