Funding for this research was provided by:
Alliance House Foundation (543108)
Received: 2 February 2018
Accepted: 24 August 2018
First Online: 10 October 2018
Ethics approval and consent to participate
: The HSE is freely available to academic institutions via the UK Data Service subject to their End User license. Ethical approval to conduct the HSE2015 survey was approved by the West London & GTAC research ethics committee (14/LO/0862). Ethical approval to conduct the 2011–14 surveys was obtained from the Oxford A Ethics Committee (2011:10/H0604/56, 2012: 10/H0604/56, 2013: 12/sc/0317, 2014: 12/sc/0317). Ethical approval to conduct the 2010 survey was obtained from the Oxford B Ethics Committee (REC reference number: 09/H0605/73). Ethical approval for the HSE surveys from 2005 to 2009 was obtained from the London MREC (2005: 04/MRE02/50, 2006: 05/MRe02/47, 2007 06/Mre02/62). Sensitive information were removed and data were anonymised. For secondary analyses, further ethical approval was not needed.
: Not applicable.
: NC is a Section Editor for BMC Public Health. All authors have no competing interests to declare.
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