Table 1

 Predictors of making serious quit attempts between International Tobacco Control Four Country Survey (ITC-4) Wave 1 and Wave 2

Entire sampleUSACanadaUKAustralia
n% attemptedORn% attemptedORn% attemptedORn% attemptedORn% attemptedOR
p<0.05 for odds ratios that are underlined.
Outcome expectancy: Based on smokers’ responses to the question: “How much do you think you would benefit from health and other gains if you were to quit smoking permanently in the next 6 months?” Coded: 1: “not at all”, 2: “slightly”, 3: “moderately”, 4: “very much”, and 5: “extremely”.
Self-efficacy: Based on smokers’ responses to the question: “If you decided to give up smoking completely in the next 6 months, how sure are you that you would succeed?” Coded: 1: “not at all sure”, 2: “slightly sure”, 3: “moderately sure”, 4: “very sure”, and 5: “extremely sure”.
Worries about health and QOL: Based on smokers’ responses to the following two questions: (1) “How worried are you, if at all, that smoking will lower your quality of life in the future?”; (2) “How worried are you, if at all, that smoking will damage your health in the future?” Both questions were coded: 1: not at all worried, 2: a little worried, 3: moderately worried, 4: very worried. Here we used the average for the two variables.
Favourable attitudes about smoking: Based on smokers’ responses to the following two questions: (1) “You enjoy smoking too much to give it up”; (2) “Smoking is an important part of your life”. Both questions were coded: 1: strongly disagree, 2: disagree, 3: neither agree or disagree, 4: agree, and 5: strongly agree. Here we used the average of the two variables.
Overall opinion of smoking: Based on smokers responses to the question of: “What is your overall opinion of smoking?”
Outcome expectancy is highly correlated with worries about health and QOL (Pearson’s correlation coefficient 0.51, p<0.01).
OR, odds ratio; QOL, quality of life.
Age at recruitment (years)
    55 and up129334%0.8829333%0.5929441%0.9446730%0.9623931%0.94
Highest level of education
    No response40530%0.777427%0.5410637%0.6712125%0.7310432%1.18
Identified majority group
    White/English only555136%Ref99534%Ref140444%Ref161531%Ref153734%Ref
Intention to quit
    No intention162214%Ref31313%Ref28318%Ref59713%Ref42914%Ref
    Plan to quit beyond 6 months238030%1.8550533%2.9556835%1.8160427%1.7070327%1.41
    Plan to quit within 6 months157652%3.7629650%4.6953254%3.2534552%4.4440350%3.18
    Plan to quit within 1 month68275%8.8213970%9.0419282%11.5214077%11.4621169%5.87
Tried to quit within last year
Longest time off smoking
    1 week or less101733%0.9021233%1.2926039%0.9025730%0.9328829%0.67
    Between 1 week and 6 months190940%1.1436540%1.7949747%1.0949534%0.9355238%1.01
    6 months or more215543%1.4542946%2.3954952%1.7056738%1.2461038%1.01
Heaviness of smoking index
Baseline smoking frequency
    Daily smoker574035%Ref114334%Ref144443%Ref157630%Ref157732%Ref
    Weekly/monthly smoker52054%1.4311056%1.3813156%1.3411054%1.5516950%1.44
Overall opinion of smoking
    Positive or neutral275828%Ref55228%Ref58735%Ref84224%Ref77725%Ref
    Very negative126749%1.2427348%1.1836255%1.1227948%1.4035346%1.34
Continuous variables
Outcome expectancy1.040.941.081.061.04
Worries about health and QOL1.
Favourable attitudes about smoking0.881.000.890.750.88
Nagelkerke’s R20.