Longitudinal association of adolescents' sense of coherence with tooth-brushing using an integrated behaviour change model

Objective: To determine the association between adolescents' sense of coherence (SOC) and their tooth-brushing behaviour. Methods: This 18-month longitudinal study involved a representative sample of 8th-graders (n = 1025) from 11 randomly selected public high schools in the Limpopo Province, South Africa. Data collected by means of a self-administered questionnaire included respondents' socio-demographic profiles, vulnerability to depression, smoking status, dental treatment attendance pattern, frequency of and motivation for tooth-brushing. Based on the responses to the question on readiness to change brushing behaviour and in line with the integrated change model, respondents were also categorized as being in the pre-contemplation, contemplation or preparation/action stages. Respondents' SOC was measured using a six-item adapted Antonovsky SOC scale. Data analysis included chi-squared analysis, t-tests and step-wise multiple logistic regression. Results: At baseline, 72.6% (n = 744) of the respondents reported that they were not consistently brushing twice daily. Of those who did not brush twice daily and were followed up on (n = 578), those living with their mother at baseline not only presented with a greater increase in their SOC over time (follow-up minus baseline), but they were also more likely to be brushing twice daily at the time of the follow-up (15.4% versus 10.6%; P = 0.04). Adding baseline intention state to a multivariate model attenuated the influence of baseline SOC to a statistically insignificant level. However, increasing within-subject SOC changes (β = 0.16; P < 0.01), living with the mother (β = 0.11; P < 0.05), smoking (β = -0.14; P < 0.05), being depression vulnerable (β = -0.23; P < 0.01) and in the preparation/action stage (β = 0.13; P < 0.05) remained associated with the transition to twice-daily tooth-brushing. Conclusions: In planning oral health promotion interventions, it should be considered that children's psychological predisposition and family environment might significantly influence their tooth-brushing behaviour.