Sonsoles Guadalix

Prevalencia de concentraciones deficientes e insuficientes de vitamina D en una población joven y sana

BACKGROUND AND OBJECTIVES: Recent studies have shown a high frequency of insufficient serum vitamin D levels in the general population, especially in the elderly and in individuals with osteoporosis. Data from the young adult population are scarce, but also reveal a high prevalence of vitamin D insufficiency and deficiency in this age group. The main reasons for this high prevalence seem to be poor dietary vitamin D intake and low sun exposure. The aim of the present study was to determine the prevalence of vitamin D insufficiency and deficiency in a young healthy population and its association with concentrations of calcium and parathyroid hormone and sun exposure. METHODS: We performed an observational, descriptive study in 116 subjects (38 men and 78 women aged 26.56 +/- 3.32 years), during the late spring and early summer of 2007. Fasting blood samples were obtained and levels of 25-hydroxivitamin D, intact parathyroid hormone, calcium, albumin and creatinine were measured. A questionnaire designed to assess sun exposure and sunshine protection during the previous 12 months was administered. RESULTS: The mean value of 25-hydroxivitamin D obtained was 24.58 +/- 6.98 ng/ml. The subjects were divided into three groups according to 25-hydroxivitamin D levels: deficient: or = 30 ng/ml (16.37%). No statistically significant differences were found between the groups or the studied variables except for age in relation to vitamin D levels. CONCLUSIONS: Our study shows a high prevalence of vitamin D insufficiency in a young healthy population with no clear relationship with sun exposure or sunscreen protection. The low intake of food rich in vitamin D and the lack of food fortification combined with scarce effective sun exposure could account for the low serum levels of vitamin D in this population.

Pituitary Stalk Lesions: The Mayo Clinic Experience

CONTEXT Pituitary stalk lesions have various etiologies, often not clinically apparent. Pathological samples from these lesions are rarely obtained, because of the critical location and function of the hypophyseal stalk. OBJECTIVES The purpose of this study was to characterize the etiological spectrum of pituitary stalk lesions seen at Mayo Clinic Rochester over 20 years and to determine whether specific magnetic resonance imaging (MRI) characteristics could provide clinician guidance with regard to the etiology of infundibular lesions. DESIGN A retrospective review of patients with pituitary stalk lesions seen at Mayo Clinic Rochester between 1987 and 2006 was conducted. Demographic, clinical presentation, imaging, laboratory, operative, and pathology data were reviewed and are reported using descriptive statistics. RESULTS Of the 152 pituitary stalk lesions included, 49 (32%) were neoplastic, 30 (20%) were inflammatory, 13 (9%) were congenital anomalies, and 60 (39%) were of unclear etiology. Diabetes insipidus was diagnosed in 43 (28%) of the 152 patients, and 49 (32%) patients had at least one anterior pituitary hormone deficit. Secondary hypogonadism was the most common endocrine deficiency. Eleven of 13 congenital lesions were round in appearance and 5 of 7 patients with neurosarcoidosis confirmed by pathology had a uniformly thickened pituitary stalk on MRI. There were no statistically significant correlations between hypopituitarism and the pattern of enhancement or size of the lesion. CONCLUSIONS Findings on MRI remain key in guiding the diagnosis of pituitary stalk lesions, particularly when used in conjunction with other clinical clues. There are no good imaging predictors for hypopituitarism, making clinical evaluation of all patients with pituitary stalk lesions crucial.

Effect of early risedronate treatment on bone mineral density and bone turnover markers after liver transplantation: a prospective single-center study

The aim of this study was to investigate the effect of risedronate (RIS) on bone loss and bone turnover markers after liver transplantation (LT). Patients with osteopenia or osteoporosis within the first month after LT were randomized to receive RIS 35 mg/week plus calcium 1000 mg/day and vitamin D3 800 IU/day (n = 45) or calcium and vitamin D3 at same dosages (n = 44). Primary endpoint was change in bone mineral density (BMD) 6 and 12 months after LT. Secondary endpoints included changes in serum β‐CrossLaps (β‐CTX) and procollagen type 1 amino‐terminal peptide (P1NP) and fracture rate. Spine X‐rays were obtained at baseline and after 12 months. There was no significant difference in BMD changes between both treatment groups at any sites; either at 6 or 12 months. Spine BMD increased in both groups at 12 months vs. baseline (P = 0.001). RIS patients had a significant increase in intertrochanteric BMD at 12 months (P < 0.05 vs. baseline). Serum β‐CTX decreased in both groups (P < 0.01), with significant differences between groups at 3 months. No significant difference in vertebral fracture incidence was found. After 12 months, BMD improved at lumbar spine and did not change at hip in both groups. Significant differences between both groups were not found. Other factors (calcium and vitamin D replacement, early prednisone withdrawal) seem to have also positive effects in BMD.

Bone loss after heart transplant: effect of alendronate, etidronate, calcitonin, and calcium plus vitamin D3

Objective To compare the effects of calcitonin, etidronate, and alendronate in preventing bone loss during the first 2 years after heart transplant. Methods A total of 222 heart transplant recipients (mean [SD] age, 52.4 [10] years, 85% male) were evaluated. Patients with normal bone mineral density (reference group, n = 102) received 1000 mg/d calcium plus 800 IU/d vitamin D3. The rest were assigned to 200 IU/d of calcitonin (n = 42), 400 mg/d etidronate orally for 14 days quarterly (n = 33), or 10 mg/d alendronate (n = 45). All patients received calcium and vitamin D. Bone mineral density was assessed by dual-energy x-ray absorptiometry in the lumbar spine, the entire femur, and the femoral neck at baseline and 6, 12, and 24 months after transplant. Results At 2 years after transplant, bone mineral density in the lumbar spine had decreased in the reference group (−3.07%), calcitonin group (−0.93%), and etidronate group (−1.87%) but not in the alendronate group (+4.9%; P < .001). After 2 years, bone mineral density in the entire femur decreased in all groups (−3.2% in the reference group, −3.6% in the calcitonin group, −4.6% in the etidronate group, and −0.5% in the alendronate group) but bone loss was significantly lower in the alendronate group (P < .001). Bone mineral density in the femoral neck also decreased in all groups. The incidence of vertebral fractures did not differ among groups. Adverse events were similar between groups. Conclusions Alendronate therapy in heart transplant recipients was associated with a significant increase in bone mineral density in the lumbar spine and less bone loss at the hip.

Post-Transplantation Bone Disease

Solid organ or stem cell transplantation is a well established procedure in the treatment of endstage diseases (renal disease, chronic liver failure, end-stage pulmonary disease, heart failure). Improved outcome for these patients has allowed us to study some of the complications. One of these is metabolic bone disease, which can hinder their long-term survival and quality of life. In this chapter we have review our current understanding of the pathophysiology of bone loss before and after solid organ transplantation, and review recommendations for the prevention and treatment of osteoporosis in patients accepted into organ transplantation programs. There are a number of risk factors contributing to bone loss in these patients: hypogonadism, vitamin D deficiency, malabsorption, low body weight, physical inactivity, excessive use of tobacco or alcohol and immunosuppressive therapy. Management of pretransplant risk factors has improved, resulting in better bone mineral density (BMD) levels before transplantation (Guichelaar et al., 2006). After transplantation, rapid and marked bone loss is observed in the first 3-6 months. The speed of the bone loss suggests that corticosteroids are heavily involved. Greater bone loss at vertebral and hip sites and high rates of incident fragility fractures have been reported (Leidig-Bruckner et al., 2001).

Serum Levels of Osteocalcin and Insulin Resistance in Patients with Impaired Glucose Tolerance or New-Onset Diabetes Mellitus After Liver Transplantation.

Liver transplantation (LT) patients are at high risk of developing new-onset diabetes after transplantation (NODAT). Osteocalcin has been proposed as a mediator between bone tissue and glucose metabolism, but its role in the pathogenesis of diabetes is not defined yet. Our objective was to assess the relationship between serum osteocalcin and glucose metabolism parameters in liver transplantation recipients. A total of 187 liver transplantation patients were cross-sectionally studied, 54 of them developed NODAT. None had been diagnosed of diabetes mellitus prior to transplant. In 133 nondiabetic patients, a 75 g oral glucose tolerance test (OGTT) was performed to assess blood glucose, insulin, and C-peptide levels at baseline and 120 min. Serum total osteocalcin was measured at baseline in all patients.After OGTT, 10.5% of LT patients had NODAT criteria, 51.9% showed impaired glucose tolerance, and 37.6% had normal glucose tolerance. Overall, NODAT prevalence was 36.3%. HOMA-IR was significantly higher in NODAT compared with impaired glucose tolerance and normal glucose tolerance groups (p<0.001). Osteocalcin was inversely correlated to HOMA-IR (r=- 0.16, p=0.05), BMI (r=- 0.27, p=0.000) and waist circumference (r=- 0.21, p=0.005). Patients in the lowest osteocalcin tertile (< 16.5 ng/ml) had significantly higher fasting plasma glucose and HOMA-IR index (p=0.029 and 0.037, respectively) than those in medium or highest tertiles. In multiple linear regression analysis, osteocalcin was negatively associated with fasting plasma glucose (standardized β coefficient-0.16; p=0.041) and 2-h insulin (standardized β coefficient-0.21; p=0.028). Prevalence of NODAT/impaired glucose tolerance is high in liver transplantation patients and is associated with insulin resistance. In these patients total osteocalcin is inversely associated with plasma glucose level and insulin resistance indexes.

Protocolo diagnóstico de la osteoporosis

Resumen La osteoporosis es una enfermedad de patogenia compleja y multifactorial, y en muchos casos la perdida osea y el aumento de fracturas estan asociados a la edad avanzada. Pueden contribuir factores geneticos para la adquisicion del pico de masa osea, alteraciones del desarrollo y del esqueleto, asi como deficiencias en esteroides sexuales en la menopausia. Sobre estos factores pueden anadirse causas secundarias de perdida osea como el uso de corticoides u otras enfermedades que afectan al metabolismo oseo. El factor mas importante de esta enfermedad radica en la disminucion de la fuerza osea y el aumento de fracturas, que se asocian a un aumento significativo de la morbilidad y mortalidad, ademas de un gasto sanitario considerable. En los ultimos anos, se han hecho avances en su concepto, diagnostico y tratamiento, paralelo a la mejor nutricion y estilo de vida. Sin embargo, muchos pacientes no son diagnosticados ni tratados, probablemente porque antes de la fractura, la enfermedad puede ser asintomatica. Debido a que la masa osea es el principal determinante de la fuerza osea, su medicion se considera un objetivo primordial con la tecnica DXA de eleccion. En el ano 2008 la OMS introdujo la herramienta FRAX basada en la combinacion de los factores de riesgo con/sin DXA de cadera. Esta herramienta permite conocer la probabilidad de fracturas a nivel de cadera, vertebras, humero y antebrazo, en 10 anos, en la toma de decision de tratamiento antirresortivo para su prevencion.

Trabecular bone score in patients with liver transplants after 1 year of risedronate treatment.

The aim of this study was to analyse the effect of risedronate on Trabecular Bone Score in liver transplant patients with low bone mass, during 1‐year follow‐up. In this retrospective cohort study, trabecular bone score (TBS) was calculated from dual X‐ray absorptiometry images of the lumbar spine (LS), collected from a prospective randomized open‐label 1‐year trial performed in liver recipient patients. A total of 89 patients with osteopenia or osteoporosis were randomized to receive RIS plus calcium and vitamin D3 or calcium and vitamin D3. TBS was low in both groups at baseline, 6 and 12 months. Baseline TBS at the LS showed degraded microarchitecture in 22.8% of patients, partially degraded in 40.3%, and normal values in 36.8% of the patients. After 1 year of treatment, no difference in TBS was observed between both groups. No correlations were found between bone mineral density (BMD) and TBS values at any follow‐up time point. No relationship was found between BMD, TBS or immunosuppressive drugs with incidental fracture. No significant effect in TBS was observed in liver transplant patients treated with RIS or calcium and vitamin D3 after 1 year of follow‐up. In these patients, the clinical usefulness of this new tool should be established.

Bone mass, vitamin D levels and immunosuppressive treatment in patients with liver transplant and risedronate treatment

As bone matures type I collagen undegoes β isomerisation at the DG motif of the CTX epitope. Measurements of αCTX and βCTX allow us to distinguish between bone turnover in newly formed and mature bone, respectively. In states of pathologically high bone turnover such as Pagets and malignant bone diseases, there is a relatively greater increase in the resorption of newly formed bone. Treatment of these with bisphosphonates results in a relatively greater decrease in the resorption of newly formed bone. The aims were to investigate 1) the relative increase in αCTX in postmenopausal osteoporosis and 2) the relative decrease in αCTX with bisphosphonate treatment. We recruited 60 postmenopausal women (mean age 68: range 55-85) with a BMD T-score of <2.5 or <1 and a fracture. They were randomised into 3 treatment groups: ibandronate (n=19), alendronate (n=23) and risedronate (n=18). 75 healthy premenopausal women (mean age 38: range 30-45) were recruited. We measured α and βCTX (Nordic Biosciences Diagnostics, Copenhagen, Denmark) in second morning void urine samples and serum βCTX (Roche Diagnostics, Pensberg, Germany). The median urinary α and βCTX and serum βCTX were significantly lower in healthy premenopausal compared to postmenopausal osteoporotic women at baseline 62%, 110% and 65% respectively (P<0.0001). The median urinary α and βCTX and serum βCTX showed a significant decrease by 68%, 88%, and 79% from baseline respectively (P<0.0001) after 13 weeks of treatment. The α/β CTX ratio increased by 62% (P<0.05). We conclude that resorption of type I collagen in postmenopausal osteoporosis is greater compared to healthy premenopausal women. There is no relative greater increase in the resorption of newly formed bone. With bisphosphonate treatment, the resorption of type I collagen is decreased after 13 weeks of treatment, but there is no greater decrease in the relative resorption of newly formed bone. In fact, there is a preferential decrease in the resorption of mature bone.