Evaluation of dietary and environmental risk factors for hyperthyroidism in cats

Objective-To identify dietary and environmental risk factors for hyperthyro idism in cats. Design-Case-control study. Animals-100 cats with hyperthyroidism and 163 control cats. Procedure-Medical records were examined, and owners completed a mailed ques tionnaire. Data collected included information regarding demographic variab les, environmental exposures, and diet, including preferred flavors of cann ed cat food. Results-Case cats were significantly less likely to have been born recently than control cats. Housing; exposure to fertilizers, herbicides, or plant pesticides; regular use of flea products; and presence of a smoker in the h ome were not significantly associated with an increased risk of disease, bu t cats that preferred fish or liver and giblets flavors of canned cat food had an increased risk. Conclusions and Clinical Relevance-Results suggest that cats that prefer to oat certain flavors of canned cat food may have a significantly increased risk of hyperthyroidism.