Maybe it depends on a lot of variables, where you grew up and where you live now (toxins) how much your body can take it all (genes?) and of course being exposed to whatever Parasites.
I know I don't get it, my friend's Grandfather drank a good amount of Scotch everyday and smoked giant cigars daily well into his late 80's with no known health problems, and I know he eats also rich fatty foods.