Table 2.
Validity characteristics of included studies
| Random-isation Described/Allocation Concealment | Researcher/Outcome Assessor/Participants Masked to intervention | Change in iron status OR 12+ wks?* | All those randomised included in outcomes?/Reason for dropouts reported? | Potential for funding bias** | Study data useable in meta-analysis? | |
|---|---|---|---|---|---|---|
| Beard 2005 | Partially/Unclear | Unclear/Unclear/Yes | Yes (SF, 29 wks) | No/Partially | Moderate | Yes |
| Bruner 1996 | Yes/Unclear | Yes/Unclear/Yes | Yes (Hb & SF) | No/Yes | High | No (no raw data, only regression) |
| Elwood 1970 | No/Unclear | Unclear/Yes/Yes | Unclear (p-values not presented) | No/Partially | High | Yes |
| Gopaldas 1985 | Partially/Unclear | No/No/Yes | Anaemic & Iron repl: Yes (Hb) | Yes/Yes (no drop-outs) | High | Yes |
| Groner 1986 | No/Unclear | Yes/Yes/Yes | Yes (Hb) | No/Yes | Moderate | Yes |
| Kashyap 1987 | Partially/Unclear | Unclear/Unclear/Yes | Anaemic & Iron repl: Yes (Hb, 17 wks) | No/Partially | Moderate | Yes |
| Kordas 2005 | Yes/Unclear | Yes/Yes/Yes | Yes (21 wks) | No/Partially | Moderate | No (only z-scores) |
| Lambert 2002 | No/Unclear | Yes/Unclear/Yes | Yes (SF, not Hb) | No/No | Moderate | No (no variance data) |
| Lynn & Harland 1998 | Yes/Unclear | Yes/Yes/Yes | Iron Defic & Iron repl: Yes (16 wks) | Unclear/No | High | Yes |
| Murray-Kolb 2007 | Yes/Unclear | No/Yes/Yes | Anaemic & Iron repl: Yes (SF, not Hb, 16 wks),Iron defic: No (not SF or Hb) | No/Partially | Moderate | No (reported only as z-scores) |
| Pollitt 1989 | No/Unclear | Unclear/Unclear/Yes | Anaemic, Iron defic & Iron repl: Yes (Hb, SF, 16 wks) | No/No | Moderate | Yes |
| Soemantri 1985 | No/Unclear | Unclear/Unclear/Unclear |
Anaemic: Yes (Hb, 13 wks) Iron repl: No (Hb) |
Unclear/No | Moderate | No (no variance or SD data) |
| Soemantri 1989 | No/Unclear | Unclear/Unclear/Yes | Anaemic & Iron repl: Yes (Hb, 13 wks) | No/No | Moderate | Yes |
| Sungthong 2004 | Yes/Yes | Yes/Yes/Yes | Yes (SF & Hb, 16 wks) | No/Yes | Low | Yes |
* Iron status was said to have changed if there were statistically significant differences in Hb or SF between iron and placebo groups at the end of the study or, where no data were provided, if the intervention period was at least 12 weeks long.
** Potential for funding bias was assessed as follows: low (when funders were clearly not industry-related, no authors worked for industry and there was no suggestion that products were donated by industry); high (when non-industry funding was reported, or when funding was not mentioned); moderate in all other studies.