Rickets | Mate kōiwi takarepa

Rickets is a condition that affects bone development in young children. It usually results from a lack of Vitamin D, calcium or phosphorous and can cause bone pain, poor growth and bone deformities.

On this page, you can find the following information:

Key points about rickets

  1. Rickets occurs in growing bones, so mostly affects infants and young children. In Aotearoa New Zealand, rickets is usually diagnosed between three and 18 months of age.
  2. Rickets can cause bone pain, poor growth and bone deformities, such as bowed legs and thickening of the ankles, knees and wrists. Children with rickets are also more likely to fracture their bones.  
  3. Rickets is usually due to a lack of vitamin D, calcium or phosphorus.
  4. About 90% of vitamin D comes from skin exposure to ultraviolet B (UVB) light from the sun and 10% from diet.
  5. Vitamin D or calcium supplements often correct bone problems associated with rickets.
  6. Children can be born with a genetic (inherited) form of rickets, although this is uncommon.

What causes rickets?

Rickets usually occurs due to a lack of vitamin D. Vitamin D helps your body to absorb calcium and phosphorus, which are needed to build strong bones. Babies, children, teenagers, pregnant women or breastfeeding mothers are at higher risk of vitamin D deficiency, as the need for vitamin D is higher in these groups.   

Babies and children are also at higher risk of vitamin D deficiency if they:

  • have dark skin or a condition that prevents sun exposure
  • are exclusively breastfed (having breastmilk only) for an extended period and the introduction of solid food is delayed
  • are born to a mother who has low vitamin D levels or has a sibling with low vitamin D levels
  • wear clothing that covers their skin most of the time for cultural or religious reasons
  • live in southern regions of Aotearoa New Zealand where there is less sun in winter and spring than in other parts of the country
  • have a condition that prevents or impairs absorption of vitamin D through the gut, such as Crohn’s disease or coeliac disease
  • have a diet that is low in vitamin D (eg, vegetarian).

Rare forms of rickets can also occur in some inherited (genetic) disorders or kidney problems.

What are the symptoms of rickets?

Rickets softens the growing tissue at the end of your bones (growth plates). This can cause:

  • bowed legs or ‘knock-knees’ where the knees tilt inwards while the ankles are apart – but it is normal to have some bowing under the age of 2 years and some children have knock knees until the age of 4
  • swelling of wrists, ankles and knee
  • pain in your spine, pelvis and legs
  • teeth to emerge from your gums later and problems with tooth enamel
  • softening of your skull bones, slow closure of soft spots (fontanelles) on the skull and a prominent forehead
  • the chest wall (breastbone) to stick out
  • bending (curvature) of your spine, although this is uncommon.

Rickets can also cause poor growth, delayed motor skills and muscle weakness. Children with rickets are more likely to fracture their bones.

How is rickets diagnosed?

A diagnosis of rickets is usually confirmed through:

  • a physical exam by your healthcare professional where they will gently press on your child’s bones checking for pain or tenderness
  • blood tests to check vitamin D, calcium and phosphate levels
  • x-rays of the affected bones.

How is rickets treated?

Most cases of rickets can be treated with vitamin D supplements. Your child may also need extra calcium and phosphorous as well. This can be done by increasing the amount of calcium-rich food your child eats or by taking supplements.  Improvements can be seen on an x-ray within days of starting supplements.

If your child’s rickets are treated when they are young, there is a good chance any bone (skeletal) problems will disappear as your child matures. In some instances, your healthcare professional may suggest treatment to correct any bone problems.

Your healthcare professional will refer you to a renal (kidney) or endocrinology (hormone) specialist if your child’s rickets is caused by an inherited (genetic) disease or kidney problem.

What should I ask my healthcare professional?

  • Does my child need a vitamin D or calcium supplement?
  • Will my child have bone problems later in life?
  • What can I do to make sure my child gets enough vitamin D safely?

How can I prevent my child getting rickets?

About 90% of vitamin D comes from skin exposure to ultraviolet B (UVB) light from the sun and 10% from diet. Babies and young children need extra protection from the sun, particularly from UV rays. However sensible sun exposure can help prevent vitamin D deficiency.   

Vitamin D is also found in small quantities in foods such as eggs, liver, fatty fish (North Sea salmon, herring and mackerel) and portobello and shiitake mushrooms (which make their vitamin D from sunlight).

 Some foods may also have vitamin D added. These include:

  • margarine and fat spreads
  • some reduced-fat dairy products (eg, milk, dried milk and yoghurt)
  • plant-based dairy substitute (eg, soy drinks).

Learn more

The following links provide further information about rickets. Be aware that websites from other countries may have information that differs from New Zealand recommendations.   

Rickets Better Health Channel, Australia
Rickets and osteomalacia NHS, UK


  1. Vitamin D deficiency – investigation and management Starship Clinical Guidelines, NZ, 2021
  2. Companion statement on vitamin D and sun exposure in pregnancy and infancy in NZ Ministry of Health, NZ, 2020

Reviewed by

Dr Sharon Leitch is a general practitioner and Senior Lecturer in the Department of General Practice and Rural Health at the University of Otago. Her area of research is patient safety in primary care and safe medicine use.
Credits: Health Navigator Editorial Team. Reviewed By: Dr Sharon Leitch, GP and Senior Lecturer, University of Otago Last reviewed: 03 Nov 2021