Vitamin D deficiency

Key messages for primary care practitioners

  • In addition to the characteristic skeletal disorders resulting from vitamin D deficiency, low vitamin D status has been increasingly associated with a wide range of health problems, however the evidence is inconclusive at present.
  • Sunlight is the major source of vitamin D and dark skinned individuals or those who for cultural or religious reasons cover their whole bodies when outdoors are at risk of deficiency, as are those whose diets (vegetarian/vegan) do not contain an adequate vitamin D supply. 
  • Low status is particularly likely during the winter months for people living in the UK, particularly among those who are dark skinned, wear concealing clothing or are housebound. In the winter months in the UK there is no sunlight of appropriate wavelength for synthesis of vitamin D via the skin and the population relies on body stores and dietary intake.
  • Practitioners should be alert to the possibility of vitamin D deficiency in migrants who have the above risk factors and test and treat them appropriately.
  • Supplementation is advised for pregnant and breast feeding women and for infants from one month to four years, especially in at risk groups. People of Asian origin, older people and people who rarely go outdoors or who always cover all their skin when they are outdoors, should also consider taking vitamin D supplements.
  • Low income families in the UK who receive one of a range of income related benefits and tax credits may qualify for Healthy Start [external link]. Pregnant women, women with a child under one and children aged 6 months to their 4th birthday can get free Healthy Start vitamin supplements. The supplements for women and children contain vitamin D.

Background information

Symptoms

Testing

Treatment

Prevention and control 

Patient information (English only)

Other useful resources

References

Background information

  • Vitamin D deficiency, which when severe classically causes rickets in children and osteomalacia in adults, has also been linked to a range of other disorders including infectious and autoimmune diseases, cardiovascular disease, type I diabetes and some cancers, however, the evidence is inconclusive at present [1]. The main functions of vitamin D are related to calcium and phosphate metabolism.
  • Vitamin D is a fat-soluble vitamin that is produced when ultraviolet rays from sunlight strike the skin and trigger its synthesis. It also occurs naturally in some animal products, including oily fish (probably the best dietary source), eggs and meat. In the UK fat spreads are fortified with vitamin D and it may be added to other foods such as breakfast cereals. The vitamin D content of most vegetables is negligible. Sunlight (ultraviolet B radiation) is the most important source for the majority of people worldwide. 
  • People with pigmented skin require considerably greater sun exposure to get the same level of vitamin D synthesis as fair skinned people.
  • Populations with inadequate exposure to sunshine, such as housebound or institutionalised people, deeply pigmented persons living in low ultraviolet radiation settings (e.g. the UK) or those who, for religious or cultural reasons cover their entire body surface when they are outdoors, are at increased risk of low vitamin D status, as are people with inadequate dietary sources e.g. non-fish eating, vegetarian and vegan diets.
  • A significant proportion of the UK population have low vitamin D status. The National Diet and Nutrition Survey (2000/01) has shown that 15% of the general adult population, aged 19-64, has low vitamin D status (a plasma 25-hydroxy vitamin D concentration below 25nmol/L) which puts them at risk of vitamin D deficiency [2].
  • Particularly high rates of Vitamin D deficiency have been found in certain ethnic minority groups including those of south Asian, African, Caribbean, and Middle Eastern descent [3].
  • In the winter months in the UK there is no sunlight of appropriate wavelength for synthesis of vitamin D via the skin and the population relies on body stores and dietary intake. 
  • Infants of vitamin D deficient mothers are at risk of deficiency as are those that are exclusively breast fed beyond six months of age. Poor childhood diet also increases the risk.
  • The Healthy Start [external link] scheme provides vitamin drops to children in families who qualify for the scheme from the age of 6 months to their 4th birthday. Pregnant women and those with a child under one year old on the scheme can also get Healthy Start women's tablets which contain vitamin D.
  • The children's drops are available to breastfed babies on the scheme from one month on health professional advice if there is any doubt about the mothers vitamin D status during pregnancy.

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Symptoms

In adults vitamin D deficiency may present with pain and muscle weakness, or as osteopaenia or low bone density indicating possible osteomalacia. In children, failure to thrive, particularly in terms of height may occur and bone and muscular weakness may lead to bony deformity and impaired respiratory function with increased susceptibility to infections. Severe deficiency can lead to hypocalcaemic seizures or cardiomyopathy and heart failure. Practitioners should be alert to the possibility of vitamin D deficiency in at risk patients with consistent symptoms. 

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Testing

Vitamin D deficiency is diagnosed most reliably by measuring serum 25-hydroxyvitamin D [4]:

  • Less than 25nmol/l (10µg/l) is classified as deficiency and is associated with rickets and osteomalacia. 

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Treatment

There are no standard UK guidelines for the treatment of vitamin D deficiency, however many areas of the UK now have local guidelines - contact your medicines management committee or Primary Care Trust for information. For a recent British Medical Journal clinical review please see Diagnosis and managment of vitamin D deficiency [external link] [4].  

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Prevention and control

The Department of Health recommends daily supplementary vitamin drops for all infants from one month to five years [5]. The Healthy Start Children's vitamin drops contain a combination of vitamins A, C and D and are available free of charge to children aged 6 months to their 4th brithday in families who qualify for the Healthy Start [external link] scheme [6].

The vitamin D dietary reference value is 7 micrograms/day for children aged 1-3 years and 10 micrograms/day for adults over 65 years [7].

Pregnancy recommendations are stated in NICE guidelines for antenatal care [8] and in Royal College of Obstetrician and Gynaecologists guidance [9]. All pregnant women and breast feeding mothers should be advised to take supplements containing 10 micrograms of vitamin D each day (such as the Healthy Start women's vitamin tablets which also contain vitamin C and folic acid and are available to women who qualify for the Healthy Start [external link] scheme during pregnancy and until their baby is one year old [6]).

All pregnant under 18s qualify for Healthy Start regardless of their income or benefits.

NHS organisations may have local arrangements where they provide Healthy start vitamins free to those not on the scheme or at a small cost.

People of Asian origin, older people, and people who rarely go outdoors or who always cover all their skin when they are outdoors, should also consider taking vitamin D.

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Patient information (English only)

Patient UK vitamin D deficiency leaflet [external link]

NHS Choices information about vitamin D [external link]

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Other useful resources   

Healthy start [external link] for information on vouchers for healthy food for children and pregnant women

Vitamin D: an essential nutrient for all..but who is at risk of vitamin D deficiency? Important information for healthcare professionals [external link] (Department of Health information leaflet)

Position statement by the Scientific Advisory Committee on Nutrition (2007) update on vitamin D [external link]

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References

  1. Holick M F. Vitamin D: a D-Lightful health perspective. Nutr Rev 2008; 66: S182-S194.
  2. National Diet and Nutrition Survey [external link]: Adults aged 19 to 64, Volume 4 2004
  3. Vitamin D deficiency in adults. Drug Ther Bull 2006;25-29.
  4. Pearce S H S, Cheetham T D. Diagnosis and management of vitamin D deficiency [external link]. BMJ 2010; 340: b5664.
  5. Department of Health. Birth to Five (2009 edition). Chapter 1: Feeding your baby [external link]
  6. NHS Healthy Start website [external link]
  7. Report on Health and Social Subjects 41 'Dietary Reference Values (DRVs) for Food Energy and Nutrients for the UK', Report of the Panel on DRVs of the Committee on Medical Aspects of Food Policy (COMA) 1991.  Department of Health.
  8. NICE guideline for antenatal care [external link]
  9. RCOG issues new guidance on vitamin supplementation in pregnancy [external link]

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