Main characteristics of the disease are the loss of bone mass means deficiency of organic part (matrix) and minerals (calcium) in the bones. The bone becomes thin, weak and loses elasticity and strength. Chances of bone fracture are increased and slight jark or impact may lead to bone fracture.
It affects the whole body skeleton but pelvic, wrist, vertebrae etc are most adversely affected parts. It increases with the age but deficiency of estrogen also caused osteoporosis in old women. It may also be caused by hormones like calcitonin, PTH and glucocorticoids.