By Jean Hofve, DVM

Many studies have shown that second-hand (environmental) smoke is a health hazard to humans, much less research has been done in animals. However, there are a few studies that shed light on the association between pets, disease, and living with a smoker.

Cats who live with a smoker have a much higher risk of oral squamous cell carcinoma, an invasive cancer occurring on the mucous membranes of the mouth. Having more than one smoker in the home, or living with a smoker for more than five years, increased the risk even more, according to a study conducted at Tufts University. Because cats groom themselves so thoroughly, it is thought that the toxins and carcinogens from smoke that settle on their fur are taken into their mouths while grooming. Over time, this can cause this nasty cancer to develop.

Exposure to smoke also increases a cat’s risk of malignant lymphoma. Since the lymph nodes filter the blood, inhaled or ingested toxins can build up and cause cancer. Cats living with secondhand smoke are three times more likely to develop lymphoma than other cats.

In addition to cancer, cats exposed to smoke can also develop other respiratory problems such as asthma and bronchitis.

Dogs have a higher risk of nasal sinus cancer and lung cancer when exposed to secondhand smoke. Long-nosed dogs like Collies, Borzois, and Greyhounds had the highest risk of nasal cancer, while short- and medium-nosed dogs had more lung cancer. Dogs also had a tendency to develop allergic reactions to smoke that are similar to flea, food, and other allergies.

Environmental smoke is classified as a Group A carcinogen, along with other well-known toxins asbestos, radon, and benzene.

If you won’t quit smoking for yourself, please do it for your pets! At the very least, only smoke outdoors, or in an area away from the animals (and children) in your home.