Niveles bajos de vitamina D y su efecto en la oseointegración: revisión sistemática / Low levels of vitamin D and effect on osseointegration: a systematic review

Introducción: la vitamina D es una hormona que se sintetiza por células de la piel mediante la luz ultravioleta (UV) y se obtiene a través de la dieta. La relación que se establece entre la deficiencia de vitamina D y el fracaso en injertos óseos o implantes se basa en las alteraciones inmunológicas e inflamatorias debido al vínculo que existe con la inmunidad innata y adaptativa. Objetivo: identificar los factores que se presentan en el periodonto cuando existen niveles bajos de vitamina D y se realizan tratamientos periodontales como injertos óseos e implantes. Material y métodos: se realizó la búsqueda primaria de artículos en bases de datos PubMed y Google Académico (en español e inglés), de acuerdo con las palabras claves: deficiencia, vitamina D, implantología y oseointegración. Resultados: la vitamina D afecta y predispone al rechazo de injertos, ausencia de oseointegración en implantes debido a la inmunomodulación. Conclusión: el éxito del tratamiento se vuelve predecible cuando se encuentran niveles óptimos de vitamina D en conjunto con técnicas de abordaje quirúrgico correctas que permitan generar una integración ideal de los tejidos periodontales (AU)

Introduction: vitamin D is a hormone that is synthesized by skin cells using UV light and consumed through the diet. The relationship established between vitamin D deficiency and the failure of bone grafts or implants is based on immunological and inflammatory alterations due to the intimate link with innate and adaptive immunity. Objective: to identify the factors that occur in the periodontium when there are low levels of vitamin D and periodontal treatments such as bone grafts and implants are performed. Material and methods: a search for articles was carried out in PubMed and Google Scholar (Spanish and English). Results: vitamin D affects and predisposes to graft rejection, absence of osseointegration in implants due to immunomodulation. Conclusion: the success of the treatment becomes predictable when optimal levels of vitamin D are found together with the correct surgical approach techniques that allow the generation of an ideal integration of the periodontal tissues.(AU)

VIH y salud ósea / HIV and bone health

Con el advenimiento de la terapia antirretroviral, el pronóstico y la sobrevida de los pacientes infectados con el virus de la inmunodeficiencia humana (VIH) han cambiado de manera radical, por lo cual en la actualidad se evidencia un aumento en el riesgo de padecer enfermedades no relacionadas con el VIH como, por ejemplo, la osteoporosis. La disminución de la densidad mineral ósea (DMO) se observa en el 40-90% de las personas infectadas por el VIH, con una prevalencia de osteopenia y osteoporosis del 52 y 15%, respectivamente. Esta población de pacientes tiene un mayor riesgo de fracturas (60%) en comparación con personas no infectadas y un riesgo de fracturas vertebrales 2,3 veces mayor que en la población general. El tenofovir fumarato se asoció con un aumento de pérdida renal de fósforo e hiperparatiroidismo secundario. El efavirenz y los inhibidores de proteasas (IP) afectan el metabolismo de la vitamina D; actúan a nivel enzimático aumentando la expresión de la enzima CYP24 que lleva a producción de vitamina D inactiva. El FRAX es una herramienta sencilla y accesible, por lo que su uso está recomendado en pacientes con VIH. Además de las medidas higiénico-dietéticas, actividad física, calcio y vitamina D, el uso de bifosfonatos está indicado en el tratamiento de la osteoporosis en estos pacientes. (AU)

With the advent of antiretroviral therapy, the prognosis and survival of patients infected with the human immunodeficiency virus (HIV) have radically changed, which is why there is now evidence of an increased risk of suffering from diseases not related to HIV such as osteoporosis. The decrease in bone mineral density (BMD) is observed in 40-90% of people infected with HIV, with a prevalence of osteopenia and osteoporosis of 52 and 15%, respectively. This patient population has a 60% higher risk of fractures compared to uninfected people and a risk of vertebral fractures 2.3 times higher than in the general population. Tenofovir fumarate administration is associated with increased renal phosphorus loss and secondary hyperparathyroidism. Efavirenz and protease inhibitors (IP) affect the metabolism of vitamin D, they act at the enzymatic level by increasing the expression of the CYP24 enzyme that leads to the production of inactive vitamin D. The FRAX is a simple and accessible tool, so its use is recommended in patients with HIV and in addition to dietary hygiene measures, physical activity, calcium, and vitamin D, the use of bisphosphonates is indicated in the treatment of osteoporosis in these patients. (AU)

Effects of vitamin D-induced supernatant of placental explants from preeclamptic women on oxidative stress and nitric oxide bioavailability in human umbilical vein endothelial cells

The study evaluated the effect of the supernatant of placental explants from preeclamptic (PE) and normotensive (NT) pregnant women after tissue treatment with or without vitamin D (VD) on oxidative stress and nitric oxide (NO) bioavailability in human umbilical vein endothelial cells (HUVEC). Placental explants were prepared from eight NT and eight PE women, and supernatants were obtained after incubation with or without hydrogen peroxide (H2O2) and/or VD. HUVEC were cultured for 24 h with supernatants, and the following parameters were analyzed in HUVEC cultures: NO, nitrate (NO3-), and nitrite (NO2-) levels, lipid peroxidation, and intracellular reactive oxygen species (ROS). Results showed that the production of NO3-, NO2-, malondialdehyde (MDA), and ROS were significantly higher in HUVEC treated with explant supernatant from PE compared to NT pregnant women, while the supernatant of PE explants treated with VD led to a decrease in these parameters. A significantly high production of NO was detected in HUVEC cultured with control supernatant of NT group, and in cultures treated with supernatant of PE explants treated with VD. Taken together, these results demonstrated that cultures of placental explants from PE women with VD treatment generated a supernatant that decreased oxidative stress and increased the bioavailability of NO in endothelial cells.

Vitamina D, miR-21 y marcadores de apoptosis en pacientes con diabetes tipo I / Vitamin D, miR-21 and apoptosis markers in patients with type 1 diabetes

La diabetes Tipo 1 (DT1) es una compleja enfermedad autoinmune con una etiología aún desconocida. La vitamina D ha sido ampliamente estudiada debido a su potencial terapéutico en los potenciales nuevos casos de DT1. Por otra parte, los microARNs (miRs) han sido propuestos como posibles biomarcadores en diversos procesos biológicos como en la apoptosis e inflamación. El objetivo de este estudio fue evaluar el efecto de la suplementación con vitamina D sobre el perfil de expresión del miR-21 y marcadores de apoptosis tales como: BCL2, STAT3, TIPE2 y DAXX, en células mononucleares periféricas provenientes de pacientes con DT1 y sujetos controles. RESULTADOS: El perfil de expresión de miR-21 se encontró disminuido en los pacientes con DT1 en comparación con los controles. La expresión relativa de BCL2 se encontró aumentada en controles al comparar con pacientes DT1 en todas las condiciones experimentales. La expresión relativa de DAXX mostró un perfil de expresión diferencial al comparar pacientes con DT1 versus controles (p=0.006). CONCLUSIÓN: El estímulo con vitamina D parece tener un posible efecto regulador sobre los genes BCL2 y DAXX.

Type 1 diabetes (T1D) is a complex chronic autoimmune disease. Vitamin D has been one of the most studied therapeutic potential outbreaks related to T1D. Specific miRNAs have been proposed as potential biomarkers in several biological processes as apoptosis and inflammation. The aim of this study was to evaluate the effect of vitamin D on the expression profiles of miR-21 and apoptotic markers BCL2, STAT3, TIPE2 and DAXX, in PBMCs from T1D patients and control subjects. RESULTS: miR-21 expression was increased in controls regarding T1D patients. BCL2 was increased in controls compared to T1D patients in all experimental conditions. DAXX showed different expression patterns between T1D patients and controls (p=0.006). CONCLUSION: Vitamin D showed a possible regulation effect on apoptosis markers mainly through the regulation of BCL2 and DAXX

Anticonvulsivantes y su efecto en el metabolismo de la vitamina D: revisión del tema, a propósito de un caso / Anticonvulsants and their effect on the metabolism of vitamin D: literature review with case report

La epilepsia es una enfermedad neurológica frecuente que afecta a cerca de 50.000 millones de personas en el mundo. En Chile, la prevalencia estimada es de 10.8 a 17 por 1.000 habitantes. La primera opción para su tratamiento son los fármacos antiepilépticos (FAE) los cuales logran un aceptable control de enfermedad en la mayoría de los casos, sin embargo, tienen la potencialidad de desencadenar una serie de efectos adversos destacando entre ellos el desarrollo de hipocalcemia (HC) secundaria a hipovitaminosis D (HD), alteración que por lo general es leve y asintomática. Presentamos el caso de una mujer perimenopausica con antecedente de epilepsia en tratamiento con anticonvulsivante que desarrolla hipocalcemia severa. Además revisamos los mecanismos descritos a través de los cuales los FAE afectan el metabolismo de esta vitamina.

Epilepsy is a common neurological disease that affects about 50,000 million people in the world. The estimated prevalence is 10.8 to 17 per 1.000 inhabitants in Chile. The first option for its treatment are antiepileptic drugs (AEDs) which achieve an acceptable control of the disease in most cases, however, they have the potential to trigger a series of adverse effects (AE) highlighting among them the development of hypocalcemia (HC) secondary to hypovitaminosis D (HD), an alteration that is generally mild and asymptomatic. We present the case of a perimenopausal woman with a history of epilepsy under treatment with an anticonvulsant who develops severe hypocalcemia. We also review the mechanisms described through which AEDs affect the metabolism of this vitamin.

Relación entre niveles de vitamina D y perfil lipídico en embarazadas de alto riesgo / Relationship between level of vitamin D and lipid profile in high risk pregnant women

En la Argentina, las embarazadas presentan alta prevalencia (80%) de hipovitaminosis D y de sobrepeso u obesidad (27,4%). Ambas condiciones pueden aumentar la morbimortalidad materno-fetal. Bajos niveles de vitamina D se han relacionado con aumento del colesterol total, LDL, triglicéridos (Tg) y descenso de HDL. Objetivo: evaluar los niveles de 25-hidroxivitamina D (25OHD) y su relación con el perfil lipídico en pacientes embarazadas de alto riesgo. Materiales y métodos: estudio de corte transversal entre septiembre de 2016 y abril de 2017. Se excluyeron pacientes que recibieron suplementos de vitamina D, con disfunción tiroidea no compensada, malabsorción, insuficiencia cardíaca, renal o hepática y dislipidemia familiar. Niveles circulantes de 25OHD < 30 ng/ml se consideraron hipovitaminosis. Resultados: se evaluaron 86 embarazadas de 29,3 ± 7,1 años durante la semana 28 ± 6,5. El IMC pregestacional fue 28,3 ± 6,5 kg/m2 y la ganancia de peso 7 ± 4,3 kg. Perfil lipídico: colesterol total 240 ± 54 mg/dl; LDL 156 ± 54 mg/dl; HDL 66 ± 15 mg/dl; Tg 204 ± 80 mg/dl. La media de 25OHD fue de 23,8 ± 9 ng/ml, con una prevalencia de hipovitaminosis D de 77,9 %. Las pacientes con hipovitaminosis D presentaron mayores valores de colesterol total y LDL (p < 0,05), con tendencia no significativa a presentar mayores valores de Tg. Conclusión: en embarazadas de alto riesgo se observó una alta prevalencia de hipovitaminosis D, asociada con mayores concentraciones de colesterol total y LDL. (AU)

In Argentina, pregnant women have a high prevalence (80 %) of hypovitaminosis D and verweight/obesity (27.4%), conditions that can increase maternal-fetal morbidity and mortality. Low levels of 25-hydroxyvitamin D (25OHD) have been linked to an increase in total cholesterol, LDL cholesterol, triglycerides (TG) and a decrease in HDL cholesterol. Objective: to evaluate the levels of vitamin D and its relationship with the lipid profile in high risk pregnant patients. Materials and methods: cross-sectional study between September 2016 and April 2017. Patients who received vitamin D supplements or had non-compensated thyroid dysfunction, malabsorption, heart failure, renal or hepatic failure, or familial dyslipidemia were excluded. Hypovitaminosis D was defined as a circulating level of 25OHD < 30 ng/ml. Results: We assessed 86 women of 29.3 ± 7.1 years during pregnancy week 28 ± 6.5. Pre-gestational BMI was 28.3 ± 6.5 kg/m2. Their weight gain was 7 ± 4.3 kg. Lipid profile: total cholesterol 240 ± 54 mg/dl; LDL cholesterol 156 ± 54 mg/dl; HDL cholesterol 66 ± 15 mg/dL; TG 204 ± 80 mg/dl. The mean 25OHD level was 23.8 ± 9 ng/ml, with a 77.9 % prevalence of hypovitaminosis D. Patients with hypovitaminosis D had higher values of total cholesterol and LDL cholesterol (p<0.05), and a non-significant trend toward higher triglyceridemia. Conclusion: A high prevalence of hypovitaminosis D, associated with high total and LDL cholesterol was found in high risk pregnant women. (AU)

On the synthesis of vitamin d in the darkness / Sobre la síntesis de vitamina D en la oscuridad

Published evidence reports the existence of two routes for the transformation of 7-dehydrocholecalciferol into previtamin D3: a photochemical route with the participation of UVB photons and another route that occurs in the darkness. Several reports appears to support the presence of these two routes in some mammals, birds, nonvascular plants (e.g.: mosses), vascular plants (e.g.: angiosperms) and lichens. The reviewed evidence suggests that in the darkness, the synthesis of vitamin D3 follows the same scheme of the photochemical pathway, but at a reduced rate respect to the synthesis under UVB radiation. The process of vitamin D synthesis in the dark, then, may be taken as an insurance for survival, at least for mammals and birds. The low rate of the synthesis of vitamin D3 in the absence of light produce low concentrations of vitamin D3 metabolites in plasma. Long term survival under these circumstances might be possible through upregulation of vitamin D receptors (VDRs). In mole rats (South African rodents that live in the dark in underground tunnels), the reduced rate of vitamin D3 synthesis produce low levels of plasma vitamin D3 and their metabolites 25(OH) D3 and 1α,25OH2 D3 . The fact that Kd and ßmax of the complex 1α,25(OH)2 D3 -VDR from the intestinal mucosa, kidneys and the Harderian glands of the mole rat Heterocephalus glaber are significantly different in each one of these tissues, is interpreted as an indicator that the VDRs are, in each tissue, adapted to the maintenance of normal physiological functions. (AU)

Varios trabajos publicados han informado que existen dos mecanismos para la transformación de 7-dehidrocolecalciferol en previtamina D3 : uno iniciado con el auxilio de fotones UVB y un segundo que ocurre en la oscuridad, sin el auxilio de radiación ultravioleta. Una serie de publicaciones contienen información que apoya la presencia de estos dos mecanismos en mamíferos, pájaros, plantas no vasculares (musgos), vasculares (angiospermas) y líquenes. La evidencia revisada sugiere que, en la oscuridad, la síntesis de vitamina D3 sigue el mismo esquema que la ruta fotoquímica y generalmente ocurre a una tasa reducida respecto de la síntesis bajo irradiación ultravioleta. La operación de la síntesis de vitamina D3 en la oscuridad, por lo menos para mamíferos y pájaros, puede tomarse como un reaseguro de sobrevida. La reducida tasa de síntesis de vitamina D en ausencia de luz produce bajas concentraciones en plasma de los metabolitos de la vitamina. La sobrevida saludable en estas condiciones sería posible mediante upregulation de los receptores. En las ratas topo Heterocephalus glaber (roedores sudafricanos que viven en permanente oscuridad, en túneles subterráneos), la reducida tasa de síntesis de vitamina D3 es la causa de los bajos niveles plasmáticos de la vitamina y sus metabolitos: 25(OH)D3 y 1α,25OH2 D3 . El hecho de que el Kd y ßmax del complejo 1α,25(OH)2 D3 -Vitamina-D-Receptor del intestino, riñón y glándulas de Harder de Heterocephalus glaber sean significativamente diferentes entre sí indicaría que los receptores se han modificado para mantener funciones fisiológicas normales en cada tejido. (AU)

Association between physical activity and vitamin D: A narrative literature review / Associação entre atividade física e vitamina D: revisão narrativa da literatura

Summary This narrative review of the medical literature assessed whether outdoor and indoor physical activity would increase the plasma levels of vitamin D. Synthesis of this liposoluble vitamin is mainly mediated by sunlight on the skin, where it is activated to perform its main action, which is to control the serum levels of calcium as soon as the element is absorbed in the intestines, assisting in the regulation of bone metabolism. Physical activity is any body movement that results in energy expenditure, while outdoor physical activity refers to physical activity carried out at public parks or other open spaces, as is the case of the popular practice of taking walks. Exercising outdoors would have both the benefits of physical activity and of sun exposure, namely the synthesis of vitamin D. However, according to the studies analyzed, increased plasma concentration of vitamin D occurs with physical activity both indoors and outdoors.

Resumo Esta revisão narrativa da literatura avaliou se tanto a atividade física realizada ao ar livre quanto aquela em ambiente interno aumentariam os níveis plasmáticos da vitamina D. A síntese dessa vitamina lipossolúvel ocorre, principalmente, por meio da radiação solar na pele, que, após sofrer processo de ativação no organismo, estabelece sua principal ação no controle dos níveis séricos do cálcio, assim que é absorvido no trato intestinal, auxiliando na regulação do metabolismo ósseo. Atividade física é qualquer movimento corporal que resulte em gasto energético, enquanto atividade física ao ar livre é aquela realizada em parques ou praças, cuja prática mais popular é a caminhada. Esse ambiente externo teria os benefícios propriamente ditos da atividade física, além da exposição solar com a síntese da vitamina D. Entretanto, segundo os estudos apresentados, há elevação da concentração plasmática da vitamina D na realização de atividade física tanto em ambiente interno quanto ao ar livre.

Women with recurrent spontaneous abortion have decreased 25(OH) vitamin D and VDR at the fetal-maternal interface

Immunological mechanisms have been proposed to underlie the pathogenesis of recurrent spontaneous abortion (RSA). Vitamin D has a potent immunomodulatory effect, which may affect pregnancy outcome. The objective of this study was to investigate 25-hydroxyvitamin D [25(OH) D] concentration and vitamin D receptor (VDR) expression in the decidual tissues of RSA patients. Thirty women with RSA (RSA group) and thirty women undergoing elective abortion (control group) were recruited during 2016 from gynecology outpatient clinics. We measured 25(OH) D, interleukin (IL)-17, IL-23, transforming growth factor β (TGF-β), VDR and 1-α-hydroxylase (CYP27B1) in decidual tissues collected during the abortion procedure. In the RSA group, 25(OH) D and TGF-β were significantly decreased while IL-17 and IL-23 were significantly increased compared with the control group. VDR expression was significantly decreased in the RSA group compared with the control group. Logistic regression analysis showed a significant negative correlation between 25(OH) D in decidual tissues and RSA. These results indicated that vitamin D concentrations in the decidua are associated with inflammatory cytokine production, suggesting that vitamin D and VDR may play a role in the etiology of RSA.

Metabolismo de la Vitamina D: rol en la génesis de enfermedades / Vitamin D metabolism: role in the genesis of diseases

La vitamina D clásicamente ha sido relacionada con el metabolismo óseo, sin embargo ejerce diversas funciones en varios tejidos del organismo que poseen el receptor para vitamina D (VCR) yson susceptibles a su efecto. La disminución de vitamina D también se ha asociado a patologías "no clásicas"como hipertensión, síndrome metabólico, resistencia a insulina, diabetes, desarrollo de algunos canceres,alteraciones pulmonares, autoinmunidad e infertilidad, entre otras. También se ha asociado la deficiencia materna de vitamina D en la génesis de patologías postnatales. Además, muchas de estas patologías se producirían por alteraciones moleculares, principalmente relacionadas con su metabolismo y con polimorfismos del receptor VCR. La vitamina D se considerara una hormona, puede ser sintetizada en la piel a partir 7-dehidrocolesterol mediante radiación ultravioleta B. Su metabolismo es complejo e implica la interacción de diversos factores en su incorporación y formación final de calcitriol, su forma activa. Para ejercer su efecto requiere de la activación del receptor VDR en la célula blanco, el cual a su vez activa secuencias de genes específicos con funciones diversas, a través de secuencias promotoras del ADN denominadas elementos de respuesta de vitamina D (VDRE). Muchos tejidos presentan el receptor VDR y enzimas necesarias para su metabolismo, por lo cual el espectro de acción de la vitamina D es muy amplio, así como la variedad de patologías que produce. Esta revisión de vitamina D, está centrada principalmente en los aspectos moleculares de su metabolismo y su rol en la génesis de enfermedades "no clásicas", producto de su disminución o alteración de su metabolismo.

Vitamin D has traditionally been associated with bone metabolism, however it exerts different functions in various tissues of the body that possess the vitamin D (VCR) receptor and they are susceptible to its effect. Decreased vitamin D has also been associated with "nonclassical" diseases such as hypertension, metabolic syndrome, insulin resistance, diabetes, development of some cancers, lung disorders,autoimmunity and infertility, among others. Maternal vitamin D deficiency has been associated in the genesis of postnatal diseases. Further, many of these pathologies are produced by molecular alterations, mainly related to metabolism and receptor polymorphisms VCR. Vitamin D is considered a hormone, can be synthesized in the skin from 7-dehydrocholesterol by ultraviolet radiation B. The metabolism is complex and involves the interaction of several factors in its incorporation and final formation of calcitriol, the active form. To produce its effect requires activation of VDR receptor on the target cell, which activates specific gene sequences with different functions, through DNA promoter sequences in identified vitamin D response elements (VDRE).Many tissues have the VDR receptor and enzymes necessary for metabolism, so the spectrum of vitamin Daction is very broad in the variety of pathologies produced. This review of vitamin D focuses primarily on the molecular aspects of its metabolism and its role in the genesis of "nonclassical", diseases, product of its reduction or alteration of metabolic diseases.

Valores de vitamina D en fracturas no consolidadas / Vitamin D levels in non-union fractures

Introducción: La falta de consolidacion de una fractura es, en general, un fenomeno multifactorial. El objetivo de este estudio fue estimar los valores de referencia de vitamina D (25OHD3) en fracturas que no consolidaron, estudiar su asociacion con la edad y su localizacion. Materiales y Métodos: Estudio prospectivo, de observacion y descriptivo en 29 pacientes con fracturas no consolidadas. Se determinaron las concentraciones sericas de vitamina D (25OHD3) junto con los estudios prequirurgicos. Se calcularon modelos generalizados para estimar los efectos de la edad y la localizacion, y detectar grupos de pacientes con niveles inferiores al valor recomendado. Resultados: El 68,9% de los pacientes tenia concentraciones sericas promedio de vitamina D inferiores al valor normal (30,0 ng/ml), que se asociaron inversamente con la edad, 40 anos fue el punto de corte a partir del cual otras caracteristicas, como la localizacion de la fractura (en huesos que afectan a los miembros inferiores), condicionan conjuntamente la falta de consolidacion. Conclusiones: La mayoria de los pacientes cuya fractura no consolido tenia deficiencia de vitamina D y este fenomeno es marcado a partir de los 40 anos de edad. Es importante identificar a los pacientes con mayor riesgo de presentar este deficit en las primeras etapas del tratamiento de las fracturas, ya que el aporte de este micronutriente es un factor reconocido para disminuir el riesgo de falta de consolidacion. Nivel de Evidencia: IV

Introduction: Absence of bone union after a fracture is generally multifactorial phenomenon. The objective of this study was to determine reference vitamin D values (25OHD3) in non-unions, and to study their association with age and localization. Methods: A prospective, observational and descriptive study was performed to evaluate 29 patients with non-union fractures. Serum vitamin D levels (25OHD3) were determined together with standard preoperative studies. Generalized models were used to estimate the effects of age and location, as well as to detect the group of patients with vitamin D levels lower than recommended. Results: The 68.9% had serum levels of vitamin-D lower than the normal value (30 ng/mL), which was inversely associated with age, being the age of 40 the cutoff point from which other characteristics, such as location, conditioned simultaneously the non-union. Conclusions: Most patients with a non-union fracture had vitamin D deficiency, and this phenomenon was more evident in patients >40 years. Prompt identification of patients with increased risk of presenting this deficiency is important, as treatment could reduce the incidence of fractures that evolve into a non-union. Level of Evidence: IV

Vitamina D: ¿qué es lo que debe saber un traumatólogo? / Vitamin D: what should an orthopaedist know?

La única patología asociada al déficit de vitamina D fue durante el siglo XX el raquitismo. Nuevas consecuencias asociadas a esta deficiencia han surgido destacando la osteomalacia, mayor riesgo de fracturas, mayor incidencia de caídas en los adultos mayores y una peor coordinación neuromuscular. El propósito de la presente revisión es proporcionar una actualización dirigida a especialistas en ortopedia y traumatología, respecto a definiciones, beneficios, patologías relevantes y guías de manejo que el especialista debe conocer respecto a este problema.

The only condition related to vitamin D deficiency during the 20th century was rickets. New conditions associated with this deficiency have been increasingly reported including: osteomalacia, increased fracture risk, greater incidence of falls among the elderly population, and a worse neuromuscular coordination. The main purpose of this review is to present an update regarding the useful aspects for the orthopaedic community related to vitamin D deficiency, including definitions, benefits, significant diseases, and management guidelines that the specialist must know.

The role of daily physical activity and nutritional status on bone turnover in cystic fibrosis: a cross-sectional study

ABSTRACT Background Nutritional status and daily physical activity (PA) may be an excellent tool for the maintenance of bone health in patients with cystic fibrosis (CF). Objective To evaluate the relationship between nutritional status, daily physical activity and bone turnover in cystic fibrosis patients. Method A cross-sectional study of adolescent and adult patients diagnosed with clinically stable cystic fibrosis was conducted. Total body, femoral neck, and lumbar spine bone mineral density (BMD) were determined by dual energy X-ray absorptiometry and bone metabolism markers ALP, P1NP, PICP, and ß-CrossLaps. PA monitoring was assessed for 5 consecutive days using a portable device. Exercise capacity was also determined. Serum 25-hydroxyvitamin D and vitamin K were also determined in all participants. Results Fifty patients (median age: 24.4 years; range: 16-46) were included. BMI had positive correlation with all BMD parameters, with Spearman’s coefficients ranging from 0.31 to 0.47. Total hip bone mineral density and femoral neck BMD had positive correlation with the daily time spent on moderate PA (>4.8 metabolic equivalent-minutes/day; r=0.74, p<0.001 and r=0.72 p<0.001 respectively), daily time spent on vigorous PA (>7.2 metabolic equivalent-minutes/day; r=0.45 p<0.001), body mass index (r=0.44, p=0.001), and muscle mass in limbs (r=0.41, p=0.004). Levels of carboxy-terminal propeptide of type 1 collagen were positively associated with the daily time spent on moderate (r=0.33 p=0.023) and vigorous PA (r=0.53, p<0.001). Conclusions BMI and the daily time spent on moderate PA were found to be correlated with femoral neck BMD in CF patients. The association between daily PA and biochemical markers of bone formation suggests that the level of daily PA may be linked to bone health in this patient group. Further research is needed to confirm these findings.

Solar ultraviolet radiation: properties, characteristics and amounts observed in Brazil and South America

Abstract The beneficial and harmful effects of human exposure to solar ultraviolet radiation (UV-R) are topics that arouse great interest not only among physicians and scientists, but also the general public and the media. Currently, discussions on vitamin D synthesis (beneficial effect) are confronted with the high and growing number of new cases of non-melanoma skin cancer and other diseases of the skin and eyes (harmful effect) diagnosed each year in Brazil. However, the lack of scientific knowledge on the UV-R in Brazil and South America leads to adoption of protective measures based on studies conducted in Europe and USA, where the amounts of UV-R available at surface and the sun-exposure habits and characteristics of the population are significantly different from those observed in Brazil. In order to circumvent this problem, the Brazilian Society of Dermatology recently published the Brazilian Consensus of Photoprotection based on recent studies performed locally. The main goal of this article is to provide detailed educational information on the main properties and characteristics of UV-R and UV index in a simple language. It also provides: a) a summary of UV-R measurements recently performed in Brazil; b) a comparison with those performed in Europe; and, c) an evaluation to further clarify the assessment of potential harm and health effects owing to chronic exposures.

No association between 25-hydroxyvitamin D levels and prediabetes in Brazilian patients. A cross-sectional study / Ausência de associação entre níveis de 25-hidroxivitamina D e pré-diabetes em pacientes brasileiros. Um estudo transversal

CONTEXT AND OBJECTIVE: Several studies have evaluated the role of low 25-hydroxyvitamin D (25OHD3) in the pathogenesis of type 2 diabetes (T2DM) and have presented controversial results. The metabolic processes that culminate in T2DM begin under prediabetic conditions. Our aim was to analyze the association between 25OHD3 and glucose metabolism in individuals who were free from but at elevated risk of diabetes. DESIGN AND SETTING: Cross-sectional study at a tertiary hospital. METHODS: Anthropometric and laboratory profiles were determined in patients with one or more of the following risk factors: hypertension; body mass index (BMI) ≥ 25 kg/m2; waist circumference > 80 cm for women and > 94 cm for men; first-degree relatives with diabetes; women with large-for-gestational-age newborns or with gestational T2DM; HDL-cholesterol (high density lipoprotein) < 35 mg/dl; and triglycerides > 250 mg/dl. The patients were divided into two groups: one with prediabetes (abnormal fasting plasma glucose or oral glucose tolerance test) and the other with normal glucose (euglycemic). RESULTS: There was no statistically significant difference between the prediabetic group (n = 38) and euglycemic group (n = 15) regarding age (66.4 ± 10.6 versus 62.6 ± 9.1 years), gender (52.6 versus 73.3% female) and BMI (30.1 ± 4.61 versus 27.9 ± 4.7 kg/m2). Low serum levels of 25OHD3 were found in both groups, without any statistically significant difference between them (29.1 ± 11.8 versus 26.87 ± 9.2 ng/dl). CONCLUSION: There was no association between 25OHD3 levels and the clinical or laboratorial variables analyzed. .

CONTEXTO E OBJETIVO: Vários estudos já avaliaram o papel da 25-hidroxivitamina D (25OHD3) na patogênese do diabetes tipo 2 (DM2) e apresentaram resultados controversos. Os processos metabólicos que culminam no DM2 se iniciam no pré-diabetes. Nosso objetivo foi analisar a associação da 25OHD3 com o metabolismo glicêmico em indivíduos sem diagnóstico mas com alto risco para diabetes. TIPO DE ESTUDO E LOCAL: Estudo transversal em hospital terciário. MÉTODOS: Medidas antropométricas e laboratoriais foram determinadas em pacientes com um ou mais dos fatores de risco: hipertensão; índice de massa corpórea (IMC) ≥ 25 kg/m2; circunferência abdominal > 80 cm no sexo feminino e > 94 cm no sexo masculino; parentes de primeiro grau com diabetes; mulheres com filho nascido grande para idade gestacional ou com DM2 na gravidez; colesterol HDL (high density lipoprotein) < 35 mg/dl e triglicerídeo > 250 mg/dl. Os pacientes foram divididos em dois grupos: um com pré-diabetes (glicemia de jejum ou teste de tolerância oral à glicose alterados) e outro com glicose normal (euglicêmicos). RESULTADOS: Entre pré-diabéticos (n = 38) e euglicêmicos (n = 15) não houve diferença estatística na idade (66,4 ± 10,6 versus 62,6 ± 9,1 anos), gênero (52,6 versus 73,3% feminino) e IMC (30,1 ± 4,61 versus 27,9 ± 4,7 kg/m2). Baixos niveis séricos de 25OHD3 foram encontrados nos dois grupos, sem diferença estatística entre eles (29,1 ± 11,8 versus 26,87 ± 9,2 ng/dl). CONCLUSÃO: Não houve associação entre os níveis de 25OHD3 e as variáveis clínicas e laboratoriais analisadas. .

Brazilian Consensus on Photoprotection

Brazil is a country of continental dimensions with a large heterogeneity of climates and massive mixing of the population. Almost the entire national territory is located between the Equator and the Tropic of Capricorn, and the Earth axial tilt to the south certainly makes Brazil one of the countries of the world with greater extent of land in proximity to the sun. The Brazilian coastline, where most of its population lives, is more than 8,500 km long. Due to geographic characteristics and cultural trends, Brazilians are among the peoples with the highest annual exposure to the sun. Epidemiological data show a continuing increase in the incidence of non-melanoma and melanoma skin cancers. Photoprotection can be understood as a set of measures aimed at reducing sun exposure and at preventing the development of acute and chronic actinic damage. Due to the peculiarities of Brazilian territory and culture, it would not be advisable to replicate the concepts of photoprotection from other developed countries, places with completely different climates and populations. Thus the Brazilian Society of Dermatology has developed the Brazilian Consensus on Photoprotection, the first official document on photoprotection developed in Brazil for Brazilians, with recommendations on matters involving photoprotection.

Influencia de la vitamina D en la salud humana / Influence of vitamin D in human health / Influência da vitamina D na saúde humana

La vitamina D es una sustancia liposoluble, que tiene dos formas: ergocalciferol (vitamina D2) o colecalciferol (vitamina D3), que se encuentran en algunas plantas y peces, y son sintetizadas en la piel a través de la luz del sol respectivamente. La deficiencia de esta vitamina puede ayudar en la aparición y agravamiento de muchas enfermedades. La deficiencia de vitamina D es común en personas de edad avanzada, sin embargo, puede estar presente en cualquier edad y se asocia con las enfermedades cardiovasculares, las enfermedades autoinmunes, el cáncer y las enfermedades metabólicas. La producción de vitamina D en la piel es modulada por la estación, la latitud, la hora del día, pigmentación de la piel, la edad y el uso de protectores solares. Su forma activa 1,25(OH)2D ejerce diversas funciones en el cuerpo, tales como la salud ósea, la homeostasis, el metabolismo celular, la regulación del sistema inmunológico, cardiovascular y sistema esquelético. En la actualidad, la falta se considera como un problema de salud pública en todo el mundo.

Vitamin D is a liposoluble substance, which has two forms: ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3), found in some plants and fish, or synthesized in the skin through sunlight, respectively. Deficiency of this vitamin may help to the onset and worsening of many diseases. Hypovitaminosis D is prevalent in the elderly, but can be present at any age, and is associated with cardiovascular diseases, autoimmune diseases, cancer and metabolic diseases. The skin vitamin D production is modulated by the season, latitude, time of day, skin pigmentation, age and use of sunscreen. Its active form 1,25(OH)2D exerts several functions in the body such as bone health, homeostasis, cell metabolism, immune system regulation, cardiovascular and skeletal systems. Currently, its lack is seen as a public health problem worldwide.

A vitamina D é uma substância lipossolúvel, que se apresenta de duas formas: ergocalciferol (vitamina D2) ou colecalciferol (vitamina D3), encontrada em plantas e alguns peixes, ou sintetizada na pele através da luz solar, respectivamente. A deficiência desta vitamina pode auxiliar no aparecimento e agravamento de diversas patologias. A hipovitaminose D é prevalente em indivíduos idosos, contudo, pode estar presente em qualquer faixa etária e está relacionada com doenças cardiovasculares, doenças autoimunes, câncer e doenças metabólicas. A produção cutânea de vitamina D é modulada pela estação, latitude, período do dia, pigmentação da pele, idade e uso de filtro solar. Sua forma ativa 1,25(OH)2D exerce diversas funções no organismo, como na saúde óssea, homeostasia, metabolismo celular, regulação do sistema imune, cardiovascular e esquelético. Atualmente, sua deficiência é vista como um problema de saúde pública em todo o mundo.