Background/Objectives: Fructose consumption in children is increasing, as is the prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD). Despite evidence linking added sugars to metabolic syndrome, fructose’s impact on liver disease in youth remains unclear, especially in pediatrics. Our study aimed to evaluate the role of fructose intake in metabolic and liver dysfunction in a cohort of pre-school children and adolescents with obesity. Methods: We recruited 41 children and adolescents with obesity (age range: 2.5–16 years, BMI SDS 2.6 ± 0.5 kg/m²). Clinical and biochemical parameters were assessed. Through ultrasound (US), MASLD, hepatorenal index (HRI), subcutaneous adipose tissue (scAT), and visceral adipose tissue (vAT) were assessed. Dietary intake was evaluated using the IDEFICS FFQ and a fructose-specific questionnaire. Results: Pubertal subjects had more scAT and vAT, higher insulin resistance, and higher liver fibrosis parameters than those prepubertal. MASLD was detected in 12 subjects, associated with higher scAT and vAT. Pubertal subjects had lower weekly fructose intake than prepubertal subjects (p < 0.02). However, they consumed less fructose from fruits (p < 0.04) and more from other sugars (p < 0.04) than younger children. Patients with MASLD reported higher fructose intake (p < 0.01), primarily from fruits (p < 0.003), likely due to misreporting, alongside higher consumption of unhealthy food, mainly rich in saturated fats. Conclusions: Fructose intake and unhealthy dietary habits were associated with MASLD in pre-school and adolescents with obesity. Advice to pay attention to fructose intake and foods rich in saturated fats is mandatory to decrease both obesity and MASLD. Further high-powered studies in any pediatric age and different geographical areas are needed to better evaluate the MASLD history.

Childhood obesity represents a multifaceted challenge to bone health, influenced by a combination of endocrine, metabolic, and mechanical factors. Excess body fat correlates with an increase in bone mineral density (BMD) yet paradoxically elevates fracture risk due to compromised bone quality and increased mechanical loading on atypical sites. Additionally, subjects with syndromic obesity, as well as individuals with atypical nutritional patterns, including those with eating disorders, show bone fragility through unique genetic and hormonal dysregulations. Emerging evidence underscores the adverse effects of new pharmacological treatments for severe obesity on bone health. Novel drugs, such as glucagon-like peptide-1 (GLP-1) receptor agonists, and bariatric surgery demonstrate potential in achieving weight loss, though limited evidence is available regarding their short- and long-term impacts on skeletal health. This review provides a comprehensive analysis of the mechanisms underlying the impact of childhood obesity on bone health. It critically appraises evidence from in vitro studies, animal models, and clinical research in children with exogenous obesity, syndromic obesity, and eating disorders. It also explores the effects of emerging pharmacological and surgical treatments for severe obesity on skeletal integrity, highlights prevention strategies, and identifies research gaps.

Human milk (HM) is a complex biofluid rich in nutrients and bioactive compounds essential for infant health. Recent advances in omics technologies—such as proteomics, metabolomics, and transcriptomics—have shed light on the influence of HM on bone development and health. This review discusses the impact of various HM components, including proteins, lipids, carbohydrates, and hormones, on bone metabolism and skeletal growth. Proteins like casein and whey promote calcium absorption and osteoblast differentiation, supporting bone mineralization. Long-chain polyunsaturated fatty acids like docosahexaenoic acid (DHA) contribute to bone health by modulating inflammatory pathways and regulating osteoclast activity. Additionally, human milk oligosaccharides (HMOs) act as prebiotics, improving gut health and calcium bioavailability while influencing bone mineralization. Hormones present in HM, such as insulin-like growth factor 1 (IGF-1), leptin, and adiponectin, have been linked to infant growth, body composition, and bone density. Research has shown that higher IGF-1 levels in breast milk are associated with increased weight gain, while leptin and adiponectin influence fat mass and bone metabolism. Emerging studies have also highlighted the role of microRNAs (miRNAs) in regulating key processes like adipogenesis and bone homeostasis. Furthermore, microbiome-focused techniques reveal HM’s role in establishing a balanced infant gut microbiota, indirectly influencing bone development by enhancing nutrient absorption. Although current findings are promising, comprehensive longitudinal studies integrating omics approaches are needed to fully understand the intricate relationships among maternal diet, HM composition, and infant bone health. Bridging these gaps could offer novel dietary strategies to optimize skeletal health during infancy, advancing early-life nutrition science.

Pediatric type 1 diabetes (T1D) disrupts musculoskeletal development during critical windows of growth, puberty, and peak bone mass accrual. Beyond classic micro- and macrovascular complications, accumulating evidence shows a dual burden of diabetic bone disease—reduced bone mineral density, microarchitectural deterioration, and higher fracture risk—and diabetic myopathy, characterized by loss of muscle mass, diminished strength, and metabolic dysfunction. Mechanistically, chronic hyperglycemia, absolute or functional insulin deficiency, and glycemic variability converge to suppress PI3K–AKT–mTOR signaling, activate FoxO-driven atrogenes (atrogin-1, MuRF1), and impair satellite-cell biology; advanced glycation end-products (AGEs) and RAGE signaling stiffen extracellular matrix and promote low-grade inflammation (IL-6, TNF-α/IKK/NF-κB), while oxidative stress and mitochondrial dysfunction further compromise the bone–muscle unit. In vitro, ex vivo, and human studies consistently link these pathways to lower BMD and trabecular/cortical quality, reduced muscle performance, and increased fractures—associations magnified by poor metabolic control and longer disease duration. Prevention prioritizes tight, stable glycemia, daily physical activity with weight-bearing and progressive resistance training, and optimized nutrition (adequate protein, calcium, vitamin D). Treatment is individualized: supervised exercise-based rehabilitation (including neuromuscular and flexibility training) is the cornerstone of skeletal muscle health. This review provides a comprehensive analysis of the mechanisms underlying the impact of type 1 diabetes on musculoskeletal system. It critically appraises evidence from in vitro studies, animal models, and clinical research in children, it also explores the effects of prevention and treatment.

Noonan syndrome (NS) is a genetic disorder characterized by distinctive craniofacial and skeletal features, short stature, mild to moderate developmental impairment, and multisystem involvement, notably affecting the cardiovascular, musculoskeletal, and endocrine systems. Although abnormalities of the bone matrix, as well as osteopenia and osteoporosis, are well recognized in individuals with NS and other RASopathies, the specific impact of RAS/MAPK pathway dysregulation on bone health remains poorly understood. Objectives: The aim of this study was to evaluate bone turnover and bone remodeling markers in a cohort of children with NS, to gain further insights into the bone status of these patients. Methods: In this cross-sectional, case-control study, we analyzed 28 children (20 males) with a molecular diagnosis of NS and 35 healthy subjects (21 males), matched by age and sex. We assessed markers of bone metabolism and bone turnover (calcium, phosphate, PTH, 25(OH)-vitamin D, osteocalcin, procollagen I N-propeptide-P1NP, bone alkaline phosphatase-BALP, C-telopeptides of type I collagen-CTX) and bone remodeling (RANKL, OPG, and sclerostin). Bone mineralization was measured at the lumbar spine (L2–L4) using dual-energy X-ray absorptiometry (DEXA). Results: Serum CTX levels were significantly higher in NS patients compared to controls (1.8 ± 0.7 vs. 1.3 ± 0.5 ng/mL, p = 0.0004). RANKL levels were higher in NS patients, although the difference did not reach statistical significance. No significant differences were found for OPG, sclerostin, or other markers of bone metabolism between patients and controls. Conclusions: Children with NS exhibit increased bone resorption, as indicated by elevated CTX levels, suggesting a potential imbalance in bone remodeling processes. Further studies are warranted to better define the impact of RAS/MAPK pathway dysregulation on bone health in this population.

Background/Objectives: Recombinant growth hormone (rhGH) treatment plays an important role in the transition phase in those subjects diagnosed as having persistent growth hormone deficiency (GHD). We aimed to identify the main predictors of persistent GHD in a large cohort of subjects with childhood-onset GHD who underwent retesting and their correlation with height gain and mid-parental height (MPH). Methods: Anthropometric data, such as growth rate; bone age (BA); IGF-1 SDS at the start, at 1 year, and at the end of rhGH therapy; GH peak at diagnosis and at retesting; brain Magnetic Resonance Imaging (MRI) at diagnosis; and height gain upon reaching final height (FH) and compared to MPH, were obtained from medical records of GHD patients. Results: Persistent GHD was detected in 37 out of 91 (40.7%) GHD subjects. In univariate analysis, persistent GHD was associated with growth rate at 1 year (p = 0.0117) and with the first test GH peak (p = 0.0290). In the regression analysis, persistent GHD was positively associated with growth rate at 1 year (p = 0.0294) and negatively with female gender (p = 0.0424). Height gain was positively associated with growth rate (p = 0.0010) and with age at onset (p = 0.0021), while an inverse association with BA at baseline (p = 0.0002) and IGF-1 SDS (p = 0.0321) was found. Conclusions: Our study confirmed that the most important predictor of persistent GHD is the growth rate in the first year of therapy. Furthermore, growth rate in the first year, female gender, and lower BA at diagnosis are predictors of rhGH efficacy both in terms of height gain and target height achievement.