Osteoporosis, osteomalacia, rickets, and Paget's disease.

Although the common form of osteoporosis associated with aging can be treated, it is best to avoid the problem by not letting the disease develop. Osteomalacia is caused by inadequate or delayed mineralization of bone and is treated by correcting the abnormal intake, loss, or metabolism of vitamin D, phosphate, and calcium. Paget's disease is characterized by osteoclastic resorption of bone with new bone laid down in a disorganized fashion.