British Study Finds No Radon, Childhood Cancer Link

By Alicia Ault

NEW YORK Jun 11, 2002 (Reuters Health) - Two recent studies of households in England, Scotland and Wales suggest that high levels of naturally-occurring radiation, such as radon, do not translate into a greater risk of cancer in children who live in those homes.

The researchers, who published their studies in the British Journal of Cancer, said there has been some suggestion from previous studies that radon and cosmic or ground radiation might contribute to childhood cancers such as leukemia and lymphoma.

But their results showed otherwise.

"Although some areas have higher levels of radon or gamma radiation than others, the differences don"t seem to be big enough to produce a detectable effect," said Sir Richard Doll, a professor at the University of Oxford, and chairman of the UK Childhood Cancer Study group that conducted the research.

In the first study, the scientists compared radon measurements from the bedrooms and living rooms of 2,226 children who had cancer with those from homes of 3,773 children who were healthy.

Higher radon levels did not seem to play any role in promoting six different cancers, including acute lymphoblastic leukemia and other leukemias, non-Hodgkin"s lymphoma, Hodgkin"s disease, central nervous system tumors and other solid tumors.

In fact, the researchers found that increasing radon levels were associated with lower cancer rates. But they said they aren"t sure why. Not surprisingly, there were higher radon readings in wealthier homes, which tend to have double-glazed windows, central heating, and other amenities that keep houses more airtight.

But the cancer rates were no higher or lower for those homes.

The authors said that even though they may not have gotten accurate average radon readings--levels vary with the season---the levels they did measure "offer no support for the suggestion that radon concentration is associated with the incidence of childhood cancer in general, or of leukemia in particular."

In the second study, a detector was used to measure natural gamma ray radiation in the homes of 2,165 children with cancer and 5,086 homes of healthy children, for 5 to 7 months. Based on the results, "there is no suggestion of either an increasing or decreasing risk from any of the groups," said the authors.

There has been scant suggestion that natural radiation from outer space or the ground might contribute to childhood cancer, but it has been a worry of British parents, according to Doll.

Alan Kinniburgh, vice president of research of The Leukemia & Lymphoma Society in White Plains, New York, said that it is reassuring to know that radon and background radiation may not be linked to these types of cancers, but the results are not surprising, since they are viewed as unlikely contributors.

Rates of leukemia, lymphoma and brain cancer in children are very low, he said, noting that there are only about 2,400 new childhood leukemias each year in the US. The likely cause in most cases seems to be gene transcription errors, not environmental factors, he said.

Radon is a naturally occurring gas that seeps into buildings from the surrounding soil. A person is unable to see or smell radon gas and the only way to know if a problem exists is to test for it. Long-term exposure is known to increase the risk of lung cancer in adults, particularly in smokers.

SOURCE:

• British Journal of Cancer 2002;86:1721-1726, 1727-1731.