Methodological issues in the epidemiological investigations of lung cancer related to low-level risks

There are several major issues that create great difficulties in the study of low-level risks for lung cancer. Further attention needs to be addressed to the difficulties in design, ascertainment, classification, confounding and analysis found in the environmental epidemiological aspects of the investigation. Host predisposition is an important factor that requires further characterization in the process of conducting these environmental epidemiological investigations. Within the exposure assessment aspects of these investigations, major difficulties arise from the need to obtain total exposure estimates, dose estimates and in evaluating the interactions of the several pollutants of concern in exposure settings of interest. Low-level risks for lung cancer imply difficulties in the assessment of exposure-dose pattern. Further, bio-markers are needed to focus more on dose. Further, low-level risk ratios produce difficulties in distinguishing the effects of confounders. In order to facilitate further studies of lung cancer related to low-level risks, we will have to create new, more specific, and more efficient study designs. These studies will require much better exposure assessment and case ascertainment than typical of previous studies, and more complete measurement of confounders.