Conceptualising engagement with digital behaviour change interventions: a systematic review using principles from critical interpretive synthesis.

"Conflict of interest OP, SM and AB declare that they have no conflict of interest. RW undertakes research and consultancy and receives fees for speaking from companies that develop and manufacture smoking cessation medications."

"The authors would like to thank Jacqui Smith, librarian at University College London, for helping to build the search strategy; Nicola Newhouse for validating the coding frame and commenting on an early draft; and Holly Walton for helping to screen articles. Olga Perski is a Ph.D. candidate funded by a grant from Bupa under its partnership with University College London. Susan Michie is part funded by grants from Cancer Research UK and NIHR’s School for Public Health Research. Robert West is funded by Cancer Research UK. The funders played no role in the design, conduct or analysis of the study nor in the interpretation and reporting of study findings."