FGF23 levels as a marker of physical performance and falls in community-dwelling very old individuals

ABSTRACT Objective: The fibroblast growth factor 23 (FGF23) has been related to biological aging, but data in elderly individuals are scant. We determined the profile of serum FGF23 levels in a population of very-old individuals and studied their correlations with parameters of bone metabolism and health markers, as functional performance. Materials and methods: This cross-sectional study was performed on 182 community dwellers aged ≥ 80 years. Serum levels of FGF23, PTH, calcium, albumin, phosphorus, creatinine, bone markers, and bone mineral density data were analyzed. Physical performance was evaluated with the stationary march (Step), Flamingo, and functional reach tests, along with questionnaires to assess falls and fractures in the previous year, energy expenditure (MET), and the Charlson index (CI). Physical activity was evaluated with the International Physical Activity Questionnaire (IPAQ). Results: Most participants (75%) had FGF23 levels between 30-120 RU/mL (range: 6.0-3,170.0 RU/mL). FGF23 levels correlated with estimated glomerular filtration rate (eGFR; r = -0.335; p = 0.001) and PTH (r = 0.318; p < 0.0001). Individuals with FGF23 in the highest tertile had more falls in the previous year (p = 0.032), worse performance in the Flamingo (p = 0.009) and Step (p < 0.001) tests, worse CI (p = 0.009) and a trend toward sedentary lifestyle (p = 0.056). On multiple regression, FGF23 tertiles remained significant, independently of eGFR, for falls in the previous year, performance in the Flamingo and stationary march tests, lean mass index, and IPAQ classification. Conclusion: In a population of very elderly individuals, FGF23 levels were inversely associated with neuromuscular and functional performances. Higher concentrations were related to more falls, lower muscle strength and aerobic capacity, and poorer balance, regardless of renal function, suggesting a potentially deleterious role of high FGF23 concentrations in musculoskeletal health.

Official Position of the Brazilian Association of Bone Assessment and Metabolism (ABRASSO) on the evaluation of body composition by densitometry—part II (clinical aspects): interpretation, reporting, and special situations

Abstract Objective: To present an updated and evidence-based guideline for the use of dual-energy x-ray absorptiometry (DXA) to assess body composition in clinical practice. Materials and methods: This Official Position was developed by the Scientific Committee of the Brazilian Association of Bone Assessment and Metabolism ( Associação Brasileira de Avaliação Óssea e Osteometabolismo , ABRASSO) and experts in the field who were invited to contribute to the preparation of this document. The authors searched current databases for relevant publications in the area of body composition assessment. In this second part of the Official Position, the authors discuss the interpretation and reporting of body composition parameters assessed by DXA and the use of DXA for body composition evaluation in special situations, including evaluation of children, persons with HIV, and animals. Conclusion: This document offers recommendations for the use of DXA in body composition evaluation, including indications, interpretation, and applications, to serve as a guiding tool in clinical practice and research for health care professionals in Brazil.

Lean mass as a determinant of bone mineral density of proximal femur in postmenopausal women

ABSTRACT Objective: To verify which component of body composition (BC) has greater influence on postmenopausal women bone mineral density (BMD). Subjects and methods: Four hundred and thirty women undergoing treatment for osteoporosis and 513 untreated women, except for calcium and vitamin D. Multiple linear regression analysis was performed in order to correlated BMD at lumbar spine (LS), total femur (FT), femoral neck (FN) with body mass (BM), total lean mass (LM) and total fat mass (FM), all determined by DXA. Results: BM significantly correlated with all bone sites in untreated and treated women (r = 0.420 vs 0.277 at LS; r = 0.490 vs 0.418 at FN, r = 0.496 vs 0.414 at FT, respectively). In untreated women, the LM correlated better than FM with all sites, explaining 179% of LS; 32.3% of FN and 30.2% of FT; whereas FM explained 13.2% of LS; 277% of FN, 23.4% of FT In treated women, correlations with BC were less relevant, with the LM explaining 6.7% of BMD at LS; 15.2% of FN, 16% of FT, whereas the FM explained 8.1% of LS; 179% of FN and 176% of FT. Conclusion: LM in untreated women was better predictor of BMD than FM, especialy for distal femur, where it explained more than 30% of the BMD, suggesting that maintaining a healthy muscle mass may contribute to decrease osteoporosis risk. Treatment with anti-osteoporotic drugs seems to mask these relationships. Arch Endocrinol Metab. 2018;62(4):431-7

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 ...

Physical exercise and osteoporosis: effects of different types of exercises on bone and physical function of postmenopausal women / Exercício físico e osteoporose: efeitos de diferentes tipos de exercícios sobre o osso e a função física de mulheres pós-menopausadas

Physical exercise is an important stimulus for osteoporosis prevention and treatment. However, it is not clear yet which modality would be better to stimulate bone metabolism and enhance physical function of postmenopausal women. This review paper aims to summarize and update present knowledge on the effects of different kinds of aquatic and ground physical exercises on bone metabolism and physical function of postmenopausal women. Moderate to intense exercises, performed in a high speed during short intervals of time, in water or on the ground, can be part of a program to prevent and treat postmenopausal osteoporosis. Mechanical vibration has proven to be beneficial for bone microarchitecture, improving bone density and bone strength, as well as increasing physical function. Although impact exercises are recognized as beneficial for the stimulation of bone tissue, other variables such as muscle strength, type of muscle contraction, duration and intensity of exercises are also determinants to induce changes in bone metabolism of postmenopausal women. Not only osteoanabolic exercises should be recommended; activities aimed to develop muscle strength and body balance and improve the proprioception should be encouraged to prevent falls and fractures.

O exercício físico é um estímulo muito importante para o tratamento da osteoporose. Contudo, ainda não está claro qual modalidade seria melhor para estimular o metabolismo ósseo e melhorar a função física de mulheres pós-menopausadas. Este trabalho visa resumir e atualizar os principais achados sobre os efeitos de diferentes tipos de exercícios aquáticos e de solo para a função física e metabolismo ósseo de mulheres pós-menopausadas. Exercícios moderados a intensos, executados em alta velocidade durante intervalos de tempo curtos, na água ou em solo, podem fazer parte de um programa para prevenir e tratar a osteoporose na pós-menopausa. A vibração mecânica se mostrou benéfica para a microarquitetura óssea, aumentando a densidade e a resistência ósseas, bem como melhorando a função física. Apesar de os exercícios de impacto serem  adequados para a estimulação do tecido ósseo, outras variáveis, como força muscular, tipo de contração, duração e intensidade dos exercícios, também são determinantes para induzir mudanças no metabolismo ósseo de mulheres pós-menopausadas. Além da ação sobre o osso, outras atividades que visem aumentar a força muscular e melhorar a propriocepção e o equilíbrio corporal também devem ser encorajadas para a prevenção de quedas e fraturas.