Estrogen level descent, endothelial cell dysfunction, ET and NO dyssecretosis, osteoclasts activity enhancement, bone absorption increase and BMD descent in postmenopausal women may cause osteoporosis. 绝经后,雌激素水平下降,内皮细胞功能障碍,ET和NO分泌失调,破骨细胞活性增强,骨吸收增加,骨密度下降,从而形成骨质疏松症。