Working with manure can drastically reduce chances of developing lung cancer, according to a report in The Daily Telegraph.
Dairy farmers are five times less likely than the general populace to develop the disease, New Scientist magazine reports.
The study found farmers typically breathed in dust that consisted largely of dried manure and all the bacteria that grew in it.
New Scientist said adults who had a greater exposure to germs than usual might build up a better resistance to bugs, including cancer.
"Some researchers are starting to wonder whether the higher incidence of certain cancers in affluent populations — including breast cancer, lymphoma and melanoma — might also have something to do with sanitized, infection-free living," the researchers said, noting the unexpected links between exposure to dirt and germs and cancer risk.
"If they're right, the implications are huge. If we can understand exactly what it is about some germs that has a protective effect, we should be able to reduce people's risk of developing certain tumors later in life by exposing them to harmless microbes."