Revision 1
March 19, 1998
by Radiation, Science, and Health, Inc.,
Edited by J. Muckerheide

1.2.6.3
Radon

1.2.6.3.3
Case-Control Studies

"In China, a meticulous study measured the radon level for 1 year in the houses of several hundred women with lung cancers and in homes of a similar number of healthy women. The results demonstrated at a 95% confidence level that women who lived in high-level radon houses (more than 350 Bq/m³) had a 80% lower lung cancer risk than those living in low-level radon houses (4 to 70 Bq/m³). (Blot et al. 1990)

"This result is opposite to the no-threshold principle estimate, according to which the lung cancer risk in high-radon houses should be 80% higher than the normal risk.

"Similarly, in one region of Japan with an average indoor level of 35 Bq/m³, the lung cancer incidence was 51% of that in a low-level radon region (11 Bq/m³) and the mortality caused by all types of cancer was 37% lower (Mifune et al 1992). Similar results showing a lack of positive correlation between lung cancer and indoor radon levels were reported from Canada, Sweden, Denmark, Finland, France, and Great Britain (see UNSCEAR, 1994, for references).

"Despite the evidence from these studies the U.S. Environmental Protection Agency has recommended remedial action when indoor radon concentrations reach 150 Bq/m³. The EPA considers that remedial action at any level down to 70 Bq/m³ would be cost-effective, even for the cost of reducing the level from 150 to 70 Bq/m³ at approximately $2 million per life hypothetically saved (Schiager 1992)"