Osteomalacia

The Facts

Bones need calcium and phosphorus to remain healthy and strong, but the body also needs vitamin D to be able to absorb these two minerals. Without this necessary vitamin, bones can become soft and flexible. This softening is called osteomalacia, or rickets when diagnosed in children.

Rickets was a common childhood illness in North America until the 1940s, when it was was discovered that vitamin D, readily available from sunlight and vitamin-enriched milk, prevented this condition. Although we haven't seen many cases of rickets in North America over the past 60 years, this condition is beginning to reappear, particularly among exclusively breast-fed babies.

Rickets is still a major childhood problem in poorer, warm countries in which babies are kept mainly inside the home and foods rich in vitamin D are not readily available.

Causes

Osteomalacia is caused by a lack of vitamin D in the body. Vitamin D deficiency can occur because of:

• conditions that interfere with the body's absorption of vitamin D, such as intestinal disorders (including Crohn's disease and celiac disease)
• conditions that prevent the body from producing or activating vitamin D, such as kidney disorders and hypoparathyroidism
• lack of vitamin D in the diet
• not enough exposure to sunshine
• having dark skin, which interferes with the effects of sunlight on vitamin D
• certain medications, including some medications prescribed for epilepsy

In North America, infants diagnosed with rickets are usually dark-skinned babies who have been exclusively breast-fed. Although mother's milk is the ideal food for babies, this source of milk does not provide enough vitamin D to meet the baby's needs. Most breast-fed babies should receive a vitamin D supplement unless they are already getting vitamin D from another source.

There is also a rare form of inherited osteomalacia, called Vitamin D-resistant rickets.