Much press has been given to the effects of secondhand smoke on people, but what, if any, is the effect on our pets? Recent studies have shown that pets are at risk as well.

Environmental tobacco smoke or secondhand smoke is composed of the smoke exhaled from a smoker as well as the smoke released from the end of a burning cigarette, pipe or cigar. It consists of more than 4,000 chemicals including carbon monoxide, formaldehyde, benzene, chromium, nickel, vinyl chloride and arsenic.

Scientific evidence carefully collected over the last 30 years shows that people repeatedly exposed to environmental tobacco smoke are more likely to develop and die from heart problems, lung cancer and breathing problems. Unfortunately, extensive studies have not been done in pets but recent research has revealed some startling information about secondhand smoke and our feline companions. Based on a 7-year study at Tufts School of Veterinary Medicine, cats in smoking households seem to be at a much higher risk of developing lymphoma, a type of cancer, than cats that live in smoke-free environments. This study revealed that cats that live in homes with one smoker have twice the risk of developing lymphoma and cats that live in households with two or more smokers have 4 times the risk. Also, cats that are exposed to a smoking environment for over 5 years and those that live in households with over 100 cigarettes smoked per day are also at a significantly higher risk. The exact cause of this increased risk of lymphoma is not known.

New studies suggest that cats are also at increased risk of feline oral squamous cell carcinomas (SCC) when exposed to environments with tobacco smoke. It has been suggested this may result from smoke and nicotine residue landing on the pet's fur and the fastidious nature of cats groom off that residue thus having oral exposure to the carcinogens.

In addition to an increased risk of developing cancer, cats that live in smoking environments are also predisposed to lung disease and eye irritation. Although secondhand smoke alone has not been shown to cause the lung disease or eye irritation, the primary culprit is thought to be chronic exposure to smoke in poorly ventilated areas. Unfortunately, many of the harmful products in smoke are in the form of gas. Therefore, environmental tobacco smoke cannot be entirely filtered out through ventilation systems or special fans. It can take many hours for the smoke of a single cigarette to clear.

Tips for Minimizing Risk

If you are a smoker and your pets are exposed to second-hand smoke, this might be a good reason to stop. Or...consider smoking outside. If neither of these are options, you might consider having smoke-free areas in the house to which your pets can escape. Regular brushing and grooming help to remove the smoke residue form their hair. This is especially important in cats that are likely to groom, lick and ingest the residue on their coats. Air purifiers may also be helpful. Some veterinarians suggest at vitamin C and other anti-oxidants to minimize the cancer generating effects. See your veterinarian to determine if these are good options for your pet.