Does tonsillectomy do more harm than good?

Does tonsillectomy do more harm than good?

A new study of over 1 million Danes reports increased risks of infection and allergy in a group of over 60,000 children who had tonsils or adenoids removed.

Byars, S. G., Stearns, S. C., & Boomsma, J. J. (2018). Association of long-term risk of respiratory, allergic, and infectious diseases with removal of adenoids and tonsils in childhood. JAMA Otolaryngology–Head & Neck Surgery. (open access)

The authors, all leaders in evolutionary medicine, conclude that “tonsillectomy was associated with a nearly tripled risk of upper respiratory tract diseases, and that adenoidectomy was associated with doubled risk of COPD and upper respiratory tract diseases and nearly doubled risk of conjunctivitis. Large increases in absolute risk for upper respiratory tract diseases also occurred. Smaller elevated risks for a broad range of other diseases translated into detectable increases in absolute disease risks with high prevalence in the population (infectious/parasitic, skin, musculoskeletal,andeye/adnexadiseases).”

An accompanying commentary notes the possible influence of confounding variables, such as a predisposition to infections or smoking in the home or  made infections and therefore surgery more likely, and also caused subsequent health problems. However, the probability that surgical removal of tonsils and adenoids cause later problems is high, and the documented benefits are low. Like many medical treatments, tonsillectomy is implemented when a problem peaks, ensuring that simple regression to the mean will create the illusion the treatment is effective.

New definitive article on mismatch

New definitive article on mismatch

Corbett, S., Courtiol, A., Lummaa, V., Moorad, J., & Stearns, S. (2018). The transition to modernity and chronic disease: mismatch and natural selection. Nature Reviews Genetics, 1. 
(not open access but worth finding)

Abstract: The Industrial Revolution and the accompanying nutritional, epidemiological and demographic transitions have profoundly changed human ecology and biology, leading to major shifts in life history traits, which include age and size at maturity, age-specific fertility and lifespan. Mismatch between past adaptations and the current environment means that gene variants linked to higher fitness in the past may now, through antagonistic pleiotropic effects, predispose post-transition populations to non-communicable diseases, such as Alzheimer disease, cancer and coronary artery disease. Increasing evidence suggests that the transition to modernity has also altered the direction and intensity of natural selection acting on many traits, with important implications for public and global health.

Adaptive Oncogenesis: How Cancer Evolves inside Us by James DeGregori

Adaptive Oncogenesis: How Cancer Evolves inside Us by James DeGregori

Just out from Harvard University Press, DeGregori's book takes a sophisticated ecological perspective on cancer evolution within the body, and the dramatic clinical implications. The reviews below give a flavor for the advances he describes and extends. Highly recommended.

“To paraphrase Dobzhansky, cancer only makes sense in the light of evolution. In Adaptive Oncogenesis: A New Understanding of How Cancer Evolves inside Us, DeGregori challenges the commonly held view that it takes time for a normal cell to mutate into a cancer cell. He makes the compelling case that the ability to select against cancer becomes weaker as an individual gets older and the odds of reproduction decline.”—Angelika Amon, Koch Institute for Integrative Cancer Research at MIT

Adaptive Oncogenesis: A New Understanding of How Cancer Evolves inside Us is a highly readable and entertaining book, offering a fascinating new look at cancer through an evolutionary and ecological lens. With novel insights and thoughtful observations, James DeGregori guides his audience through the promise of new ideas, examining novel applications of Darwin’s principles as well as modern technological advancements connected to cancer biology and treatment.”—Robert A. Gatenby, Moffitt Cancer Center

“DeGregori’s vision of cancer as an adaptive ecosystem is insightful and cogent. Adaptive Oncogenesis: A New Understanding of How Cancer Evolves inside Us, an evolutionary explanation for the risk of cancer as we age, is a provocative and refreshing revision of the prevailing gene-centric paradigm.”—Mel Greaves, The Institute of Cancer Research

“With engaging prose and an authoritative review of new research, Adaptive Oncogenesis: A New Understanding of How Cancer Evolves inside Us corrects the fundamental attribution error that has focused cancer research on malignant cells and their genes. Adaptive oncogenesis, or ‘EcoOncogenesis,’ shows that the ecosystems surrounding cells are equally important, responsible for creating selection forces that speed or slow the evolution of cancer. With huge implications for prevention and treatment, this book is required reading for cancer researchers and clinicians, and a pleasure read for anyone who appreciates fascinating new science.”—Randolph Nesse, Center for Evolution and Medicine at Arizona State University

“To understand how and why tumors progress, James DeGregori argues that we must apply evolutionary principles to cancer. This book is a seamless discussion of natural evolutionary processes, ranging from longevity in rodents to bacterial antibiotic resistance, and drawing parallels to tumorigenesis. It is a must-read for everyone who wants to understand tumor evolution.”—Kornelia Polyak, Dana-Farber Cancer Institute

“At every point in our lives, the body holds the mutations necessary to cause cancer; why then does cancer develop primarily at certain times or after specific exposures? With crisp thinking and engaging prose, James DeGregori’s surprisingly readable book argues that cancer is a disease caused by damaged tissues rather than gene mutations. The implications of this revolutionary work have the potential to change the focus of cancer research, and especially research on cancer prevention, with emphasis on using the body’s own calculus of natural selection to keep cancers in check.”—Garth Sundem, author of Brain Trust: 93 Top Scientists Reveal Lab-Tested Secrets to Surfing, Dating, Dieting, Gambling, Growing Man-Eating Plants, and More!

Last day for ISEMPH Early Registration

Last day for ISEMPH Early Registration

April 30 is the last day for reduced fee early registration for the Aug 1-4 ISEMPH meeting in Park City, Utah. 

Keynote Speakers
Val Curtis, London School of Hygiene & Tropical Medicine
Maria Gloria Dominguez-Bello, NYU School of Medicine
Katie Hinde, Arizona State University
Chris Kuzawa, Northwestern University
Andrew Read,Penn State University
Jacob Scott, Cleveland Clinic

Park City is a mountain recreation town just above Salt Lake City. Photo by PeteysHead – Own work, CC BY-SA 4.0,
Ev Apps Special Issue on Infection

Ev Apps Special Issue on Infection

The April 2018 issue of Evolutionary Applications is devoted to Evolutionary Perspectives on Human Infectious Diseases: Challenges, Advances and Promises.  It is open access. Enjoy!  

13 articles about evolution and human infectious disease

Echaubard Pierre, Rudge James W., & Lefevre Thierry. (2018). Evolutionary perspectives on human infectious diseases: Challenges, advances, and promises. Evolutionary Applications, 11(4), 383–393.

Birget Philip L. G., Greischar Megan A., Reece Sarah E., & Mideo Nicole. (2017). Altered life history strategies protect malaria parasites against drugs. Evolutionary Applications, 11(4), 442–455.

Borlase Anna, Webster Joanne P., & Rudge James W. (2017). Opportunities and challenges for modelling epidemiological and evolutionary dynamics in a multihost, multiparasite system: Zoonotic hybrid schistosomiasis in West Africa. Evolutionary Applications, 11(4), 501–515.

Flores‐Ferrer Alheli, Marcou Olivier, Waleckx Etienne, Dumonteil Eric, & Gourbière Sébastien. (2017). Evolutionary ecology of Chagas disease; what do we know and what do we need? Evolutionary Applications, 11(4), 470–487.

Glunt Katey D., Coetzee Maureen, Huijben Silvie, Koffi A. Alphonsine, Lynch Penelope A., N’Guessan Raphael, … Thomas Matthew B. (2017). Empirical and theoretical investigation into the potential impacts of insecticide resistance on the effectiveness of insecticide‐treated bed nets. Evolutionary Applications, 11(4), 431–441.

Grear Daniel A., Hall Jeffrey S., Dusek Robert J., & Ip Hon S. (2017). Inferring epidemiologic dynamics from viral evolution: 2014–2015 Eurasian/North American highly pathogenic avian influenza viruses exceed transmission threshold, R0 = 1, in wild birds and poultry in North America. Evolutionary Applications, 11(4), 547–557.

Huijben Silvie, & Paaijmans Krijn P. (2017). Putting evolution in elimination: Winning our ongoing battle with evolving malaria mosquitoes and parasites. Evolutionary Applications, 11(4), 415–430.

Joseph Udayan, Vijaykrishna Dhanasekaran, Smith Gavin J.D., & Su Yvonne C.F. (2017). Adaptive evolution during the establishment of European avian‐like H1N1 influenza A virus in swine. Evolutionary Applications, 11(4), 534–546.

Kosoy Michael, & Kosoy Roman. (2017). Complexity and biosemiotics in evolutionary ecology of zoonotic infectious agents. Evolutionary Applications, 11(4), 394–403.

Lefevre Thierry, Ohm Johanna, Dabiré Kounbobr R., Cohuet Anna, Choisy Marc, Thomas Matthew B., & Cator Lauren. (2017). Transmission traits of malaria parasites within the mosquito: Genetic variation, phenotypic plasticity, and consequences for control. Evolutionary Applications, 11(4), 456–469.

Lourenço José, Tennant Warren, Faria Nuno R., Walker Andrew, Gupta Sunetra, & Recker Mario. (2017). Challenges in dengue research: A computational perspective. Evolutionary Applications, 11(4), 516–533.

Rosenberg, K. R., & Trevathan, W. R. (2018). Evolutionary Perspectives on Cesarean Section. Evolution, Medicine, and Public Health. Sternberg Eleanore D., & Thomas Matthew B. (2017). Insights from agriculture for the management of insecticide resistance in disease vectors. Evolutionary Applications, 11(4), 404–414.

Viana Mafalda, Faust Christina L., Haydon Daniel T., Webster Joanne P., & Lamberton Poppy H. L. (2017). The effects of subcurative praziquantel treatment on life‐history traits and trade‐offs in drug‐resistant Schistosoma mansoni. Evolutionary Applications, 11(4), 488–500.

Nina Wale wins $5,000 Omenn Prize

Nina Wale wins $5,000 Omenn Prize

The Gilbert S. Omenn Prize of $5,000 for the best paper on evolution and medicine or public health published in any journal goes to a paper by Nina Wale and colleagues.

Wale, N., Sim, D. G., Jones, M. J., Salathe, R., Day, T., & Read, A. F. (2017). Resource limitation prevents the emergence of drug resistance by intensifying within-host competition. Proceedings of the National Academy of Sciences, 114(52), 13774–13779.

The Prize is made possible by the generosity of Gilbert Omenn. The Committee for this year was chaired by Cynthia Beall, and its members are Sean Byars, Katia Koelle, Robert Perlman and Jonathan Wells.

Abstract: Slowing the evolution of antimicrobial resistance is essential if we are to continue to successfully treat infectious diseases. Whether a drug-resistant mutant grows to high densities, and so sickens the patient and spreads to new hosts, is determined by the competitive interactions it has with drug-susceptible pathogens within the host. Competitive interactions thus represent a good target for resistance management strategies. Using an in vivo model of malaria infection, we show that limiting a resource that is disproportionately required by resistant parasites retards the evolution of drug resistance by intensifying competitive interactions between susceptible and resistant parasites. Resource limitation prevented resistance emergence regardless of whether resistant mutants arose de novo or were experimentally added before drug treatment. Our work provides proof of principle that chemotherapy paired with an “ecological” intervention can slow the evolution of resistance to antimicrobial drugs, even when resistant pathogens are present at high frequencies. It also suggests that a broad range of previously untapped compounds could be used for treating infectious diseases.