Bone disease causeCredit:
Nearly every disease known to affect the adult skeleton is directly related to the imbalances between bone deposit and bone resoprtion. In order for homeostasis to occur, the rate of bone resorption should equal to the rate of bone deposit. When this is not attained, then homeostatic imbalances occur.
Osteomalacia and RicketsOsteomalacia - Diseases of the boneCredit:
Osteomalacia literally translates to “soft bones”. This happens when a specific bone is not properly mineralized and it holds under its name a number of known disorders. What happens in osteomalacia is the osteoids are produced, however there are no calcium salts being deposited. Without calcium salts, calcification will not occur thereby leading the bones to weaken and be soft. It can be easily detected when a feeling a pain is felt whenever weight is introduced to affected bones. 
When osteomalacia affects adults, a similar condition affects children and is known as rickets. Taking into consideration the rate of bone growth in children, rickets is far more serious and server when compared to adult osteomalacia. Some manifestations of this condition are children having bowed legs and some deformities involving the rib cage and the skull. Since no calcification occurs, the epiphyseal plates continue to grow and widen; the end parts of long bones become abnormally long and enlarged.Rickets - Bone diseaseCredit:
The cause of osteomalacia and rickets is fairly simple, that is insufficient supply of calcium or by way of deficiency in vitamin D. Since the cause is already identified, it will then be easy to prevent further damage by consuming vitamin-D fortified milk and by exposure to sunlight, which excites the body in the formation of vitamin D. 
 Signs and symptoms of OsteoporosisCredit:
As stated earlier, homeostatic imbalances of the bone occur when there is no equilibrium between bone deposit and bone resorption. Osteoporosis is a condition where the rate of bone resorption (desctruction) is greater than the rate of bone deposit. What then happens is that the bones become so weak and fragile that even a slip can break the bones. 
Even though bone resorption outpaces the rate of bone deposit, the matrix of the bone remains normal. What is different now is that the bone mass is reduced, making the bone light and porous. Osteoporosis can be prevented or to a lesser degree be delayed. The key thing to note here is adequate consumption of calcium in the early stages of life, when the bones are still in the process of increasing their density. Intake of fluoridated water also helps in hardening the bones and an added bonus is that it also helps harden the teeth. Over consumption of carbonated beverages takes away the minerals in your bone, contributing to a fall in bone density.
Paget’s disease
What happens in Paget’s disease is that there is disorganized and excessive bone deposit and bone resorption. This means that new bones are hastily made and there is an abnormally unequal ratio of compact bone to spongy bone. Since the bone is hastily made, mineralization has not occurred yet, leading to weak spots in the bone.