Erratum

Following publication of the original article [1] it was brought to our attention that one of the authors’ funders had been omitted from the acknowledgements. Please therefore note that the revised acknowledgements section should read as follows:

“N.T. (006/P&C/CORE/2013/OXFSTATS), and C.F. (006/PSS/CORE/2016/OXFORD) receive funding from the British Heart Foundation (BHF). CV is grateful for Clarendon and Nuffield Department of Population Health funding.”