Peer support to encourage adoption and maintenance of a Mediterranean diet
Background: Strong evidence links consumption of the Mediterranean diet (MD) to a reduced risk of Cardiovascular Disease (CVD) and type II diabetes, however, there is uncertainty about whether non-Mediterranean regions will adopt this dietary pattern and how to best measure MD adherence among these populations. To date, interventions that have encouraged individuals to adopt a MD have used intensive dietary change methods that would be expensive and time consuming to roll out. Peer support (PS) is a potential novel and cost effective strategy for achieving dietary change towards a MD. Further research on the effectiveness of PS for encouraging dietary change, however, is needed. Aims: This thesis therefore aimed to assess the feasibility of PS for encouraging adoption and maintenance of a MD in a Northern European population at high CVD risk. Methods: This PhD comprised (i) a systematic review of the effect of PS in encouraging dietary change in adults; (ii) qualitative analysis of barriers to a MD in a Northern European population; (iii) validation of a Mediterranean diet score (MDS) to assess MD adherence in a Northern European population and (iv) development and interim-analysis of a pilot RCT to assess the effectiveness of PS for encouraging MD adoption and maintenance in a Northern European population at high CVD risk (TEAM-MED study). Results: The systematic review (Chapter 2) found that more studies reported a positive effect of PS or mixed results, than studies that did not find an effect of PS for achieving dietary change. However, as evidence was mixed, the effect of PS in encouraging dietary change in adults is not clear and further information is needed. Individuals at high risk of CVD from a Northern European population showed preference towards a group based PS model which was developed for assessment in the TEAM-MED study (Chapter 3). Qualitative research among this population indicated a limited knowledge of, and a number of barriers towards consuming a MD (Chapter 4). These factors were addressed in the TEAM-MED study. Validation of the TEAM-MED study MDS deemed this to be a reliable tool for assessing MD adherence among Northern European populations (Chapter 5). The TEAM-MED study interim-analysis (Chapter 6) demonstrated transferability of the MD to a non- Mediterranean region. No significant difference in MD adherence was found between a PS and a proven intensive intervention and minimal intervention for encouraging dietary change at this early stage of analysis. Conclusion: Findings revealed that evidence for the effect of PS for encouraging dietary change is not yet clear, but interim-analysis of the TEAM-MED study has shown potential for the use of PS to facilitate dietary change. Future PS interventions in non-Mediterranean populations could consider use of the group based PS model and validated MDS developed for this work in a Northern European population. These interventions should define key study characteristics, such as the training and support needs of peer supporters. Interventions to encourage dietary change towards a MD in non-Mediterranean populations should tailor the intervention through addressing awareness, attitudes and barriers towards the MD.
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