Osteomalacia is a condition that is at times confused with osteoporosis. Although osteomalacia is also a condition associated with changes in the bone mineral, it is a significantly different condition from osteoporosis. It is therefore important to differentiate between the two conditions as the causes and treatment differ significantly. Osteomalacia is the adult form of the bone disease known as rickets in children.
Bone develops during the course of early life as flexible cartilage that makes up the human skeleton and soft bone tissue becomes calcified thereby making it harder. This hardening tends to occur to a greater degree once a person stops growing in early adulthood. Vitamin D is an important facilitator of this hardening process through the deposition of calcium and phosphates. Osteomalacia arises with a deficiency of vitamin D. This leads to low calcium levels. Sometimes a deficiency of parathyroid hormone (PTH) can also be responsible for impaired bone mineralization.
Sunlight plays an important role in vitamin D synthesis. Compounds on the skin are converted into vitamin D when it is exposed to sunlight. Further conversion in the body makes this vitamin D into more potent forms. Limited exposure to sunlight can therefore affect vitamin D synthesis. This is more significant in the elderly who may not venture outdoors for sufficient periods of time due to various reasons. Living in regions with shorter hours of daylight and low intensity sunlight can also be a factor in vitamin D deficiency.
However, it is important to note that various other diseases of the different systems of the body can lead to osteomalacia. This includes disorders of the gut, kidney, liver and the use of certain medication.
In osteomalacia the process of building bone is disrupted as opposed to the breakdown of already developed bone in osteoporosis. Therefore osteomalacia leads to soft bones. Osteoporosis causes the bones to become weak and brittle. Fractures are therefore more likely with osteoporosis usually as a result of falls. Although fractures can also occur in osteomalacia, it is more commonly marked by deformities as the bones bend due to the force placed on it as a result of body weight.
As with osteoporosis, the early stages of osteomalacia are largely asymptomatic. As the condition progresses there may be a dull aching type of bone pain. In the later stages and severe cases there may also be prominent muscle weakness. A person with osteomalacia may therefore experience :
Osteomalacia is not treated with the same drugs as osteoporosis. The two disease mechanisms are different. The treatment of osteomalacia is usually simpler.Vitamin D supplements are usually sufficient to correct osteomalacia. In some cases, calcium and phosphorus supplements are also prescribed when the levels of these minerals in the body is very low.
Where osteomalacia is due to underlying diseases of the parathyroid gland, kidney or liver disease and disorders of the gut leading to malabsorption, these conditions need to first be treated. Only then can vitamin and mineral supplementation be effective in treating and managing osteomalacia.