| Study | Reason for exclusion |
|---|---|
| Brigham 1993 | Randomised controlled cross‐over trial; data not presented for outcomes at the end of the first parallel comparison |
| Cable 1988 | Study in blood donors; ongoing donations (blood losses) during study |
| Powell 1991 | Randomised controlled cross‐over trial; data not presented for outcomes at the end of the first parallel comparison |
| Powers 1988 | Data for men and women not disaggregated |
| Schoene 1983 | Randomised controlled cross‐over trial; data not presented for outcomes at the end of the first parallel comparison |
| Simon 1984 | Study in blood donors; ongoing donations (blood losses) during study |
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