[mh] = Medical Subject Headings in MEDLINE; [pt] = publication type in MEDLINE; [sh] = Subject Heading in CINAHL [de] = Descriptor in MANTIS Note:1One study did not have an abstract online. 2Not all studies had abstracts. 3Web of Science does not have a controlled vocabulary. 4Eleven studies had no keywords generated. * is a truncation symbol for a wild card search in PubMed and Web of Science.