Biomedical subjects

Elizabeth A Casman

Publications and source records attributed to Elizabeth A Casman.

4 recordsLinked to original sources

PubMed2005

Use of expert judgment to bound lung cancer risks.

A bounding analytic technique for inferring the contribution of poorly characterized risk factors to a common health endpoint is demonstrated. Lung cancer mortalitywas chosen for the case study because the exposures responsible for the bulk of the deaths are very well-known, and the contribution of other putative causes is a focus of ongoing research and regulatory scrutiny. We elicited expert opinions on the upper and lower bounds on the fractions of the total lung cancer mortality due to individual risk factors. Interactive second-order uncertainty analysis was used to improve the experts' confidence in their bounds. From this information we calculated an upper bound on the residual fraction of deaths due to minor causes not selected by the experts.

Environmental Exposure↗

PubMed2004

The potential of next-generation microbiological diagnostics to improve bioterrorism detection speed.

Emerging, rapid, multivalent, microbial diagnostic technologies can produce results in hours, as contrasted to the standard methods that require at least the better part of a week. Used in bioterrorism surveillance in medical settings, the new biodetectors could significantly reduce the time between a covert attack and its detection. By how much is determined by the intensity of sampling. If used to screen all patients reporting flu-like symptoms to their doctors, this basic level of "front-line" sampling would reduce life-threatening medical floundering and missteps and give responders 3-5 days of warning that they otherwise would not have had. Being miniaturized and amenable to mass production, these devices could reduce the cost of screening to a fraction of current costs and so it is tempting to imagine their use in more intensive bioterrorism screening programs aimed at the apparently healthy population, programs that could detect a covert attack even before the victims felt ill. This article examines the tradeoffs between surveillance effort and probability of detection for such programs. Dual-use deployment, where the biodetector provides some medically useful information in addition to bioterrorism surveillance, is discussed.

Bioterrorism↗

PubMed2004

Bounding poorly characterized risks: a lung cancer example.

For diseases with more than one risk factor, the sum of probabilistic estimates of the number of cases caused by each individual factor may exceed the total number of cases observed, especially when uncertainties about exposure and dose response for some risk factors are high. In this study, we outline a method of bounding the fraction of lung cancer fatalities not due to specific well-studied causes. Such information serves as a "reality check" for estimates of the impacts of the minor risk factors, and, as such, complements the traditional risk analysis. With lung cancer as our example, we allocate portions of the observed lung cancer mortality to known causes (such as smoking, residential radon, and asbestos fibers) and describe the uncertainty surrounding those estimates. The interactions among the risk factors are also quantified, to the extent possible. We then infer an upper bound on the residual mortality due to "other" causes, using a consistency constraint on the total number of deaths, the maximum uncertainty principle, and the mathematics originally developed of imprecise probabilities.

Asbestos↗

PubMed2004

Elicitation of expert judgments of uncertainty in the risk assessment of herbicide-tolerant oilseed crops.

One of the lay public's concerns about genetically modified (GM) organisms (GMO) and related emerging technologies is that not all the important risks are evaluated or even identified yet--and that ignorance of the unanticipated risks could lead to severe environmental or public health consequences. To some degree, even the scientists who participated in the analysis of the risks from GMOs (arguably the people most qualified to critique these analyses) share some of this concern. To formally explore the uncertainty in the risk assessment of a GM crop, we conducted detailed interviews of seven leading experts on GM oilseed crops to obtain qualitative and quantitative information on their understanding of the uncertainties associated with the risks to agriculture from GM oilseed crops (canola or rapeseed). The results of these elicitations revealed three issues of potential concern that are currently left outside the scope of risk assessments. These are (1) the potential loss of the agronomic and environmental benefits of glyphosate (a herbicide widely used in no-till agriculture) due to the combined problems of glyphosate-tolerant canola and wheat volunteer plants, (2) the growing problem of seed lot contamination, and (3) the potential market impacts. The elicitations also identified two areas where knowledge is insufficient. These are: the occurrence of hybridization between canola and wild relatives and the ability of the hybrids to perpetuate themselves in nature, and the fate of the herbicide-tolerance genes in soil and their interaction with soil microfauna and -flora. The methodological contribution of this work is a formal approach to analyzing the uncertainty surrounding complex problems.

Agriculture↗