Developing a realist informed framework for cultural adaptation of lifestyle interventions for the prevention of type 2 diabetes in South Asian populations in Europe

Aims Selected lifestyle interventions proven effective for White‐European populations have been culturally adapted for South Asian populations living in Europe, who are at higher risk of type 2 diabetes. However, a limited theoretical basis underpins how cultural adaptations are believed to augment intervention effectiveness. We undertook a realist review to synthesise existing literature on culturally adapted type 2 diabetes prevention interventions, to develop a framework that shows ‘how’ cultural adaptation works, for ‘whom’ and in ‘what contexts’. Methods We followed the stepped methodological approach of realist review. Our work concluded a European‐wide project (EuroDHYAN), and core studies were identified from the preceding EuroDHYAN reviews. Data were extracted, coded into themes and synthesised to create ‘Context–Mechanism–Outcome’ configurations and to generate a refined explanatory framework. Results We identified eight core intervention papers. From this evidence, and supporting literature, we examined the ‘Team’ domain of cultural adaptation and identified a mechanism of shared cultural identity which we theorised as contributing to strong team‐participant relationships. We also identified four key contexts which influenced intervention outcomes: ‘research setting’ and ‘heterogeneous populations’ (intrinsic to the intervention) and ‘broader environment’ and ‘socio‐cultural stress’ (extrinsic barriers). Conclusions This work instigates research into the mechanisms of cultural adaptation which, if pursued, will allow a more nuanced understanding of how to apply adaptations, and for whom. In practice we recommend greater consideration of heterogeneous and intersecting population characteristics; how intervention design can safeguard sustainability; and how the four key contexts identified influence how, and whether, these interventions work.