Osteomalacia
(Rickets · Soft Bones)
In this condition factsheet:
The Facts on Osteomalacia
Bones need calcium and phosphorus to remain healthy and strong, but the body also needs vitamin D to be able to absorb these 2 minerals. Without this necessary vitamin, bones can become soft and flexible. This softening is called osteomalacia, or rickets when diagnosed in children. The condition is called osteomalacia when the bone softening occurs after the growth plates have closed.
Rickets was a common childhood illness in North America until the 1940s, when it was discovered that vitamin D, readily available from sunlight (which produces vitamin D in the body) and vitamin D-enriched milk, prevented this condition. Although we haven't seen many cases of rickets in North America since the mid-1900s, this condition occasionally still appears, particularly among exclusively breast-fed babies.
Rickets is still a major childhood problem in poorer, colder countries where babies are kept mainly inside the home and foods rich in vitamin D are not readily available.
Osteomalacia is a disease of bone formation. It is important to differentiate it from osteoporosis, which is a disease of bone that is already formed.
Causes of Osteomalacia
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–this commonly affects 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 tumours
In Canada, there is a greater proportion of exclusively breast-fed Indigenous infants that are diagnosed with rickets.
Although breast 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 hypophosphatemic rickets.
Symptoms and Complications of Osteomalacia
The main symptom of osteomalacia is bone pain, which occurs most often in the hips. Bone tenderness may also occur in the arms, legs, and spine. And as osteomalacia progresses, weakness may also develop.
Because low levels of vitamin D prevent calcium absorption, people with vitamin D deficiency may also have symptoms of low calcium such as muscle spasm, cramping and numbness, tingling in the limbs, and numbness around the mouth or in the hands and feet.
Babies with rickets have difficulty sitting and crawling and are slow to walk. Rickets can also lead to bowed legs, an abnormally shaped skull, spine deformities, or "pigeon breast" (protrusion of the breastbone) in older children.
Rickets can also cause a child to be shorter than average.
