ABSTRACT Objectives: To analyze and compare intrinsic and extrinsic factors that cause falls among women receiving treatment for osteoporosis. Subjects and methods: A cross-sectional study of women ≥50 years receiving treatment for osteoporosis. Participants filled out questionnaires (demographic characteristics), and researchers took anthropometric measurements of bone mineral density, handgrip strength (HGS), ankle range of motion (ROM), and gait speed (GS). We also evaluated the Timed Up and Go Test (TUGT), Five Times Sit-to-Stand Test (SST), and Falls Efficacy Scale–International (FES-I) and investigated the extrinsic factors for falls. Results: We included 144 participants (71.6 [8.3 years]), who reported 133 falls. We classified participants into a non-faller group (NFG; 0 falls, n = 71, 49.5%), a faller group (FG; 1 fall, n = 42, 28.9%), and a recurrent-faller group (RFG; more than 1 fall, n = 31, 21.5%). Most patients had an increased risk of falling according to the TUGT, SST, reduced ankle ROM, and GS (P < .005 for all). FES-I was associated with sporadic and recurrent falls. For the multivariate analysis, the number of falls was influenced by the presence of ramps (RR 0.48, 95% CI, 0.26-0.87, P = .015), uneven surfaces (RR 1.6, 95% CI. 1.05-2.43, P = .028), and antislippery adhesive on stairs (RR 2.75, 95% CI, 1.77-4.28, P < .001). Conclusion: Patients receiving treatment for osteoporosis are influenced by intrinsic and extrinsic factors that cause falls. Lower-limb strength and power-discriminated participants at a higher risk of falls, but extrinsic factors varied. Only uneven floors and antislippery adhesives on stairs were associated with increased frequency of falls.

ABSTRACT Stress fractures (SF) represent 10%-20% of all injuries in sport medicine. An SF occurs when abnormal and repetitive loading is applied on normal bone: The body cannot adapt quickly enough, leading to microdamage and fracture. The etiology is multifactorial with numerous risk factors involved. Diagnosis of SF can be achieved by identifying intrinsic and extrinsic factors, obtaining a good history, performing a physical exam, and ordering laboratory and imaging studies (magnetic resonance imaging is the current gold standard). Relative energy deficiency in sport (RED-S) is a known risk factor. In addition, for women, it is very important know the menstrual status to identify long periods of amenorrhea in the past and the present. Early detection is important to improve the chance of symptom resolution with conservative treatment. Common presentation involves complaints of localized pain, with or without swelling, and tenderness on palpation of bony structures that begins earlier in training and progressively worsens with activity over a 2- to 3-week period. Appropriate classification of SF based on type, location, grading, and low or high risk is critical in guiding treatment strategies and influencing the time to return to sport. Stress injuries at low-risk sites are typically managed conservatively. Studies have suggested that calcium and vitamin D supplementation might be helpful. Moreover, other treatment regimens are not well established. Understanding better the pathophysiology of SFs and the potential utility of current and future bone-active therapeutics may well yield approaches that could treat SFs more effectively.

Abstract Phosphorus is one of the most abundant minerals in the human body; it is required to maintain bone integrity and mineralization, in addition to other biological processes. Phosphorus is regulated by parathyroid hormone, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], and fibroblast growth factor 23 (FGF-23) in a complex set of processes that occur in the gut, skeleton, and kidneys. Different molecular mechanisms – overproduction of FGF-23 by tumors responsible for oncogenic osteomalacia, generation of an FGF-23 mutant that is resistant to cleavage by enzymes, and impaired FGF-23 degradation due to a reduction in or loss of the PHEX gene – can lead to FGF-23-stimulating activity and the consequent waste of urinary phosphate and low levels of 1,25(OH)2D3. Conventional treatment consists of multiple daily doses of oral phosphate salts and vitamin D analogs, which may improve radiographic rickets but do not normalize growth. Complications of the conventional long-term treatment consist of hypercalcemia, hypercalciuria, nephrolithiasis, nephrocalcinosis, impaired renal function, and potentially chronic kidney disease. Recently, burosumab, an antibody against FGF-23, was approved as a novel therapy for children and adults with X-linked hypophosphatemia and patients with tumor-induced osteomalacia. Burosumab showed good performance in different trials in children and adults. It increased and sustained the serum phosphorus levels, decreased the rickets severity and pain scores, and improved mineralization. It offers a new perspective on the treatment of chronic and disabling diseases. Arch Endocrinol Metab. 2022;66(5):658-65

ABSTRACT Objective: Evaluating the prevalence of sarcopenia in women submitted to bariatric surgery – Roux-en-Y gastric bypass. Design: Observational, cross-sectional study. Subjects and methods: Women (18-65 years old) who underwent bariatric surgery (BG) ≥ 2 years and reached stable weight ≥ 6 months, were investigated. Control group (CG) comprised non-operated matched women with obesity. Body composition was determined through dual-energy X-ray absorptiometry. Low lean mass (LLM) was defined as appendicular lean mass index (ALM kg/height m2) < 5.5 kg/m2. Physical strength was assessed through dynamometer and sit-to-stand test (SST), whereas performance was assessed through 4-m gait speed and Short Physical Performance Battery Tests (SPPB). Sarcopenia was diagnosed in the presence of LLM and low strength. Results: One-hundred and twenty women (60 in each group, 50 ± 9.7 years old) were investigated. All anthropometric and body composition parameters were lower in BG than in CG, whereas strength and performance were similar between groups. Women with reduced strength presented high total fat mass and low physical activity level (p < 0.005). LLM was observed in 35% of BG and in 18.3% of CG (p = 0.04), whereas sarcopenia was diagnosed in 28.3% of BG and in 16.6% of CG (p = 0.12). Sarcopenic women in BG had better performance both in SST (p = 0.001) and SPPB (p = 0.004). Total lean mass (OR:1.41, 95% CI [1.18; 1.69], p < 0.001) and obesity (OR: 38.2 [2.27; 644.12], p < 0.001) were associated with sarcopenia in the multivariate analysis. Conclusion: Despite great weight loss, sarcopenia prevalence did not increase in BG and its presence was influenced by total lean mass and obesity.

ABSTRACT Objective: To evaluate the reasons for request of bone mineral density (BMD) evaluation and correlate the BMD results with previous fractures, risk factors for osteoporosis, and clinical characteristics in patients with obesity. Subjects and methods: Cross-sectional, retrospective, single-site study including adult patients with body mass index (BMI) ≥ 30 kg/m2 and BMD evaluation between January 2015 and May 2016 selected from a BMD database. Data on demographic characteristics, lifestyle habits, comorbidities, medications, risk factors, previous fractures, and indications for BMD evaluation were collected from the participants’ medical records. Results: The study included 619 patients (89.9% women, mean BMI 34.79 ± 4.05 kg/m2). In all, 382 (61.7%), 166 (26.8%), and 71 (11.5%) patients had class 1, 2, and 3 obesity, respectively. The most frequent (29.9%) reason for BMD evaluation was for osteoporosis monitoring. In all, 69.4% of the patients had low BMD. Multivariate analysis showed that age, calcium supplementation, and previous osteoporosis or osteopenia were associated with low BMD, while age, vitamin D supplementation, use of proton pump inhibitors (PPIs), and low BMD were associated with previous fractures (p < 0.05 for all). Conclusions: Among patients with obesity identified from a tertiary hospital database, those with low bone mass and risk factors traditionally associated with fractures had an increased history of fractures. Patients with greater BMI had better bone mass and fewer fractures. These findings indicate that the association between reduced weight, risk factors for osteoporosis, and fractures remained despite the presence of obesity in our population.

ABSTRACT Objective We investigated changes in body composition and nutritional and metabolic parameters in a group of postmenopausal women who were classified as sufficient, insufficient and deficient in vitamin D. Subjects and methods A total of 106 postmenopausal women were included in this cross-sectional study and classified according to their serum levels of 25-OH-vitamin D as sufficient (≥ 30 ng/mL; group S), insufficient (20.1 and 29.9 ng/mL; group I) or deficient (≤ 20 ng/mL; group D) in vitamin D. Body composition was measured by dual-energy X-ray absorptiometry (DXA); dietary recall questionnaires were completed; and blood samples were analysed to compare the metabolic and nutritional status of the study groups. Results Eleven (10.4%) of the women were classified in group S, 50 (47.2%) in group I and 45 (42.4%) in group D, with a mean serum level for 25-OH-D of 21.1 ± 7.0 ng/mL in all participants. Body composition did not differ among the groups. Serum levels of 25-OH-D were negatively correlated with serum levels of triglycerides, total cholesterol and LDL cholesterol. Conclusions Vitamin D insufficiency and deficiency were highly prevalent in our group of postmenopausal women, showing an association with an unfavourable lipid profile.

ABSTRACT Objective To present an update on the diagnosis and treatment of hypoparathyroidism based on the most recent scientific evidence. Materials and methods The Department of Bone and Mineral Metabolism of the Sociedade Brasileira de Endocrinologia e Metabologia (SBEM; Brazilian Society of Endocrinology and Metabolism) was invited to prepare a document following the rules set by the Guidelines Program of the Associação Médica Brasileira (AMB; Brazilian Medical Association). Relevant papers were retrieved from the databases MEDLINE/PubMed, LILACS, and SciELO, and the evidence derived from each article was classified into recommendation levels according to scientific strength and study type. Conclusion An update on the recent scientific literature addressing hypoparathyroidism is presented to serve as a basis for the diagnosis and treatment of this condition in Brazil.

Abstract Background: The aim of this study was to evaluate the prevalence of pre-sarcopenia and bone mineral density after hematopoietic stem cell transplantation. Methods: The study group consisted of over 18-year-old patients who had been submitted to allogeneic transplantation at least one year previously. Patients and healthy controls were matched by sex, ethnic background, age, and body mass index. Body composition and bone mineral density were measured by dual-energy X-ray absorptiometry. A 24-h food recall and food frequency survey were performed. The biochemical evaluation included calcium, parathormone and vitamin D. Eighty-seven patients (52 men; age: 37.2 ± 12.7 years; body mass index: 25 ± 4.5 kg/m2) were compared to 68 controls [31 men; age 35.4 ± 15.5 years (p = 0.467); body mass index 25.05 ± 3.7 kg/m2 (p = 0.927)]. Results: There was no significant difference in the dietary intake between patients and controls. The mean levels of vitamin D were 23.5 ± 10.3 ng/mL; 29 patients (41.0%) had insufficient and 26 (37.14%) deficient levels. A higher prevalence of reduced bone mineral density was observed in 24 patients (25%) compared to 12 controls (19.1% - p < 0.001). Pre-sarcopenia was diagnosed in 14 (14.4%) patients and none of the controls (p = 0.05). There was a higher prevalence of pre-sarcopenia (66%) in patients with grades III and IV compared to those with grades 0-II graft-versus-host disease (10.9%) (p = 0.004). Conclusion: patients submitted to transplantation had a higher prevalence of pre-sarcopenia and greater changes in bone mineral density compared to controls; the severity of graft-versus-host disease had an impact on the prevalence of pre-sarcopenia.

RESUMO Objetivo: Avaliar a incidência e o impacto econômico das fraturas de fêmur no Estado do Paraná, Brasil. Métodos: Este estudo descritivo incluiu homens e mulheres ≥ 60 anos de idade com fraturas de quadril, tratados no serviço de emergência do Sistema Único de Saúde, de janeiro de 2010 a dezembro de 2014. Os dados foram coletados na base de dados DATASUS, usando-se filtros para selecionar os pacientes; os resultados foram apresentados de forma descritiva e proporcional. A incidência padronizada de fratura femoral foi calculada por sexo e faixa etária em 10 mil habitantes do Estado do Paraná e no Brasil, referente ao ano de 2012. Resultados: Durante o período de estudo, foram registradas 11.226 fraturas, 66,8% em mulheres e 33,2% em homens. Houve predomínio de fraturas em brancos e mais idosos. A taxa de mortalidade durante a internação foi 5,9%, maior nos homens, na faixa etária de 80 anos ou mais, negros e asiáticos. O custo total foi R$29.393.442,78 e o custo médio por internação foi R$2.618,34. A taxa mais alta de fraturas ocorreu na região leste do estado, predominantemente na Capital, Curitiba. A taxa de incidência padronizada foi superior nas mulheres e na população paranaense. Conclusão: As fraturas de fêmur têm alta incidência em idosos no Estado do Paraná, com alto impacto econômico. Nível de Evidência II, Estudos Prognósticos - Investigação do Efeito de uma Característica de um Paciente sobre o Desfecho da Doença.

ABSTRACT Objectives: To evaluate the incidence and economic impact of femur fractures in the state of Paraná, Brazil . Methods: This descriptive study included men and women ≥ 60 years of age with hip fractures which were treated by the Public Health System in emergency care from January 2010 to December 2014. Data were collected from the DATASUS public health database using filters to select patients; results were presented descriptively and as proportions. The standardized incidence of femur fracture was calculated by sex and age for 10,000 inhabitants in Paraná state and in Brazil for the year 2012 . Results: During the study period, 11,226 fractures were registered, 66.8% in women and 33.2% in men. There was a preponderance of fractures in Caucasians and in older age groups. Mortality during hospitalization was 5.9%, higher in males, in patients aged ≥80 years, and in Blacks and Asians. The total cost was R$ 29,393,442.78 and the average cost per hospitalization was R$ 2,618.34. The eastern region of the state had the highest rate of fractures, predominantly in the capital, Curitiba. The standardized incidence rate was higher in females and in the population of Paraná . Conclusion: Femur fractures have a high incidence rate in the elderly population of Paraná and a large economic impact. Level of Evidence II, Prognostic Studies Investigating the effect of a Patient Characterisctic on the Outcome of Disease.

Racional : Alguns nutrientes são essenciais para a prevenção da perda de massa óssea que ocorre após a cirurgia bariátrica. Objetivo : Avaliar nos pacientes que foram submetidos à cirurgia bariárica pela técnica de bypass gástrico os nutrientes envolvidos no metabolismo ósseo e sua relação com: a concentração sérica de cálcio; a vitamina D e paratormônio; o uso de suplementos alimentares e a exposição solar. Métodos : Estudo observacional com pacientes que foram previamente submetidos à cirurgia, 12 meses ou mais que compuseram o grupo operado (OG), em comparação a um grupo controle (GC). Resultados : Foram avaliados 56 pacientes no OG e 27 no GC. A média de idade foi de 36,4±8,5 anos. Os indivíduos do OG, em comparação com o CG, consumiram diariamente quantidades insuficientes de proteína e cálcio. O OG apresentou maior prevalência de baixa exposição solar, níveis mais baixos de 25OH vitamina D (21,3±10,9 vs 32,1±11,8 ng/ dL) e aumento dos níveis séricos de paratormônio (68,1±32,9 vs 39,9±11,9 pg/ml, p<0,001). Hiperparatiroidismo secundário foi presente apenas no OG (41,7%). A densidade mineral óssea da coluna lombar foi significativamente menor no OG. Quatro indivíduos do OG tiveram baixa densidade mineral óssea comparado com a idade cronológica, e nenhum do CG. Conclusão : Os componentes da dieta que afetam a massa óssea em pacientes submetidos à cirurgia bariátrica estavam inadequados. A suplementação alimentar foi insuficiente e a exposição solar baixa. Estas alterações foram acompanhadas de hiperparatireoidismo secundário e alta prevalência de baixa massa óssea em coluna lombar nestes pacientes.

Background : Essential nutrients are considered for the prevention of the bone loss that occurs after bariatric surgery. Aim : Evaluate nutrients involved in bone metabolism, and relate to serum concentrations of calcium, vitamin D, and parathyroid hormone, and the use of supplements and sun exposure on the bone mass of patients who had undergone gastric bypass surgery. Methods : An observational study, with patients who had undergone the surgery 12 or more months previously, operated group (OG), compared to a control group (CG). Results : Were included 56 in OG and 27 in the CG. The mean age was 36.4±8.5 years. The individuals in the OG, compared to CG, consumed inadequate amounts of protein and daily calcium. The OG had a higher prevalence of low sun exposure, lower levels of 25OH Vitamin D (21.3±10.9 vs. 32.1±11.8 ng/dl), and increased serum levels of parathyroid hormone (68.1±32.9 vs. 39.9±11.9 pg/ml, p<0.001). Secondary hyperparathyroidism was present only in the OG (41.7%). The mean lumbar spine bone mineral density was lower in the OG. Four individuals from the OG had low bone mineral density for chronological age, and no one from the CG. Conclusion : The dietary components that affect bone mass in patients undergoing bariatric surgery were inadequate. The supplementation was insufficient and the sun exposure was low. These changes were accompanied by secondary hyperparathyroidism and a high prevalence of low bone mass in lumbar spine in these subjects.

Objetivo: Avaliar a prevalência de sarcopenia em pacientes com DPOC e determinar se sarcopenia está correlacionada com a gravidade e o prognóstico de DPOC. Métodos: Estudo retrospectivo em pacientes com DPOC atendidos no ambulatório de pneumologia de nossa instituição. Os pacientes realizaram absorciometria de dupla energia por raios X. O diagnóstico de sarcopenia foi baseado no índice de massa muscular esquelética, definido como massa magra apendicular/altura2 somente para indivíduos com baixo peso, sendo ajustado pela massa gorda para aqueles com peso normal/sobrepeso. A gravidade da doença (estádio da DPOC) foi avaliada com os critérios da Global Initiative for Chronic Obstructive Lung Disease (GOLD). O grau de obstrução e o prognóstico foram determinados pelo índice Body mass index, airflow Obstruction, Dyspnea, and Exercise capacity (BODE). Resultados: Foram incluídos 91 pacientes (50 mulheres), com média de idade de 67,4 ± 8,7 anos e média de IMC de 25,8 ± 6,1 kg/m2. Sarcopenia foi diagnosticada em 36 (39,6%) dos pacientes, sem diferenças relacionadas a sexo, idade ou status tabágico. Não houve associação de sarcopenia com estádios GOLD ou VEF1 (utilizado como indicador do grau de obstrução). O IMC, a porcentagem de gordura corporal e a massa magra total foram menores nos pacientes com sarcopenia do que naqueles sem a doença (p < 0,001). A prevalência de sarcopenia foi maior nos pacientes com BODE nos quartis 3 ou 4 que naqueles com BODE nos quartis 1 ou 2 (p = 0,009). A análise multivariada mostrou que os quartis do BODE estavam significativamente associados à sarcopenia, independentemente de idade, gênero, status tabágico e estádio GOLD. Conclusões: Em pacientes com DPOC, sarcopenia parece estar associada a alterações desfavoráveis na composição corporal e pior prognóstico.

Objective: To evaluate the prevalence of sarcopenia in COPD patients, as well as to determine whether sarcopenia correlates with the severity and prognosis of COPD. Methods: A cross-sectional study with COPD patients followed at the pulmonary outpatient clinic of our institution. The patients underwent dual-energy X-ray absorptiometry. The diagnosis of sarcopenia was made on the basis of the skeletal muscle index, defined as appendicular lean mass/height2 only for low-weight subjects and adjusted for fat mass in normal/overweight subjects. Disease severity (COPD stage) was evaluated with the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria. The degree of obstruction and prognosis were determined by the Body mass index, airflow Obstruction, Dyspnea, and Exercise capacity (BODE) index. Results: We recruited 91 patients (50 females), with a mean age of 67.4 ± 8.7 years and a mean BMI of 25.8 ± 6.1 kg/m2. Sarcopenia was observed in 36 (39.6%) of the patients, with no differences related to gender, age, or smoking status. Sarcopenia was not associated with the GOLD stage or with FEV1 (used as an indicator of the degree of obstruction). The BMI, percentage of body fat, and total lean mass were lower in the patients with sarcopenia than in those without (p < 0.001). Sarcopenia was more prevalent among the patients in BODE quartile 3 or 4 than among those in BODE quartile 1 or 2 (p = 0.009). The multivariate analysis showed that the BODE quartile was significantly associated with sarcopenia, regardless of age, gender, smoking status, and GOLD stage. Conclusions: In COPD patients, sarcopenia appears to be associated with unfavorable changes in body composition and with a poor prognosis.

Hypercalcemia is found frequently in patients with cancer. Besides the etiology related to the malignancy, other causes should be considered in the differential diagnostic, as primary hyperparathyroidism, granulomatous diseases and the use of thiazide diuretics. We present a case report of a severe hypercalcemia due to a rare association and review the relevant literature. A female patient, 57 years old, sent to the Endocrinology Service of Hospital das Clínicas da Universidade do Paraná (SEMPR) in order to investigate severe hypercalcemia with frequent need of hospitalization. The patient was in chemotherapy treatment for recurrence of clear cell renal cancer. During the investigation she presented high level of parathyroid hormone (PTH) and parathyroid scintigraphy suggestive of hyperplasia/ adenoma of parathyroid, histopathological diagnosis was confirmed after parathyroidectomy. After surgery the patient presented undetectable levels of PTH. However, she continued with progressive increase of serum calcium, with no signs of bone metastases or change in vitamin D metabolism. The investigation showed high levels of PTH-related protein (PTHrP), leading us to the diagnosis of hypercalcemia of malignancy. The patient presented severe hypercalcemia due to the rare association of primary hyperparathyroidism and humoral hypercalcemia of malignancy due to secretion of PTHrP by tumor cells. The presence of isolated primary hyperparathyroidism, as a cause of hypercalcemia in cancer patients, has been described in approximately 5-10% of the patients. However, the association of primary hyperparathyroidism and humoral hypercalcemia of malignancy (which means with concomitant elevation of PTH and PTHrP) is rare, only three cases have been described in the literature. Arch Endocrinol Metab. 2015;59(1):84-8

Objetivo: Conduzir uma atualização das últimas evidências científicas a respeito da apresentação, diagnóstico e manejo clínico da doença de Paget óssea. Materiais e métodos: Este documento foi concebido pelo Departamento de Metabolismo Ósseo da Sociedade Brasileira de Endocrinologia e Metabologia (SBEM) a partir daquele oriundo do Programa de Diretrizes da Associação Médica Brasileira (AMB). Realizamos uma revisão dos artigos mais relevantes obtidos nos bancos de dados PubMed e Cochrane, além de abstracts apresentados nos encontros anuais da Endocrine Society, Sociedade Brasileira de Endocrinologia e da American Society for Bone and Mineral Research dos últimos cinco anos e classificamos as evidências em níveis de recomendações de acordo com a força científica por tipo de estudo, adaptando o primeiro relato do “Oxford Centre for Evidence-based Medicine”. Todos os graus de recomendação, incluindo-se o “D”, foram baseados em evidência científica, sendo as diferenças entre o A, B, C e D devidas exclusivamente ao desenho empregado na geração da evidência. Conclusão: Apresentamos uma atualização científica a respeito da doença de Paget óssea, classificando e graduando em níveis de recomendações as principais evidências científicas sobre as suas causas, as variadas formas de apresentação, seu diagnóstico e tratamento.

Objective: To conduct a literature review on the diagnosis and management of Paget’s disease of bone. Materials and methods: This scientific statement was generated by a request from the Brazilian Medical Association (AMB) to the Brazilian Society of Endocrinology and Metabolism (SBEM) as part of its Clinical Practice Guidelines program. Articles were identified by searching in PubMed and Cochrane databases as well as abstracts presented at the Endocrine Society, Brazilian Society for Endocrinology Annual Meetings and the American Society for Bone and Mineral Research Annual Meeting during the last 5 years. Grading quality of evidence and strength of recommendation were adapted from the first report of the Oxford Centre for Evidence-based Medicine. All grades of recommendation, including “D”, are based on scientific evidence. The differences between A, B, C and D, are due exclusively to the methods employed in generating evidence. Conclusion: We present a scientific statement on Paget’s disease of bone providing the level of evidence and the degree of recommendation regarding causes, clinical presentation as well as surgical and medical treatment. Arq Bras Endocrinol Metab. 2014;58(6):587-99

Background: Sub-optimal levels of vitamin D have been found to be highly prevalent in all age groups, with epidemiologic studies demonstrating a link between vitamin D deficiency and disease susceptibility, such as infection and cancer, and mortality rates. In adult transplant patients, it has been suggested that the immunomodulatory properties of vitamin D may have an important role in the prevention and treatment of graft-versus-host disease. Objective: The objective of this study was to assess serum 25-hydroxyvitamin D levels of children and adolescents submitted to allogeneic hematopoietic stem cell transplantation. Methods: Serum 25-hydroxyvitamin D levels of 66 patients, aged 4-20 years, were assessed at three stages: before hospitalization for hematopoietic stem cell transplantation and at 30 and 180 days after hematopoietic stem cell transplantation. The control group consisted of 25 healthy children. Results: At the pre-hematopoietic stem cell transplantation stage, patients had lower levels of 25-hydroxyvitamin D compared to controls (25.7 ± 12.3 ng/mL vs. 31.9 ± 9.9 ng/mL; p-value = 0.01), and a higher prevalence of 25-hydroxyvitamin D deficiency (32% vs. 8%; p-value = 0.01). Prevalence increased significantly after hematopoietic stem cell transplantation (p-value = 0.01) with half of the patients having vitamin D deficiency at 180 days after transplantation. At this stage, mean serum 25-hydroxyvitamin D levels were 20.9 ± 10.9 ng/mL, a significant decline in relation to baseline (p-value = 0.01). No correlation was found between 25-hydroxyvitamin D levels and vitamin D intake, graft-versus-host disease, corticoid use or survival rates. Conclusion: Low levels of 25-hydroxyvitamin D were detected even before hematopoietic stem cell transplantation and were significantly lower at 180 days after hematopoietic stem cell transplantation, thus recommending vitamin D supplementation for children and adolescents submitted to hematopoietic stem cell transplantation.