What fraction of medical conditions recognised today would have been impossible, or extremely unlikely, for someone to have in ancient Greece? (or Babylonia or even Renaissance Florence, take your pick) What of the reverse? Is it closer to 1% or 10%?
diabetes and heart disease both strongly linked to the modern diet and modern drug addiction habits. without refined sugar and corn syrup type 2 diabetes is almost unheard of. without caffeine, tobacco, and very high meat consumption heart disease is much much more rare.