Before refrigeration, food stabilization was by salt. Were these diseases prevalent hundreds or thousands of years ago?
Did medical science even KNOW how to diagnose those diseases years ago?
I'm not sure they did. Ankylosing Spondylitis (a genetic borne disease I have) has been around for thousands of years, it's only recently (as in the last 20-30 years) been determined to be genetic in nature and have it's roots in T-Cell (TNF)factor.
Speculation is that the Neanderthal's originally had it, and it found its way into Northern/Northeastern European bloodlines as evidenced by hunched backs and necks, over-sized knuckles later in life, and other joint destruction such as hips, knees and even jawlines. (pronounced jawlines for example.) Of course, the Neanderthal's didn't have refrigeration, and the European's cured meat and preserved food with salt so there may be some link?
Dunno, speculation on my part.
“Before refrigeration, food stabilization was by salt. Were these diseases prevalent hundreds or thousands of years ago?
No, it killed you by the time you were 35 instead.