Study	Reason for exclusion
Abdelraheim 2017	Wrong study design
Anwar 2002	Wrong study design
Bellhouse 2018	Wrong study design.
Burbos 2011	Wrong study design
Cooper 2014	Wrong study design
Doll 2016	Wrong study design
Johnson 2011	Wrong study design
Kang 2013	Wrong study design
Kwon 2007	Wrong study design
Mbah 2015	Wrong population.
Mohamed 2003	Wrong study design
Ramanathan 2011	Wrong study design
Redman 2000	Wrong study design
Robinson 2009	Wrong study design
Smailyte 2015	Wrong study design
Vandborg 2011	Wrong study design

GP: general practitioner; RCT: randomised controlled trial