Vitamin D Deficiency in Australia: Who Should Be Tested and Who Should Not

This article sets out what Australian sources state about vitamin D deficiency, and in particular about who should be tested for it and who should not. It is general information only and is not a substitute for the advice of a general practitioner (GP). The authorities referred to throughout are the Royal Australian College of General Practitioners (RACGP), the Medicare Benefits Schedule (MBS), the Australian Bureau of Statistics (ABS) and the bodies that publish sun protection guidance.

Two statements are often placed side by side as though they conflict. The first is that vitamin D deficiency is common in Australia, particularly in winter. The second is that the RACGP does not recommend routine testing for it. Both are supported by the sources, and this article explains how they fit together. In summary, a population figure describes how many people have a low reading, while a testing criterion describes who is likely to benefit from a test. The two are different questions, and each is answered in a different document.

How common is vitamin D deficiency in Australia?

The most cited Australian measure comes from the ABS. Its article on vitamin D draws on the Australian Health Survey: Biomedical Results for Nutrients, 2011-12, and was released on 11 December 2013. The figures below describe 2011-12 and are reported as published.

1. About 23 per cent of adults, or about 4 million people, had a blood level of 25-hydroxyvitamin D below 50 nanomoles per litre (nmol/L).
2. The proportion differed by season: 36 per cent in winter, against 14 per cent in summer.
3. It also differed by age: 31 per cent of adults aged 18 to 34 years, against 15 per cent of those aged 65 to 74 years.

The ABS grouped low readings into bands. A reading of 30 to 49 nmol/L was classed as mild, 13 to 29 nmol/L as moderate and below 13 nmol/L as severe.

Two points follow from these figures. The first is that the seasonal gap is large, which is consistent with the common observation that winter is when low readings are most frequent. The second is that a figure of this kind is a statistic about a population. It is not a criterion for testing an individual. The finding that roughly one adult in four had a low reading in 2011-12 does not lead the RACGP to recommend that every adult be tested, as the sections below explain. The age pattern may also be unexpected: in this survey the proportion was higher among adults aged 18 to 34 years than among those aged 65 to 74 years.

What the cut-offs mean, and why documents differ

A reading has meaning only against a cut-off, and Australian documents do not all use the same set of bands.

The ABS and the RACGP each use 50 nmol/L as the line below which a reading is regarded as low. The ABS then divides low readings into mild, moderate and severe, as set out above. The RACGP guidance, in its resource titled First do no harm and revised on 1 November 2022, refers to 12.5 nmol/L in connection with short-term high-dose therapy, which is close to, but not identical with, the ABS boundary of 13 nmol/L for a severe reading. An older article in Australian Prescriber, published in 2010, used a different set of bands again, and no value is taken from it here.

The practical consequence is that a reported number should not be read from memory, or from a table on a web page. A result is read against the current guidance by the treating doctor, who will also consider the person’s circumstances and the reason the test was requested. For that reason this article provides no table for a reader to interpret a personal result.

A note on symptoms is also appropriate. Tiredness, aches and low mood are often mentioned in connection with low vitamin D. They are not specific to it, since each has many other causes, and a level can only be established by a blood test. A symptom alone is therefore not a reliable basis for concluding that vitamin D is low, or that it is adequate.

Who the Medicare rebate covers

The RACGP guidance, revised on 1 November 2022, states that vitamin D testing is “not routinely recommended for adults (including those who are pregnant), children or healthy infants”. It also states that testing funded by the MBS is limited to patients who meet listed criteria. Those criteria are set out in MBS item 66833, which sits in Category 6 (Pathology), Group P2. There are 11 of them, labelled (a) to (k). The item’s start date, description and fee were last updated on 1 November 2014.

Three clauses summarise the position as the sources state it.

1. The RACGP does not recommend routine testing of adults, children or healthy infants.
2. Testing outside the listed criteria is not among the situations that the MBS funds.
3. The wording of the criteria is for the treating GP to apply. One criterion, for example, refers to “chronic and severe lack of sun exposure for cultural, medical, occupational or residential reasons”. Whether a particular person’s circumstances fall within that wording is a clinical judgement, and this article does not suggest that any reader does or does not qualify.

The text of the 11 criteria is set out in the MBS itself. It is not reproduced here, because the schedule is the authoritative source, its wording is applied by the doctor, and the item may be amended. A reader who wishes to see the criteria should read item 66833 directly, or ask a GP to explain how it applies.

A rebate and a recommendation are easily confused. The question of who may have a test funded is answered by the MBS. The question of who should be tested is answered, for general practice, by the RACGP. The table below sets out what each source establishes, and what it leaves open.

What follows a low result

Treatment follows a doctor’s reading of a result and is not a matter for self-selection. The RACGP resource is nonetheless the document on which general practice relies, and its statements are set out below as published, with their date, for information only.

1. The RACGP guidance states cholecalciferol 25 to 50 micrograms (1,000 to 2,000 international units, IU) daily for adults with mild, uncomplicated deficiency.
2. The RACGP guidance states a target of about 10 to 20 nmol/L above the 50 nmol/L cut-off.
3. The RACGP guidance states that short-term high-dose therapy is not used routinely, and describes it in connection with a serum level below 12.5 nmol/L, higher body mass, or the advice of a specialist.
4. The RACGP guidance states that a result should not be retested within 3 months, and that the same laboratory should be used for the repeat. It also notes that the half-life of 25-hydroxyvitamin D is about 3 weeks.
5. The RACGP guidance states that supplementation is contraindicated in granulomatous disease, metastatic bone disease and sarcoidosis.

Each figure above is the RACGP’s, as revised in November 2022. None is a recommendation to a reader. A suitable amount for any person depends on the result, on other medicines taken, and on conditions such as those in clause 5, and for that reason it is a GP, and not a table, that settles it. The final clause also bears on supplements bought without a test. A person with one of the listed conditions would be affected by it whether or not a result had been obtained, and the point is a reason for speaking to a doctor before starting any supplement, not a reason for alarm.

Sun protection and vitamin D: how the two messages fit

A second source of hesitation is that the advice appears to point in two directions. Skin cancer prevention guidance asks Australians to protect their skin. Vitamin D, to the extent that the body makes it in the skin, depends on some exposure to sunlight. The sources cited here reconcile the two by treating them as questions about groups of people, and not as a single rule for everyone.

Neale and others published a revised position statement for Australian adults in the Australian and New Zealand Journal of Public Health in February 2024. Its abstract states that the balance of risks and benefits of sun exposure differs by person, and gives three examples.

The Cancer Institute NSW publishes guidance on sun exposure and vitamin D that is organised by skin type. For the general population, it advises protecting the skin when the UV Index is 3 or above. For skin types 1 to 4, it advises five forms of sun protection on days forecast to reach 3 or more, and advises against spending time outdoors deliberately in order to make vitamin D. For skin types 5 and 6, it advises spending enough time outdoors where possible, with no routine sunscreen unless the person is outdoors for a long period.

Read together, the two documents do not contradict one another. They describe different people. A person told to protect the skin, and a person told that routine sun protection is not recommended, have each been given advice suited to their own risks. Neither document is a licence to seek sun for its own sake, and neither states a number of minutes outdoors, so none is given here. Which group applies to a particular person is a matter for that person and a doctor, and not for a general article.

What people say, and what the guidance says

Three beliefs are common in public discussion of vitamin D. Each can be set against what the sources say.

1. That sunscreen and sun protection campaigns are the cause. The sources cited here do not link the survey figures to sunscreen use, so this article makes no claim either way. What the sources do state is that the balance of risk and benefit varies by skin type and risk, which is the reason for group-specific advice.
2. That winter days are short and many people work indoors. The ABS figures support the seasonal part of this belief, since 36 per cent of adults were below 50 nmol/L in winter against 14 per cent in summer. The ABS figures cited here are reported by season and age and not by occupation, but one MBS criterion refers to chronic and severe lack of sun exposure for occupational reasons, among others, so the concern is recognised in the schedule.
3. That it is better to be deficient than sunburnt. This presents a choice between two harms. The guidance does not frame it that way. It states that the balance differs by person, and it directs people at higher skin cancer risk to protect their skin, while describing a different position for deeply pigmented skin.

There is a fair point in the common concern that a person with a real risk factor should be able to ask for a test. The RACGP does not dispute that. The listed criteria exist for people in that position, and a person who believes that a criterion applies is entitled to raise it with a GP, who applies the wording.

Questions to take to a GP

A person considering a test or a supplement may wish to raise the following with a GP. The list is a prompt for discussion and not advice.

1. Does any risk factor that applies to me match a listed criterion for a funded test?
2. Have any symptoms persisted, and could they have another cause?
3. Which medicines and conditions do I have that bear on a test or a supplement?
4. What does a result mean against the current RACGP guidance, and which laboratory and units were used?
5. If a level is low, when should it be retested?

Points to Confirm With Your GP

This article has set out general information only. The RACGP is the authority on whether testing is recommended, the MBS is the authority on which tests are funded, and the ABS is the source of the survey figures. Each figure is attributed to its document and date, and none replaces a doctor’s reading of an individual result. A person with a question about vitamin D, a test or a supplement should confirm the position with a GP.

Sources: RACGP, First do no harm: Vitamin D testing, revised 1 November 2022 (https://www.racgp.org.au/clinical-resources/clinical-guidelines/first-do-no-harm/gp-resources/vitamin-d-testing); Medicare Benefits Schedule, item 66833 (https://www9.health.gov.au/mbs/fullDisplay.cfm?q=66833); Australian Bureau of Statistics, Vitamin D, from the Australian Health Survey 2011-12, released 11 December 2013 (https://www.abs.gov.au/articles/vitamin-d); Neale and others, Balancing the risks and benefits of sun exposure, Australian and New Zealand Journal of Public Health, February 2024 (https://research.bond.edu.au/en/publications/balancing-the-risks-and-benefits-of-sun-exposure-a-revised-positi/); Cancer Institute NSW, Sun exposure and vitamin D (https://www.cancer.nsw.gov.au/prevention-and-screening/preventing-cancer/preventing-skin-cancer/reduce-your-skin-cancer-risk/sun-exposure-and-vitamin-d)