Original sentence: Although diabetes has been recognized since antiquity, and treatments of various efficacy have been known in various regions since the Middle Ages, and in legend for much longer, the elucidation of the pathogenesis of diabetes occurred mainly in the 20th century
Edited sentence: Although diabetes has been recognized since antiquity, and treatments of various efficacy (all close to nil, however) have been known in various regions since the Middle Ages, and in legend for much longer, the elucidation of the pathogenesis of diabetes occurred mainly in the 20th century