Residential radon exposure and lung cancer: Variation in risk estimates using alternative exposure scenarios

Abstract

The most direct way to derive risk estimates for residential radon progeny exposure is through epidemiologic studies that examine the association between residential radon exposure and lung cancer. However, the National Research Council concluded that the inconsistency among prior residential radon casecontrol studies was largely a consequence of errors in radon dosimetry. This paper examines the impact of applying various epidemiologic dosimetry models for radon exposure assessment using a common data set from the Iowa Radon Lung Cancer Study ( IRLCS ). The IRLCS uniquely combined enhanced dosimetric techniques, individual mobility assessment, and expert histologic review to examine the relationship between cumulative radon exposure, smoking, and lung cancer. The a priori defined IRLCS radon -exposure model produced higher odds ratios than those methodologies that did not link the subject's retrospective mobility with multiple, spatially diverse radon concentrations. In addition, the smallest measurement errors were noted for the IRLCS exposure model. Risk estimates based solely on basement radon measurements generally exhibited the lowest risk estimates and the greatest measurement error. The findings indicate that the power of an epidemiologic study to detect an excess risk from residential radon exposure is enhanced by linking spatially disparate radon concentrations with the subject's retrospective mobility.

Radon and Lung Cancer in the American Cancer Society Cohort

“…Although this could conceivably be an artifact of the choice of administrative data boundaries, this finding may also be due to higher residential radon concentrations in the Northeast and other factors unaccounted for in the analysis including possible regional differences in time spent at home (53). Although there is no information on time-activity patterns for characterizing time spent at home for individuals in the CPS-II cohort, results from the U.S. National Human Activity Pattern Survey showed that time spent in a residence was consistent across all 10 regions of the United States (54).…”

Exposure to residential radon causes lung cancer

“…18 -20 Epidemiologists maintain that the ecologic study design should be reserved for generating hypotheses rather than estimating risk. Our research group 13 and others 21 have argued that the lack of significant findings of some of the earlier residential case-control studies is attributable to random misclassification of risk factors, primarily from poor assessment of radon exposure, which reduces a study's power to detect an association.…”

“…These findings strongly suggest that previous radon studies may have actually underestimated the risk posed by residential radon, because exposure misclassification was found to bias the studies toward finding no association. 13 In summary, risk estimates from rigorously designed analytic epidemiologic studies provide compelling evidence that prolonged residential radon exposure increases the risk of lung cancer.…”

“…Nonetheless, Duport's statement indirectly addresses the importance of accurate dosimetry in environmental epidemiology, a topic of great priority to our research group. 12,13,22 In fact, substituting less accurate dosimetry data in case-control studies reduces the ability to detect an association. [10][11][12][13]21,22 Furthermore, studies that incorporate enhanced dosimetry methods find higher risk estimates.…”

“…[10][11][12][13]21,22 Furthermore, studies that incorporate enhanced dosimetry methods find higher risk estimates. [10][11][12][13] In summary, an abundance of scientific evidence has clearly demonstrated that prolonged residential radon exposure increases the risk of lung cancer.…”