Vitamin D Deficiency

(Rickets; Osteomalacia)

ByLarry E. Johnson, MD, PhD, University of Arkansas for Medical Sciences
Reviewed/Revised Nov 2022

  • Infants develop rickets: The skull is soft, bones grow abnormally, and infants are slow to sit and crawl.

  • Blood tests and sometimes x-rays are done to confirm the diagnosis.

(See also Overview of Vitamins.)

  • Vitamin D2 (ergocalciferol): This form is synthesized from plants and yeast precursors. It is also the form usually used in high-dose supplements.

  • Vitamin D3 (cholecalciferol):

calcitriol. This active form promotes absorption of calcium and phosphorus from the intestine. Calcium and phosphorus, which are minerals, are incorporated into bones to make them strong and dense (a process called mineralization). Thus, calcitriol is necessary for the formation, growth, and repair of bones.

psoriasis, hypoparathyroidism, and renal osteodystrophy

fat-soluble vitamin, which dissolves in fat and is best absorbed when eaten with some fat.

osteoporosis worse.


Did You Know...

Inadequate exposure to sunlight

  • Inadequate exposure to sunlight

Some experts recommend that the arms and legs or the face, arms, and hands should be exposed to direct sunlight for 5 to 15 minutes at least 3 times a week, but some people, such as those who have darker skin or are older, may need more exposure to sunlight. However, many dermatologists do not recommend increased sunlight exposure because risk of skin cancer is increased.

Other causes

Muscle spasms (tetany) may be the first sign of rickets in infants. They are caused by a low calcium level

In young infants who have rickets, the entire skull may be soft.

Older infants may be slow to sit and crawl, and the spaces between the skull bones (fontanelles) may be slow to close.

In children aged 1 to 4 years, bone growth may be abnormal, causing an abnormal curve in the spine (scoliosis) and bowlegs or knock-knees. These children may be slow to walk.

In adults, the bones, particularly the spine, pelvis, and leg bones, weaken. Affected areas may be painful to touch, and fractures may occur.

In older people, bone fractures, particularly hip fractures, may result from only slight jarring or a minor fall.

  • Blood tests

  • Sometimes x-rays

  • People who report an inadequate diet or inadequate exposure to sunlight

  • Newborns with tetany (a type of muscle spasms)

  • Children with signs of rickets

  • Older adults, especially those with decreased bone density (for example, with osteoporosis) or broken bones

X-rays may also be taken. The characteristic changes in bone may be seen on x-rays before symptoms become noticeable.

  • Sometimes calcium and phosphate supplements

If muscle spasms are present or calcium is thought to be deficient, calcium supplements are also given. If phosphate is deficient, phosphate supplements are given. Usually, this treatment leads to a complete recovery.

Spotlight on Aging: Vitamin D Deficiency

  • Their requirements are higher than those of younger people.

  • They tend to spend less time outdoors and thus are not exposed to enough sunlight.

  • They may not be exposed to enough sunlight because they are housebound, live in long-term care facilities, or need to stay in the hospital for a long time.

Drugs Mentioned In This Article
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