E&eb 235: Evolution and Medicine

Cancer is a leading cause of death in the United States and other developed countries, spiking in incidence in the 20 century. Along with other explanations, the hygiene hypothesis should be considered. The hygiene hypothesis posits that the rise in autoimmune and atopic diseases in the twentieth century arises from the decrease in exposure to microbial environmental factors that co-evolved with our immune system. In order to establish the significance of the relationship between cancer incidence and pathogen exposure, correlations between cancer incidence and per capita GDP, life expectancy, tobacco consumption, and fertility were calculated. A significant strong positive association between cancer incidence and per capita GDP was found, while those between cancer incidence and life expectancy, tobacco consumption, and fertility were weak and not significant. In light of these results, a connection between the hygiene hypothesis and inflammation as a cause of cancer was drawn, and treatment with pathogens, specifically virotherapy, is discussed. Finally, further research on the hygiene hypothesis in relation to cancer is recommended.