AMHERST, MASSACHUSETTS. Feline malignant lymphoma is a common disease among domestic cats. Examination of the structure of the cancerous cells involved has shown them to be very similar to those found in human non-Hodgkin's lymphoma. Researchers at the University of Massachusetts and Tufts University School of Veterinary Medicine have just released the results of a study which concludes that cats exposed to cigarette smoke are two to three times more likely to develop malignant lymphoma than are cats that live in smoke-free homes.
The study involved 80 cats (average age of 11 years) diagnosed with malignant lymphoma and 114 controls who all had renal disease. There are no known links between renal disease and malignancy. The researchers found that cats that had been exposed to indoor cigarette smoke had a 2.4 times higher incidence of lymphoma. The risk increased with the length of exposure with cats having been exposed for five years or more having a 3.2 times higher risk than cats living in a smoke-free home. The amount of smoking was also a significant risk factor. Cats living in homes in which a pack or more of cigarettes was smoked per day had a 3.3 times greater risk.
The researchers conclude that second hand smoke is a significant risk factor in feline lymphoma and urge
further research to investigate a possible connection with human non-Hodgkin's lymphoma.