Vitamin D Deficiency

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Vitamin D is essential for musculoskeletal health as it promotes calcium absorption from the bowel, enables mineralisation of newly formed osteoid tissue in bone and plays an important role in muscle function. The main manifestation of vitamin D deficiency is osteomalacia in adults and rickets in children. The main symptoms of osteomalacia include proximal muscle weakness, persistent muscle pain and waddling gait. Less severe vitamin D deficiency, termed vitamin D insufficiency, may lead to secondary hyperparathyroidism, bone loss, muscle weakness, falls and fragility fractures in older people. 

Previously, the lack of national guidance on the indications for vitamin D measurements, on the interpretation of the results and on the correction of vitamin D deficiency has resulted in confusion among patients and health-care professionals and in the proliferation of conflicting guidelines and inconsistent practice across the UK. As a result, NHS Highland has developed this guideline on the management of vitamin D deficiency in adult patients, based on:

This guidance does not apply to the management of patients at risk of vitamin D deficiency or with osteoporosis. Population groups at higher risk of having a low vitamin D status include:

  • All pregnant and breastfeeding women, particularly teenagers and young women
  • Infants and children under 5 years
  • People over 65   People who have low or no exposure to the sun. For example, those who cover their skin for cultural reasons, who are housebound or confined indoors for long periods  
  • People who have darker skin, for example, people of African, African–Caribbean and South Asian origin.

There is already clear guidance nationally and locally for these groups of patients (refer to Highland Formulary, section 9.6 and section 6.6).

Testing of vitamin D levels

Vitamin D status is currently best assessed by measurement of serum 25(OH)D. Although vitamin D deficiency is highly prevalent, universal testing of asymptomatic populations is not recommended.  Testing should be limited to patients showing clinical signs of vitamin D deficiency.

Indication for 25(OH)D measurement

Suspected Rickets*

Suspected Osteomalacia*

Primary Hyperparathyroidism

Some lymphomas*

Malabsorption syndromes

Inflammatory bowel disease, particularly Crohn’s disease

Bariatric surgery

Cystic Fibrosis

Consider testing for 25(OH)D measurement

Older patients with a history of falls or non-traumatic fractures adults and children with a BMI >30kg/m2

*Muscle weakness or tiredness in association with bone pain where other causes have been excluded

Selecting patients for treatment
  • In children, see the Royal College of Paediatrics and Child Health – Guide for Vitamin D in Childhood, October 2013.
  • In pregnancy, follow the guidance below but consider the additional points:
    • Do not treat in the 1st trimester.
    • Treatment should only be in consultation with the patient’s obstetrician.
    • Avoid the use of products containing vitamin A (such as Cod Liver Oil) as this is a known teratogen.
    • For further information, consult UKMi Medicines Q&As (https://www.evidence.nhs.uk/ source UKMi).
  • Toxicity has been reported during vitamin D treatment of tuberculosis and in patients with active sarcoidosis. Specialist advice should be sought before starting these patients on vitamin D therapy.
  • There is no strong evidence that correcting vitamin D deficiency with vitamin D alone will increase the risk of renal stones. However, further advice should be sought in patients with active nephrolithiasis and each patient should be managed on a case-by-case basis.
Lifestyle advice

Sunshine and diet are important for maintaining adequate levels of vitamin D and should be discussed with patients. In Scotland, most of us can get the vitamin D that we need from exposure to as little as 10 to 15 minutes unprotected sunlight daily in the summer months (April to September). Small amounts of vitamin D are found naturally in oily fish, eggs and meat. Cod liver oil is for some a good source of vitamin D maintenance.  Vitamin D is added to margarines and some breakfast cereals, soya and dairy products, powdered milks and low fat spreads.

Treatment

 

Vitamin D deficiency

Vitamin D insufficiency

Vitamin D sufficiency

Serum 25(OH)D level (nmol/L)

less than 25 nmol/L

25 to 50 nmol/L and symptomatic

Greater than 50 nmol/L

Loading regimen

Colecalciferol 3200 units capsules, 2 daily (6400 units daily) for 6 weeks only (off label dosing information).

In patients with difficulty in swallowing, give Colecalciferol (InVita) 25,000 units/1ml oral solution, 2 mls every week for 6 weeks.

Avoid the use of a single mega-dose (300,000units or higher) for loading patients.

None

None

Maintenance therapy

Colecalciferol 800units tablets or capsules in doses equivalent to 800 to 1600 units daily.

In patients with difficulty in swallowing, give Colecalciferol 25,000 units/1ml oral solution, 1 or 2 mls every month.

Patients should be treated for a minimum of 3 months and it may be more prudent to wait until 6 months have passed. Stop treatment unless ongoing cause of deficiency or in light of specialist advice.

In patients with a known ongoing cause of deficiency a dose of 1600 units daily should be used, and treatment should be continued until the cause of deficiency has resolved or on advice from a specialist.

None

Monitoring

Check calcium levels also prior to starting treatment.

The risk of developing hypercalcaemia whilst on vitamin D therapy is low. However, as high serum calcium can lead to renal and cardiovascular damage assess U&Es and adjusted calcium one month after administration of last loading dose for those patients receiving a loading regimen.   For those patients receiving ongoing long-term treatment 6 monthly assessment of U&Es and adjusted calcium, should be completed.

For most patients, routine monitoring of serum 25(OH)D is unnecessary. Serum 25(OH)D testing is only offered on an annual basis per patient, unless there is a specific reason for the request, which has to be identified and agreed with the laboratory in Glasgow, who perform the test. It may be appropriate to monitor 25(OH)D in patients receiving long-term therapy with symptomatic vitamin D deficiency, malabsorption syndromes, or where poor compliance with medication is suspected.

None

  • Colecalciferol (vitamin D3) is recommended as the vitamin D preparation of choice for treatment of vitamin D deficiency.
  • Ergocalciferol (vitamin D2) should only be used in those who cannot take colecalciferol for cultural, dietary or religious reasons because of the animal versus plant sourcing of vitamin D or the use of gelatine in some preparations. Please contact Medicines Information telephone no 01463 704288 to identify a suitable product.
  • Supplements should be taken with food to aid absorption.
  • Calcium/vitamin D combination products should not be used as sources of vitamin D for the treatment regimens outlined here, given the resulting high dosing of calcium.
  • Patients with malabsorption syndromes oral dosing has been shown to be effective in the majority of patients, but they may require higher dosing than other patients. Seek specialist advice or refer to national guidance for doses (see above).
  • For up-to-date information on choices refer to the Highland Formulary.
  • Patients with peanut allergy should avoid the capsules, which contain arachis (peanut) oil.   The tablets and oral solution do not contain arachis (peanut) oil and are suitable for those with peanut allergy.
  • There may be sub-groups of patients identified who require a more aggressive replacement or maintenance schedule. This should only be provided under specialist supervision in a secondary-care setting.
Editorial Information

Last reviewed: 31 August 2015

Next review: 31 August 2017

Author(s): Policy Procedure and Guideline Subgroup of the ADTC

Version: 1

Approved By: high-uhb.tam@nhs.net

Reviewer Name(s): Jane Smith, Roderick Harvey