[Santa's NaughtiNess]

Originally Posted by Soldier Boy

I mean there is quite a significant amount of research and data on the causes of cancer. Obviously we don't know all of them but we do (even as common sense) know that fit and healthy people are less likely to get cancer than unhealthy people, and also that there's a generic element (more likely to get certain cancers if other people in your immediate family have had it). And that carcinogens exist. It's not still a complete mystery.

But it does hit healthy people as well.
For example, my late grandfather was a heavy smoker, but was healthy pretty much his while life.