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

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.