Review of sun exposure guidance documents in Australia and New Zealand March 2022, Volume 32, Issue 1

Introduction

Australia and New Zealand have the highest and second highest rates of melanoma globally, as a consequence of mostly fair-skinned populations living in areas with high ambient ultraviolet (UV) radiation. In 2017, melanoma was the fourth most commonly diagnosed cancer in Australia, with 14 846 new cases and 1420 deaths that year.¹ Keratinocyte cancers, due to their extraordinarily high incidence, carry a very large economic burden; in 2008–09 they accounted for 8% of all health system spending on cancer in Australia (excluding cancer screening).² In addition to skin cancers, exposure to UV radiation causes premalignant skin lesions, photoageing of the skin, and eye diseases such as cataracts and pterygium.

Exposure to solar UV radiation also has benefits, most notably production of vitamin D. Adequate vitamin D status is critical to maintain optimal musculoskeletal health, and there may be other health benefits such as boosting the immune response to infection and reducing the risk of autoimmune diseases such as multiple sclerosis.³ Despite Australia’s high risk of skin cancer, the prevalence of vitamin D deficiency is not trivial; the 2011–12 Australian Health Survey found that overall 23% of Australians were vitamin D deficient (defined as blood levels of 25-hydroxyvitamin D (25(OH)D) <50 nmol/l), and in southern states in winter this was close to 50%.⁴

The UV radiation wavelengths that are the primary drivers of skin cancer and that generate vitamin D overlap to a large extent. This makes balancing the risks and benefits of sun exposure challenging.⁵ Policy, guidance and position statement documents are important for informing the population about health topics of relevance.⁶ Given the complexity in minimising the risks of sun exposure while avoiding vitamin D deficiency, it is critical that documents providing guidance are evidence based, clear and consistent in order to reduce confusion and increase behavioural action among consumers.^7,8 However, there is currently no information about how many documents include information about balancing the risks and benefits of sun exposure and about the consistency of the advice given.

This review aimed to identify guidance documents regarding the risks and benefits of sun exposure developed by government and nongovernment organisations in Australia and New Zealand, and to review their recommendations in relation to sun protection; non-vitamin D benefits of sun exposure; balance between risks and benefits of sun exposure; and sun exposure to generate vitamin D. Consistency and variation in advice with respect to sun exposure to generate vitamin D across these documents was examined in detail.

Methods

A desktop review of publicly available websites was undertaken between February and April 2021 to identify policies, guidelines or position statements relating to the risks and benefits of sun exposure in Australia and New Zealand. Search terms “sun exposure” AND/OR “vitamin D” were paired with “policy” AND/OR “guideline” AND/OR “position statement”.

Inclusion and exclusion criteria

To be included in the review, documents had to provide information about both the risks and benefits of sun exposure and recommendations regarding sun exposure to produce vitamin D production. The review was restricted to documents available on government websites, and those of public health organisations, large clinical organisations (including professional societies or large hospitals) and cancer advocacy organisations. If organisations published more than one relevant document, these were included if directed to different audiences. News and general health information webpages and blog pages were excluded.

Review process

The review aimed to extract broad information under four pre-specified themes: 1) sun protection; 2) non-vitamin D benefits of sun exposure; 3) balance between risks and benefits of sun exposure; and 4) sun exposure and vitamin D production (Table 1). Detailed information was captured for advice about sun exposure and vitamin D production across seven key subthemes: the recommended length/frequency of sun exposure; recommended time of day for sun exposure; types of activities that are recommended/advised for sun exposure; advice for different skin types; effect of sunscreen use on vitamin D production; recommended skin area for exposure; and advice in relation to vitamin D supplementation (Table 2).

Pre-specified themes were identified by areas of interest to the Sun Exposure Summit hosted by the Australian Skin and Skin Cancer Research Centre in March 2021. Subthemes for the review were also based on pre-specified areas of interest, and the reviewers were also open to additional themes that emerged from the analysis of the documents.

Guidance documents were assessed against the inclusion and exclusion criteria by two reviewers independently and differences of opinion were resolved through consultation. We then mapped which documents contained advice specific to each of the themes and subthemes.

Results

Number of policies identified

We initially identified 25 weblinks to potentially eligible documents. Six of these were not published by eligible organisation types and were therefore excluded. Of the 19 documents that met the inclusion criteria, 13 were Australian, five were from New Zealand, and one served both Australia and New Zealand; they were published by 17 organisations. Documents were developed by a variety of organisations, including five by government departments, four by hospitals and 10 by peak bodies/colleges/advocacy groups. Some of these organisations developed more than one document.

Seven documents were directed to the general public, seven to clinicians, three to both clinicians and the general public, and two to organisations such as local councils.

Themes and subthemes

Table 1 identifies whether documents provided information in relation to subthemes of the four major themes. Table 2 provides detail about the advice provided in relation to sun exposure and vitamin D production.

Table 1.     Recommendations included in 19 sun exposure guidance documents

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^a Document reference number (see full references at end of manuscript):
9 – Cancer Council Australia: Position statement – sun exposure and vitamin D – risks and benefits
10 – Cancer Australia: Lifestyle risk factor – sun exposure
11 – Victoria Health: Vitamin D and sun exposure
12 – Australasian College of Dermatologists: Consensus statement – sun protection and sunscreens
13 – Public Health Association Australia: Skin cancer prevention: policy position statement
14 – Sports Medicine Australia: UV exposure and heat illness guide
15 – New Zealand Government Ministry of Health: Companion statement on vitamin D and sun exposure in pregnancy and infancy in New Zealand.
16 – New Zealand Government Ministry of Health and Cancer Society of New Zealand: Consensus statement on vitamin D and sun exposure in New Zealand
17 – Australian Cancer Network Melanoma Guidelines Revision Working Party: Clinical practice guidelines for the management of melanoma in Australia and New Zealand
18 – Cancer Society of New Zealand: Position statement: the risks and benefits of sun exposure in New Zealand
19 – DermNet NZ: Vitamin D
20 – The Royal Children’s Hospital Melbourne: Kids health information. Safety: sun protection
21 – South Eastern Sydney Local Health District: Vitamin D in pregnancy and breastfeeding
22 – Sydney Children’s Hospital: Vitamin D therapy
23 – South Australian Health, Government of South Australia: Vitamin D deficiency in Children
24 – Health Navigator New Zealand: Vitamin D and sensible sun exposure
25 – The Royal Children’s Hospital Melbourne: Immigrant Health Service. Low vitamin D
26 – Australian and New Zealand Bone and Mineral Society, Endocrine Society of Australia and Osteoporosis Australia: Vitamin D and adult bone health in Australia and New Zealand: a position statement
27 – Osteoporosis Australia (Healthy Bones Australia): Vitamin D – consumer guide

Table 2.     Variation of vitamin D–specific sun exposure advice/recommendations

UVB/UV-B = ultraviolet B; UVR = ultraviolet radiation
^a Wording provided in this column is not a representation of full advice and may be linked to complementary or tandem advice about length/frequency of exposure time required, as detailed elsewhere in the table.

Of the 19 documents included, all provided some information about the harms of sun exposure^9-27 and 14 gave recommendations about use of sunscreen.^{9-17,20-22,25,26} Although the UV index was frequently used to underpin recommendations about when sun protection is required (N = 16)^9-22,25,27, some documents specified times of the day^{9-11,14-20,22,24-26} or year^{9-11,15-22,24-26} when sun protection was not required, while some gave information about the length of time outdoors before sun protection was required.^{9-11,14,16-19,21,24,25,27} Only eight documents provided sun protection advice for people with darker skin.^{10,11,14,18-20,22,25}

The lack of recognition of diversity was also evident in advice about balancing the risks and benefits of sun exposure. Only nine documents recognised that the balance varies according to an individual’s risk of skin cancer^{10,12,16,18,19,21-24} and only two of these also reflected that risk of vitamin D deficiency needs to be considered.^10,18

There was considerable variation between documents regarding their advice about the frequency, duration and timing of sun exposure needed to maintain vitamin D levels. In terms of frequency, four documents suggested most days^9-11,21, and two advised daily exposure.^15,16 Four of these documents used the UV index to underpin advice.^9-11,14 Regarding duration of time outdoors, in seven documents this varied according to time of day^{11,15,16,22,24,26,27} and seven provided advice according to season^{11,14-16,24,17,26}, with five providing advice according to both season and time of day.^{11,15,16,22,24,27} The advised time outdoors varied. For example, advice for exposure time in summer varied from 5 to 9 minutes per day, while advice for winter months was 30 minutes to 3 hours per day, with the difference not underpinned by skin type.

There was similar variability in the advice about the time of day optimal for time outdoors to make vitamin D in the body. For example, three documents recommended that exposure should occur mid-morning or mid-afternoon when the UV index was 3 or above^9,10,27, while two suggested early morning or late afternoon sun exposure between September and April^15,16, even though there is minimal ultraviolet B radiation available at these times to support vitamin D production.

Of the 19 documents, eight provided advice about recommended exposure times according to different skin types.^{11,14,17,20,21,23-26} Within these, the recommendations about how much more time outdoors is needed for people with darker compared with lighter skin varied. One document stated that people with naturally dark skin will need three to six times more exposure than those with light skin¹¹, while another stated that two to three times more exposure is required for those with darker skin.¹⁴ One document provided considerable detail about the exact amount of sun exposure needed to generate vitamin D according to skin colour.²⁵ One stated that extended and deliberate sun exposure without any form of sun protection when the UV index is 3 or above is not recommended for children with naturally dark skin, even for those diagnosed with vitamin D deficiency.²⁰

Thirteen documents provided advice in relation to vitamin D production and sun protection.^{9-16,18,19,21,26,27} Two documents noted that wearing covering clothing can lead to vitamin D deficiency due to limited UV radiation reaching the skin^22,24, while with respect to sunscreen, three documents commented on whether sunscreen application prevents vitamin D production.^9,12,16 Of these, two suggested that sunscreen used in a real-life setting will not influence vitamin D production^12,16, while one suggested the opposite.⁹

Five documents provided advice about the amount of skin that should be exposed to promote vitamin D production. Of these, two recommend hands and arms or equivalent area should be exposed^9,10, while three policies recommend face, arms and hands or equal surface area.^11,15,16

Of the five documents that gave advice about vitamin D supplementation, three gave advice targeted to children^20,25, and three to adults.^17,19,26 Most of these documents were targeted to clinicians and as they tended to be more focused on clinical care.^17,22,26 One document recommended that lack of sun exposure is not advised without vitamin D supplementation¹⁷, and two suggested that supplementation may be required for those months when the UV index is below 3, particularly for people who are vitamin D deficient.^18,19 Another document stated that people who are at high risk for vitamin D deficiency may require supplementation.²⁰ Two documents specifically stated that darker-skinned children cannot maintain vitamin D levels during winter time in the southern states of Australia and New Zealand, but did not recommend a specific supplement dose.^22,25

Only two documents stated that exposure to the sun confers benefits in addition to generating vitamin D.^10,18 These were melatonin production and reduction of sleep disorders. Neither document gave specific advice about behaviours necessary to obtain these sun exposure benefits.

Discussion

Although communicating the risks and benefits of sun exposure is challenging, it is important that policy documents provide consistent evidence-based recommendations to their target audience. In this review, we found considerable variation in the extent and emphasis of advice provided in the 19 guidance documents assessed. While there could be many factors contributing to this, the differences in advice given could cause confusion and reduce the likelihood of positive health-related behavioural action among the target populations.

The UV index is recognised internationally as the best method of communicating the intensity of UV radiation, and therefore the times when sun protection is required. Despite this, it was not mentioned in several documents, which either gave no information or used other methods to communicate this information.²⁸ Recent studies have shown that communication about the UV index is suboptimal and its impact on sun exposure behaviours remains low.²⁹ Ensuring that it is routinely included in all documents advising about sun exposure and protection may lead to greater awareness and use.

The advice about sun exposure needed to generate vitamin D varied markedly. The intensity of UV-B radiation, needed to generate vitamin D, varies according to latitude, season and time of day making it challenging to communicate advice at a broad public health level. Although some documents were very specific about the length of time, time of day, and amount of skin that needed to be exposed, others provided more general advice. This variation could reflect a number of factors including the intent of the guidance document, the organisation developing the document, and the uncertainty in the literature about how much UV radiation is required to maintain adequate vitamin D status. In particular, the clinical focus of documents prepared by hospitals resulted in a greater emphasis on supplementation and more technical advice than those targeted towards the general public. This confusion suggests that greater clarity might be needed in policy and guidance documents to avoid both over- and under-exposure.

The majority of the documents targeted their advice towards people with pale white to light brown skin colour, perhaps reflecting the organisations from which the documents emanated, which were often focused on cancer prevention. However, this has resulted in limited advice for people with darker skin types, for whom specific advice was lacking in most documents. The US Preventive Services Taskforce (USPSTF) emphasises the importance of communicating skin colour-specific sun exposure recommendations.³⁰ Australia has a very diverse population, and it is important that advice regarding sun protection and vitamin D account for this diversity moving forward.³¹

While the variability in the advice given may reflect the different target audiences or focus of the organisation, it is also likely that the controversy in the literature about the relative importance of vitamin D has contributed to the discrepancies. The lack of agreement in the literature about the 25(OH)D concentration that indicates vitamin D deficiency is a challenge that needs to be resolved.³² Irrespective of the cause, the consequences of the variable advice is reflected in surveys which suggest that the general public and clinicians are uncertain about how to balance the risks and benefits of sun exposure. Studies undertaken in Australia have found that almost 50% of people believe that using sun protection limits the ability to produce vitamin D, people are confused about using sunscreen, and very little guidance is provided by health professionals in relation to balancing the harms and risks of sun exposure.^33,34 This emphasises that sun exposure messaging and policies should be refocused to clearly communicate both the risks and benefits of sun exposure to improve overall health outcomes.³⁵

Spending time outdoors confers benefits beyond those related to vitamin D. Some of these may be induced by the UV-B wavelengths, but others, particularly those related to circadian rhythm, are likely to be mediated by other wavelengths. Advice to spend time outdoors early in the morning may achieve these benefits but is unlikely to result in any UV-B–mediated benefits; this wavelength dependence was not well reflected by the policies.

Previous studies have shown that lack of consistency in advice can result in people ignoring the guidance or being confused.^36-37 Varying recommendations relating to the harms and benefits of sun exposure and vitamin D production poses the question about whether guidance documents across Australia and New Zealand are currently effective in clearly articulating and communicating the relevant evidence-based information (or lack thereof) to the general public, clinicians or health professionals.³⁸ Policy communicators should be encouraged to align documents to government-endorsed recommendations or highlight areas where more research is needed before such recommendations can be made. This will reduce the risk of inconsistency, confusion and miscommunication of recommendations/advice. This will require collaboration between governments, researchers, policy makers, health promotion professionals and consumers in developing, endorsing and communicating clear and relevant recommendations.

This study has some limitations. It was undertaken using a rapid desktop review approach, and some relevant documents may have been missed. The complexity of language variations and the structure of recommendations, particularly those relating to how to maintain adequate vitamin D through time outdoors, may have influenced the way in which recommendations have been grouped in themes/subthemes. The exclusion criteria may also be considered a limitation as the manuscript does not explore documents that identified only risks or benefits of sun exposure.

Conclusion

This review identified considerable variability in the advice about the risks and benefits of sun exposure, both in the actual advice and in the wording used to convey the recommendations. The lack of recognition of diversity in how to balance the risks and benefits of sun exposure is a notable gap. Key stakeholders need to work together to increase the consistency and, if necessary, highlight the need for further research before evidence-based guidelines to inform clinicians and the general public can be provided. Such documents are key to support informed decisions about how to balance the well-known risks of skin cancer against the benefits of sun exposure.

Acknowledgement

This manuscript is part of a special issue focusing on skin cancer prevention. The special issue was supported by and developed in partnership with Cancer Council, and also supported by the Australian Radiation Protection and Nuclear Safety Agency, the Australasian College of Dermatologists and the Australian Skin and Skin Cancer Research Centre.

Peer review and provenance

Externally peer reviewed, commissioned.

Copyright:

© 2022 Verma et al. This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International Licence, which allows others to redistribute, adapt and share this work non-commercially provided they attribute the work and any adapted version of it is distributed under the same Creative Commons licence terms.