Diseases & Conditions
Rickets is a bone disease in children that causes weak bones, bowed legs, and other bone deformities. Children with rickets do not get enough calcium, phosphorus, or Vitamin D — all of which are important for healthy growing bones.
Although considered a disease of the past, rickets has not been eliminated in the world, and it seems to be getting more common in the United States.
Rickets is most commonly an inherited disease, but it can also result from nutritional deficiency of vitamin D and calcium in a child's diet. Hereditary rickets requires very specialized medical care. This article does not provide detailed information about hereditary rickets; instead, it focuses on nutritional rickets.
Who Is at Risk for Nutritional Rickets?
A number of factors decrease the amount of vitamin D a person can make, and therefore contribute to the risk of developing nutritional rickets:
- Lack of sun exposure. Our skin makes Vitamin D when it is exposed to sunlight. Not enough enough sun exposure means not enough Vitamin D. Factors that limit our exposure to sunlight include:
- High levels of air pollution
- The use of sunscreen
- Living in northern climates
- Naturally dark skin
- Poor diet. Children adopted from abroad or children experiencing extreme poverty sometimes have rickets due to a poor diet history. Lack of variety in the diet or a strictly vegetarian diet can contribute to rickets.
- Low calcium. Children with rickets usually take in less than 300 mg of calcium per day (about one cup of milk). Growing children need from 400 mg (babies) to 1,500 mg (teens in the adolescent growth spurt) of calcium daily for good bone health.
- Lactose intolerance. Children who are lactose intolerant or on diets that restrict dairy intake are at higher risk for rickets.
- Breast feeding. Because breast milk contains very little Vitamin D, rickets can develop in babies who are exclusively breast fed for a long time.
A child with rickets may have the following signs and symptoms:
- Weak muscle tone
- Delayed development, decreased growth, or "failure to thrive"
- Bowed legs and widening of the wrist and ankle bones
- Stooped posture
- Chest and rib deformities — Some children develop nodules (bumps) at the end of their ribs (known as rachitic rosary). Chest deformities can develop from deformities of the ribs, and lead to lung infections.
The doctor will examine your child, looking for the signs and symptoms of rickets discussed above. In addition to a physical examination, your child's doctor may recommend specific tests to help determine whether your child has rickets.
X-rays create clear images of bones. X-rays of children with rickets may show fractures (broken bones) or breaks that are healing or have healed. They may also show decreased bone density, as well as bowing or other deformities of the arms or legs, and problems around the growth plates. Growth plates are areas of developing cartilage that regulate bone growth.
The level of calcium in our blood must stay constant. If we do not take in enough calcium, our body will pull the calcium it needs out of our bones. This makes bones weak and fragile.
The doctor can test the calcium, phosphorus, and Vitamin D levels in your child's blood. However, normal blood calcium and phosphorus do not rule out rickets. Low blood calcium and phosphorus levels can indicate very serious rickets or the type of rickets that runs in families.
Your child's doctor may also test your child's blood to determine the levels of specific hormones that control bone activity.
Treatment of rickets begins with Vitamin D and calcium supplementation.
Children who have been diagnosed with nutritional rickets will immediately start Vitamin D supplementation of 1,000 to 2,000 internaitonal units (IU) per day. Sometimes much higher levels of Vitamin D are used under a doctor's care.
Calcium intake should be 1,000 to 1,500 mg daily, whether through calcium-rich foods or supplementation.
Children with inherited rickets are usually treated by an expert in hormones (endocrinologist).
The key to preventing rickets is to make sure your child is getting enough Vitamin D and calcium.
Calcium is found in many foods, and a diet containing dairy and other calcium-rich foods can provide adequate daily calcium. Infants need about 400 mg of calcium daily (about 1 1/2 cups of milk). A rapidly growing teen might need 1,500 to 2,000 mg of daily calcum to form strong bones. Learn more: Calcium, Nutrition, and Bone Health
Lactose intolerant children, or children who do not eat dairy, can take calcium supplements in liquid, gummy, chewable, or pill form. Supplemental calcium should not be taken all at once because our bodies cannot absorb more than about 500 mg at one time. Excessive amounts of supplemental calcium (more than about 2,000 mg) are not helpful and can cause constipation and other problems.
Vitamin D, unlike calcium, is not found in very many foods.
- Fatty fish, such as salmon, mackerel, and tuna, are the best dietary sources of Vitamin D.
- Fortified foods provide most of the Vitamin D in the American diet.
- Almost all of the U.S. milk supply is fortified with 100 IU of Vitamin D per cup. Other dairy products made from milk, such as cheese and ice cream, are generally not fortified.
- Ready-to-eat breakfast cereals often contain added Vitamin D, as do some brands of orange juice, yogurt, margarine, and other food products.
- Infant formula in the U.S. is fortified with 40 to 100 IU of Vitamin D per 100 kcal.
General recommendations for Vitamin D intake include:
- Infants. According to the American Academy of Pediatrics guidelines (published in Pediatrics in November 2008 and reinforced by a 2000 Pediatrics study), "[i]t is now recommended that all infants and children, including adolescents, have a minimum daily intake of 400 IU of Vitamin D beginning soon after birth." This amount is found in infant vitamin preparations.
- Nursing mothers. Nursing mothers should take 4,000 IU of Vitamin D daily to increase the amount of Vitamin D in their breast milk.
- Older children. Research suggests older children and adolescents should get 600 to 1,500 IU of Vitamin D every day.
Although recovery may take many months, outcomes for children treated with rickets are good. Deformities of the bones from rickets, even severe bowed legs, can get better over time without surgery.
In advanced cases, surgery may be necessary to correct severely bowed or knock-kneed legs and other bone deformities.
Other problems, such as chest or pelvic deformities and growth retardation, may be permanent. For example, before rickets prevention was understood, pelvic deformities from rickets made natural childbirth difficult or impossible. Caesarean section surgery was developed in part to help childbearing women who have permanent deformities resulting from childhood rickets.
Rickets remains a serious nutritional disorder that results from calcium or Vitamin D deficiency. Prevention of rickets is important. Playing outside in the sun for safe amounts of time and eating dairy products and other calcium-rich foods are key to preventing rickets. Vitamin D should be supplemented for most children.
Rickets is treated with calcium and vitamin D and has a good outlook after treatment.
AAOS does not endorse any treatments, procedures, products, or physicians referenced herein. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific orthopaedic advice or assistance should consult his or her orthopaedic surgeon, or locate one in your area through the AAOS Find an Orthopaedist program on this website.