Science / Technology - Colloquium
Monday, February 25, 2008
4:00 PM-5:00 PM
Olin Hall
107
The risk of lung cancer from exposure to residential radon and its radioactive progeny has been thought to follow the Linear-No-Threshold hypothesis, that is, any amount is bad for a person and twice the amount is twice as bad. This has been difficult to establish because the risk at typical residential exposures is small and because of confounding factors, such as smoking. Individual North American case/control studies have been unable to establish the LNT relationship with the requisite statistical certainty, and a recently published pooling of those studies has also been unable to do so. During 199097 WPI in cooperation with the Fallon Health Maintenance Organization (lead researchers: Joel H. Popkin and Zenaida Popkin) undertook a case/control study of this risk. Our results have been analyzed by a Johns Hopkins University biostatistician, Richard E. Thompson. Forty-three IQP students were involved in the study over the seven years of data taking. The study enrolled 200 lung cancer cases and 397 controls matched in age and sex, all from the Fallon clientele. Each was administered a questionnaire concerning smoking habits, use of the house, job exposures to known or suspected carcinogens, etc. Multiple, year-long measurements of radon concentrations were made in each house. The risk was analyzed by conditional logistic regression by both stratifying the data with respect to radon concentration and by a natural cubic spline fitting technique, each of which let the data determine its own functional form. Smoking, years of residency, education, income, and exposure to known or suspected carcinogens were controlled for. Contrary to the LNT hypothesis, we found that small concentrations of radon typical of most houses (but not large concentrations) are actually protective with respect to lung cancer. Furthermore, over a portion of the exposure range the results are statistically significant, an unusual result for a study of this size.. Opposition to our non-LNT results not our methodology has delayed publication to the present time.
Cost: FREE
Sponsored by: WPI Physics Department, Dr. Stephan Koehler
Suggested Audiences: College
E-mail:
sak@wpi.edu
Phone: 508-831-5090
Last Modified: February 19, 2008 at 10:12 AM
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