Conference Proceedings, (2016). American College of Veterinary Internal Medicine, Denver:
Hyperthyroidism is the most common endocrinopathy of middle-aged and older cats. Although it was not recognised as a clinical entity until the late 1970s it is now very common world-wide (or at least in the industrialized nations where it has been studied), although in some countries it is likely that it remains under-diagnosed.1,2 It is unclear whether feline hyperthyroidism existed as a clinical entity prior to this; histopathological studies had sometimes recognised thyroid nodules but these were apparently not associated with signs of thyrotoxicosis. A number of factors could have contributed to the emergence of this clinical condition including aging of the feline population, and an increasing willingness of owners to pay for veterinary care, widespread availability of diagnostic tests, and increased veterinary recognition, but it is generally believed that this is unlikely to solely account for the rapid and dramatic increase in disease prevalence.