Scientists Claim to Have Found Link Between Radon Gas, Leukemia
LONDON (AP) _ Three British scientists claimed Friday they had found a previously unsuspected link between naturally occurring radioactive radon gas and cancers including leukemia.
In an article in The Lancet, a respected British medical journal, three physicists from Bristol University said an international analysis found a connection between radon levels and the incidence of certain non-lung cancers.
The study used data from 15 countries, including the United States.
Radon is a dense, odorless gas, created by the radioactive decay of small quantities of uranium found in many types of rock. It has been known for decades to cause lung cancer.
But it previously was not thought to have any relationship with other cancers because scientists believed radon’s rapid decay meant it could only be dangerous to the lungs.
The scientists said they found an association of radon exposure and leukemia in both children and adults; brain, spine, bone and skin cancer in children; and kidney and skin cancer in adults.
″Our observations in general clearly warrant urgent and detailed further investigations to determine whether radon is indeed the causative factor as we hypothesize,″ the Bristol University team concluded.
Margo Oge, director of the radon program at the U.S. Environmental Protection Agency, said that researchers sought such a link before but have been unable to verify one.
Studies purporting to link radon to non-lung cancers ″haven’t been able to pass scientific scrutiny,″ Oge said in a telephone interview. She said she could not comment on the British study in greater detail because she had not yet seen it.
Dr. Denis Henshaw, one of the authors of the report, acknowledged the results ″may seem somewhat startling at first.″
But, he said, ″it is good news scientifically because we believe we may have found a cause for cancer you can do something about.″
Radon seeps into homes and buildings through foundations and floorboards. Steps can be taken to keep it out, including sealing floorboards with plastic sheeting and installing below-floor extractor fans to channel the gas away.
The scientists said they stumbled on the link to other cancers last September when they realized radon is highly soluble in the fatty globules found in bone marrow.
″Previous researchers seem to have made the mistake of only considering the amount of radon in the blood, where it appeared the effect was negligible,″ said physicist Jonathan Eatough. ″But when the fatty globules are examined, the radon becomes a significant factor in the dose to the bone marrow.″
The scientists said they discovered the radon count in fatty globules could be up to 16 times greater than for blood. They said they believe the globules act like sponges and are able to concentrate inhaled radon that enters the bloodstream.
Radon, being radioactive, damages red marrow cells that lie alongside the fatty globules.
Once the scientists found the fatty-globule connection, they began an extensive international comparison where the incidence of cancers and radon levels were well documented.
The scientists said they do not yet have firm evidence of a causal relationship, but they tried to assess what percentage of cancers might be linked to radon exposure in the home.
Worldwide, the scientists estimate that nearly a quarter of myeloid leukemia cases are caused by the gas.
In Britain, they said 6 percent of childhood cancers, 12 percent of myeloid leukemia in adults, and 72 percent of the skin cancer melanoma in adults, may be linked to radon.
The results are more startling in other countries where radon levels are higher, the scientists said.
In Sweden, for instance, the scientists said up to 35 percent of myeloid leukemia cases could be linked to radon and in Germany and Italy, 25 percent of such cases.
The scientists said the association of radon exposure and incidents of skin cancer was unexpected.
But they said it could explain current anomalies in the pattern of these cancers, such as the high incidence of melanoma in Scandinavian countries, even though the population there is not exposed to high levels of harmful ultra-violet rays from the sun.
The countries in the study were Canada, Denmark, Finland, France, West Germany, Ireland, Italy, Japan, Norway, Netherlands, Poland, Switzerland, Sweden, Britain and the United States.