Osteoporosis exists as a variety of factors that cause old bone to be removed faster than new bone can be formed . By thinning and weakening the bones , osteoporosis causes a million and a half fractures annually .
骨質疏鬆症的一些因素,使舊骨質流失的速度,超過製造新骨質。骨質疏鬆症使骨頭變得薄弱,使美國每年發生一百五十萬件骨折病例。