Thursday, April 24, 2008

One scare deserves another: Global warming cancer warning

I was born and bred in the tropics but have fair, Irish-type skin and I have lots of skin cancer so I have no doubt that warmer climates can be bad for you -- but the problem is a known effect of greater exposure to UV, not warmth! The study below is epidemiological so we must not be surprised to see the usual blinkered idiocies in it. And we don't have to look far to find such idiocies. The authors seem to overlook, for instance, the possibility that people go out in the sun more when it is warmer!! So it might not be warmth itself that causes the observed effect but rather the increased UV that people get as a result of going out in the sun more when it is warm. Quite brain-dead. Anyway the worriers below will no doubt be pleased to hear that temperature records kept by the Hadley Centre and others show that global warming peaked in 1998 and has not risen since

Global warming could lead to higher rates of skin cancer by amplifying the harmful effects of the sun's rays, scientists said. New evidence suggests that the same amount of sunshine becomes more likely to trigger cancer as temperature rises. The findings imply that a 2-4% increase in average summer temperatures could produce "substantial increases" in numbers of new skin cancers, say the researchers.

Scientists from the Netherlands and Argentina analysed data from two surveys of non-malignant skin cancer in the US. The incidence of cancer in the 10 regions studied correlated strongly not only with local levels of sunlight, but also with average daily maximum temperature in summer.

For cases of one type of skin cancer called squamous cell carcinoma, incidence increased by 5.5% per degree centigrade rise in temperature. The incidence of another type, basal cell carcinoma, rose by 2.9% per degree centigrade increase.

The findings tied in with previous research on mice which showed that increasing room temperature enhanced the induction of cancer by a given level of ultraviolet (UV) radiation. Effective UV dose in the mouse experiments increased by 3-7% for every degree centigrade of extra warmth.

The new research led by Dr Jan van der Leun, from the energy consultants Ecofys Netherlands in Utrecht, appears in the Royal Society of Chemistry journal Photochemical & Photobiological Sciences.

Ambient UV radiation only explained about 80% of the variation in skin cancer incidence, the scientists said. Other factors included genetic background and sun-seeking behaviour - and now, it appeared, temperature.

The researchers wrote: "Mainly owing to the substantial summer temperature differences between the West coast and other parts of the USA with comparable ambient UV loads [But ambient UV loads may not be the same as experienced UV loads -- due to different behaviors by people under different temperatures], we found evidence that some of the remaining variance in incidence may be attributed to temperature. These figures would imply, for instance, that with a long term increase of summer temperatures by 2-4% we could end up with substantial increases in incidence of skin carcinomas, which have already risen to very high numbers over the last century in white Caucasians."


Thalidomide returns

Thalidomide, the drug that blighted a generation of children half a century ago, is back on the market in Europe as a powerful cancer treatment. The European drug agency yesterday gave clearance for thalidomide to be sold on prescription for treating newly diagnosed multiple myeloma. It has been available, in a limited way, for some years since its powerful effects on cancer and leprosy were identified.

But campaigners, including those damaged by the drug when they were still in the womb, are anxious that its new-found popularity does not lead to more babies being harmed. Freddie Astbury, the president and founder of the campaign group Thalidomide UK, said that since the drug resurfaced, hundreds of damaged babies had been born in Brazil, where it has been used since 1985 to treat leprosy. There had been no such cases in the US or Europe, he said, but admitted that he was worried by the increased availability of the drug. “The trouble is that some hospitals in Europe have chosen to get the drug from Brazil, where it is cheaper,” he said.

Thalidomide UK and other patient groups had been working with the European Medicines Agency (EMEA) for more than five years on a plan to control access to the drug once it was licensed, Mr Astbury said. “We’re never fully going to know how the plan will work until the drug is used on a large number of patients,” he said. “I’d never say there will never be another thalidomide child in Europe, but I think they are the best guidelines we could have achieved.”

The approval given by the EMEA means that the US company Celgene will be the only licence-holder in Europe, and will be responsible for ensuring that the guidelines are observed. No other manufacturers and distributors of thalidomide can now supply the drug across the EU.

Thalidomide was originally marketed in the late 1950s as a treatment for morning sickness in pregnant women. It was only when babies began being born disabled that the dangers became apparent. The catastrophe was a landmark in the development of safer systems for approving drugs.


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