What Is Osteomalacia?

Osteomalacia means soft bones. Like osteoporosis, osteomalacia weakens the bones and makes bones more likely to break. However, the process is different from that in osteoporosis. In osteoporosis, bone is broken down faster than it is re-formed. In osteomalacia, the two activities are balanced, but the bone that is formed does not become dense and hard (mineralized). Among older people, osteomalacia is much less common than osteoporosis.

Osteomalacia is usually caused by vitamin D deficiency or by a digestive tract or kidney disorder. These disorders can interfere with the body's use of vitamin D. Rarely, osteomalacia is caused by a low phosphate level.

Osteomalacia causes fatigue and pain in the back, ribs, and hips. Muscles in the upper arms and thighs become weak. People with osteomalacia may have trouble getting up from a chair or climbing steps. They may waddle when they walk. Like osteoporosis, osteomalacia leads to bone fractures.

Doctors diagnose osteomalacia with blood tests, x-rays, and sometimes a biopsy. Osteomalacia is treated with vitamin D or phosphate supplements depending on the cause.