Socioeconomic and country variations in knowledge of health risks of tobacco smoking and toxic constituents of smoke: results from the 2002 International Tobacco Control (ITC) Four Country Survey.

BACKGROUND Socioeconomic status is strongly associated with smoking prevalence and social class differences contribute substantially to social inequalities in mortality. This research investigated socioeconomic and country variations in smokers' knowledge that smoking causes heart disease, stroke, impotence and lung cancer, that smoke contains cyanide, mercury, arsenic and carbon monoxide, and whether nicotine causes most of the cancer. METHODS Data were from the International Tobacco Control (ITC) Four Country Survey, a cohort survey of over 9000 adult smokers from four countries: the United States, Canada, the United Kingdom, and Australia. Data were collected via telephone interviews in 2002. RESULTS Higher education and income were associated with higher awareness. For example, the odds of knowing that smoking causes heart disease, stroke and lung cancer were respectively 71%, 34% and 83% larger for respondents with high versus low income. The odds of knowing that smoke contains cyanide, mercury, arsenic and carbon monoxide were respectively 66%, 26%, 44% and 108% larger for respondents with a university degree than those with a high school diploma or lower level of education. Results also revealed that awareness of harms of smoking was generally the highest in Canada and the lowest in the UK. CONCLUSIONS Lower socioeconomic status was associated with lower awareness of the harms of smoking and misunderstanding around nicotine. There is a need to improve knowledge of the dangers of smoking among the disadvantaged segments of the population.