Historical analysis of inverse correlation between soil-transmitted helminthiasis and pancreatic cancer.

In this descriptive epidemiological study, the soil-transmitted helminth (STH) burden and pancreatic cancer (PC) mortality rates of different countries and peoples are compared to demonstrate an inverse correlation. Formerly ubiquitous helminth infection possibly played a significant role in defending the human host against PC until the advancement of modern hygiene, with helminth eradication in recent times in developed countries and urban centers. It is posited that a high rate of infection by STH in developing countries and rural areas protects the human host from the development of PC, possibly by immune modulation. This hypothesis is used to explain increased PC rates in minority groups in the United States who had decreased helminth exposure in the late 20th century.