By Richard Gray–
Researchers studying how sun exposure affects the risk of developing melanomas discovered that those who spent between four to five hours in the sun each day over the weekend were less likely to develop tumours.
The findings appear to contradict the commonly-held belief that longer time spent in the sun increases the risk of skin cancer.
Instead, the study shows that while excessive exposure to the sun – and particularly sunburn – can lead to melanomas, regular doses of sun for up to five hours a day at weekends can be protective.
The study comes just days after Andy Flowers, the England Cricket team head coach, underwent surgery to remove a malignant melanoma below his right eye.
Professor Julia Newton Bishop, an epidemiologist who led the research at Leeds University, said it seems regular exposure helps the skin adapt and protect itself against the harmful affects of sunshine. Increased levels of vitamin D made in the skin while exposed to sunlight may also be protective.
Professor Newton Bishop said: “The relationship between the amount of sun we are exposed to and the risk of melanoma is complicated – we have known for a long time that melanomas are something to do with sun exposure and fair skin.
“Our paper suggests that moderate regular sun exposure may actually reduce the risk. We are talking about quite high levels of sun exposure for the protective effect with an average of four to five hours a day at weekends.
“It appears that in moderation, sun exposure can be protective, but it is when you have extreme sun exposure that it becomes a problem. So in the UK sunburn is a potent risk factor because we have a habit of not getting much sun at home and then suddenly exposing our skin when we go abroad.”
Malignant melanoma is the most serious type of skin cancer and around 10,000 people in the UK are diagnosed with the disease each year. The incidence of the disease is rising faster than any other cancer in the UK and has quadrupled since then 1970s. Around 2,000 die each year in this country from skin cancer.
Public health experts blame the rise in skin cancer in the UK on growing use of sun beds and an increase in the number of holidays people take abroad.
Harmful ultraviolet light from the sun is thought to trigger skin cancer by causing damage to the DNA in the skin.
But the new study by Professor Newton Bishop and her colleagues, which is published in the European Journal of Cancer, suggests that regular sun exposure can help the body prevent this damage.
The researchers examined the sun exposure behaviour and skin type of 960 melanoma patients and 687 controls who had not been diagnosed with skin cancer.
After adjusting the results to account for deprivation, they found that participants with fair skin, freckles and blonde or red hair, were most at risk of developing melanomas as where those who had suffered severe sunburn.
But they also found that regular exposure to the sun at weekends of more than five hours had the most significant effect that protected the participants from developing melanoma.
Unfortunately for those with sensitive skin, this protective effect was not seen in people who had red hair and freckles, perhaps due to their tendency to burn far more quickly.
The researchers also measured levels of vitamin D in 1,167 of the participants, who were aged between 18 and 76 years old, and found that those who received regular doses of sun exposure at weekends also had raised levels of vitamin D.
Professor Newton Bishop said: “There is some evidence from other studies that suggests that vitamin D may help to reduce melanoma size and improve prognosis, but it could be that there is some adaptation going on in the skin which reduces the damage from ultraviolet light.
“Melanoma, in the UK, is a cancer of people who work inside who have short bursts of sunshine when they are on holiday. If they are working in offices all week, then when they go sunbathing on holiday, they don’t have the protection that might naturally develop.
“Regardless, people need to take steps to avoid getting sunburnt – particularly at this time of year when the days are shorter and there is much less sunshine around. People who go away for winter sun holidays are particularly at risk.”
Researchers at Mayo Clinic have found a significant difference in cancer progression and death in chronic lymphocytic leukemia (CLL) patients who had sufficient vitamin D levels in their blood compared to those who didn’t.
In the Mayo Clinic study, published online in the journal Blood, the researchers found that patients with insufficient levels of vitamin D when their leukemia was diagnosed progressed much faster and were about twice as likely to die as were patients with adequate levels of vitamin D.
They also found solid trends: increasing vitamin D levels across patients matched longer survival times and decreasing levels matched shortening intervals between diagnosis and cancer progression. The association also remained after controlling for other prognostic factors associated with leukemia progression.
The finding is significant in a number of ways. For the first time, it potentially offers patients with this typically slower growing form of leukemia a way to slow progression, says the study’s lead author, Tait Shanafelt, M.D., a hematologist at Mayo Clinic in Rochester, Minn. “This finding may be particularly relevant for this kind of leukemia because although we often identify it at an early stage, the standard approach is to wait until symptoms develop before treating patients with chemotherapy,” Dr. Shanafelt says. “This watch and wait approach is difficult for patients because they feel there is nothing they can do to help themselves.” “It appears vitamin D levels may be a modifiable risk factor for leukemia progression. It is simple for patients to have their vitamin D levels checked by their physicians with a blood test,” he says. “And if they are deficient, vitamin D supplements are widely available and have minimal side effects.”
This research adds to the growing body of evidence that vitamin D deficiency is a risk factor for development and/or progression of a number of cancers, the researchers say. Studies have suggested that low blood vitamin D levels may be associated with increased incidence of colorectal, breast and other solid cancers. Other studies have suggested that low vitamin D levels at diagnosis may be associated with poorer outcomes in colorectal, breast, melanoma and lung cancers, as well as lymphoma.
Replacing vitamin D in some patients has proven to be beneficial, the researchers say. For example, they cite a placebo-controlled clinical trial that found women who increased their vitamin D intake reduced their risk of cancer development.
In this study, the research team enrolled 390 CLL patients into a prospective, observational study. They tested the blood of these newly diagnosed patients for plasma concentration of 25-hydroxyl-vitamin D and found that 30 percent of these CLL patients were considered to have insufficient vitamin D levels, which is classified as a level less than 25 nanograms per milliliter. After a median follow-up of three years, CLL patients deficient in vitamin D were 66 percent more likely to progress and require chemotherapy; deficient patients also had a two-fold increased risk of death.
To confirm these findings, they then studied a different group of 153 untreated CLL patients who had been followed for an average of 10 years. The researchers found that about 40 percent of these 153 CLL patients were vitamin D deficient at the time of their diagnosis. Patients with vitamin D deficiency were again significantly more likely to have had their leukemia progress and to have died, Dr. Shanafelt says.
“This tells us that vitamin D insufficiency may be the first potentially modifiable risk factor associated with prognosis in newly diagnosed CLL,” he says.
The study was funded by the National Institutes of Health, Gabrielle’s Angel Foundation for Cancer Research, the Henry J. Predolin Foundation, Vysis, Inc., and the Mayo Hematologic Malignancies Fund. The authors declare no conflicts of interest.
By Andrew Schneider
WASHINGTON (May 24) — Almost half of the 500 most popular sunscreen products may actually increase the speed at which malignant cells develop and spread skin cancer because they contain vitamin A or its derivatives, according to an evaluation of those products released today.
AOL News also has learned through documents and interviews that the Food and Drug Administration has known of the potential danger for as long as a decade without alerting the public, which the FDA denies.
The study was released with Memorial Day weekend approaching. Store shelves throughout the country are already crammed with tubes, jars, bottles and spray cans of sunscreen.
The white goop, creams and ointments might prevent sunburn. But don’t count on them to keep the ultraviolet light from destroying your skin cells and causing tumors and lesions, according to researchers at Environmental Working Group.
In their annual report to consumers on sunscreen, they say that only 39 of the 500 products they examined were considered safe and effective to use.
The report cites these problems with bogus sun protection factor (SPF) numbers:
- The use of the hormone-disrupting chemical oxybenzone, which penetrates the skin and enters the bloodstream.
- Overstated claims about performance.
- The lack of needed regulations and oversight by the Food and Drug Administration.
But the most alarming disclosure in this year’s report is the finding that vitamin A and its derivatives, retinol and retinyl palmitate, may speed up the cancer that sunscreen is used to prevent.
A dangerous additive
The industry includes vitamin A in its sunscreen formulations because it is an anti-oxidant that slows skin aging.
But the EWG researchers found the initial findings of an FDA study of vitamin A’s photocarcinogenic properties, meaning the possibility that it results in cancerous tumors when used on skin exposed to sunlight.
“In that yearlong study, tumors and lesions developed up to 21 percent faster in lab animals coated in a vitamin A-laced cream than animals treated with a vitamin-free cream,” the report said.
The conclusion came from EWG’s analysis of initial findings released last fall by the FDA and the National Toxicology Program, the federal government’s principle evaluator of substances that raise public health concerns.
EWG’s conclusions were subsequently scrutinized by outside toxicologists.
Based on the strength of the findings by FDA’s own scientists, many in the public health community say they can’t believe nor understand why the agency hasn’t already notified the public of the possible danger.
“There was enough evidence 10 years ago for FDA to caution consumers against the use of vitamin A in sunscreens,” Jane Houlihan, EWG’s senior vice president for research, told AOL News.
“FDA launched this one-year study, completed their research and now 10 years later, they say nothing about it, just silence.”
On Friday, the FDA said the allegations are not true.
“We have thoroughly checked and are not aware of any studies,” an FDA spokesperson told AOL News. She said she checked with bosses throughout the agency and found no one who knew of the vitamin A sunscreen research being done by or on behalf of the agency.
But documents from the FDA and the National Toxicology Program showed that the agency had done the research.
“Retinyl palmitate was selected by (FDA’s) Center for Food Safety and Applied Nutrition for photo-toxicity and photocarcinogenicity testing based on the increasingly widespread use of this compound in cosmetic retail products for use on sun-exposed skin,” said an October 2000 report by the National Toxicology Program.
FDA’s own website said the animal studies were done at its National Center for Toxicological Research in Jefferson, Ark.