Sambrook P, Kelly P, Eisman J
Garvan Institute of Medical Research, St. Vincent's Hospital, Darlinghurst, Australia.
Baillieres Clin Rheumatol. 1993 Oct;7(3):445-57. doi: 10.1016/s0950-3579(05)80072-x.
Bone can be divided into two kinds of tissue, cortical and trabecular bone. The skeleton comprises approximately 80% cortical bone, mainly in peripheral bones, and 20% trabecular bone, mainly in the axial skeleton. Bone density increases with skeletal growth to a peak in late adolescence or early adulthood. Bone loss subsequently occurs with ageing in both sexes, and in females accelerated loss occurs at the menopause. The risk of osteoporotic fracture in later life is the result of peak bone mass achieved at skeletal maturity and subsequent age-related and postmenopausal bone loss. Peak bone mass is largely genetically determined but is also influenced by environmental factors such as dietary calcium and physical activity. Bone loss with ageing occurs at different rates and different times in different skeletal sites. Femoral neck bone loss probably occurs in a linear fashion throughout life from early adulthood but may be accelerated at the menopause. Spinal bone loss may commence before the menopause but is rapidly increased in the immediate postmenopausal years. Bone strength is directly related to bone density, but the loading force is also relevant to risk of fracture.
骨可分为两种组织，即皮质骨和小梁骨。骨骼约80%为皮质骨，主要分布在四肢骨；20%为小梁骨，主要分布在中轴骨。骨密度随骨骼生长而增加，在青春期后期或成年早期达到峰值。随后，随着年龄增长，两性都会出现骨质流失，而女性在绝经后骨质流失加速。晚年骨质疏松性骨折的风险是骨骼成熟时达到的峰值骨量以及随后与年龄相关和绝经后骨质流失的结果。峰值骨量很大程度上由基因决定，但也受饮食钙和体育活动等环境因素影响。随着年龄增长，不同骨骼部位的骨质流失速率和时间各不相同。股骨颈骨质流失可能从成年早期开始就以线性方式终生发生，但在绝经后可能加速。脊柱骨质流失可能在绝经前就已开始，但在绝经后立即迅速增加。骨强度与骨密度直接相关，但负荷力也与骨折风险相关。
