Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Trends in beliefs about the harmfulness and use of stop-smoking medications and smokeless tobacco products among cigarettes smokers: Findings from the ITC four-country survey | Borland et al. Harm Reduction Journal 2011 8 21 http content 8 1 21 HARM REDUCTION JOURNAL RESEARCH Open Access Trends in beliefs about the harmfulness and use of stop-smoking medications and smokeless tobacco products among cigarettes smokers Findings from the ITC four-country survey 1 12 3 3 Ron Borland Jae Cooper Ann McNeill Richard OConnor and K Michael Cummings Abstract Background Evidence shows that smokers are generally misinformed about the relative harmfulness of nicotine and smokeless forms of nicotine delivery in relation to smoked tobacco. This study explores changing trends in the beliefs about the harmfulness and use of stop smoking medications and smokeless tobacco in adult smokers in four countries where public education and access to alternative forms of nicotine is varied Canada the US the UK and Australia . Methods Data are from seven waves of the ITC-4 country study conducted between 2002 and 2009 with adult smokers from Canada the US the UK and Australia. For the purposes of this study data were collected from 21 207 current smokers. Using generalised estimating equations to control for multiple response sets multivariate models were tested to look for main effects of country and trends across time controlling for demographic variables. Results Knowledge remained low in all countries although UK smokers tended to be better informed. There was a small but significant improvement across time in the UK but mixed effects in the other three countries. At the final wave between US and UK reported that NRT is a lot less harmful than cigarettes. In Canada and the US where smokeless tobacco is marketed only around one in six believed some smokeless tobacco products could be less harmful than cigarettes. Conclusions Many smokers continue to be misinformed about the relative safety of nicotine and alternatives to smoked tobacco especially in the US and Canada. Concerted efforts to educate UK smokers have probably .