Cigarette manufacturers influenced scientific papers that questioned the link between secondhand smoke and sudden infant death, according to a new study of once-secret industry documents.

The key article, commissioned by Philip Morris and published in a respected pediatric epidemiology journal in 2001, discounts the significance of research showing a link between exposure to secondhand cigarette smoke and sudden infant death syndrome (SIDS).

The article has been cited in at least 19 other scientific papers, misleading physicians, their patients and researchers about the risk of secondhand smoke exposure.

"Undermining people's understanding of the link between secondhand smoke and SIDS places infants everywhere at increased risk," according to Stanton Glantz, PhD, director of the Center for Tobacco Control Research and Education at the University of California - San Francisco (UCSF) and senior author of the new study analyzing the tobacco company documents.