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| Database | Number of results | Excluded – Not primary study | Excluded – Not in English | Excluded – Not relevant to PICO | Excluded – Not controlled trial studies | Excluded –Not accessible by database | Total relevant papers |
| CAB Abstracts | 473 | 53 | 60 | 351 | 0 | 0 | 9 |
| Biosis Previews | 348 | 43 | 0 | 299 | 0 | 0 | 6 |
| Total relevant papers when duplicates removed | 9 | ||||||
