How many cases does it take to make residential radon epidemiology (EPI) studies meaningful?
To have a reasonable certainty in the conclusions, many thousands of cases are required to detect the increased risk of lung cancer due to radon. This is because the more things that cause a disease the harder it is to separate one cause from another, thus it takes many cases to pinpoint the risk from each separate cause. The U.S. Public Health Service radon experts estimate that 10,000 to 30,000 cases, and twice as many controls would be needed to conduct a definitive epidemiologic study of residential radon lung cancer risk. The residential studies conducted to date have all included between 50 and 1500 cases and thus have been too small to provide conclusive information.
