A lot of it has to also do with genetics. Some population groups are more resilient to certain kind of chronic ailments. Anecdotally, in NE India, there is a m

A lot of it has to also do with genetics. Some population groups are more resilient to certain kind of chronic ailments. Anecdotally, in NE India, there is a midsize city Aizawal which is known as the cancer capital of India. Stomach cancer is pervasive in that community. Their diet is mostly smoked pork. The part of population which consumes less smoked meat, remarkably showed a lesser prevalence of abdominal cancer. It is heuristically known. An empirical fact, if you might call it - as no one has systematically measured the cause-effect. The conclusion may even be flawed, but so far it looks like the observation supports the hypothesis.