Osteomalacia: Overview, Causes, Treatment and Conclusion

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What is osteomalacia?

Osteomalacia means softening of the bones. It happens when bones do not get enough minerals, mainly calcium and phosphate, to harden properly. Soft bones are weak and break more easily.

The most common cause is a lack of vitamin D, which the body needs to absorb calcium. When the same thing happens in children, it is called rickets.

Osteomalacia is not the same as osteoporosis, although both can cause bones to break. In osteomalacia, new bone is laid down but does not mineralize, so it stays soft. In osteoporosis, bone is mineralized normally but there is less of it.

Soft bones can ache, bend and break, and muscle weakness is common. According to MedlinePlus, symptoms include widespread bone pain (especially in the hips), muscle weakness and fractures after little or no injury.

There are rare types of osteomalacia. Some are caused by kidney problems or rare tumors that make the body lose phosphate. Some of these are inherited, and some medicines can also cause it.

Causes of Osteomalacia:

The body needs enough calcium, phosphate and vitamin D to mineralize bone. Vitamin D deficiency is the most common cause of osteomalacia.

Vitamin D deficiency

Your skin makes vitamin D in sunlight, and you also get it from food. People who get little sun, cover most of their skin, have darker skin, or live far from the equator are more likely to run low. In the UK, the NHS notes that people cannot make enough vitamin D from sunlight between September and March.

The recommended daily amount for most adults aged 19 to 70 is 600 IU, rising to 800 IU after age 70. Pregnant and breastfeeding women also need 600 IU.

• If you rarely spend time outdoors, eat vitamin D-rich foods and ask your doctor whether you need a supplement.
• Rare causes of osteomalacia.

Although vitamin D deficiency is the most common cause of osteomalacia, your doctor will need to check if it is caused by anything else. Rare causes include:

• Gut problems that reduce absorption, for example untreated celiac disease or weight-loss (gastric bypass) surgery
• Liver disease
• Kidney failure
• Some anti-seizure (epilepsy) medicines.

If any of the above applies to you, you may need additional protection against osteomalacia. It is important to talk to your doctor about this.

Treatment

Treatment cures osteomalacia in most cases, but it can take several months for bone pain and muscle weakness to improve. When the cause is vitamin D deficiency, doctors prescribe vitamin D and often calcium supplements. Treatment often starts with a higher dose for a while, followed by a lower daily maintenance dose. Your doctor will set the dose and check your blood levels, so do not take high-dose vitamin D on your own.

Some people need long-term vitamin D supplements, especially if the cause cannot be fixed. If you stop taking vitamin D, the condition may come back. Food and safe sun exposure help keep levels up once treatment is done.

Foods with vitamin D include:

• Fortified breakfast cereals
• Fortified yogurt
• Egg yolks
• Fish (tuna, salmon, swordfish, sardines)
• Liver
• Fortified milk
• Orange juice (fortified with vitamin D)
• Fortified plant milks

You can also get more vitamin D by spending time in the sun. But talk to your doctor about this and do apply sunscreen. Too much sun can increase your chances of skin cancer. If your body has trouble absorbing vitamin D, your doctor will need to treat the cause if possible. You will need to take larger doses of calcium and vitamin D than the usual daily recommendation. To treat broken or deformed bones from osteomalacia, your doctor may give you a brace to wear. If the problem is severe, you may need surgery.

People with kidney failure or inherited forms of osteomalacia often need lifelong care from a specialist team, with regular blood tests. They may need phosphate supplements or special forms of vitamin D, such as calcitriol. This is because the kidneys normally convert ordinary vitamin D into calcitriol, the active form needed for bone mineralization.

Conclusion

Osteomalacia is softening of the bones caused by poor mineralization, usually because of a lack of vitamin D. It causes bone pain, muscle weakness and fractures.

Rare forms are caused by kidney problems, phosphate loss or certain medicines, so your doctor will look for the cause. If you have ongoing bone pain or weakness, see a doctor for blood tests rather than treating yourself.

Sources

• Osteomalacia, MedlinePlus (U.S. National Library of Medicine)
• Rickets and osteomalacia, NHS
• Vitamin D, MedlinePlus (U.S. National Library of Medicine)