HOLD onto your hats. The thinned ozone layer is likely to increase the risk of British children suffering skin cancer during their lifetime by up to 16 per cent, according to a new review of the risks of ultraviolet radiation to heath, published this week by the National Radiological Protection Board. And hats, especially for schoolchildren stuck in sunny playgrounds at midday, are the best protection.
Sunshine is proving increasingly deadly to the young in Britain, says the board. Cases of malignant melanoma have doubled in the past 15 years. It accounts for 1 in 12 cancers among people in their 20s and 30s. A prime cause of the increase, says Chris Sharp of the NRPB, is people taking more clothes off more often, whether at home or on Mediterranean holidays.
But the increase in ultraviolet radiation reaching the surface of the Earth through the thinned ozone layer may also have to share the blame. A study of sunlight reaching the NRPB鈥檚 Oxfordshire headquarters has found a 5 per cent increase in UV radiation since 1988, though the trend is not yet statistically significant.
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The report is based on a detailed review of research from an advisory group chaired by cancer specialist Sir Richard Doll. It says that 鈥渃umulative exposure鈥� to sunlight, especially in the first two decades of life, is at least as important as accidental sunburn in increasing the risk of skin cancer and of cataracts. Exposure during childhood appears to increase risk into old age.
鈥淵oung men who spent much of the Second World War stripped to their shorts on duty in the Far East are showing high rates of skin cancer today,鈥� says Sharp. He applauded efforts by the Health and Safety Executive to persuade building workers to keep their clothes on.
鈥淐hildren should not be sent out in the sun in the middle of the day if they don鈥檛 want to go,鈥� says Sharp. The rule applies particularly to those with large numbers of moles, who seem to be especially at risk.
The board is calling for better daily forecasts of high UV radiation levels. 鈥淐urrent Meteorological Office forecasts 鈥� giving, for instance, a burning time of 30 minutes are 鈥� of limited use,鈥� says Sharp. 鈥淪ome people will start burning in 10 minutes, and the result is people start ignoring the forecasts.鈥�
The board also warns that sunbeds and sunlamps, used for cosmetic tanning, can increase risks and 鈥渟hould be discouraged鈥�. The conventional view that the lower-frequency UVA radiation given off by sunlamps makes them safe is unsound, it says. According to Doll鈥檚 report, there is 鈥渋ncreasing evidence that UVA may also contribute to the production of cancer as it penetrates deeper into the skin and has the capacity to damage DNA indirectly and to induce skin tumours鈥�.
The range of diseases that may be caused by sunlight is increasing, and now includes lip cancer, chronic lymphatic leukaemia and degeneration of the retina, a major cause of blindness, says the report.
The study has been unable to resolve the critical question of whether slapping on sunscreens and donning sunglasses may sometimes increase dangers. Sunscreens protect against sunburn, the report agrees, 鈥渂ut the protection against melanoma provided by sunscreens is unclear鈥�.
One European study found that people who used sunscreens suffered more melanomas 鈥� possibly because the protection encouraged them to stay in the sun longer, says Sharp. Similarly, some sunglasses protect against glare, but may not protect against cataracts.