Promoting positive attitudes to breastfeeding: the development and evaluation of a theory-based intervention with school children involving a cluster randomised controlled trial.

The objective of this study was to design, implement and evaluate an intervention based on the theory of planned behaviour (TPB) to enhance young peoples' motivations to breastfeed/support a partner to breastfeed. Six semi-structured focus groups were first conducted with 48 13-14-year-olds from two schools in Northern Ireland. The salient beliefs elicited were subsequently used to design a TPB-based questionnaire that was then administered to 2021 13-14-year-old pupils (852 males; 1169 females) from 36 post-primary schools to identify the most important determinants of breastfeeding. The results were used to inform the design and implementation of an intervention package that was subsequently evaluated using a cluster randomised controlled trial involving 44 randomly selected schools across Northern Ireland. Questionnaires were administered to 18 intervention and 26 control schools at baseline and again at 1 and 6 months post-intervention to evaluate its effectiveness. Multi-level modelling was employed to analyse the data. The results revealed significant effects on women's intention to breastfeed, β = 0.208, t(1275) = 2.715, P = 0.007; attitudes, β = 0.223, t(1275) = 4.655, P < 0.001; moral attitudes, β = 0.231, t(1275) = 4.211, P < 0.001; subjective norm, β = 0.118, t(1275) = 2.521, P = 0.012; and knowledge, β = 0.109, d.f. (1275) = 7.843, P < 0.001. However, for men, the results revealed significant effects on only the construct of knowledge, β = 0.104, t(541) = 4.345, P < 0.001.The research has provided evidence to support the need for breastfeeding education in schools and has shown how a theoretical framework may be used to inform the design and evaluation of a health behaviour intervention.