Rates of one form of skin cancer may be elevated in areas with naturally high levels of the radioactive gas radon, a UK study suggests. But researchers caution the findings do not prove that radon raises people's risk of the disease, known as squamous cell carcinoma - a highly curable type of skin cancer.
Their study looked only at wider geographical patterns, showing a correlation between an area's radon levels and rates of the skin cancer. Radon - a gas produced from the decay of naturally occurring uranium in soil and water - is already considered a risk factor for lung cancer.
The US Environmental Protection Agency (EPA) estimates that radon contributes to about 21,000 lung cancer deaths each year - although smoking is also involved in the majority of those cases.
For the new study, reported in the journal Epidemiology, UK researchers looked at skin cancer rates across 287 postal codes in south-west England. They found that the rates of squamous cell carcinoma varied by postal code. In some areas, the yearly rate was about 35 cases or fewer per 100,000 people; in others, it was as high as 182 cases per 100,000.
There was an association between an area's average household radon level and its rate of squamous cell skin cancer. In postal codes where the radon level topped 230 Becquerel per cubic meter (Bq/m3), the rate of the cancer was 76 percent higher versus areas with the lowest average radon levels.
In the UK, radon levels above 200 Bq/m3 are considered "action" levels - that is, people are advised to take steps to cut their home's radon concentration. That can mean measures like sealing off cracks in basements and floors, and installing ventilation systems.