Table 1

Search strategy

For Medline:
61 or 2 or 3 or 4 or 5
7limit 6 to humans
  • Adapted for: MEDLINE in-process, EMBASE, CINAHL, PsychINFO, British Nursing Index, Cochrane Central Register of Controlled Trials, Health Technology Assessment Database, NHS Economic Evaluation Database, BIOSIS, Science Citation Index, Social Science Citation Index, Index to Scientific and Technical proceedings and System for Information on Grey Literature.