The report covers a conference held at the House of Commons in November 2005 and endeavours to devour some of the claims made by sunscreen manufacturers and cancer charities about the nature of sunlight and its effects on our health. The main argument HRF makes is that safe sunbathing is good for you, and more to the point, not getting enough sun exposure is actually potentially very harmful. Of course, it does not suggest getting sunburn.

“Dermatologists always say that tanning is bad because sunlight damages DNA of skin cells and kills them,” Gillie told me, “The way they say it makes it seem quite scary. But it doesn’t surprise me that skin cells die in the process of protecting us against the sun – bowel cells die protecting us against food.”

He adds that this process of cell death is a normal cycle of cell multiplication and death in the skin that
speeds up when the skin is exposed to UV. “I contend that a tan is part of a normal process and not pathological as dermatologists have been telling us,” he adds, “And having a tan is definitely associated with protection against cancer e.g. prostate cancer, and there is evidence for other cancers too.”

With this in mind, the HRF has come up with a how to on sunbathing so that UV users and sunworshippers can glean all the benefits with none of the harm:

1. Sunbathe safely – WITHOUT BURNING – every day if you can
2. In the UK, midday* is the best time to sunbathe
3. Start by sunbathing for 2-3 minutes, each side, gradually increase from day to day
4. Don’t use sunblock or suntan cream, when doing so
5. If you get hot or uncomfortable expose a different area or use suncream
6. When abroad, reduce exposure
7. Children benefit too, but need guidance
8. A tan is natural and is generally associated with good health

Why midday? The sun is strongest in the middle of the day and so maximum vitamin D synthesis occurs in the shortest time. This is important especially in the UK climate where it’s often overcast and UV intensity can be low. More to the point, one’s lunch hour is a great time to get out of the workplace on a sunny day (unless you’re a gardener of course, in which case you may want to sit in darkened room to eat your sandwiches), and that can have psychosociological benefits too.

Gillie adds, “Gardening is very good – you need to get as much sun/vit D as you can to see you through the winter,” he told me, “My suggestion is to protect your face with a hat much of the time because the face is otherwise always exposed – but be sure to take your shirt off and wear shorts whenever it is hot – and avoid burning.”

The full report is available as a pdf (912kb) here. I raised the issue of sunshine safety and cancer prevention in a previous write-up – sunshine, but organisations such as Cancer Research UK and RAFT (the Restoration of Appearance and Function Trust) contend that sunlight is the major risk factor for skin cancer.

UPDATE: New York Times and others are reporting on research this week that suggests that some types of sunscreen may do more harm than good, especially if they give users a false sense of security about sun exposure. Other recent work suggests that in the laboratory, at least, UVB (ultraviolet-B rays; 315–280 nm) do more damage to the DNA of skin cells (and so putatively lead to melanomas) than UVA (ultraviolet-A; 400–315 nm, lower energy per photon). The difference between UVA and UVB is simply a matter of wavelength/frequency of the ultraviolet electromagnetic radiation. The longer the wavelength (shorter frequency), the lower the energy.

How to Sunbathe Safely is a post from: Sciencebase Science Blog

Instead, the paper’s author suggest that anyone who dares to partake of the great outdoors should wear heavy cotton clothing such as denim, wool, or polyester, to block out those damaging rays. But, should this advice be well taken? Is the sun really to blame for the apparent increased incidence of skin cancer we hear reported or could it be that our car and desk bound sedentary lifestyles in which most people barely see the sun except on their foreign holidays are more to blame for compromising our immune systems and making us more susceptible to skin and various other forms of cancer.

We’ve covered this issue previously in Sciencebase, recent evidence points to a lack of vitamin D (manufactured in the skin during sunlight exposure) as being a much higher risk factor for various cancers than sun exposure itself.

The Lancet Review authored by dermatologist Stephan Lautenschlager of Triemli Hospital, in Zurich, Switzerland, analysed the various sun protection strategies used around the globe. “Wearing sun protective clothes and a hat and reducing sun exposure to a minimum should be preferred to sunscreens,” the team writes, “Often this solution is deemed to be unacceptable in our global, outdoor society, and sunscreens could become the predominant mode of sun protection for various societal reasons, for example healthiness of a tan, relaxation in the sun.”

The Review says that linen and loosely woven cotton represent less effective sun protection and that tightly woven, thick garments made of denim, wool or polyester offer the best protection; not exactly the kind of clothing anyone but heavy metal fans would want to wear on a scorching hot sunny day.

The paper points out that several studies have shown that sunscreen protects against acute UV skin damage and non-melanoma skin cancer, it is not known whether sunscreen stops melanoma developing. And, perhaps therein lies the rub, the connection between sunlight exposure and skin cancer itself is not as cut and dried as some commentators suggest.

“Suggesting wearing denim in hot weather is I think so stupid – it is very uncomfortable. Special clothing is not needed in the UK – on rare very hot days it is better simply to seek the shade – after some exposure to get your dose of D without burning, says Oliver Gillie of London-based lobby group Health Research Forum. He points out once more that insufficient exposure to sunlight could be doing us more harm than good in terms of increasing cancer risk because of a lack of vitamin D.

“A link between heart disease and insufficient vitamin D is emerging,” he told Sciencebase, “and the National Heart Forum is interested in this aspect of the debate.” Given that until now the sunlight and skin cancer debate has essentially been a Cancer Research UK monopoly, it will be interesting to see how the heart charity approaches the issues.

There have been numerous other research developments that have not seen the media light of day. “There are links with infectious disease,” adds Gillie, “Vitamin D is important for maintaining immune system resistance a fact well-known to those treating tuberculosis a century ago and well before the advent of antibiotics.”

Cancer Research UK says that 90% of melanoma is caused by sun exposure. “This is a very contentious figure,” Gillie points out, “and is disputed.” He adds that it could be that as few as one in ten melanoma cases are caused by sun exposure. “Poor immunity is a big factor in melanoma and people who are on immune suppressing drugs e.g. transplant patients are at high risk,” he says.

Such observations certainly cloud the picture of sun exposure as the big skin cancer killer. He also points out that purported mechanisms for DNA damage and thence skin cancer formation based on the photochemistry of DNA itself no longer stack up because it is now known that melanin, the pigment that gives rise to a tan is a protective agent against the very mutagenic molecules thought to form on sun exposure. Indeed, Raymond Barnhill and colleagues writing in the Journal of the National Cancer Institute (2005, 97, 195-199) found that people with melanoma survive longer if they have more sun exposure. This is doubly ironic in that post-treatment melanoma patients are usually advised to stay out of the sun.

If the British weather is kind for once this Bank Holiday Monday, it will pour sunshine down on all of us. So, leave the denim at home, unless you are a heavy metal fan, and make sure your icecream doesn’t melt while you are sunning yourself.

Do heavy metal fans get skin cancer is a post from: Sciencebase Science Blog

Either way, the recent Lancet paper, which received lots of media attention, got her all hot and bothered. She’s an earlier finisher, and is likely to be on HRT for ten years or so, is that going to mean she will get ovarian cancer. The tabloid hype surrounding the paper would seem to suggest so, but as with all statistical health studies that get pounced on by the media it’s worth taking a closer look.

Interpreting the results and scaling up to whole number women, as opposed to fractional women, over 5 years, ovarian cancer incidence for those who have never used HRT was 26 per 10,000. It was 30 per 10,000 for HRT users.

The researchers conclude that, “Women who use HRT are at an increased risk of ovarian cancer. Since 1991, use of previous has resulted in 72 additional cancers per year and 55 additional deaths in the UK.” Their results are based on the million women study, in which 500,000 were HRT and 500,000 were not.

Of course, ovarian cancer is the fourth most common cancer in women in the UK, with some 6700 developing the malignancy and 4600 dying from it every year. The high incidence of deaths is presumably down to the hidden nature of this form of cancer, which is often not detected until it has reached a lethal stage. 72 additional cancers and 55 additional deaths is a significant but not an enormous increase.

The researchers also add that, “In total, ovarian, endometrial, and breast cancer account for 39% of all cancers registered in women in the UK.1 and 2 The total incidence of these three cancers in the study population is 63% higher in current users of HRT than in never users (31 vs 19 per 1000 over 5 years, figure 6). Thus, when ovarian, endometrial, and breast cancer are taken together, use of HRT results in a material increase in the incidence of these common cancers.”

But, these are risk factors and there is simply no way of making any kind of prediction, with current medical knowledge, of whether or not a particular woman on HRT will suffer any form of cancer because of the HRT drugs she is taking. The researchers mention that as HRT use has declined in the US (partly because of the negative publicity it receives), we are also now seeing falling breast cancer rates there.

According to the author of the paper, Valerie Beral of Cancer Research UK, “It is a small but significant risk. It’s more an issue for women to think about how much they want to take HRT to relieve their symptoms against the known risks.”

However, it’s not all about hot sweats and sexual libido, as life expectancy rises in general and the aspirations of older people for a happy and active retirement rises concomitantly, it will be interesting to see whether a few less cancers will be offset by a rise in osteoporosis incidence and the other “side-effects” of the menopause (particularly early onset menopause).

An elderly neighbour of mine has been in and out of hospital with bone density issues and fractures repeatedly and at one point suffered a potentially lethal hospital-acquired MRSA (multiple-resistant Staphylococcus aureus) infection as a result. To my mind, she would most likely not have suffered in this way had she taken HRT during the early menopause. But, equally there is also the thought that had she died of cancer sooner than the osteoporosis kicked in, she would not have suffered bone density problems later in life either.

For every statistic, a counter statistic can be found and when the overall risks are very small it is difficult for the public, the media, and even the medical scientists to know for sure which way to push the agenda.

Should you worry about HRT and cancer? is a post from: Sciencebase Science Blog

Intriguingly, health and medicine writer Caroline Richmond pointed out that just such a study was actually published just three days prior to The Times article appearing.

The abstract for this paper by STUK, Radiation and Nuclear Safety Authority, Helsinki, Finland says:

“We conducted a population-based case-control study to investigate the relationship between mobile phone use and risk of glioma among 1,522 glioma patients and 3,301 controls. We found no evidence of increased risk of glioma related to regular mobile phone use (odds ratio, OR = 0.78, 95% confidence interval, CI: 0.68, 0.91).” The study encompasses digital and analog mobile phone use lasting ten years.

More than 200,000 volunteers and £3 million ($6m) of government and phone industry money will be needed to assess long-term risks of five years or so for cancer and Parkinson’s and Alzheimer’s diseases. Challis is currently negotiating for the necessary funding.

It is odd that this news story broke so close to the publication online in International Journal of Cancer. It also makes one wonder why there seems to be such a continued “hope” among certain segments of the media to find a correlation between mobile phone use and brain cancer. Surely, there isn’t an expectation that if such a correlation were ever demonstrated that the industry would cough up compensation to the literally millions upon millions of regular, long-term mobile phone users. Moreover, if such a demonstration were published might not a similar investigation raise concerns about other electromagnetic radiation sources again, such as powerlines, computer screens, microwave ovens and most recently wireless internet connections?

What do Sciencebase readers think? Would this be £3m well spent, or shouldn’t The Times simply publish a front page story about the STUK study, so similar to the one that Challis is after, that has already been carried out, peer reviewed and published.

Mobile Phones and Cancer is a post from: Sciencebase Science Blog

Members of the plant family Ranunculaceae are ever-popular at this time of year, especially in Europe, where the Christmas rose, Helleborus niger, is wheeled out as a natural decoration for countless households. Interesting then, that extracts of this plant have been used as a heart tonic in herbal medicine alongside the likes of digitalin (from foxglove) and strophanthin from the West African plant Strophanthus gratus.

H. niger contains various potent toxins in addition to cardiac glycosides helleborin, hellebrin and helleborein and saponosides and the ranunculoside derivative, protoanemonine. It was searching for information on the compound hellebrigenin (3-acetate) that brought one Sciencebase reader to this site, so here’s the structure of the molecule. This biologically active compound, which also goes by the name (3beta,5beta,14beta)-3,5,14-trihydroxy-19-oxobufa-20,22-dienolide, is a cardioactive steroid compound as well as having been demonstrated (in the 1960s) to have activity against tumour growth.

More on the Christmas Rose here.

Christmas rose and hellebrigenin is a post from: Sciencebase Science Blog

The researchers behind the work are from Duke University Medical Center, the National Institute of Advanced Industrial Science and Technology in Japan, and the Medical Research Council’s Laboratory of Molecular Biology in the UK. They explain that molecular motors are responsible for driving the separation of chromosomes during cell division. This process does not proceed normally in certain genetic disorders and if unchecked can lead to cancer.

Read the full story in my latest news round-up from spectroscopynow.com

X-rays solve transport problem is a post from: Sciencebase Science Blog

One thing the sun worshippers and those of tan-free skin agree on – getting sun burn is no fun. Now, researchers in England (A country fabled for its sunny climes) are giving volunteers a tan in a bid to find a treatment for sunburn. Anna Nicolaou of the University of Bradford, in the renowned sunspot of the North of England, is examining the biological mechanisms underlying sunburn and why it particularly affects people who don’t get a “good” tan.

The research team hopes to discover whether melanocytes that do not actively produce melanin discharge inflammatory mediators, including pro-inflammatory hormones called prostaglandins, which cause the redness, irritation and swelling of the skin that is observed in sunburn. They also hope to discover why people who tan easily are less likely to develop sunburn, contrasting to pale-skinned people who tend to sunburn easier.

You can find out more via the Bradford U press site.

Meanwhile, at the other end of the beach.

A new light-activated ingredient that mops up damaging iron could help reduce the effects of sunburn, according to research published in the Journal of Investigative Dermatology by UK scientists.

“When skin is exposed to high doses of sunlight, such as when you are sunbathing, a massive amount of free iron is released in skin cells,” explains Pourzand, “This free iron can act as catalysts for the generation of more harmful free radicals that cause severe cell damage.”

The net effect of mopping up iron released as the skin burns, is to reduce inflammation and pain, which are exacerbated by iron, and to prevent the build up of free radicals, which have been linked to an increased risk of skin cancer.

The researchers, Charareh Pourzand of the University of Bath and James Dowden, now at Nottingham University, are currently testing prototypes of the ingredient in the lab using three-dimensional human skin cultures and anticipate trialling the ingredient with human volunteers in the next two to three years.

Find out more at the Bath U press site

Sun, Sun, Sun is a post from: Sciencebase Science Blog

Now, US researchers have shown that applying too little suncream can actually turn the UV-absorbing chemicals against you.

When skin is exposed to sunlight, ultraviolet radiation (UV) is absorbed by skin molecules that then can generate harmful compounds, called reactive oxygen species or ROS, which are highly reactive molecules that can cause “oxidative damage.” For example, ROS can react with cellular components like cell walls, lipid membranes, mitochondria and DNA, leading to skin damage and increasing the visible signs of aging. The link with skin cancer itself is actually not so clear cut as some lobbyists claim.

However, when sunscreen is applied to the skin the UV filters in the sunscreen, reduce the amount of UV radiation penetrating the skin. Over time, though, the filters themselves are absorbed by the skin leaving the surface vulnerable to UV once more. The UV filters (octylmethoxycinnamate, benzophenone-3 and octocrylene) widely used in sunscreens themselves generate reactive oxygen species (ROS) in skin when exposed to ultraviolet radiation, augmenting the ROS that is naturally produced. [These new results are similar to those on which I reported in C&I ten years ago, DB]

Kerry Hanson of the University of California Riverside and colleagues now report that these three UV filters only work well if sunscreen is reapplied frequently to prevent ultraviolet radiation from reaching these filters. Without reapplication, these compounds could be just as harmful as not using sunscreen at all.

The team will publish their findings in a forthcoming issue of Free Radical Biology & Medicine.

“Sunscreens do an excellent job protecting against sunburn when used correctly,” said Hanson, who works in the laboratory of Christopher Bardeen, an assistant professor of chemistry at UCR. “This means using a sunscreen with a high sun protection factor and applying it uniformly on the skin. Our data show, however, that if coverage at the skin surface is low, the UV filters in sunscreens that have penetrated into the epidermis can potentially do more harm than good. More advanced sunscreens that ensure that the UV-filters stay on the skin surface are needed; such filters would reduce the level of UV-induced ROS. Another solution may be to mix the UV-filters with antioxidants since antioxidants have been shown to reduce UV-induced ROS levels in the skin.”

“For now, the best advice is to use sunscreens and re-apply them often – the Skin Cancer Foundation recommends every two hours, and especially after sweating or swimming, which can wash away sunscreen – to reduce the amount of UV radiation from getting through to filters that have penetrated the skin,” Bardeen said. “This, in turn, would reduce ROS generation.”

But, having read this please also read my write-up on how to sunbathe safely

Sunscreen and skin damage is a post from: Sciencebase Science Blog

Certain types of skin cancers, age-related macular degeneration (AMD) and diabetic retinopathy are likely to be among the first uses for the drug, which has already shown efficacy in pre-clinical models.

“This may be a ‘one-size fits all’ therapy, because it targets a master regulator gene called c-Jun which appears to be involved in all of these diseases,” explains Levon Khachigian, of the Centre for Vascular Research (CVR), at the University of New South Wales. “c-Jun is an important disease-causing gene,” adds Khachigian. “It stands out because we don’t see much of it in normal tissue but it is highly expressed in diseased blood vessels, eyes, lungs, joints, and in the gut – in any number of areas involving inflammation and aggressive vascular growth.

The experimental drug they are testing goes by the enigmatic name of Dz13, and with equal enigma behaves like a secret agent finding its target, c-Jun, and killing it point blank. “It is a specific, pre-programmed ‘molecular assassin’,” says Khachigian.

He and colleagues report full details in Nature Biotechnology this month. The next step will be to test the drug in a small human trial on non-melanoma skin cancers. “If such a trial were successful, it would be a significant development given the high rates of skin cancer and because the main treatment currently is surgical excision, which can cause scarring,” said Khachigian.

Chemical panacea is a post from: Sciencebase Science Blog

Lia Bartella MD and her colleagues found that NMR could reduce the need for biopsy by 58%. They demonstrated that 23 of 40 suspicious lesions could have been spared biopsy, and none of the resultant cancers would have been missed, in a study group. “All cancers in this study were identified with MR spectroscopy,” explains Bartella, “There were no false-negative results. These results should encourage more women to take this potentially life-saving test.”

More…

A peak you reach is a post from: Sciencebase Science Blog