Passive smoking: confirming the risks.

Nonsmoking adults chronically exposed to pollutants emitted by the cigarettes of a spouse or coworkers face a roughly 20 percent increased risk of lung cancer, according to a new study conducted jointly at centers throughout Europe. That increase disappears, however, if exposures occurred only during childhood or ceased at least 15 years ago, the authors report in the Oct. 7 JOURNAL OF THE NATIONAL CANCER INSTITUTE.

Paolo Boffetta of the International Agency for Research on Cancer in Lyon, France, and his coworkers studied the smoke-exposure history of 650 people with lung cancer and 1,542 others who were free of all diseases linked to cigarettes. None of the participants had ever smoked.

This "eagerly awaited" study "is among the largest and most exhaustive examinations of passive smoking's effects on lung cancer," comment William J, Blot and Joseph K. McLaughlin of the International Epidemiology Institute in Rockville, Md., in an editorial accompanying the new report. The new European data reinforce a host of earlier, weaker studies. When all are considered together, Blot and McLaughlin argue, "the inescapable scientific conclusion is that environmental tobacco smoke is a low-level lung carcinogen" and that investments in antismoking campaigns stand to benefit both smokers and others.