Update on trabecular bone score

ABSTRACT Trabecular bone score (TBS) is an indirect and noninvasive measure of bone quality. A low TBS indicates degraded bone microarchitecture, predicts osteoporotic fracture, and is partially independent of clinical risk factors and bone mineral density (BMD). There is substantial evidence supporting the use of TBS to assess vertebral, hip, and major osteoporotic fracture risk in postmenopausal women, as well as to assess hip and major osteoporotic fracture risk in men aged > 50 years. TBS complements BMD information and can be used to adjust the FRAX (Fracture Risk Assessment) score to improve risk stratification. While TBS should not be used to monitor antiresorptive therapy, it may be potentially useful for monitoring anabolic therapy. There is also a growing body of evidence indicating that TBS is particularly useful as an adjunct to BMD for fracture risk assessment in conditions associated with increased fracture risk, such as type-2 diabetes, chronic corticosteroid excess, and other conditions wherein BMD readings are often misleading. The interference of abdominal soft tissue thickness (STT) on TBS should also be considered when interpreting these findings because image noise can impact TBS evaluation. A new TBS software version based on an algorithm that accounts for STT rather than BMI seems to correct this technical limitation and is under development. In this paper, we review the current state of TBS, its technical aspects, and its evolving role in the assessment and management of several clinical conditions.

Digital vertebral morphometry performed by DXA: a valuable opportunity for identifying fractures during bone mass assessment

Objectives To evaluate the usefulness of vertebral morphometry in identifying unreferred vertebral fractures and correlate potential risk factors. Subjects and methods Female patients above 45 years, postmenopausal for at least 2 years, diagnosed with osteoporosis and undergoing treatment for at least three months were considered eligible. All of them underwent bone densitometry and vertebral morphometry performed by concomitant DXA. The presence of fractures was defined between T7 and L4; only moderate and severe fractures were considered for analysis. All volunteers were submitted to laboratory tests, anthropometry and responded a questionnaire on their lifestyle habits and medical history. Results Thirty two (17%) out of the 188 female patients presented with at least one vertebral fracture, among whom only 4 (12.5%) were previously aware of the fracture. The fractures were mainly located on the thoracic spine. Nine patients had severe fractures (28.1%), whereas 23 had moderate fractures (71.9%). On average, patients with fractures were 5 years older and weighed 5 kilograms less than those without fractures. The creatinine clearance was on average 9 mL/min less in patients with vertebral fracture. The assessment of vertebral fractures by morphometry is a fast, accurate and complementary method associated with low radiation exposure for identifying moderate and severe vertebral fractures. Predisposition to vertebral fractures does not depend solely on BMD. .

Modifiable factors of vitamin D status among a Brazilian osteoporotic population attended a public outpatient clinic / Fatores modificáveis do status de vitamina D em uma população brasileira de osteoporóticos assistidos em um ambulatório público

Objectives To evaluate the serum 25-hydroxyvitamin D [25(OH)D] concentration in Brazilian osteoporotic patients and the modifiable factors of vitamin D status in this population. Subjects and methods In a cross-sectional study, 363 community-dwelling patients who sought specialized medical care were evaluated between autumn and spring in São Paulo, Brazil. Serum levels of 25(OH)D and parathormone (PTH), biochemical and anthropometric measurements, and bone density scans were obtained. The group was assessed using two questionnaires: one questionnaire covered lifestyle and dietary habits, skin phototype, sun exposure, medical conditions, and levels of vitamin D supplementation (cholecalciferol); the other questionnaire assessed health-related quality-of-life. Logistic regression and a decision tree were used to assess the association between the variables and the adequacy of vitamin D status. Results The mean age of the overall sample was 67.9 ± 8.6 years, and the mean 25(OH)D concentration was 24.8 ng/mL. The prevalence of inadequate vitamin D status was high (73.3%), although 81.5% of the subjects were receiving cholecalciferol (mean dose of 8,169 IU/week). 25(OH)D was positively correlated with femoral neck bone mineral density and negatively correlated with PTH. In the multivariate analysis, the dose of cholecalciferol, engagement in physical activity and the month of the year (September) were associated with improvement in vitamin D status. Conclusions In this osteoporotic population, vitamin D supplementation of 7,000 IU/week is not enough to reach the desired 25(OH)D concentration (≥ 30 ng/mL). Engagement in physical activity and the month of the year are modifiable factors of the vitamin D status in this population. .

Objetivos Avaliar a concentração sérica de 25-hidroxivitamina D [25(OH)D] em pacientes osteoporóticos brasileiros e os fatores modificáveis do status de vitamina D nesta população. Sujeitos e métodos Em um estudo transversal, 363 pacientes, residentes na comunidade, que procuravam atendimento médico especializado, foram avaliados entre o outono e a primavera, em São Paulo, Brasil. Níveis séricos de 25(OH)D e paratormônio (PTH), avaliações bioquímicas e antropométricas e exames de densitometria óssea foram obtidos. O grupo foi avaliado por meio de dois questionários: um questionário abordou estilo de vida e hábitos alimentares, fototipo de pele, exposição solar, problemas médicos e os níveis de suplementação de vitamina D (colecalciferol); o outro questionário avaliou a qualidade de vida relacionada à saúde. Regressão logística e árvore de decisão foram utilizadas para avaliar a associação entre as variáveis e a adequação do status de vitamina D. Resultados A idade média da amostra foi de 67,9 ± 8,6 anos e a concentração média de 25(OH)D foi de 24,8 ng/mL. A prevalência de um status de vitamina D inadequado foi elevada (73,3%), apesar de 81,5% dos indivíduos receberem colecalciferol (dose média de 8.169 UI/semana). 25(OH)D correlacionou-se positivamente com a densidade mineral óssea do colo de fêmur e negativamente com PTH. Nas análises multivariadas, a dose de colecalciferol, a prática de exercícios físicos e o mês do ano (setembro) foram associados com a melhora do status de vitamina D. Conclusões Nesta população osteoporótica, a suplementação de 7.000 UI/semana não é suficiente para atingir a concentração desejada ...

Evidence-based non-skeletal actions of vitamin D / Evidências das ações não esqueléticas da vitamina D

Vitamin D is a major regulator of mineral homeostasis through its action in the kidney, intestine, bone and parathyroid glands. On these tissues, its active form, calcitriol, acts by binding to a specific nuclear receptor that belongs to the steroid/thyroid hormone receptor family. This receptor, however, has also been identified in several additional human tissues. So, apart from its traditional actions related to calcium, vitamin D and its synthetic analogs are being increasingly recognized for their anti-proliferative, pro-differentiative and immunomodulatory activities. Low levels of vitamin D have been linked to many chronic diseases. Decreased muscle function and increased fall risk in elderly people; prostate, breast and colorectal cancers; diabetes mellitus; and other health problems have been associated to low circulating levels of 25-hydroxyvitamin D. This paper presents an overview of the available scientific evidence for the non-calcemic actions of vitamin D in humans.

A vitamina D é um importante regulador da homeostase mineral por meio de sua ação nos rins, no intestino, nos ossos e nas glândulas paratireoides. Nesses tecidos, sua forma ativa, o calcitriol, atua ligando-se a um receptor nuclear específico, pertencente à família de receptores dos hormônios esteroides e tireoidianos. Contudo, esse receptor também foi identificado em outros tecidos humanos. Assim, além de suas ações tradicionais, relacionadas ao metabolismo do cálcio, a vitamina D e análogos sintéticos estão, cada vez mais, sendo reconhecidos por seus efeitos antiproliferativos, pró-diferenciação e imunomodulatórios. Baixas concentrações séricas de vitamina D têm sido associadas a várias doenças crônicas. Redução da função muscular e aumento do risco de quedas em idosos; câncer de próstata, mama e colorretal; diabetes melito; e outros problemas de saúde têm sido associados a concentrações circulantes baixas de 25-hidroxivitamina D. Este trabalho apresenta uma visão geral sobre as evidências científicas disponíveis das ações não calcêmicas da vitamina D em humanos.