Vitamin D testing rarely justified

Created February 2012

From New Zealand Doctor

Testing for vitamin D status at $31 a pop is on the rise - but rarely justified.

Most patients at high risk of deficiency can be prescribed a supplement, or advised on safely getting more sun, without a test, New Zealand researchers suggest.

Those at high risk include people with deeply pigmented skin, the frail elderly, and people who actively avoid the sun for cultural or medical reasons, according to the authors of a viewpoint in the latest issue of the New Zealand Medical Journal (10 February online).

The article says the number of requested tests in the Auckland region grew by 380 per cent between 2000 and 2010.

In the summer months, 13 tests may be needed to determine one case of deficiency.

Test the right patients

Vitamin D measurements should arguably be requested only when the result is likely to change patient management, say the viewpoint's authors.

The few clear-cut cases include investigation of rickets or osteomalacia and other uncommon metabolic bone diseases, and hypocalcaemia.

The article says active, community-dwelling New Zealanders with regular sunlight exposure do not need vitamin D testing or supplements.

Tests may need to be restricted, which might reduce the number of testing sites to only the most accurate assay-providers, say the authors.

The authors include Auckland University medicine professors Ian Reid and Tim Cundy, and bone and joint senior research fellow Mark Bolland.

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There are many high risk categories

Many reasons why vitamin D deficiency has become epidemic 26 as of Feb 2012 list without hyperlinks follows

  1. Air conditioning - to avoid the hot sun

  2. Increased use of multi-media indoors - TV, DVD, video games, and internet access

  3. More indoor jobs - more office workers, fewer farmers

  4. Living in cities more - where there is less UV and they have less opportunity to be outdoors

  5. Want whiter skin - especially women

  6. Fear skin cancer -

  7. Cholesterol reduced - which the skin need to produce vitamin D

  8. More Obesity -

  9. Soft drink cola - uses up Calcium which uses up vitamin D

    • surfers in Hawaii (PDF), who drank large amount of cola soft drink, had low levels of vitamin D

  10. Meat from factory farms - has far less vitamin D than from free-range farms

  11. Some drugs consume vitamin D

  12. increased use of polyunsaturated fats decreased bio-availablity of vitamin D

  13. Eat less liver - which used to have very large amounts of vitamin D

  14. Less Magnesium in foods - Magnesium is needed to utilize vitamin D (as well as build bones)

  15. Seniors

  16. Excessive clothing (burka, nun habit, . . .)

  17. Have a condition which Consumes vitamin D

  18. Have a condition which Prevents Adsorption in the gut

  19. Have a condition which Prevents Conversion to active vitamin D

  20. Have a condition which requires more vitamin D - or time in the sun

  21. Lactose Intolerance or Vegan – and thus not get vitamin D from milk in US and a few other countries

  22. Health reasons to avoid sun (skin cancer, burn easily - redhead, etc) - ALTERNATIVES

  23. Work long hours or night shift   Long hours reduced vitamin D by 8% – April 2011

  24. Live far from equator even more of a problem if the region is also cloudy (Washington State,

  25. DDT and some other pesticides in our bodies reduce the vitamin D perhaps 3 ng

  26. Myths about vitamin D caused people and researchers to not consider useful amounts

After surgery/trauma -which uses a lot of vitamin D

Critical Care patients need vitamin D

See also VitaminDWiki

Tags: Tests