Watching the cricket with Dad in the last summer of his life, the skin cancer ads were on high rotation. Enormous black melanoma cells split and rampaged through animated arteries as we sat there in awkward, painful silence. Those same cells were rampaging through his body and he’d be dead by autumn. “There’s nothing healthy about a tan,” said the urgent, formal voiceover.
Dad was the sort of bloke who, proudly, had never sunbaked in his life. He claimed to have been sunburnt only once, when he was 12, in Cairns in 1942. By contrast, when I was that age, in the 1970s, tanning was almost a competitive sport. You’d get that first burn out of the way sometime in late spring, peel a layer, and you’d be set for summer. My brother had a melanoma cut out last year, one of 14,000 Australians to do so in 2017. This is said to be Australia’s “national cancer” and it is my family cancer, too. Aside from a first cousin’s fatal lung tumour, I can’t think of any other cancer that any blood relative has had.
You’d think I’d be slip-slop-slapping with the best of them with my fair-skinned children. And I do, I do, but every time I lather on the factor 30, I can’t help wondering if it’s doing any good. Global melanoma rates continue to rise. The only demographic anywhere in which it is falling, we’re told, is Australians under 40, demonstrating the flow-on effect of this country’s ground-breaking “Slip, Slop, Slap” campaign which began in 1981. I was surprised, however, to find that this isn’t the full story. Fewer are dying, but when researchers burrowed into the stats coming out of GP clinics in Queensland, they found that young adults are getting the cancer in greater numbers than my generation did at the same age.
At the same time, there’s a lot of new research on the benefits of sunshine that has nothing to do with the well-known, but probably overstated benefits of vitamin D for conditions such as heart disease, diabetes, prostate cancer, breast cancer, obesity and multiple sclerosis. People with more of the “sunshine vitamin” in their system have fewer of these diseases. Yet giving people vitamin D pills in trials appears to do almost nothing to fix them. This has raised the notion that vitamin D might just be an indicator of how much sun you’re getting and that maybe there’s something else in the sun that’s good for you. And it has made a lot of smart people question that urgent voiceover’s claim that there’s nothing healthy about a tan.
First up. Pretty much no one has ever said there’s anything healthy about sunburn. “Don’t get burnt” remains as imperative as it’s ever been. Beyond that, however, the story gets a whole lot more interesting. So I’m reading through the literature, following one citation to the next, and I come across this line from the Cancer Epidemiology, Biomarkers and Prevention journal, published by the American Association for Cancer Research, in 2011. “Despite public perception, the scientific evidence that sunscreen prevents skin cancer is controversial.” It makes me stop, grab a coffee, call out to the wife: “The evidence that sunscreen prevents skin cancer is controversial.” Who knew?
For example, in 1995, a study of 400 melanoma patients and 600 without the cancer in Sweden found sunscreen users were 1.8 times more likely to get melanoma than those who never used it. “Our results support the hypothesis that sunscreens do not protect against melanoma,” the authors concluded. Critics explain this and other such results by the fact that sunscreen users stayed in the sun longer. But isn’t that the point? Such results from Europe may be scoffed at – because what would they know about melanoma? Australia is the melanoma capital of the world. Right? Wrong. That title actually belongs to the Land of the Long White Cloud. New Zealand, the bulk of whose population live further south than the NSW-Victoria border, tops the world in the melanoma death rate. Queensland would win if it was a country, but as a nation, Australia comes second. Norway third. Swaziland is sixth. Unlike other skin cancers, melanoma is slippery and complicated.
The 10-times more common and 100-times less deadly types of skin cancer, basal cell carcinoma and squamous cell carcinoma, are directly related to how much sun you’ve had in your life. They’re the ones routinely gouged off people’s noses and hands, the parts of the body most exposed to sunlight. Whereas it’s been known since at least the 1970s that melanoma is a cancer of office workers like my dad, rather than outdoor workers. And it hits them on the body parts that don’t see so much sun, but which get burnt on occasion, like men’s torsos and the back of women’s legs.
Here’s the thing: while melanoma rates do tend to increase as you get closer to the equator, the rates of many other diseases fall away. It was reported as early as 1950 that the US had four times more multiple sclerosis (MS) deaths at 40 degrees from the equator than at 30 degrees, which, in Australia, is equivalent to the latitudes of Launceston in Tasmania and Coffs Harbour on the NSW north coast. An Oxford University study in 1961 got similar results studying the ethnic European populations of the southern hemisphere, including Australia.
In 2004, Dr Michael Goldacre from Oxford University thought that a neat way to study the link between MS and sunshine would be to look for correlations between skin cancer and MS. He found that skin cancer was indeed 50 per cent less common in people with MS. This result didn’t prove anything, but it raised the intriguing question: is the sun protective against MS? Associate Professor Ingrid van der Mei from the University of Tasmania’s Menzies Institute for Medical Research had begun working on this question in the 1990s. “Back in the 1960s, we actually knew that there was a bit of a latitude gradient for MS, but at the time we had no idea that ultraviolet light could actually influence your immune system,” she says.
“They stopped the research for maybe 30 years, then, in the 1990s, there was this whole area of photoimmunology where we did realise the immune effects that sunlight might have.”
Australia was a perfect place to look, because it had a lot of people with the same fair skin tones living between, say, Cairns in the tropics and Hobart, where she was. And when she started correlating the numbers, they stacked up. Tasmania had six times the rate of MS as north Queensland. But she found an even stronger correlation when she calculated the number of sunny days in her key locations.
Temperature and rainfall didn’t seem to have an influence. That led to a more detailed study of the sun-exposure histories of MS patients compared to those who didn’t have the disease. She found that more sun exposure in childhood seemed to reduce the risk of developing MS. She also found that the link between a lack of sunshine and MS was stronger than the positive link between too much sun and melanoma. “I’m not sure why that is,” she says. “It just shows that the link between MS and [lack of] sunshine is really strong.”
All skin cancers combined kill about 2000 Australians a year, most of them elderly. MS is not fatal, but it most commonly hits women in their 30s and causes a lifetime of creeping, severe debilitation. Currently, 25,600 Australians carry that life sentence, up 20 per cent in just the past seven years, at a cost of $1.75 billion, almost three times melanoma’s economic burden. Van der Mei’s notion that sunlight was more closely linked to MS than melanoma had a lot of critics. They rightly pointed out that our recall of sun exposure as children is pretty flimsy, yet the bulk of evidence pointing to melanoma being caused by sun exposure has been gleaned from the exact same type of study.
Van der Mei conducted more studies, showing in 2010 that MS relapses decreased as vitamin D levels increased. So will vitamin D stop MS? The world’s first trial of the vitamin to prevent MS is currently being conducted in Australia and New Zealand. But smaller studies conducted overseas have shown that giving vitamin D to patients in the early stages of the disease had no benefit. It’s been known for about a century that vitamin D deficiency caused the bone-warping disease, rickets. Increasing vitamin D above a concentration of 50 nanomoles per litre gave no extra bone benefits, so that became the desired level. Few other benefits of vitamin D were known.
But in the first decade of this century, vitamin D was hot. A lot of studies came out showing associations between it and a veritable textbook full of ailments. These can perhaps be best summarised by a 2014 review of the literature in the BMJ (formerly the British Medical Journal) which looked at 95 studies covering almost 900,000 people. It concluded that for every extra 25 nmol/l of vitamin D in the blood, death from all causes fell by 16 per cent. The strongest benefits were seen in heart disease, lymphoma, upper digestive tract cancer and respiratory diseases. It was even true for melanoma. Call it the Sunshine Paradox. You’re more likely to get the sunlight disease, melanoma, and more likely to die from it, if you have low levels of the sunlight vitamin. It found that vitamin D deficiency caused more ill health in the US than both alcohol and lack of exercise.
The largest ever study of vitamin D deficiency in Australia found that 58 per cent of women in the southern states were deficient in spring, when there is the lag from winter darkness, but even in summer, 42 per cent were deficient. The authors recommended safe sun exposure as the best way to fix it.
Vitamin D pills have been pushed as a way to tackle the effects of a lack of sunshine. Australians spend $150 million a year on them. With all this swirling around about how good vitamin D appeared to be and how deficient the population was, the race was on to prove that vitamin D pills would cure all sorts of ailments.
Over the past few years, however, as the randomised controlled trial results came in, they have been consistently underwhelming.
Despite the fact that low vitamin D levels in the blood were strongly associated with bad health, taking vitamin D pills didn’t do much to make it better. Not even for osteoporosis, the complaint for which it is most commonly prescribed. But the poor showing of vitamin D trials has opened the shutters for a more dangerous idea. That it’s the sunshine, stupid.
Back in the 1990s, Scott Byrne, now an associate professor at Sydney’s Westmead Institute for Medical Research, was doing his PhD on the ways in which sunlight caused skin cancer. It appeared to turn off the immune system, thus allowing non-melanoma skin cancers to proliferate. “That’s why sunlight is such a powerful carcinogen,” he says. “It has the capacity to both damage the DNA which is required for the development of cancers, and it suppresses the very immune response that helps us fight those cancers.” Through his PhD and postdoctoral research in the US, the young Australian discovered that one of the culprits of this immune suppression, “regulatory B cells”, was activated by UV radiation.
The wonder drugs of modern melanoma treatment, the immunotherapies, enlist the patient’s own immune system to fight the cancer. Some of them do this by turning off these very same regulatory B cells. One of the side effects of immunotherapy, however, can be autoimmune disease, whereby the strengthened immune system gets out of control and starts attacking the patient’s own body.
Byrne became fascinated by this yin-yang aspect of UV radiation, the way it caused cancer and fought autoimmune disease. “The best drugs we have at our disposal for treating multiple sclerosis, for treating type 1 diabetes, for treating rheumatoid arthritis and so on, are drugs which actually suppress the immune system. Here we were with sunlight suppressing the immune system, so I started doing a bit of reading around sunlight and autoimmunity.”
When he came across the latitude gradient of MS, it sparked his interest in finding out what was happening. “There’s obviously something evolutionarily unique about this thing we get exposed to. We’ve evolved to live under the sun.”
Using mice with an MS-like disease, Byrne’s team at the University of Sydney showed, in 2016, that UV light did activate the regulatory B cells and it did suppress the disease. This was a major breakthrough, because others had already shown that vitamin D had nothing to do with it. “We’re not proposing and we certainly don’t want the message to be that we need to get more sunlight,” says Byrne. “Because we know that sunlight causes skin cancer and that’s a really big problem in this country.
“Long-term, where everyone seems to be going is precision medicine. Which is personalised medicine where a patient goes to their GP who has all their information – their lifestyle, their genetic profile – and they’ll be able to say to this person, ‘You need to get X amount of sunshine, at this time of day, three times a week.’ But we’re a long way from that.”
Byrne’s work has only touched the surface. He reels off a list of other immune mechanisms unrelated to regulatory B cells that are known to be activated by sunlight. “One of the questions I always get asked by scientists at conferences: ‘Hey, you just told us that sunlight is immune suppressive. Why then don’t we erupt in infections when we go out in the sun?’ And the answer is that ultraviolet radiation actually activates other defence mechanisms against those types of infections, protecting us from them.” There is solid science, for example, that UV radiation might be behind why we rarely get flu in summer, and that sunlight therapy was a sometimes surprisingly effective treatment for tuberculosis before the era of antibiotics.
In Western Australia, Professor Prue Hart was working on the same ideas as Byrne. She and other researchers at Perth’s Telethon Kids Institute have shown that just exposing obese mice to UV radiation makes them significantly thinner and reduces markers for metabolic disorders like type 2 diabetes. Hart had already published research into low vitamin D levels in children: basically that kids with low vitamin D at age six were significantly more likely to have asthma, eczema and allergies by 14. But she also knew that vitamin D pills had been shown not to fix these problems. She suspected that low vitamin D was not the cause of their ill-health, but rather, was a marker of low sun exposure; that UV light was giving some other benefit.
She received funding to recruit 40 people in the early, precursor stages of multiple sclerosis. But sunny Perth was not a good place to find early MS sufferers and she only signed up 20 subjects. All 20 were given vitamin D supplements to remove that as a variable. Then, three times a week for eight weeks, half of them were stripped to their undies and put in an upmarket sun booth to give them the equivalent of a few minutes of midday summer sun – the same treatment dermatologists give people with the skin condition psoriasis (another disease which appears to have increased in recent decades and which has a strong latitude gradient). The dose steadily increased as their skin tanned. After one year, seven of the 10 in the treatment group had progressed to full-blown MS, whereas all 10 of the group that didn’t get the UV blast developed the disease.
The small numbers meant it wasn’t statistically significant, but the study, published in 2017, was sufficiently tantalising to catch the attention of dermatologist Professor Richard Weller in Scotland. Weller, like all good dermatologists, had believed that “we should all live in caves and never let a photon hit our skins”. But he was studying the mechanisms of skin behaviour in sunlight and was looking at nitric oxide (NO), a simple molecule which had earnt three pharmacologists the 1998 Nobel Prize for medicine for their discoveries of how important it was for widening arteries, regulating blood pressure, battling infections, initiating erections, preventing blood clots and acting as a signal in the nervous system. Like vitamin D, NO was hot.
Weller went on to discover that the skin released NO into the body when exposed to sunlight. Being a dermatologist, his first thought was that it probably played a role in causing skin cancer. “But, in fact, I found the most important thing was this nitric oxide released by the skin in sunlight lowers blood pressure,” he says. “The importance of that is that high blood pressure is the leading cause of premature death and disease in the world today. And sunlight – separately from vitamin D – lowers blood pressure.”
A 1998 German study – published in the British medical journal The Lancet – had exposed a group of people with mild hypertension to summer-sun equivalent on tanning beds three times a week for six weeks and another group to winter-sun equivalent. After three months, all 18 people in the summer-sun group had normal blood pressure whereas the winter-sun group remained hypertensive. The difference was assumed to be vitamin D, but again, numerous attempts to produce the same effect with pills have failed.
As a graduate doctor, Weller had spent a year working in Cairns and had noted that Australians seemed healthier than Brits. “You put it down to your athletic lifestyle, your sporting prowess, but it’s a bloody lie. You’re a bone-idle bunch of bludgers. You smoke, you drink too much. You’re just the same as us Brits.” It all got him thinking about the role of sunlight in longevity. “So I then went and looked at the data and, lo and behold, all the data is that the more sun you have, the longer you live. There’s good data in Scandinavia showing that patients with non-melanoma skin cancer, basal cell skin cancer in particular, have a longer life expectancy than people who’ve never seen a doctor.” He’s referring to a study of 30,000 women – but not men – followed for 20 years which found that as sun exposure increased, so did life expectancy – up to 2.1 years – mainly because of lower cardiovascular disease and other non-cancer causes of death. In fact – and don’t try this at home – women who smoked and got a lot of sun lived longer than non-smokers who avoided the sun.
“When you’re diagnosed with [non-melanoma] skin cancer, your life expectancy goes up,” says Weller. “So the first thing I say to my patients when I diagnose these things is: ‘Congratulations, you’ve got a basal cell cancer, you’ll be leaving my consulting room with a longer life expectancy than when you came in.’ This tells us two things: number one, I’m a bad dermatologist; number two, I’m a good doctor, because what matters is a long, healthy life. Yes, you might have wrinkled, aged skin with ugly scars from your skin cancers. You look old, but by god, you are old.”
Blood pressure also has a latitude gradient. “More sunlight equals lower blood pressure, whether you’re looking at populations around the world or individuals by season … if I did what my dermatology colleagues want and got everybody to live in a cave and completely eradicated skin cancer but had a 1 per cent rise in deaths from heart disease and stroke, we’d be behind. And if everybody lived in a cave, you would still not eradicate skin cancer.”
In Australia, you’re 19 times more likely to die of all heart diseases than all skin cancers. The highest rate of heart disease deaths in 2015 was in Tasmania with 257 per 100,000, the lowest was the Northern Territory, with 111 per 100,000, though the other states aren’t in strict latitudinal order. Meanwhile, Scotland has one of the highest rates of MS in the world and the Orkney Islands in the far north – where one woman in every 170 has the condition – has the highest. So it was a natural fit that Weller would attempt to replicate Hart’s study where finding patients was easier. “If we can show this works, we have a safe, cheap treatment for MS. All around the world we have phototherapy units in dermatology departments.”
I asked Weller what he’d do with his kids if he lived in Australia. He stressed that sunburn in childhood was a risk factor for melanoma and that most people should continue slip-slop-slapping. His children are from Ethiopia, however, and even in Scotland they have mandated sunscreen application. “I have to give a letter to my children’s school every year saying, ‘Relax, give the sunscreen to somebody else. It’s Scotland. It’s raining. Get real.'”
Then he gets controversial. “There is absolutely no evidence that sunscreen saves lives.” Weller is talking about all-cause mortality: that any lives saved by avoiding skin cancer may be outnumbered by those lost through the net effects of sunlight deprivation.
Earlier this month, the Pacific nation of Palau joined Hawaii in banning sunscreens containing various chemicals, including oxybenzone and octinoxate, thought to be harmful to young coral. Sunscreens don’t just sit on your skin. They are absorbed by the body and get into the circulation system. A study of human breast milk in Switzerland found that 85 per cent of 54 samples had UV filters in them, correlating with the mothers using sunscreen or, more often, other cosmetics containing UV filters.
Some sunscreens have copped a bit of heat in recent years for using nanoparticles and others causing allergic reactions. Perhaps of more concern is their potential to disrupt hormones. The Cancer Council of Australia’s website says “there is no evidence of any chemicals approved for use in Australian sunscreens disrupting the endocrine system”. It cites a review of the literature by the Therapeutic Goods Administration in 2001. Not surprisingly, there’s been a bit of science done in the past 17 years.
Dr Joanna Ruszkiewicz from the department of molecular pharmacology at the Albert Einstein College of Medicine in New York conducted the most recent review of all the studies on the endocrine disruptors in sunscreen. I tracked her down via Skype in Peru, where she was trekking.
Yes, she’d been wearing sunscreen that day. She thought sun protection important. But her review most definitely contradicted the Cancer Council’s claim that there were no endocrine disruptors in sunscreen. However, she said the paucity of research meant the extent of those effects remained unknown. Would she wear it if she were pregnant? “No. And if I had a child, I would not put it on them until they were about five.”
For all the vigour with which sunscreen has been thrust upon us, there has only been one randomised controlled study on whether it works against melanoma. That was performed by Professor Adele Green in Nambour, Queensland in the 1990s, and when I read her paper, it was convincing. Green recruited 1621 residents of the Sunshine Coast town and asked half to apply factor-16 sunscreen to their head, neck and arms every day for five years, and the other half to do what they always did. Ten years after the study finished, 11 of the daily sunscreen group had developed a melanoma compared to 22 in the control group, just scraping into “statistical significance”.
Now the senior scientist at the QIMR Berghofer Medical Research Institute in Brisbane, Green is one of the world’s pre-eminent skin cancer experts, having devoted much of her career to the subject since her PhD in the 1980s. A 1981 article in The Lancet had pointed out the lack of direct evidence that sunlight caused melanoma. In an effort to rectify this, Green began a ground-breaking study in which she selected 183 melanoma sufferers and matched them to 183 people of similar age from the same suburb in Queensland. Each was asked to recall all episodes of severe sunburn where pain had persisted for more than 48 hours. The core finding was you more than doubled your risk of melanoma if you’d had six or more severe burns in your life (like me). You increased it by 1.5 times with two to six severe burns. But the strongest predictor of whether one person got melanoma over another – stronger than burn history, sun exposure or skin type – was the presence of moles on their arms (phew, not me).
While we are told that melanoma rates in younger Australians have started to fall, Green was one of the authors of a 20-year study, published in April, that showed that melanoma rates in Queensland were actually rising in all age groups. This seemed extraordinary – that young adults today are getting more melanomas than when my cohort was their age. The death rate from melanoma, however, has plummeted. Young adults are 81 per cent less likely to die of it today than we were in the early 1980s. Green says they were counting in situ melanomas, the small, early stage of the cancer which hasn’t yet spread. The rate of in situ melanomas has spiked sharply in this shaded generation. The statistic about melanoma rates falling in the young concerns “invasive” melanoma. Green explains that it’s all down to increased awareness and screening.
“The more you look for melanomas, the more you find because of the vast sea of moles … As you can imagine, there’s a spectrum of moles that go from normal to funny looking, and some of those can be quite risky.” Technology is picking up more of these atypical moles and calling them melanoma than would have been found in the past, she says, hence the increased incidence, and it’s also catching the invasive melanomas much earlier, saving lives. This could also explain why Norway’s death rate is almost the same as ours. They just aren’t as vigilant.
When I float the idea past Green that staying out of the sun might increase our risk of conditions like MS, she dismisses it in the Australian context. “If you were talking about northern Norway versus southern Norway, you might have something to talk about there. For a Queenslander, just walking out in our sunlight, we’ve got such a huge ultraviolet index year round, anyone who’s not living in a cave is going to get a modicum of ultraviolet light and vitamin D, that’s all passé and agreed … Then, if you’ve got dark skin and you’re at a high latitude – that is where protection might actually have some ill effect.”
What about the non-vitamin D benefits? “There’s a lot of work going on in that. There are vague studies, but nothing has ever been nailed … In this country, yes, you can have very good mental effects of ultraviolet, but there’s not too many things where people can say we need more than a bit of ultraviolet for our general wellbeing. But I do contest what you’re hinting at, which is certainly out in the literature with some people saying ultraviolet is all good and not bad. I’m saying that excessive ultraviolet in a fair-skinned person is bad, without protection …
“When people start talking about sun protection doing away with the benefits of ultraviolet, I challenge them to come up with anything substantive that’s consistent and strong and biological, to prove that.”
Craig Sinclair from Cancer Council Victoria recalls the period 10 years ago when that organisation started copping flak for its strident opposition to people getting sunlight. “There was a period there where vitamin D was set up as the saviour of all ills, really, and there were many who were critical of our SunSmart message, saying it had gone too far. We were obviously concerned about that. We had never confronted a situation except when dealing with the solarium industry, where people were criticising our long-established and well-trusted brand.”
Sinclair’s solution was to get Osteoporosis Australia, the Australia and New Zealand Bone and Mineral Society, the Endocrine Society of Australia and the Australasian College of Dermatologists in one room with the Cancer Council and nut out some common ground. They came up with the solution that when the UV index was over three, it was time to cover up. And when it was less than three – in the southern states, that’s all winter and early morning and late afternoon in summer – it was time to get some sun. The Cancer Council has a SunSmart app that you can personalise for your skin type and location. It tells you when to cover up each day to comply with the new guidelines.
I’ve downloaded it, but never got around to using it. Because the message I’ve taken from all this doesn’t seem that complicated. Know your skin. Get out in the sun, but respect it like the god it has often been perceived to be. Don’t burn.