Smokers and nonsmokers alike have had their consciousness raised about the effects of secondhand smoke on humans. But, until now, no one had considered cats.

A recent study in the American Journal of Epidemiology found that cats living with a smoker are twice as likely to develop lymphoma, the most common cancer in cats, as are those in smoke-free homes. Felines living with two smokers face four times the risk.

Cats may be particularly affected by household smoke (including fireplace smoke) because they spend so much time indoors and because, when grooming, they ingest particles that have fallen on their fur.

Aside from quitting, smokers can minimize risk to their cats by keeping them out of rooms where people light up. Brushing or bathing the cats may also help.