Objectives Our objectives were to conduct a web-based survey using adult participants to investigate 1) differences in attitudes towards smoking in the presence of non-smokers between smokers and non-smokers and 2) the potential impact of knowledge regarding the harmful effects of smoking and secondhand smoke (SHS) on smoker behavior in a restaurant.Method Japanese smokers and non-smokers aged 20 to 69 were separately sampled and both groups were randomly allocated to either a knowledge group or a control group. The participants were asked to complete an online questionnaire to capture their attitudes and how they think they would behave in a restaurant where it was not clear whether smoking is prohibited or not. Data were analyzed using a t-test for numerical variables and a χ2 test for categorical variables. Logistic regression analysis was also conducted to elucidate the factors influencing the smoking behavior near non-smokers.Results Overall, 2,157 participants were surveyed (smokers, n=1,084; non-smokers, n=1,073). Among smokers who intended to smoke in the restaurant, 24.8% answered that they would ask for permission from nearby persons before lighting up. However, only 2.8% of non-smokers had ever actually been asked for such permission. The percentage of smokers who would smoke in the restaurant was significantly lower in the knowledge group (16.4%) than the control group (22.8%). The most common reason for refraining from smoking was a lack of an ashtray on the table in both groups. Among the non-smokers, 37.4% of the knowledge group and 27.6% of the control group answered that they did not like nearby smoking. A multiple logistic regression analysis revealed that smoking in restaurants was significantly associated with nicotine dependence, household income, pregnancy, smoking place in the home, age, and SHS knowledge.Conclusion This study suggested that most non-smokers do not inform smokers that they do not like nearby smoking. It was also found that smoking behaviors could be influenced by non-smokers' preference for nearby smoking and by environmental factors such as the presence of an ashtray on the table. Knowledge about the harmful effects of smoking and SHS may influence the attitudes and behavior towards nearby smoking among both smokers and non-smokers.
Keywords: attitudes; behaviors; non-smoker; restaurant; smoker.