Ranz D., Tetrick M., Opitz B., et al.
Feline hyperthyroidism is the most common endocrine disorder of middle-aged to old cats in the United States. In Germany, the latest investigations have shown increasing feline hyperthyroidism (1,2). The role of iodine in feline hyperthyroidism is still not clear. A deficient or excess level of dietary iodine has been suggested by several authors as an important factor in the development of feline hyperthyroidism (3). Analyses from other countries have shown that iodine levels in prepared cat foods vary widely (4,5). Recommended iodine levels have been reported by several authors; however, figures disagree by a factor of 10 to 30 (4–8). To get more information about the iodine supplied by commercial cat foods available in Germany, iodine was measured in 92 prepared cat foods. In addition, data were collected during a feeding study investigating iodine intake and excretion in the cat, to look for a suitable variable to estimate iodine status and to check hitherto existing iodine requirement figures.