Oral Health-related Outcome Expectancy of Smoking Predicts Adolescents' Smoking Initiation

Objective: Underpinned by the outcome expectancy theory, this study sought to test the hypothesis that adolescents with strong negative oral health-related outcome expectations of smoking are less likely to initiate smoking. Methods: A prospective study, involving all consenting 8th Graders from 3 selected schools in the Tshwane-North school district. Of the 569 learners who provided baseline data, 487 (85.6% follow-up rate) provided follow-up data one year later (44.2% were males). Data was collected through a questionnaire, which included a 5-point likert-scale type question on dental disease belief related to smoking (smoking causes plaque and bad breath) and an affective evaluation of this effect (bad breath causes peer rejection). Health-risk behaviours recorded included past-month tobacco and alcohol use. Outcome expectancy (OE) scores at baseline were computed as a product of belief and evaluation. Analysis was restricted to those who were non-smokers at baseline (n=410). Outcome variable was current smoking status. T-test, chi-square and multivariate logistic regression was used in the data analysis. Results: The mean age of the learners was 14yrs. At one-year follow-up, 11.4% had initiated smoking. Compare to non-smokers, current smokers were more likely to report frequent bleeding gums (51.2% vs. 33.1%; p=0.02), but there was no significant difference in proportions brushing twice daily (64.4% vs. 56.5%; p=0.30). Compared to those who initiated smoking, those who reported continued abstinence from smoking had a higher oral health-related negative outcome expectation score of smoking at baseline (15.1 vs. 11.7; p<0.01). Significant predictors of smoking initiation included having the strongest negative outcome expectation (Odd ratio [OR]; 95% confidence interval of 0.37; 0.16-0.87), binge-drinking at baseline (OR=2.56; 1.08-6.07) and having all/most friends smoking at baseline (OR=1.95; 1.01-3.75). Conclusion: Our study findings support the development of smoking prevention programmes that includes oral health-related cognitive restructuring and life skills training to resist peer pressure.