Jaspurr was diagnosed as hyperthyroid at eleven years. He had been overweight for several years, reaching a peak of 23 pounds in 2007. In 2013, I noticed that his rear quarters were starting to appear narrower, although he still appeared hefty in the chest area, and had the hanging belly flab he had had for years. At first I attributed the narrower rear area to his arthritis, although he did not limp.

Indeed, he still "went ballistic" several times a day - racing from the end of our living room down to the end of the hall, wheeling around the corner, then down the other hall into the bedroom he and the other male cats shared with my son.

New Factors Involving Feline Hyperthyroidism

Jaspurr is my third hypothyroid cat in eleven years. There have been at least three significant developments since Bubba was diagnosed in 2002.

1. Flame Retardants (PBDEs) and Hyperthyroid Cats
   PBDE (polybrominated diphenyl ether) flame retardants are found in all kinds of household items, including furniture, construction, and carpet, and are known thyroid disrupters. In 2003, Jean-Michel Cousteau shared that his crew had found extremely large concentrations of PBDEs in whales off the west coat. Crew members who were tested, also showed high levels of PBDEs. According to this article, "PBDEs were introduced at about the same time hyperthyroidism was first described in cats." And Dr. Mark E. Peterson writes, "Cats would be expected to have a higher exposure to PBDE than humans due to intake of dust-bound PBDEs from their behavior e.g. walking close to the floor, collecting dust in their fur, and then ingesting these dust-enriched chemicals because of the their natural cleaning behavior."

1. BPA Lining in Pet Food Cans and Hyperthyroid Cats
   The AVMA (American Veterinary Medicine Association) published a study in 2004 which concluded among other things that cat food cans could be a possible factor for hyperthyroid cats.
2. Soy in Cat Food
   Lisa A. Pierson, D.V.M. writes, "Soy is a known disruptor of thyroid gland function. If you have read my Feeding Your Cat: Know the Basics of Feline Nutrition which outlines what it means to be an obligate carnivore, you will understand that soy has no logical place in cat food."
3. Could Genetics Be a Factor for Hyperthyroid Cats?
   There does not yet seem to be a consensus, but some experts believe that hyperthyroid disease can be hereditary. PETMD writes, "There is no known genetic predisposition for hyperthyroidism, but it is quite common in cats." From Cat Health Guide: "It is not clear what causes the condition although researchers suspect that it is due to heredity, genetics (inherited), something in your cat's environment or diet."
   The fact that I've had two littermate brothers with hyperthyroidism is not conclusive, since they have both been subject to the environmental factors listed above. But I have to think that there somehow must be a connection to this hereditary thing too.