Warning: Smoking cigarettes can cause cancer–in your pets.
That conclusion emerges from a new survey of the home environments of nearly 200 cats hospitalized at the Tufts University School of Veterinary Medicine in North Grafton, Mass. Eighty of the cats had malignant lymphoma–a feline corollary to non-Hodgkin’s lymphoma in people; the other cats were diagnosed with a comparably serious disease having no link to smoking.
Compared with animals living in smokefree homes, cats who dwelled for some time with a smoker at least doubled their risk of developing the cancer, report Elizabeth R. Bertone of the University of Massachusetts–Amherst, and her colleagues in the Aug. 1 American Journal of Epidemiology. The longer cats were exposed and the smokier their domicile, the worse their risk. Those in the highest exposure group faced almost a quadrupling in lymphoma risk.
As cancers go, this lymphoma is relatively common, Bertone notes. She says that it strikes up to 75 cats per 100,000–or nearly four times the human incidence of non-Hodgkin’s lymphoma. Most of the cats’ lymphomas in the new study started in the nasal or gastrointestinal area, which would be consistent with exposures from inhalation of smoke particles or particle ingestion as the animals groom their fur. The new findings prompted the veterinary group to look for other smoke-linked health effects, including oral cancer, that also might reflect exposure to smoke particles during grooming. A preliminary look at those new data, Bertone told Science News, is pointing to “findings that are similar [to those for lymphoma], though not as dramatic.”