I give you a fascinating pair of articles from Wired on the topic of the dramatic rise of autoimmune diseases in modern times.
The first extracts some verbiage from a book on the topic, but specifically addresses the island of Sardinia in the Mediterranean:
That is a great set-up for the 2nd article:
A fast-growing body of research suggests that immune systems, produced by millions of years of evolution in a microbe-rich world, rely on certain exposures to calibrate themselves. Disrupt those exposures, as we have through modern medicine, food and lifestyle, and things go haywire.