Evolutionary theory unites all aspects of modern biology. So, wouldn’t you want your doctor to understand how evolutionary theory explains the development of drug resistance in bacteria? Or any other host of clinical ailments? I know I would! Unfortunately, medical curricula in the United States do not explicitly integrate evolutionary theory into coursework and training. Dr. Benjamin Auerbach is an expert in the intersection between evolutionary theory, anatomy, and biological anthropology. Below, he addresses the importance of training medical practitioners as scientists not as mechanics. —JMO
By Benjamin Auerbach, PhD, Department of Anthropology, University of Tennessee
You probably have heard the maxim about cleanliness, but good hygiene in all aspects of your life couldn’t be more important, or serious, than it is now. And I’m not referring to the most widespread flu outbreak on record (in the 13 years these data have been tracked). Instead, I’m referring to a bigger problem. In July 2017, the World Health Organization issued a news release that gonorrhea, the sexually-transmitted bacterial disease also known as “The Clap,” is becoming resistant to antibiotics—in other words, it is becoming a “superbug”. Antibiotic-resistant gonorrhea infections have been identified in at least 77 countries. This is alarming news for the post-antibiotic era, which has witnessed the rise of multiple antibiotic-resistant or untreatable superbugs. Gonorrhea joins a growing list that includes well-publicized drug-resistant strains of tuberculosis, MRSA (methicillin-resistant Staphylococcus aureus), and Clostridium difficile (colloquially called C. diff) bacteria, as well as less-publicized but equally deadly bacteria that cause pneumonia (Streptococcus pneumoniae), gastroenteritis (“stomach flu” caused by Campylobacter strains), and sepsis (Pseudomonas aeruginosa), among half a dozen others.
The World Health Organization has called for medical practitioners to encourage better preventative measures, in addition to pushing for more governmental funding to find new antibiotic drugs to treat the lengthening rogues list of superbug bacteria. At first glance, the search for more drugs seems like a reasonable response to the crisis. But when we consider the realities of evolution, and the history of antibiotic resistance, searching for new drugs may be more an act in futility. Bacterial strains evolved resistance to most antibiotics within a decade—and some much faster—after the drugs were introduced. (The CDC provides a frightening summary of these trends here). This is because the introduction of antibiotics is creating a selection pressure on bacteria, favoring the survival of strains that develop resistance. If the medical doctors who run the WHO were thoroughly trained in biology, then why would they think that more drugs are a solution to this epidemic problem?
Few scientific surveys have been conducted on the matter, but one survey made twelve years ago by the Louis Finkelstein Institute found that only 63% of practicing United States physicians in a sample of nearly 1500 accepted evidence from evolutionary theory to explain medical matters. Even if this number had a margin of error +10%, that is still an alarming number of physicians who do not incorporate evolutionary theory—the unifying concept that underlies all biology—into their medical practices. And while this trend in evolutionary skepticism may be absent in some countries or even greater in other countries, a thorough background and training in understanding evolution and its processes is lacking in medical educations globally.
How to bring evolutionary and critical thinking widely into medicine
Dr. Randy Nesse, founder of the International Society for Evolution, Medicine, and Public Health (ISEMPH) with Dr. Stephen Stearns, has stated: “Medicine without evolution is like engineering without physics.” The society is fairly young, but it’s mission could not be more timely or important. The Third Annual meeting of ISEMPH was held in August 2017, in Groningen, Netherlands. Like the previous two years, talks and discussions at the conference showed that evolutionary biology in medicine and public health has the power to help us understand disease processes and yield clinical solutions that would otherwise be missed or misunderstood.
The conference was modest in size compared with other society meetings I regularly attend (around 150 participants, in contrast to ten times that many at the AAPA annual meeting, or 100 times that many at Experimental Biology, for example), the topics were timely and wide-ranging. Moreover, the opportunities for productive discussions about research and education made this meeting, like its predecessors, an indispensable experience and opportunity for both new collaborations between fields that at first seem disparate, but have great potential for overlap. Talks ranged from using social insect networks to better understand immune systems, to how previously unidentified animal species (like seals) spread diseases (like tuberculosis) globally, to the use of evolutionary models to better test hypothesized trade-offs in health with respect to age. While these were excellent and enlightening, an equally important conversation that took place this year centered on how to best integrate evolutionary theory and methods into medical education.
Why scientific thinking and evolution matters in medicine
A long-standing concern of ISEMPH and its membership is that more than cursory education in the most basic evolutionary theory, or how scientific inquiry is conducted, is lacking from many medical curricula. This is alarming when we consider that medicine is a form of applied biology. As evolutionary theory is the fundamental string that ties together all biology (much as physics underlies all engineering), learning a form of applied biology should logically begin with an education in evolution. Furthermore, scientific literacy, and the ability to tell well-executed science from poorly executed research, is essential when evaluating a burgeoning literature ranging from experimental therapies to evolving pathogens.
Medical curricula worldwide, but especially in North America, tend to provide scant education in the fundamentals of biology (Brass 2009; Fincher et al. 2009). These programs increasingly make changes to basic science training that may enhance an appreciation of scientific inquiry, but reduce the time available to engage in it in favor of clinical training (Steinberg et al. 2016). It would be naïve to assume that medical students (less nursing, pharmaceutical, or allied health students) have the background to critically evaluate scientific research—best learned by performing it—as well as understand the fundamentals of biology, before entering medical schools. Thus, the resulting landscape is inconsistent, where some students have previous experience performing primary research and taking advanced coursework in biology, while others have, at best, limited exposure to these. The Association of American Medical Colleges reports that the number of medical schools offering or requiring medical students to engage in basic research as part of their education has increased recently. In 2012, 49 out of 136 schools surveyed had student research requirements, whereas in 2016, the proportion increased to 62 out of 145 schools surveyed. Perhaps these requirements, which may be important for medical schools to maintain accreditation, can ameliorate this foundational deficit.
The consequences of not being able to critically read and evaluate scientific studies are obvious, especially if medical practitioners defer to other sources to provide guidance about choosing treatment options (Steinberg et al.’s 2016 paper provides an excellent commentary on this emerging issue). But there are also important, if less obvious, costs to consider when doctors are not trained with a solid understanding of evolutionary theory. Broadly, understanding through which processes healthy variation, disease conditions, and pathogens evolved provides a richer and deeper understanding that leads to more successful treatments. One of these is preventing unintentional evolution from occurring, such as what we are seeing occur with gonorrhea. Another is identifying when certain medical interventions should be withheld to allow patients time to recover using responses that have evolved to promote healing. For example, when patients are septic, it is often more effective to allow fevers to persist than administer drugs to suppress fever (Sundén-Cullberg et al. 2017), and mortality rates are lower with higher fevers too. There are multiple other examples, which may be found across the evolutionary medicine literature. Medical practitioners thinking with evolutionary theory in their toolkit may not be at the forefront of discovery, but they would be more apt to incorporate these ways of thinking into their practices.
Educating evolutionary thinking to medical practitioners
Ideally, entrance to advanced medical training should require evidence that individuals are able to critically evaluate scientific publications and have a clear understanding of evolutionary processes. This type of requirement is not occurring in the near future, and so other solutions must be, and are being sought. The keys to addressing this concern, then, are to 1) identify what needs to be taught to students, and 2) determine when these concepts should be part of the curriculum.
A workshop at the ISEMPH conference discussed these two issues. Given the difficulties inherent in changing medical school curricula, especially in the United States, adding evolutionary theory to premedical curricula would be more efficient and involve less bureaucracy. Providing undergraduate students with the opportunity to expand their understanding of evolution within the structure of a premed course builds interest that may be further shaped before they enter advanced medical training. What topics should be taught is a subject of ongoing discussion, but a broad understanding of evolutionary principles, especially evolutionary processes (natural selection, genetic drift, sexual selection, etc.), is foundational. Additional concepts, such as trade-offs, mismatch, and life history traits (concepts at the core of evolutionary medicine) should also be taught; these are all well-covered in the expanding number of evolutionary medicine textbooks available.
One of the most profound insights I had from the 2017 ISEMPH conference is that many individual instructors are making headway in bringing evolutionary theory into medical and premedical coursework at their institutions. It is heartening to see evolutionary medicine appearing widely in classrooms, especially at the undergraduate level. Research and education centers in evolutionary medicine at Arizona State University, Yale University, the University of Zurich, the University of Auckland, and the Research Triangle in North Carolina, are among those leading this change, though courses are widespread. The keys to further success in this incorporation are coordination and networking; individuals seeking to add evolutionary theory to their premedical or medical curriculum have a growing set of resources available, now coordinated by the EvMedEd initiative. Instructors may find course syllabi, lectures, articles, and other media here. Outside of human anatomy, I have rarely found such a strong, coordinated effort to provide resources for education within a professional organization. I strongly recommend that anyone with even a passing interest in evolutionary medicine visit the EvMedEd site and learn more about the field.
Agnosticism is important in pursuing scientific answers
As an addendum, a valuable sentiment that also was discussed at ISEMPH’s meeting, both formally and informally, was the importance of ethics and rigor in research. Perhaps Stephen Stearns stated it best in a lecture, when he said, “Scientists should be prepared to die agnostic rather than compromise rigor.” With the pressures of publishing and funding within academia, it has, unfortunately, become a luxury for researchers—especially in competitive fields and institutions—to conclude in studies that the results are, at best, ambiguous, even if this is what the analysis yields. Publishing negative or simply inconclusive results is made difficult in fields that expect more definitive answers than what the evidence may support. Yet, as Stearns said, scientists should stand behind uncertainty and inconclusiveness, rather than exaggerate or falsely promote certainty. For a method of investigation that traditionally celebrates the discovery of new unknowns and questions, modern science often is trapped by the constraints imposed by funding cycles, granting agencies, and highly sought journals. Both scientists in this unhealthy cycle and students of medicine, then, could learn a lot about the importance of not knowing, and the importance of agnosticism in scientific research. Often, we do not have the answers we seek from our research, but the new questions raised are often just as valuable, and patience and persistence will lead us toward more certainty in the long run. Likewise, patience and persistence are already pointing to ways to help a new generation of medical students be more like biologists, and less like mechanics.
Steinberg BE, Goldenberg NM, Fairn GD, Kuebler WM, Slutsky AS, Lee WL. 2016. Is basic science disappearing from medicine? The decline of biomedical research in the medical literature. FASEB Journal 30:515-518.
Sundén-Cullberg J, Rylance R, Svefors J, Norrby-Teglund A, Björk J, Inghammar M. 2017. Fever in the emergency department predicts survival of patients with severe sepsis and septic shock admitted to the ICU. Crit Care Med 45:591-599.
Dr. Benjamin Auerbach is associate professor of anthropology at the University of Tennessee. He is an anatomist, statistician, and biological anthropologist, specializing in the application of quantitative genetics and functional anatomy to understand the evolution of traits in mammals, especially primates. His work concerns the study of variation in shape and size (morphology), examining these qualities in relation to environmental factors, namely climate and subsistence. Dr. Auerbach has spent much of the last two decades extensively studying morphological variation to build an understanding of the ways in which environments shaped human variation globally. From this experience, he now applies these methods to ascertain the evolutionary processes influencing trait evolution in Old World primates and in Australian marsupials. Dr. Auerbach’s edits and writes The OVAL Window blog.