Study	Reason for exclusion
Bae 2012	The trial included adult participants (RCT) with an age range of 12 to 40 and a mean age of 23.5 years, which was not stated in the abstract
Broberg 1990	Inadequate randomisation was the reason for exclusion
Greene 1997	On obtaining unpublished data, we discovered that the participants were adults
Kardorff 2003	Inadequate randomisation was the reason for exclusion
van Os‐Mendendorp 2012	Aggregated child and adult data were presented. We contacted the author who advised that it was not possible to provide child‐only data