Table 1.
Electronic databases searched for this review
| Database | Period/Issue covered |
| Medline (OVID) | 1999–02/2004 |
| EMBASE | 1999–03/2004 |
| CINAHL | 1999–03/2004 |
| The Cochrane Library Database of Systematic Reviews | 1999–2004 Issue 1 |
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