RESUMO
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.
RESUMO
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.