Smokers' and non-smokers' estimates of their personal risk of cancer and of the incremental risk attributable to cigarette smoking

Estimates were obtained from 420 members of the public, 117 of whom were smokers, of the risk of an hypothetical target person, described as a 35-year-old man with no previous illness, contracting cancer as a consequence of exposure to combinations of different risk factors. The presence/absence of three risk factors-cigarette smoking, occupational radioactive exposure, and radon gas in the home-was used to generate eight target descriptions. Ratings were on an open-ended ratio scale where 0 represented no risk and 100 an average level of risk for men of the same age. In addition, subjects rated their own risk of contracting cancer. Results showed that, compared with non-smokers, smokers gave higher estimates of their own risk, but lower ratings of the incremental risk attributable to cigarette smoking by the target. Smokers and non-smokers did not differ in the incremental risk they attributed to occupation or radon. The findings are used to question the view that smokers 'already know' that they are damaging their health and that their attitudes hence have little relevance to their behaviour.