Osteomalacia - Causes of rickets

Rickets usually occurs because of a lack of vitamin D and calcium, although it can also be caused by a genetic defect or another health condition.

Lack of vitamin D and calcium

The most common cause of rickets is a lack of vitamin D or calcium in a child’s diet. Both are essential for children to develop strong and healthy bones.

The main sources of vitamin D are:

• Sunlight – your skin produces vitamin D when it is exposed to the sun. We get most of our vitamin D this way.
• Food – vitamin D is also found in some foods such as oily fish, eggs and fortified breakfast cereals.

Calcium is commonly found in dairy products (such as milk, cheese and yoghurt) and green vegetables (such as broccoli and cabbage).

Over time, a vitamin D or calcium deficiency causes rickets in children and osteomalacia (soft bones) in adults.

See preventing rickets for more information and advice to help ensure your child gets enough vitamin D and calcium.

Who's at risk?

Any child who does not get enough vitamin D or calcium can develop rickets, but there are certain groups of children who are more at risk.

For example, rickets is more common in children of Asian, African-Caribbean and Middle Eastern origin because their skin is darker and needs more sunlight to get enough vitamin D.

Babies born prematurely are also at risk of developing rickets because babies build up stores of vitamin D while in the womb.

As the amount of vitamin D in breast milk varies, the Department of Health recommends that all pregnant and breastfeeding women should take a daily supplement of 10 micrograms (µg) of vitamin D. This ensures that the mother’s vitamin D requirements are met and that adequate foetal stores are built up for early infancy.

Genetic defect

Rare forms of rickets can also be inherited (passed on from a parent to a child).

For example, hypophosphatemic rickets is a genetic disorder in which the kidneys and bones deal abnormally with phosphate (calcium phosphate is what makes bones and teeth hard). This leaves too little phosphate in the blood and bones, leading to weak and soft bones.

Other types of genetic rickets affect special proteins in the body that are used by vitamin D.

Underlying conditions

Occasionally, rickets develops in children with rare forms of kidney, liver and intestinal conditions. These can affect the absorption of vitamins and minerals.