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Vitamin D is necessary for the active (transcellular) absorption of calcium and for skeletal health. Inadequate vitamin D in infants leads to increased risks of poor bone mineralization and ultimately rickets. Rickets is uncommon in full-term infants with a much higher risk in very premature infants. However, the primary cause of rickets in premature infants is a deficiency of calcium and phosphorus, not vitamin D. Available research, as well as most guidelines, recommend an intake of 400 IU daily of vitamin D as adequate for bone health in preterm and full-term infants. Higher doses have not been consistently shown to have specific clinical benefits for healthy infants. There are no strong data to support either routine testing of serum 25-hydroxyvitamin D or targeting high serum 25-hydroxyvitamin D levels (e.g., 30 ng/mL) in healthy preterm or full-term infants. Vitamin D is commonly provided to infants via drops for breastfed babies or via infant formula, although alternative dosing approaches exist for breastfed infants, which some families may prefer. These include the use of drops placed on the mother's breast, dissolvable doses, and high maternal doses (approximately 6,400 IU daily). Infant formula contains vitamin D, and most infants will reach an intake from formula of about 400 IU daily within the first 2 months of life if they are consuming routine cow milk-based formula. Although vitamin D toxicity is very uncommon, caution should be used to avoid extremely concentrated high doses found in some commercially available drops. Infants with liver or kidney disease may need special attention to vitamin D intake and status. Further research is needed to define the role of vitamin D in non-bone health outcomes of infants and to identify methods to enhance compliance with current recommendations for vitamin D intake in infants., (© 2020 S. Karger AG, Basel.)

Background: Vitamin D supplementation is known to both prevent and treat rickets, a disease of hypomineralized bone. Childhood is a period of great bone development and, therefore, attention to the vitamin D needed to optimize bone health in childhood is imperative., Summary: Observational studies have pointed to a vitamin D status, as indicated by a 25-hydroxyvitamin D concentration, of 50 nmol/L to ensure avoidance of rickets and of 75 nmol/L to optimize health. However, the benefits of achieving these levels of vitamin D status are less evident when pediatric randomized, controlled trials are performed. In fact, no specific pediatric vitamin D supplementation has been established by the existing evidence. Yet, study of vitamin D physiology continues to uncover further potential benefits to vitamin D sufficiency. This disconnection between vitamin D function and trials of supplementation has led to new paths of investigation, including establishment of the best method to measure vitamin D status, examination of genetic variation in vitamin D metabolism, and consideration that vitamin D status is a marker of another variable, such as physical activity, and its association with bone health. Nevertheless, vitamin D supplementation in the range of 10-50 μg/day appears to be safe for children and remains a promising intervention that may yet be supported by clinical trials as a method to optimize pediatric health. Key Message: Pediatric vitamin D status is associated with avoidance of rickets. Randomized, controlled trials of vitamin D supplementation for pediatric bone health are limited and equivocal in their results. Beyond bone, decreased risk for autoimmune, infectious, and allergic diseases has been associated with higher vitamin D status. The specific vitamin D supplementation to optimize toddler, child, and adolescent outcomes is unknown, but doses 10-50 μg/day are safe and may be beneficial., (© 2020 S. Karger AG, Basel.)

Background: Vitamin D and calcium deficiencies are common worldwide, causing nutritional rickets and osteomalacia, which have a major impact on health, growth, and development of infants, children, and adolescents; the consequences can be lethal or can last into adulthood. The goals of this evidence-based consensus document are to provide health care professionals with guidance for prevention, diagnosis, and management of nutritional rickets and to provide policy makers with a framework to work toward its eradication., Evidence: A systematic literature search examining the definition, diagnosis, treatment, and prevention of nutritional rickets in children was conducted. Evidence-based recommendations were developed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system that describes the strength of the recommendation and the quality of supporting evidence., Process: Thirty-three nominated experts in pediatric endocrinology, pediatrics, nutrition, epidemiology, public health, and health economics evaluated the evidence on specific questions within five working groups. The consensus group, representing 11 international scientific organizations, participated in a multiday conference in May 2014 to reach a global evidence-based consensus., Results: This consensus document defines nutritional rickets and its diagnostic criteria and describes the clinical management of rickets and osteomalacia. Risk factors, particularly in mothers and infants, are ranked, and specific prevention recommendations including food fortification and supplementation are offered for both the clinical and public health contexts., Conclusion: Rickets, osteomalacia, and vitamin D and calcium deficiencies are preventable global public health problems in infants, children, and adolescents. Implementation of international rickets prevention programs, including supplementation and food fortification, is urgently required., (© 2016 S. Karger AG, Basel and The Endocrine Society.)

Background/aims: Vitamin D-deficient rickets (DR) has recently re-emerged among developed countries. Vitamin D deficiency can influence biochemical results of patients with fibroblast growth factor 23 (FGF23)-related hereditary hypophosphatemic rickets (HR), making differential diagnosis difficult. In the present study we evaluated the utility of serum FGF23 levels in the diagnosis of DR and during its treatment., Methods: The study group comprised 24 children with DR and 8 children with HR. Serum FGF23 levels and bone metabolism-related measurements were assessed., Results: Serum FGF23 levels in patients with DR were less than 19 pg/ml, while those in patients with HR were more than 57 pg/ml. There were significant differences in serum levels of calcium, phosphate, parathyroid hormone, and 1,25-dihydroxyvitamin D, as well as tubular maximum phosphate reabsorption per glomerular filtration rate between patients with DR and HR, but these values were not fully mutually exclusive. In addition, serum FGF23 and phosphate levels were increased following treatment., Conclusion: Serum FGF23 level is the most critical biochemical marker for distinguishing DR from HR and might be a good indicator of biochemical response to the intervention. Serum FGF23 levels show utility for the diagnosis of DR and in the assessment of its response to treatment.

The conditions related to abnormalities of calcium and bone metabolism are large in number and cover problems of hypocalcaemia, hypercalcaemia, primary and secondary osteoporosis, rickets resulting from both vitamin D and phosphate metabolic disorders, and a series of miscellaneous conditions. Included in this chapter is a series of 36 cases drawn from our clinics and from colleagues who have presented these clinical problems at recent Advanced Courses in Paediatric Bone and Calcium Metabolism run by the British Paediatric and Adolescent Bone group. The series of cases is not fully comprehensive but is designed to cover the major aspects of bone and calcium related disorders and can be added to online in due course., (Copyright (c) 2009 S. Karger AG, Basel.)

Background: Dorfman-Chanarin syndrome is a rare, autosomal recessive, inherited, lipid storage disease. It is characterized by nonbullous congenital ichthyosiform erythroderma, leukocyte vacuoles and variable involvement of the liver, muscles and central nervous system, due to errors of triacylglycerol metabolism. To date only 32 cases of this syndrome have been described worldwide., Aims: To report the case of a boy with Dorfman-Chanarin syndrome with rickets., Case Report: A boy of Turkish origin was born of a nonconsanguineous marriage after an uncomplicated perinatal period. On examination the patient had failure to thrive, diffuse erythroderma and ichthyosis and clinical features suggesting rickets. A light-microscopic examination of peripheral smear revealed vacuolated leukocytes typical of Jordans' anomaly. Lipid analysis showed an increase in triacylglycerol and very low density lipoprotein. A radiographic study of the wrist revealed rickets., Conclusion: The clinical progression in these patients ranges from mild to fatal. We believe that patients with ichthyosis should be evaluated bearing in mind the possibility of Dorfman-Chanarin syndrome. This may increase the number of reported Dorfman-Chanarin syndrome cases, and the pathogenesis and progression of the disease will become clearer., (2007 S. Karger AG, Basel)

Calcium and phosphorus disturbances in childhood are discussed in vitamin D deficiency rickets, neonatal tetany and beta-homozygous thalassaemia. The nutritional, epidemiological, hereditary and other factors facilitating the development of the disease in these three groups of children are illustrated. The level of culture and sociability of the community must be taken into consideration for the success of the preventive medicine services, especially with regard to vitamin D deficiency rickets. The administration of phosphorus and vitamin D or metabolites of vitamin D to thalassaemic children would probably produce beneficial effects on bone and muscle changes.