“The China Study”, by T. Colin Campbell, is the bible of veganism. It is a huge book which covers a lot of ground and makes many valuable points. The name of the book comes from a series of observational studies done in 69 counties in China called the China-Oxford-Cornell Project. Dr. Campbell himself led two of these studies, and from this project, he concludes that “plant-based foods are beneficial, and animal-based foods are not.” This conclusion has been disputed. See, for instance, Minger here, or Masterjohn here. OR see for yourself.
We found data for the 1989 study and and have cooked up an app that allows you to quickly see the association between any of dozens of dietary items versus several dozens causes of death.