Disparities between public health educational materials and the scientific evidence that smokeless tobacco use causes cancer.

BACKGROUND AND METHODS We reviewed 4 dozen health education brochures on the dangers of smokeless tobacco (ST) use, printed between 1981 and 2001 and available to the public in 2002. Collectively, these brochures state that ST use causes oral leukoplakia, other oral conditions, and cancers of the oral cavity, larynx, pharynx, esophagus, stomach, pancreas, lung, breast, prostate, bladder, and kidney. We then reviewed the scientific literature to determine whether these claims were substantiated. RESULTS Only for oral leukoplakia and several oral conditions is the evidence persuasive for causation by ST. The evidence that ST causes oral cancer is very suggestive, whereas the evidence for causation of other cancers is either absent or contradictory. CONCLUSIONS Communication of the health risks of using ST must be done accurately and should be data based. Broadening the message to include additional diseases for which the evidence is inadequate could cause the message about true risks, as well as the messenger, to be discounted.