Vitamin D Deficiency including Osteomalacia and Rickets - Causes

Who gets vitamin D deficiency?

Vitamin D deficiency means that there is not enough vitamin D in your body. This may be because:

  • Your body has an increased need for vitamin D.
  • Your body is unable to make enough vitamin D.
  • You don't have enough vitamin D in your diet.

You have an increased need for vitamin D

Growing children, pregnant women, and breast-feeding women need extra vitamin D because it is required for growth. So, vitamin D deficiency is more likely to develop in the following groups of people:

  • Pregnant or breast-feeding women. Vitamin D deficiency is even more likely to develop in women who have had several babies with short gaps between pregnancies.
  • Breast-fed babies whose mothers are lacking in vitamin D, or with prolonged breast-feeding, as there is little vitamin D in breast milk.

Your body is unable to make enough vitamin D

This can occur for various reasons:

  • People who get very little sunlight on their skin are at risk of vitamin D deficiency. This is more of a problem in the more northerly parts of the world (including the UK) where there is less sun. In particular:
    • People who stay inside a lot. For example, those in hospital for a long time, or housebound people.
    • People who cover up a lot of their body when outside.
    • The strict use of sunscreen may increase the risk of vitamin D deficiency, particularly if high sun protection factor (SPF) creams (factor 15 or above) are used. However, there is no evidence that the normal use of sunscreen does actually cause vitamin D deficiency in real life. Everyone, especially children, should always be protected from the harmful effect of the sun's rays. See separate leaflet called Sun and Health for more information.
  • Elderly people are unable to produce as much vitamin D. This leaves older people more at risk of vitamin D deficiency.
  • People who have darker skin are not able to make as much vitamin D.
  • Some medical conditions can affect the way the body handles vitamin D. People with Crohn's disease, coeliac disease, and some types of liver and kidney disease, are all at risk of vitamin D deficiency.
  • Rarely, some people without any other risk factors or diseases become deficient in vitamin D. It is not clear why this occurs. It may be due to a subtle metabolic problem in the way vitamin D is made or absorbed. So, even some otherwise healthy, fair-skinned people who get enough sun exposure can become deficient in vitamin D.
  • Vitamin D deficiency can also occur in people taking certain medicines. Examples include: carbamazepine, phenytoin, primidone, barbiturates and some anti-HIV medicines.

Not enough dietary vitamin D

Vitamin D deficiency is more likely to occur in people who follow a strict vegetarian or vegan diet, or a non-fish-eating diet.

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Author:
Dr Colin Tidy
Peer Reviewer:
Prof Cathy Jackson
Document ID:
7187 (v12)
Last Checked:
04 May 2017
Next Review:
03 May 2020

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.