Acknowledgement

This project is funded by the Efficacy and Mechanism Evaluation (EME) Programme, an MRC and NIHR partnership.

Disclaimer

The views expressed in this publication are those of the author(s) and not necessarily those of the MRC, NHS, NIHR or the Department of Health and Social Care. 

*The EME Programme is funded by the MRC and NIHR, with contributions from the CSO in Scotland and Health and Care Research Wales and the HSC R&D Division, Public Health Agency in Northern Ireland.