This is not to say that Taubes and Von Bubnoff see no value in epidemiology. They cite its ability expose unexpected side effects of prescription drugs, track the progression of chronic illnesses within and between populations, and identify predictors of disease. Three major success stories in the field are the linking of dirty drinking water to cholera, smoking to lung cancer, and exposure to the sun to skin cancer. In addition to describing these merits of observational studies, Taubes and Von Bubnoff also point out that the clinical trials are not without their own deficiencies. For instance, there are some things that clinical trials simply cannot test. Large populations are difficult to assess, especially over long periods of time; and there are also ethical considerations. You cannot design a clinical trial to test the relationship between arsenic and leukemia, for example, because you cannot ask a control group to expose itself to potentially harmful levels of chemicals. That is where observational studies come in and, according to Taubes, “The appropriate question is not whether there are uncertainties about the epidemiologic data, rather, it is whether the uncertainties are so great that one cannot draw useful conclusions from the data.”
I called Dr. Julie Parsonnet, an epidemiologist at Stanford University who I had met at a conference in California recently, and asked for her take on Taubes’ article. She agreed that despite a “veneer of negativity,” his work mostly treats the distinction between epidemiological and clinical trial research fairly. Parsonnet emphasizes, though, that the latter can often be as problematic and unreliable as the former. “All research has to be looked at in the context of everything else that’s known about the subject,” she told me. Taubes, to his credit, predicts in his piece that epidemiologists like Parsonnet “will argue that they are never relying on any single study,” and that “this in turn leads to the argument that the fault is with the press, not the epidemiology.”
This is an astute and incredibly important observation. Epidemiological studies may be inferior to clinical trials at producing conclusive answers to some medical quandaries, but the real problem is that most people, including many journalists who write about this stuff, do not know the key differences between both types of research.
Matthew Nisbet, an assistant professor of communication at American University, who runs a blog about how journalists and others frame science, criticizes Taubes for not making enough of this angle and leaving the impression that “science can’t be trusted.” Monday, on his blog, Nisbet wrote that readers need epidemiology articles that are more like “a detective story hung around just how amazingly complex it is to figure out the linkages between diet, drug therapies, and human health.” Indeed, there are a few excellent of examples of such work, including one about a potential cancer cluster by Chris Bowman at The Sacramento Bee.
But where I agree that Taubes’ article tended to be couched in an unnecessarily negative tone, I also believe his approach was valid. As Nisbet himself asks, “Is it really ‘bad science’ or is it bad communication?” Regardless of whether a reporter seeks to discuss epidemiology generally, like Taubes and Von Bubnoff, or specifically, like Bowman, there is the original dilemma that most readers do not know the basic differences between observational studies and clinical trials. With this in mind, the generalized approach that Taubes took seems all the more useful.
“The fundamental problem is not necessarily reconcilable here,” Parsonnet told me, “because people have an innate desire to protect their health and the press has an innate desire to provide interesting information to sell newspapers.” As long as that is the case, there will continue to be three basic types of epidemiological journalism: that which typically finds its way into papers and magazines, heralding the latest research; that which, like Bowman’s piece in the Bee, relies on its own investigations; and that which, like Taubes’ and Von Bubnoff’s work, takes the wide-angle, explanatory approach.