As Australians hit the pool and beach this summer, scientists will be finalising new sun exposure guidelines. Why are they needed?
Generations of Australians have heeded sun-safe messages, slapping on wide-brimmed hats, long-sleeved shirts, wraparound sunglasses, and plenty of sunscreen.
But people need a small amount of sun exposure to produce Vitamin D and so confusion arises about whether sun safety prevents people getting enough sun. Up to one in four of us are deficient in vitamin D.
The latest guidelines will build upon those first published two decades ago, which recognised the importance of vitamin D in promoting good bone and musculoskeletal health.
“One of the reasons that the (original) risk and benefit position paper was put together was because of the recognition that sun is not all bad,” says Associate Professor Stephen Shumack of The Australasian College of Dermatologists.
Vitamin D is synthesised in the skin through exposure to ultraviolent radiation. While also present in some foods, it’s difficult to maintain adequate vitamin D status through dietary sources alone.
As well as being linked with an increased risk of falls and fractures, deficiency in the “sunshine vitamin” is also associated with other health impacts, including insulin resistance and type 2 diabetes, an increased risk of dementia, and in Covid-19 patients, longer stays in hospital.
Professor Rachel Neale at QIMR Berghofer Medical Research Institute says the new position statement has its origins in the 2021 Sun Exposure Summit where medical professionals and researchers gathered to discuss whether existing advice had the balance right.
She said it was too early to release further details. However, it is expected that the new guidelines will be released in the first half of 2023 after sign-off from partner organisations including the Cancer Council.
It’s a delicate balancing act because sunshine has well-documented “feel good” benefits.
Sunlight boosts the body’s production of serotonin to such an extent that solariums are used to treat seasonal affective disorder (a form of depression) in Scandinavian countries which have long, dark winters, says Shumack.
(Since 2015, commercial solariums have been banned in Australia.)
Exposure to sunlight also helps regulate the body’s circadian clock, and the sleep-wake cycle.
Read more: Explainer: how is sunscreen made and tested?
But when it comes to the sun, it’s possible to have too much of a good thing.
Despite decades of sun safety campaigns, from Sid the Seagull in the 1980s to the current Slip, Slop, Slap, Seek and Slide message amplified through $10 million in federal government funding during National Skin Cancer Action Week in November, Australia has the highest rate of skin cancer in the world.
This includes melanoma, the deadliest form, along with basal cell carcinoma and squamous cell carcinoma.
According to the Cancer Council, two in three Australians will be diagnosed with skin cancer during their lifetime, and as many as 2,000 Australians die of skin cancer each year.
A history of sunburn is strongly associated with the development of melanoma.
Despite this, a January 2019 nationally representative survey of Australian adults found approximately one in five adults (21%) were sunburnt on the previous summer weekend when they were outdoors, the Cancer Council states.
The guidelines will be welcomed by medical practitioners concerned that publicity about lagging vitamin D levels has been seized upon by sun-lovers to justify them baking in their backyards.
“You hear grandmother over the back fence say, ‘Look I’m lying in the sun for two hours four times a week in summer just to get my vitamin D up,’ when realistically in summer you only need a couple of minutes a couple of times a week to get the vitamin D levels up,” Shumack says.
More recently, researchers have sought to quantify the extent to which media articles about vitamin D deficiency have tended to “glorify sun-seeking” and “encourage Australians to relinquish their sun protection practices in pursuit of vitamin D”.
Results from a cross-sectional population-based study of 3614 adults published in 2021 in the Health Promotion Journal of Australia revealed that one in three (29%) respondents in 2016-17 expressed vitamin D concerns.
These concerns were measured by asking respondents whether they believed the statement that “people who use sunscreen do not get enough Vitamin D from the sun”. One in five (20%) agreed while a further 9% were unsure.
This reflected an increase in vitamin D concerns from 2010-2011 (19%) and 2013-2014 (28%), then measured by respondents’ concerns about their own vitamin D levels.
In the 2016-17 study, the researchers noted that those with vitamin D concerns were less likely to use sun protection, including on summer weekends during peak UV hours and during incidental activities outdoors.
They were also more likely to express pro-tanning beliefs and to actively seek a tan.
“Conflicting messages” could “propagate confusion about the risks and benefits of sun exposure among the general population”, the study’s authors note.
The new position statement sets out to clear up the confusion and to provide a more nuanced and tailored approach to sun exposure depending, among other things, on an individual’s skin colour.
It’s being built upon Position statement – Sun exposure and vitamin D – risks and benefits document published in 2016.
The current guidelines recommend the use of the Global Solar UV Index to indicate safe levels of sun exposure, noting that deliberate sun exposure without any form of sun protection when the UV Index is 3 or above is not recommended, even for those diagnosed with vitamin D deficiency.
These guidelines are endorsed by the Cancer Council Australia’s principal Public Health Committee, Australian and New Zealand Bone and Mineral Society, the Australasian College of Dermatologists, Endocrine Society of Australia and Osteoporosis Australia.
Research is still teasing out the role of vitamin D in human health and how it relates to sun exposure.
Supplements may be recommended for those low in vitamin D – but the evidence on whether this translates to expected health outcomes is mixed.
For example, the large-scale VITamin D and OmegA-3 TriaL (VITAL) in the US involving 25,871 adult participants found that supplementation didn’t reduce the risk of falls, while a Finnish study suggested vitamin D supplementation didn’t lower the incidences of major cardiovascular disease events or invasive cancer.
In the meantime, just as sun safe campaigns have long moved on from Sid the Seagull, so too have interventions designed to target a new generation of sun-worshippers.
Read more: How vitamin D helps prevent chronic disease.
Professor Monika Janda from the Centre for Health Services Research at The University of Queensland first worked with skin cancer patients in her homeland of Austria where, she says, melanoma rates are rising due to Europeans’ love of sun-soaked holidays in Spain and Portugal.
Among her recent research projects was a two-way interactive text-messaging intervention promoting sun protection which revealed levels of engagement as high as 82% even in the final phase, when the novelty had presumably worn off.
Driving behavioural change meant being creative and maximising the use of digital technologies used by young people who, recent research shows, are still getting sunburned.
Simple vanity also seems to be emerging as another unlikely ally in the quest for sun safety.
“There seems to be a trend for young women to be very concerned about skin aging and so they are increasingly using daily sunscreen for that reason,” Janda says.
“We’ve discussed with the sunscreen industry and the beauty industry how we could also reach young men with that message, because it would be ideal if they brush their teeth in the morning and put sunscreen on as a daily routine.
“We’re all getting older, so we have to be very mindful of protecting our skin so that it still serves us well into our 80s and 90s.”