Juul, Anders

Abstract Background Central precocious puberty (CPP), which is traditionally defined as the development of secondary sexual characteristics before age 8 years in girls and age 9 years in boys, results from the premature activation of the hypothalamic–pituitary–gonadal (HPG) axis. CPP can be associated with short adult stature, adverse psychosocial outcomes, and increased cardiometabolic and cancer risks in adulthood. Gonadotropin-releasing hormone (GnRH) agonists can effectively suppress premature activation of the HPG axis and have the potential to increase adult height as well as improve psychosocial and long-term health outcomes among patients with CPP. However, as secular trends have continued to shift toward earlier age of pubertal onset, some subpopulations of children with CPP, as it is currently defined, may not require the same extent of diagnostic evaluation and treatment. Objective Develop evidence-based recommendations related to the diagnosis and treatment of CPP. Methods A multidisciplinary panel of clinical experts, along with experts in guideline methodology and systematic literature review, used the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach to address 10 clinical questions related to the diagnosis and treatment of CPP. Systematic reviews of health-related benefits and harms were conducted for each clinical question. The guideline development panel (GDP) also used the GRADE evidence-to-decision (EtD) framework to address stakeholder values and preferences, costs and required resources, cost-effectiveness, acceptability, feasibility, and potential impacts on health equity. Results In girls with thelarche (Tanner stage B2) between ages 7.0 and 8.0 years, the GDP suggests watchful waiting via periodic physical examinations (every 4-6 months) rather than immediately performing evaluation with laboratory testing or radiologic imaging. In addition, the GDP suggests that all girls with breast development (ie, Tanner stage B2) before age 7 years should first be observed for 4 to 6 months to differentiate unsustained or slowly progressive puberty vs rapidly progressive puberty. These recommendations are largely based on evidence that girls with slowly progressive puberty attain a normal adult height without treatment. When hormonal evaluation is performed to confirm central (GnRH-dependent) activation as the cause of precocious puberty, the GDP suggests starting the evaluation with ultrasensitive basal luteinizing hormone (LH) concentration rather than routine GnRH/GnRH agonist (GnRHa) stimulation testing for all patients. While brain magnetic resonance imaging has been a traditional part of CPP evaluation, the GDP suggests that it should not be routinely performed in girls ages 6.0 to 8.0 years and boys ages 8.0 to 9.0 years without central nervous system (eg, neuro-ophthalmologic) symptoms, largely based on a low prevalence of pathologic intracranial findings in these age groups. The GDP suggests against routine genetic testing for patients with CPP, although they judged that genetic testing (eg, MKRN3 sequencing) should be considered for patients with familial CPP through a shared decision-making process. The GDP suggests GnRHa treatment for many children with CPP, although available evidence suggests that some patient subgroups (eg, older girls with slowly progressive CPP) may be less likely to receive a net benefit with this treatment. Rather than always starting GnRHa treatment with a monthly injectable formulation, the GDP suggests that treatment should be initiated with the formulation (such as a longer-acting formulation) that is anticipated to be used long-term. The GDP suggests against routine addition of growth hormone therapy to increase adult height. They also suggest against the routine biochemical testing (eg, LH, sex steroids) to monitor pubertal suppression while receiving GnRHa, instead reserving biochemical testing to confirm clinically suspected treatment failure. Finally, the GDP suggests against routinely continuing GnRHa treatment beyond chronologic age 10.0 to 11.0 years (girls) or 11.0 to 12.0 years (boys) and/or bone age 11.0 to 12.0 years (girls) or 12.0 to 13.0 years (boys). Conclusion These clinical recommendations were developed to address important uncertainties in the diagnosis and treatment of children with CPP. They are based on the best available scientific evidence regarding clinical outcomes judged to be most important to patients and families. The GDP's overarching goal was to suggest diagnostic and therapeutic strategies that will most likely provide net clinical benefits while simultaneously considering important contextual factors such as cost and feasibility. The guideline-development process highlighted important knowledge gaps and the substantial need for additional research.

Abstract Poor growth in early life is associated with numerous adverse outcomes later in life. In 123 adolescents 16–18 yr of age, the previous findings of a positive relation between size in early life and later bone mass was confirmed. These associations were mediated by the current height and weight, but it was not confirmed that alterations of the GH–IGF axis cause this. Introduction: Numerous studies have found associations between low birth weight and disease later in life, including decreased bone mass. Materials and Methods: A longitudinal cohort of 16- to 19-year-old adolescents (n = 123) with data on third trimester fetal growth velocity (FGV) was assessed by serial ultrasound measurements, birth weight (BW), and weight at 1 yr. A follow-up study included DXA scan, anthropometric measurements, and measurements of the growth hormone (GH) –IGF-I axis in a representative subpopulation (n = 30). Results: BW and weight at 1 yr were positively associated with whole body BMC (p = 0.02 and p < 0.0001, respectively), lumbar spine BMC (p = 0.001 and p = 0.03, respectively), and lumbar spine BMD (p = 0.04). After correction for adolescent height and weight, no association remained significant. There was no relation between IGF-I and IGF binding protein 3 (IGFBP-3) levels in adolescence and size in early life or bone mass. In the subpopulation, GH secretion (median, 2.58 versus 4.05), GH pulse mass (median, 10.7 versus 19.4 mU/liter), and total GH (median, 74.9 versus 108.8 mU/liter/12 h) were decreased in the small for gestational age (SGA) group compared with the appropriate for gestational age (AGA) group; this did not reach statistical significance. Likewise, there were no differences in IGF-I, IGF-II, and IGFBP-1, −2, and −3 levels between the SGA and AGA groups. A statistically significant positive association between FGV and adolescent IGF-II was found (B = 199.9, p = 0.006). Significant negative associations between GH measurement and BMC, as well as BMD, were found (B = −0.008, p = 0.005 and B = −0.008, p = 0.006, respectively). Conclusions: This study confirms the previous findings of a positive relation between size in early life and later BMC, an association apparently independent of the distal part of the GH/IGF-I axis. However, this association may be mediated mainly by postnatal growth determining size of the skeletal envelope rather than an effect of fetal programming on bone mass per se.