Keeping a dog mostly indoors and cats exclusively indoors typically benefits the pet by reducing their exposure to communicable diseases that can be caught from other animals and insects. Yet researchers have found that dogs and cats kept indoors suffer from a higher rate of diabetes, kidney disease and hypothyroidism compared with pets that are kept outdoors.

The researchers tested 58 varieties of dog and cat food as well as 60 urine samples from dogs and cats and found certain parabens, which are a preservative, in the food and urine samples. They discovered that the highest level of parabens were methyl paraben and the metabolite called 4-hydroxybenzoic acid (4-HB). Parabens are used as preservatives both in human and pet food as well as cosmetics. The use of them is regulated by the FDA.

The researchers found that there were higher levels in dry dog food and less in wet food. Cat food had the highest levels. The researchers also determined that dogs are exposed to parabens through non-food sources as well as food, whereas a cat’s exposure was only from food.

This is the first study to consider the affects of paraben on diseases in dogs and cats. More research is needed to further examine the initial findings.