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, especially kidney disorders, where it can be a major problem (it can be brought on by liver disease and, rarely, by hypoparathyroidism)
- lack of vitamin D in the diet
- not enough exposure to sunshine, which commonly occurs in people who are confined indoors for prolonged periods of time because of age, disability, or illness (infants in tropical areas are often kept swaddled in clothes and get too little sun)
- having dark skin, which interferes with the effects of sunlight on vitamin D
- certain medications, including some medications prescribed for epilepsy
- very rare tumors
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.