The use of social media in public health: mass communication and behaviour change

This thesis comprises the following studies: 1) a systematic review investigating SM-based health interventions, specifically regarding methodological approaches and intervention design; 2) an exploratory thematic and source analysis of physical activity (PA), diet and weight loss tweets; and 3) a four-week feasibility intervention using Instagram to target post-graduate students with a PA, nutrition and general wellbeing intervention.<br><br>Results: The systematic review highlighted uncoordinated methodological approaches to SM-based health interventions, a lack of interpretation of SM metrics (such as likes and comments), the presence of social support behaviour change techniques (BCTs), and a lack of popular platforms including newer platforms including Instagram.

The source and thematic analysis demonstrated that the majority of PA, weight loss and diet tweets were from non-professionals and non-educational in nature. Humour and pop-culture references were present in tweets from non-professionals and information intermediaries, suggesting that information intermediaries, rather than professional tweets, are a potentially more accessible and relatable source of information for the general public.

The feasibility intervention showed Instagram to be a feasible and acceptable platform for targeting postgraduate students, demonstrated that humour and pop-culture have the potential to increase levels of engagement, and that the use of an information intermediary account was perceived as credible and trustworthy.<br><br>Discussion: This thesis identifies several themes and recommendations for future research. Key themes highlighted include: i) the need for more co-ordinated approaches to the design of SM-based health interventions; ii) a need for clarity in the collection and interpretation of SM metrics; iii) the potential of information intermediaries as a potential middle-ground approach for SM-based health promotion; iv) the capability of SM platforms for the implementation of social network-based BCTs; and, v) the feasibility of Instagram as platform to engage post-graduate students in a health intervention.