All I know in regard to health is in 1995, I went to my great grandma's 101st birthday party, and she was a meat eater and that when she did go, it wasn't due to any specific disease. Just old body parts.
And there are lots of ways to get meat that's not so mass produced they need to suffer the ways described in this thread. I'm all for the humane treatment of animals. ALL for it, but its hardly fair to pretend all meat comes from animals treated that way. No. You make choices on where you buy it from. It's like condemning anyone who owns a puppy because puppy mills exist. It just doesn't make sense.